Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing

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Bègue N, Baron A, Krysztofiak G, Berthet G, Kloss C, Jégou F, Khaykin S, Ranaivombola M, Millet T, Portafaix T, Duflot V, Keckhut P, Vérèmes H, Payen G, Sha MK, Coheur P-F, Clerbaux C, Sicard M, Sakai T, Querel R, Liley B, Smale D, Morino I, Uchino O, Nagai T, Smale P, Robinson J and Bencherif H (2024), "Evidence of a dual African and Australian biomass burning influence on the vertical distribution of aerosol and carbon monoxide over the southwest Indian Ocean basin in early 2020", Atmospheric Chemistry and Physics. Vol. 24(13), pp. 8031 – 8048. [Abstract] [BibTeX] [DOI]
Abstract: During the 2020 austral summer, the pristine atmosphere of the southwest Indian Ocean (SWIO) basin experienced significant perturbations. This study examines the variability of aerosols and carbon monoxide (CO) over this remote oceanic region and investigates the underlying processes in the upper troposphere- lower stratosphere (UT-LS). Aerosol profiles in January and February 2020 revealed a multi-layer structure in the tropical UT-LS. Numerical models - the FLEXible PARTicle dispersion model (FLEXPART) and the Modèle Isentropique de transport Mésoéchelle de l'Ozone Stratosphérique par Advection (MIMOSA) - indicated that the lower-stratospheric aerosol content was influenced by the intense and persistent stratospheric aerosol layer generated during the 2019-2020 extreme Australian bushfire events. A portion of this layer was transported eastward by prevailing easterly winds, leading to increased aerosol extinction profiles over Réunion on 27 and 28 January. Analysis of advected potential vorticity revealed isentropic transport of air masses containing Australian biomass burning aerosols from extratropical latitudes to Réunion at the 400K isentropic level on 28 January. Interestingly, we found that biomass burning (BB) activity in eastern Africa, though weak during this season, significantly influenced (contributed up to 90% of) the vertical distribution of CO and aerosols in the upper troposphere over the SWIO basin. Ground-based observations at Réunion confirmed the simultaneous presence of African and Australian aerosol layers. This study provides the first evidence of African BB emissions impacting the CO and aerosol distribution in the upper troposphere over the SWIO basin during the convective season. © 2024 Nelson Bègue et al.
BibTeX: @article{Begue2024, author = {Bègue, Nelson and Baron, Alexandre and Krysztofiak, Gisèle and Berthet, Gwenaël and Kloss, Corinna and Jégou, Fabrice and Khaykin, Sergey and Ranaivombola, Marion and Millet, Tristan and Portafaix, Thierry and Duflot, Valentin and Keckhut, Philippe and Vérèmes, Hélène and Payen, Guillaume and Sha, Mahesh Kumar and Coheur, Pierre-François and Clerbaux, Cathy and Sicard, Michaël and Sakai, Tetsu and Querel, Richard and Liley, Ben and Smale, Dan and Morino, Isamu and Uchino, Osamu and Nagai, Tomohiro and Smale, Penny and Robinson, John and Bencherif, Hassan}, title = {Evidence of a dual African and Australian biomass burning influence on the vertical distribution of aerosol and carbon monoxide over the southwest Indian Ocean basin in early 2020}, journal = {Atmospheric Chemistry and Physics}, year = {2024}, volume = {24}, number = {13}, pages = {8031 – 8048}, doi = {10.5194/acp-24-8031-2024} }
Bernath PF, Bhusal M and Liévin J (2024), "Opacities of S-type Stars: The Singlet B 1Π-X 1Σ+, B 1Π-A 1△, and C 1Σ+-X 1Σ+ Band Systems of ZrO", Astrophysical Journal. Vol. 960(1) [Abstract] [BibTeX] [DOI]
Abstract: The ZrO B 1Π-X 1Σ+, B 1Π-A 1Δ, and C 1Σ+-X 1Σ+ band systems are important opacity sources in the near-infrared and optical spectra of S-type stars. A total of 21 rovibronic bands with v″ ≤ 7 and v ′ ≤ 5 were observed and fit for the B 1Π-X 1Σ+ transition, five bands for the 90ZrO B 1Π-A 1Δ transition and one band for the 90ZrO C 1Σ+-X 1Σ+ transition. All band systems were analyzed using high-temperature, high-resolution emission spectra collected at the National Solar Observatory (Kitt Peak). A modern spectroscopic analysis was performed using the PGOPHER program to provide updated spectroscopic constants. In general, we improve the accuracy of the line positions reported in the literature and slightly extend the vibrational analysis. Equilibrium molecular constants were then derived and combined with new ab initio calculations of transition dipole moment functions to produce line lists with line strengths. © 2023. The Author(s). Published by the American Astronomical Society.
BibTeX: @article{Bernath2024, author = {Bernath, Peter F. and Bhusal, Manish and Liévin, Jacques}, title = {Opacities of S-type Stars: The Singlet B 1Π-X 1Σ+, B 1Π-A 1△, and C 1Σ+-X 1Σ+ Band Systems of ZrO}, journal = {Astrophysical Journal}, year = {2024}, volume = {960}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.3847/1538-4357/ad0386} }
Bernath PF, Bhusal M and Liévin J (2024), "Visible Opacities of S-type Stars: The d 3Φ-a 3Δ Band System of ZrO", Astrophysical Journal. Vol. 975(2) [Abstract] [BibTeX] [DOI]
Abstract: ZrO is a well-studied metal monoxide because of its astrophysical importance in characterizing S stars. The bands of the d 3Φ-a3Δ system (γ system) with v ′ ≤ 4 and v″ ≤ 5 are rotationally analyzed using the PGOPHER program to provide spectroscopic constants. The high-resolution ZrO emission spectrum was recorded with a Fourier transform spectrometer using a high-temperature carbon furnace source. New ab initio calculations of the transition dipole moment were carried out in order to determine the vibronic band strengths. The spectroscopic constants, along with the band strengths, are used to calculate a line list for the γ system. This line list can be used to determine Zr abundances in S stars. We also correct the line strengths for the B 1Π-A 1Δ transition calculated in our previous work. © 2024. The Author(s). Published by the American Astronomical Society.
BibTeX: @article{Bernath2024a, author = {Bernath, Peter F. and Bhusal, Manish and Liévin, Jacques}, title = {Visible Opacities of S-type Stars: The d 3Φ-a 3Δ Band System of ZrO}, journal = {Astrophysical Journal}, year = {2024}, volume = {975}, number = {2}, doi = {10.3847/1538-4357/ad82ec} }
Bertin T and Vander Auwera J (2024), "CO2 collision-induced line parameters for the ν3 band of 12CH4 measured using a hard-collision speed-dependent line shape and the relaxation matrix formalism", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 324 [Abstract] [BibTeX] [DOI]
Abstract: Ten high resolution Fourier transform spectra of the pentad region near 3.3μm of methane diluted in carbon dioxide at total pressures up to 800 hPa have been recorded at 296.5(5) K. Including a high resolution spectrum of pure methane at low pressure, these spectra have been analyzed using multi-spectrum fitting techniques. The methane lines were modeled using hard-collision speed-dependent line profiles and line mixing was included in the strongest absorption regions, considering the first order Rosenkranz approximation and the relaxation matrix formalism. CO2 broadening and shift coefficients have been measured, together with the speed dependence of broadening. Results obtained using the two line mixing models are intercompared and compared with previous work. © 2024 Elsevier Ltd
BibTeX: @article{Bertin2024, author = {Bertin, T. and Vander Auwera, J.}, title = {CO2 collision-induced line parameters for the ν3 band of 12CH4 measured using a hard-collision speed-dependent line shape and the relaxation matrix formalism}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2024}, volume = {324}, doi = {10.1016/j.jqsrt.2024.109069} }
Betnga WT, Perrin A, Manceron L, Vander Auwera J, Hindle F, Cuisset A, Mouret G, Bocquet R, Roy P, Landsheere X, Voute A and Tchana FK (2024), "New line list for the ν4 bands of the trans (790.117 cm–1) and cis (851.943 cm–1) conformers of nitrous acid (HONO): Accurate positions and absolute intensities", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 325 [Abstract] [BibTeX] [DOI]
Abstract: The goal of this work was to update and significantly improve the line lists that have been generated recently for 11 µm bands of the trans- and cis- conformer forms of nitrous acid (HONO) [Armante R, Perrin A, Kwabia Tchana F, Manceron L. The ν4 bands at 11 μm: linelists for the trans- and cis- conformer forms of nitrous acid (HONO) in the 2019 version of the GEISA database. Molecular Physics 2021;120:e1951860]. That 2019 version of the 11 µm line list was generated using the spectroscopic parameters that were available, at that time, in the literature. During the present study, we used high-resolution Fourier transform spectra recorded at 11 µm to perform a large investigation of line positions and intensities for the ν4 bands of the trans- and cis-conformer of HONO. The resulting set of experimental ν4 (absolute) intensities and of 41 energy levels were used to determine, by least squares fit computations, improved position and intensity parameters for the ν4 bands of the trans- and cis-conformer of HONO. For trans-HONO, the ν4 band appeared not to be perturbed, while for cis-HONO a weak high order B-type Coriolis, coupling together the 41 and 61 energy levels was evidenced for the first time. This new list is of potential interest for the IASI-NG (Infrared Atmospheric Sounding Interferometer - New Generation) instrument which will be launched on board the METOP-SG satellite in 2025. © 2024 Elsevier Ltd
BibTeX: @article{Betnga2024, author = {Betnga, W. Tchana and Perrin, A. and Manceron, L. and Vander Auwera, J. and Hindle, F. and Cuisset, A. and Mouret, G. and Bocquet, R. and Roy, P. and Landsheere, X. and Voute, A. and Tchana, F. Kwabia}, title = {New line list for the ν4 bands of the trans (790.117 cm–1) and cis (851.943 cm–1) conformers of nitrous acid (HONO): Accurate positions and absolute intensities}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2024}, volume = {325}, doi = {10.1016/j.jqsrt.2024.109082} }
Bogomolov AS, Glorieux R, Herman M, Corbo T, Collignon S, Hays BM, Lederer D, Moazzen-Ahmadi N, Libert A, Tomasetti B, Fréreux J and Lauzin C (2024), "Improvements on the FANTASIO set-up and new spectroscopic results concerning the Ar-H2O van der Waals complex in the 2OH overtone region", Molecular Physics. [Abstract] [BibTeX] [DOI]
Abstract: We present a series of improvements of the FANTASIO experimental set-up that couples a supersonic expansion to a cavity ring-down spectrometer originally reported by M. Herman, et al., Mol. Phys. 105, 815 (2007). In particular, the implementation of a new pulsed slit valve of 80 mm in length is detailed. The design is based on a powerful piezo stack actuator. Schlieren imaging is used to verify the homogeneity of the molecular beam and the quality of the pulsed slit performance. The ability to form weakly bound van der Waals complexes is assessed using the cavity ring-down spectrometer and a new chirped-pulse Fourier transform microwave spectrometer with the 12–18 GHz operating range. The water hexamer and heptamer were observed using this microwave spectrometer. Following enhancements and an extended laser coverage of the CRDS in the 2OH region, we observed and analyzed seven sub-bands of the Ar-H216O van der Waals complex, along with one sub-band of the much less abundant Ar-H218O isotopologue. © 2024 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX: @article{Bogomolov2024, author = {Bogomolov, Alexandr S. and Glorieux, Robin and Herman, Michel and Corbo, Thomas and Collignon, Simon and Hays, Brian M. and Lederer, Dimitri and Moazzen-Ahmadi, Nasser and Libert, Alexis and Tomasetti, Benjamin and Fréreux, Joffrey and Lauzin, Clément}, title = {Improvements on the FANTASIO set-up and new spectroscopic results concerning the Ar-H2O van der Waals complex in the 2OH overtone region}, journal = {Molecular Physics}, year = {2024}, doi = {10.1080/00268976.2024.2413417} }
Cacciani P, Čermák P, Votava O, Vander Auwera J and Campargue A (2024), "The ammonia absorption spectrum revisited between 5650 and 6350 cm−1", Molecular Physics. Vol. 122(7-8) [Abstract] [BibTeX] [DOI]
Abstract: The ammonia spectrum is revisited in the important 1.6 µm atmospheric transparency window between 5650 and 6350 cm (Formula presented.) on the basis of recently recorded high-resolution Fourier transform spectra. These spectra offer an improved frequency sampling and better traceability of the measurement conditions compared to previously studied Kitt Peak spectra (Cacciani et al. J. Quant Spectrosc Radiat Transf 2021; 258:107334. https://doi.org/10.1016/j.jqsrt.2020.107334). Overall, 4812 (Formula presented.) NH (Formula presented.) lines were measured in the 5650–6350 cm (Formula presented.) region corresponding to 4866 transitions including 2066 new ones compared with our previous study, included in the HITRAN2020 database. The energy of 1023 upper state levels (including 107 new ones) was derived from 2608 assigned transitions. Independently, ammonia spectra recorded in a supersonic jet expansion using a tunable extended cavity diode laser allow us to check the absolute transition energies in the 5980–6080 cm (Formula presented.) range. Accurate jet spectra calibration was achieved using CH (Formula presented.) reference line positions known with kHz accuracy. The position agreement with the FTS data is within the (Formula presented.) cm (Formula presented.) uncertainty of the positions measured in the jet expansion. A recommended line list of 5620 transitions is provided for (Formula presented.) NH (Formula presented.) in the considered 5650–6350 cm (Formula presented.) region. © 2023 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX: @article{Cacciani2024, author = {Cacciani, P. and Čermák, P. and Votava, O. and Vander Auwera, J. and Campargue, A.}, title = {The ammonia absorption spectrum revisited between 5650 and 6350 cm−1}, journal = {Molecular Physics}, year = {2024}, volume = {122}, number = {7-8}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268976.2023.2256893} }
Carvajal Gallego H, Pain J-C, Godefroid M, Palmeri P and Quinet P (2024), "Statistical RTA simulations of atomic data for astrophysical opacity modeling in the context of kilonova emission", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 57(3) [Abstract] [BibTeX] [DOI]
Abstract: When considering some complex lanthanide ions characterized by a half-filled 4f subshell, the atomic structure Hamiltonian matrix sizes are so large that their diagonalization is challenging and therefore the atomic data of these ions are only used to compute the expansion opacity of a kilonova with difficulty. To avoid this problem, we propose a statistical simulation method to compute kilonova expansion opacities based on the resolved transition array (RTA) method of Bauche et al (1991 Phys. Rev. A 44 5707). The atomic structure relativistic Hartree-Fock (HFR) method has been employed to compute the radial integrals necessary for our statistical RTA simulations where the atomic data are randomly drawn using their corresponding statistical distributions and to determine the exact expansion opacities where the atomic data are obtained by the diagonalization of the Hamiltonian matrix. The statistical RTA simulations carried out for two specific ions, i.e. Sm VIII and Eu VI, for which it is still possible to diagonalize the Hamiltonian matrix, reproduce well the expansion opacities computed using HFR atomic data. Based on this good agreements, the statistical RTA method was used to compute the expansion opacity of Dy VIII, which is determined through diagonalization with difficulty. The proposed statistical RTA simulation method allows the computation of reliable astrophysical expansion opacities which are of paramount importance for kilonova light curve modeling and spectral analysis. © 2024 IOP Publishing Ltd.
BibTeX: @article{CarvajalGallego2024, author = {Carvajal Gallego, H. and Pain, J.-C. and Godefroid, M. and Palmeri, P. and Quinet, P.}, title = {Statistical RTA simulations of atomic data for astrophysical opacity modeling in the context of kilonova emission}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2024}, volume = {57}, number = {3}, doi = {10.1088/1361-6455/ad2182} }
Cauët E, Schittecatte G, Van Den Bulcke M, Yogeswaran S, Volders P-J, Vandermeulen A, Van Steen K, Van Roose W, Van Lint J, Van Den Bulck I, Van De Voorde L, Sys G, Schreurs W, Schelfhout B, Salgado R, Rommel W, Meca C, Maes B, Macq B, Lippens E, Leloup A, Lejeune S, Lauwers S, Lahousse L, Jodogne S, Hustinx R, Hovelinck R, Haustermans K, Hasaers K, Gijssels S, Gevaert T, Ertaylan G, Dhont J, Dendooven A, Deman F, Delsupehe L, De Witte C, Demetter P, De Broe S, Croes R, Coche E, Chavez M, Broeckx G, Baatout S, Antoine-Poirel H, Allaoui EM and Albarani V (2024), "Policy brief Belgian EBCP mirror group Artificial Intelligence in cancer care", Archives of Public Health. Vol. 82(Suppl 1) [Abstract] [BibTeX] [DOI]
Abstract: Artificial Intelligence (AI) is already a reality in health systems, bringing benefits to patients, healthcare providers, and other stakeholders in the health care. To further leverage AI in health, Belgium is advised to make policy-level decisions about how to fund, design and undertake actions focussing on data access and inclusion, IT-infrastructure, legal and ethical frameworks, public and professional trust, in addition to education and interpretation. EU initiatives, such as European Health data space (EHDS), the Genomics Data Infrastructure (GDI) and the EU Cancer Imaging Infrastructure (EUCAIM) are building EU data infrastructures. To continue these positive developments, Belgium should continue to invest and support existing European data infrastructures. At the national level, a clear vision and strategy need to be developed and infrastructures need to be harmonized at the European level. © The Author(s) 2024.
BibTeX: @article{Cauet2024, author = {Cauët, Emilie and Schittecatte, Gabrielle and Van Den Bulcke, Marc and Yogeswaran, Suresh and Volders, Pieter-Jan and Vandermeulen, Ad and Van Steen, Kristel and Van Roose, Wim and Van Lint, Johan and Van Den Bulck, Isabelle and Van De Voorde, Lien and Sys, Gwen and Schreurs, Wim and Schelfhout, Bart and Salgado, Roberto and Rommel, Ward and Meca, Carlos and Maes, Brigitte and Macq, Benoit and Lippens, Evi and Leloup, Arthur and Lejeune, Stephane and Lauwers, Steven and Lahousse, Lies and Jodogne, Sébastien and Hustinx, Roland and Hovelinck, Rudy and Haustermans, Karin and Hasaers, Koen and Gijssels, Stefan and Gevaert, Thierry and Ertaylan, Gokhan and Dhont, Jennifer and Dendooven, Amelie and Deman, Frederik and Delsupehe, Louis and De Witte, Chloë and Demetter, Pieter and De Broe, Sofie and Croes, Romaric and Coche, Emmanuel and Chavez, Marcela and Broeckx, Glenn and Baatout, Sarah and Antoine-Poirel, Hélène and Allaoui, El Maati and Albarani, Valentina}, title = {Policy brief Belgian EBCP mirror group Artificial Intelligence in cancer care}, journal = {Archives of Public Health}, year = {2024}, volume = {82}, number = {Suppl 1}, note = {All Open Access, Gold Open Access}, doi = {10.1186/s13690-024-01367-5} }
Crippa M, Guizzardi D, Pagani F, Schiavina M, Melchiorri M, Pisoni E, Graziosi F, Muntean M, Maes J, Dijkstra L, Van Damme M, Clarisse L and Coheur P (2024), "Insights into the spatial distribution of global, national, and subnational greenhouse gas emissions in the Emissions Database for Global Atmospheric Research (EDGAR v8.0)", Earth System Science Data. Vol. 16(6), pp. 2811 – 2830. [Abstract] [BibTeX] [DOI]
Abstract: To mitigate the impact of greenhouse gas (GHG) and air pollutant emissions, it is of utmost importance to understand where emissions occur. In the real world, atmospheric pollutants are produced by various human activities from point sources (e.g. power plants and industrial facilities) but also from diffuse sources (e.g. residential activities and agriculture). However, as tracking all these single sources of emissions is practically impossible, emission inventories are typically compiled using national-level statistics by sector, which are then downscaled at the grid-cell level using spatial information. In this work, we develop high-spatial-resolution proxies for use in downscaling the national emission totals for all world countries provided by the Emissions Database for Global Atmospheric Research (EDGAR). In particular, in this paper, we present the latest EDGAR v8.0 GHG, which provides readily available emission data at different levels of spatial granularity, obtained from a consistently developed GHG emission database. This has been achieved through the improvement and development of high-resolution spatial proxies that allow for a more precise allocation of emissions over the globe. A key novelty of this work is the potential to analyse subnational GHG emissions over the European territory and also over the United States, China, India, and other high-emitting countries. These data not only meet the needs of atmospheric modellers but can also inform policymakers working in the field of climate change mitigation. For example, the EDGAR GHG emissions at the NUTS 2 level (Nomenclature of Territorial Units for Statistics level 2) over Europe contribute to the development of EU cohesion policies, identifying the progress of each region towards achieving the carbon neutrality target and providing insights into the highest-emitting sectors. The data can be accessed at 10.2905/b54d8149-2864-4fb9-96b9-5fd3a020c224 specifically for EDGAR v8.0 (Crippa et al., 2023a) and 10.2905/D67EEDA8-C03E-4421-95D0-0ADC460B9658 for the subnational dataset (Crippa et al., 2023b). © 2024 Copernicus Publications. All rights reserved.
BibTeX: @article{Crippa2024, author = {Crippa, Monica and Guizzardi, Diego and Pagani, Federico and Schiavina, Marcello and Melchiorri, Michele and Pisoni, Enrico and Graziosi, Francesco and Muntean, Marilena and Maes, Joachim and Dijkstra, Lewis and Van Damme, Martin and Clarisse, Lieven and Coheur, Pierre}, title = {Insights into the spatial distribution of global, national, and subnational greenhouse gas emissions in the Emissions Database for Global Atmospheric Research (EDGAR v8.0)}, journal = {Earth System Science Data}, year = {2024}, volume = {16}, number = {6}, pages = {2811 – 2830}, doi = {10.5194/essd-16-2811-2024} }
Dang R, Jacob DJ, Zhai S, Yang LH, Pendergrass DC, Coheur P, Clarisse L, Van Damme M, Choi J-S, Park J-S, Liu Z, Xie P and Liao H (2024), "A Satellite-Based Indicator for Diagnosing Particulate Nitrate Sensitivity to Precursor Emissions: Application to East Asia, Europe, and North America", Environmental Science and Technology. [Abstract] [BibTeX] [DOI]
Abstract: Particulate nitrate is a major component of fine particulate matter (PM2.5) and a key target for improving air quality. Its formation is varyingly sensitive to emissions of nitrogen oxides (NOx ≡ NO + NO2), ammonia (NH3), and volatile organic compounds (VOCs). Diagnosing the dominant sensitivity is critical for effective pollution control. Here, we show that satellite observations of the NO2 column and the NH3/NO2 column ratio can effectively diagnose the dominant sensitivity regimes in polluted regions of East Asia, Europe, and North America, in different seasons, though with reduced performance in the summer. We demarcate the different sensitivity regimes using the GEOS-Chem chemical transport model and apply the method to satellite observations from the OMI (NO2) and IASI (NH3) in 2017. We find that the dominant sensitivity regimes vary across regions and remain largely consistent across seasons. Sensitivity to NH3 emissions dominates in the northern North China Plain (NCP), the Yangtze River Delta, South Korea, most of Europe, Los Angeles, and the eastern United States. Sensitivity to NOx emissions dominates in central China, the Po Valley in Italy, the central United States, and the Central Valley in California. Sensitivity to VOCs emissions dominates only in the southern NCP in the winter. These results agree well with those of previous local studies. Our satellite-based indicator provides a simple tool for air quality managers to choose emission control strategies for decreasing PM2.5 nitrate pollution. © 2024 The Authors. Published by American Chemical Society.
BibTeX: @article{Dang2024, author = {Dang, Ruijun and Jacob, Daniel J. and Zhai, Shixian and Yang, Laura Hyesung and Pendergrass, Drew C. and Coheur, Pierre and Clarisse, Lieven and Van Damme, Martin and Choi, Jin-Soo and Park, Jin-Soo and Liu, Zirui and Xie, Peifu and Liao, Hong}, title = {A Satellite-Based Indicator for Diagnosing Particulate Nitrate Sensitivity to Precursor Emissions: Application to East Asia, Europe, and North America}, journal = {Environmental Science and Technology}, year = {2024}, doi = {10.1021/acs.est.4c08082} }
De Kreijger S, Cauët E, Elias B and Troian-Gautier L (2024), "Synthesis of Ru(ii) and Os(ii) photosensitizers bearing one 9,10-diamino-1,4,5,8-tetraazaphenanthrene scaffold", Dalton Transactions. Vol. 53(24), pp. 10270 – 10284. [Abstract] [BibTeX] [DOI]
Abstract: The synthesis of eight Ru(ii) and Os(ii) photosensitizers bearing a common 9,10-disubstituted-1,4,5,8-tetraazaphenanthrene backbone is reported. With Os(ii) photosensitizers, the 9,10-diNH2-1,4,5,8-tetraazaphenanthrene could be directly chelated onto the metal center via the heteroaromatic moiety, whereas similar conditions using Ru(ii) resulted in the formation of an o-quinonediimine derivative. Hence, an alternative route, proceeding via the chelation of 9-NH2-10-NO2-1,4,5,8-tetraazaphenanthrene and subsequent ligand reduction of the corresponding photosensitizers was developed. Photosensitizers chelated via the polypyridyl-type moiety exhibited classical photophysical properties whereas the o-quinonediimine chelated Ru(ii) analogues exhibited red-shifted absorption (520 nm) and no photoluminescence at room temperature in acetonitrile. The most promising photosensitizers were investigated for excited-state quenching with guanosine-5′-monophosphate in aqueous buffered conditions where reductive excited-state electron transfer was observed by nanosecond transient absorption spectroscopy. © 2024 The Royal Society of Chemistry
BibTeX: @article{DeKreijger2024, author = {De Kreijger, Simon and Cauët, Emilie and Elias, Benjamin and Troian-Gautier, Ludovic}, title = {Synthesis of Ru(ii) and Os(ii) photosensitizers bearing one 9,10-diamino-1,4,5,8-tetraazaphenanthrene scaffold}, journal = {Dalton Transactions}, year = {2024}, volume = {53}, number = {24}, pages = {10270 – 10284}, doi = {10.1039/d4dt01077a} }
Demaison J and Liévin J (2024), "Equilibrium Values for the Si-H Bond Length and Equilibrium Structures of Silyl Iodide and Halosilylenes", Molecules. Vol. 29(13) [Abstract] [BibTeX] [DOI]
Abstract: The equilibrium structures of silyl iodide, SiH3I, and silylene halides, SiHX (X = F, Cl, Br, I), were determined by using the mixed regression method, where approximate values of the rotational constants are supplemented by the structural parameters of a different origin. For this goal, it is shown that the r(Si-H) bond length can be determined by using the isolated SiH stretching frequency and that an accurate estimation of the bond angles is obtained by an MP2 calculation with a basis set of triple zeta quality. To check the accuracy of the experimental structures, they were also optimized by means of all electron CCSD(T) calculations using basis sets of quadruple zeta quality. © 2024 by the authors.
BibTeX: @article{Demaison2024a, author = {Demaison, Jean and Liévin, Jacques}, title = {Equilibrium Values for the Si-H Bond Length and Equilibrium Structures of Silyl Iodide and Halosilylenes}, journal = {Molecules}, year = {2024}, volume = {29}, number = {13}, note = {All Open Access, Gold Open Access}, doi = {10.3390/molecules29133101} }
Demaison J, Liévin J and Perrin A (2024), "Equilibrium structure of nitrogen dioxide revisited", Molecular Physics. Vol. 122(18) [Abstract] [BibTeX] [DOI]
Abstract: The equilibrium structure of nitrogen dioxide was determined using different methods: experimental, semiexperimental, mass-dependent, using an empirical correction to the effective (r0) structure, and ab initio optimizations. For this goal, recently determined rotational constants of vibrationally excited states have been used. The coupled cluster method, CCSD(T), fails to give an accurate structure. However, an accurate structure can be obtained by taking into account a small correction calculated at the CCSDTQ level of theory. Furthermore, the multireference configuration interaction method, MRCI + Q, gives a satisfactory result which can still be improved by interpolation. The semiexperimental and mass-dependent methods, as well as the corrected r0 structure give accurate results and are furthermore much easier to use than the experimental method. It has to be noted that the different methods give compatible results. The mean of the results gives the following equilibrium structure: r(NO) = 1.1944(6) Å and ∠(ONO) = 133.89(11)°. © 2024 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX: @article{Demaison2024, author = {Demaison, Jean and Liévin, Jacques and Perrin, Agnès}, title = {Equilibrium structure of nitrogen dioxide revisited}, journal = {Molecular Physics}, year = {2024}, volume = {122}, number = {18}, doi = {10.1080/00268976.2024.2318016} }
Di Gioacchino T, Clarisse L, Noppen L, Van Damme M, Bauduin S and Coheur P (2024), "Spatial and Temporal Variations of Thermal Contrast in the Planetary Boundary Layer", Journal of Remote Sensing (United States). Vol. 28 [Abstract] [BibTeX] [DOI]
Abstract: High-spectral resolution infrared sounders on board satellites can measure atmospheric trace gases confined to the planetary boundary layer (PBL). However, their sensitivity to the PBL depends on the temperature difference between the surface and the atmosphere, the so-called thermal contrast (TC). After reviewing the physical aspects of TC and how it drives measurement sensitivity, we characterize the global and temporal behavior of TC in clear-sky conditions. Combining land surface temperatures from the Copernicus Global Land Services dataset with air temperatures from the European Centre for Medium-Range Weather Forecasts reanalysis v5, we obtain global monthly averages of TC at high spatial (31 km) and temporal (1 h) resolution. TCs are analyzed as a function of time of the day, time of the year, location and land cover. Daytime maxima are observed from 1130 to 1330 local time, from 5–10 K in winter to 10–30 K in summer. A large dependency on land cover type is observed, both in the magnitude of the daily variations, and in the seasonality. For bare soils, shrublands, sparse and herbaceous vegetation, a maximum is seen in summer with daily TC amplitudes over 30 K. In contrast, for forests, wetlands, and croplands, the seasonal maximum occurs in spring, with daily variations below 15 K. Nighttime TCs typically range between −5 and −10 K. Occasionally, very favorable nighttime measurement conditions occur during winter and autumn due to large temperature inversions. Throughout the paper, we illustrate important concepts by means of satellite observations of NH3 over the Po Valley (Italy). Copyright © 2024 Tommaso Di Gioacchino et al.
BibTeX: @article{DiGioacchino2024, author = {Di Gioacchino, Tommaso and Clarisse, Lieven and Noppen, Lara and Van Damme, Martin and Bauduin, Sophie and Coheur, Pierre}, title = {Spatial and Temporal Variations of Thermal Contrast in the Planetary Boundary Layer}, journal = {Journal of Remote Sensing (United States)}, year = {2024}, volume = {28}, note = {All Open Access, Gold Open Access}, doi = {10.34133/remotesensing.0142} }
Franco B, Clarisse L, Theys N, Hadji-Lazaro J, Clerbaux C and Coheur P (2024), "Pyrogenic HONO seen from space: Insights from global IASI observations", Atmospheric Chemistry and Physics. Vol. 24(8), pp. 4973 – 5007. [Abstract] [BibTeX] [DOI]
Abstract: Nitrous acid (HONO) is a key atmospheric component, acting as a major source of the hydroxyl radical (OH), the primary oxidant in the Earth's atmosphere. However, understanding its spatial and temporal variability remains a significant challenge. Recent TROPOspheric Monitoring Instrument (TROPOMI)/Sentinel-5 Precursor (S5P) ultraviolet-visible (UV-Vis) measurements of fresh fire plumes shed light on the impact of global pyrogenic HONO emissions. Here, we leverage Infrared Atmospheric Sounding Interferometer (IASI)/MetOp's global infrared satellite measurements, complementing midday TROPOMI observations with morning and evening overpasses, to detect and retrieve pyrogenic HONO in 2007-2023. Employing a sensitive detection method, we identify HONO enhancements within concentrated fire plumes worldwide. Most detections are in the Northern Hemisphere (NH) mid- and high latitudes, where intense wildfires and high injection heights favour HONO detection. IASI's nighttime measurements yield 10-fold more HONO detections than daytime measurements, emphasizing HONO's extended lifetime in the absence of photolysis during the night. The annual detection count increases by at least 3-4 times throughout the IASI time series, mirroring the recent surge in intense wildfires at these latitudes. Additionally, we employ a neural-network-based algorithm for retrieving pyrogenic HONO total columns from IASI and compare them with TROPOMI in the same fire plumes. The results demonstrate TROPOMI's efficacy in capturing HONO enhancements in smaller fire plumes and in proximity to fire sources, while IASI's morning and evening overpasses enable HONO measurements further downwind, highlighting the survival of HONO or its secondary formation along long-range transport in smoke plumes. © 2024 Bruno Franco et al.
BibTeX: @article{Franco2024, author = {Franco, Bruno and Clarisse, Lieven and Theys, Nicolas and Hadji-Lazaro, Juliette and Clerbaux, Cathy and Coheur, Pierre}, title = {Pyrogenic HONO seen from space: Insights from global IASI observations}, journal = {Atmospheric Chemistry and Physics}, year = {2024}, volume = {24}, number = {8}, pages = {4973 – 5007}, doi = {10.5194/acp-24-4973-2024} }
Honet A, Henrard L and Meunier V (2024), "Robust correlated magnetic moments in end-modified graphene nanoribbons", Carbon Trends. Vol. 16 [Abstract] [BibTeX] [DOI]
Abstract: We conduct a theoretical examination of the electronic and magnetic characteristics of end-modified 7-atom wide armchair graphene nanoribbons (AGNRs). Our investigation is performed within the framework of a single-band Hubbard model, beyond a mean-field approximation. First, we carry out a comprehensive comparison of various approaches for accommodating di-hydrogenation configurations at the AGNR ends. We demonstrate that the application of an on-site potential to the modified carbon atom, coupled with the addition of an electron, replicates phenomena such as the experimentally observed reduction of the bulk-states (BS) gap. These results for the density of states (DOS) and electronic densities align closely with those obtained through a method explicitly designed to account for the orbital properties of hydrogen atoms. Furthermore, our study enables a clear differentiation between magnetic moments already described in a mean-field (MF) approach, which are spatially confined to the same sites as the topological end-states (ES), and correlation-induced magnetic moments, which exhibit localization along all edges of the AGNRs. Notably, we show the robustness of these correlation-induced magnetic moments relative to end modifications, within the scope of the method we employ. © 2024 The Author(s)
BibTeX: @article{Honet2024, author = {Honet, Antoine and Henrard, Luc and Meunier, Vincent}, title = {Robust correlated magnetic moments in end-modified graphene nanoribbons}, journal = {Carbon Trends}, year = {2024}, volume = {16}, note = {All Open Access, Gold Open Access}, doi = {10.1016/j.cartre.2024.100377} }
Kuttippurath J, Patel V, Kashyap R, Singh A and Clerbaux C (2024), "Anomalous increase in global atmospheric ammonia during COVID-19 lockdown: Need policies to curb agricultural emissions", Journal of Cleaner Production. Vol. 434 [Abstract] [BibTeX] [DOI]
Abstract: The restrictions imposed on human activities during the COVID-19 lockdown (LD) period provided a new scenario to identify potential sources of atmospheric pollution. There are several studies that deal with changes in air quality around the world during LD, but very few on atmospheric ammonia (NH3). Therefore, we examine the changes in global NH3 during LD (April–May 2020) in comparison to the pre-lockdown (PreLD, April–May 2017–2019) and post-lockdown (PostLD, April–May 2021) periods, and assess the factors responsible for these changes. We observe an increase in NH3 during LD across the latitudes, with very high values in the western Europe, Eastern China (EC), the Indian subcontinent and the eastern United States of America (USA). However, a decline in NH3 is observed in some regions of South America (SA) and North America (NA). Similar changes in NH3 during LD are also observed in smaller spatial scales, as found in 3000 cities across the globe. The reduction of sulphur dioxide (SO2), nitrogen dioxide (NO2), nitric acid (HNO3), humidity and cloud cover as a result of restrictions on human activities, particularly in the western Europe and the USA, may have impeded the conversion of NH3 to particulates, which led to a higher NH3 there. Nevertheless, agricultural activities and livestock are the most prominent sources of atmospheric NH3, and were not under restriction during LD, show an enhancement in terms of the use of nitrogen fertilizer, crop production and area harvested, which also cause a rise in NH3 in these regions. Therefore, it is evident that the changes in meteorology and atmospheric composition, together with increased agricultural activities, led to the global increase in atmospheric NH3 during LD. That is, most pollutants show a decline during LD, but NH3 exhibits a rise due to its sources such as agricultural activities. Henceforth, environmental regulations, policies and advanced technologies are required in the agricultural sector, such as fertilizer deep placement using urea briquettes and restricted application of nitrogen fertilizers, to curb NH3 emissions. © 2023 Elsevier Ltd
BibTeX: @article{Kuttippurath2024, author = {Kuttippurath, J. and Patel, V.K. and Kashyap, R. and Singh, A. and Clerbaux, C.}, title = {Anomalous increase in global atmospheric ammonia during COVID-19 lockdown: Need policies to curb agricultural emissions}, journal = {Journal of Cleaner Production}, year = {2024}, volume = {434}, doi = {10.1016/j.jclepro.2023.140424} }
Ma M, Li Y, Godefroid M, Gaigalas G, Li J, Bieroń J, Chen C, Wang J and Jönsson P (2024), "Natural Orbitals and Targeted Non-Orthogonal Orbital Sets for Atomic Hyperfine Structure Multiconfiguration Calculations †", Atoms. Vol. 12(6) [Abstract] [BibTeX] [DOI]
Abstract: Hyperfine structure constants have many applications, but are often hard to calculate accurately due to large and canceling contributions from different terms of the hyperfine interaction operator, and also from different closed and spherically symmetric core subshells that break up due to electron correlation effects. In multiconfiguration calculations, the wave functions are expanded in terms of configuration state functions (CSFs) built from sets of one-electron orbitals. The orbital sets are typically enlarged within the layer-by-layer approach. The calculations are energy-driven, and orbitals in each new layer of correlation orbitals are spatially localized in regions where the weighted total energy decreases the most, overlapping and breaking up different closed core subshells in an irregular pattern. As a result, hyperfine structure constants, computed as expectation values of the hyperfine operators, often show irregular or oscillating convergence patterns. Large orbital sets, and associated large CSF expansions, are needed to obtain converged values of the hyperfine structure constants. We analyze the situation for the states of the (Formula presented.) odd and (Formula presented.) even configurations in N I, and show that the convergence with respect to the increasing sets of orbitals is radically improved by introducing separately optimized orbital sets targeted for describing the spin- and orbital-polarization effects of the (Formula presented.) and (Formula presented.) core subshells that are merged with, and orthogonalized against, the ordinary energy-optimized orbitals. In the layer-by-layer approach, the spectroscopic orbitals are kept frozen from the initial calculation and are not allowed to relax in response to the introduced layers of correlation orbitals. To compensate for this lack of variational freedom, the orbitals are transformed to natural orbitals prior to the final calculation based on single and double substitutions from an increased multireference set. The use of natural orbitals has an important impact on the states of the (Formula presented.) configuration, bringing the corresponding hyperfine interaction constants in closer agreement with experiment. Relying on recent progress in methodology, the multiconfiguration calculations are based on configuration state function generators, cutting down the time for spin-angular integration by factors of up to 50, compared to ordinary calculations. © 2024 by the authors.
BibTeX: @article{Ma2024, author = {Ma, Mingxuan and Li, Yanting and Godefroid, Michel and Gaigalas, Gediminas and Li, Jiguang and Bieroń, Jacek and Chen, Chongyang and Wang, Jianguo and Jönsson, Per}, title = {Natural Orbitals and Targeted Non-Orthogonal Orbital Sets for Atomic Hyperfine Structure Multiconfiguration Calculations †}, journal = {Atoms}, year = {2024}, volume = {12}, number = {6}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atoms12060030} }
Pope RJ, O'Connor FM, Dalvi M, Kerridge BJ, Siddans R, Latter BG, Barret B, Le Flochmoen E, Boynard A, Chipperfield MP, Feng W, Pimlott MA, Dhomse SS, Retscher C, Wespes C and Rigby R (2024), "Investigation of the impact of satellite vertical sensitivity on long-term retrieved lower-tropospheric ozone trends", Atmospheric Chemistry and Physics. Vol. 24(16), pp. 9177 – 9195. [Abstract] [BibTeX] [DOI]
Abstract: Ozone is a potent air pollutant in the lower troposphere and an important short-lived climate forcer (SLCF) in the upper troposphere. Studies investigating long-term trends in the tropospheric column ozone (TCO3) have shown large-scale spatio-temporal inconsistencies. Here, we investigate the long-term trends in lower-tropospheric column ozone (LTCO3, surface-450 hPa sub-column) by exploiting a synergy of satellite and ozonesonde data sets and an Earth system model (UK's Earth System Model, UKESM) over North America, Europe, and East Asia for the decade 2008-2017. Overall, we typically find small LTCO3 linear trends with large uncertainty ranges using the Ozone Monitoring Instrument (OMI) and the Infrared Atmospheric Sounding Interferometer (IASI), while model simulations indicate a stable LTCO3 tendency. The satellite a priori data sets show negligible trends, indicating that any year-to-year changes in the spatio-temporal sampling of these satellite data sets over the period concerned have not artificially influenced their LTCO3 temporal evolution. The application of the satellite averaging kernels (AKs) to the UKESM simulated ozone profiles, accounting for the satellite vertical sensitivity and allowing for like-for-like comparisons, has a limited impact on the modelled LTCO3 tendency in most cases. While, in relative terms, this is more substantial (e.g. on the order of 100 %), the absolute magnitudes of the model trends show negligible change. However, as the model has a near-zero tendency, artificial trends were imposed on the model time series (i.e. LTCO3 values rearranged from smallest to largest) to test the influence of the AKs, but simulated LTCO3 trends remained small. Therefore, the LTCO3 tendencies between 2008 and 2017 in northern-hemispheric regions are likely to be small, with large uncertainties, and it is difficult to detect any small underlying linear trends due to interannual variability or other factors which require further investigation (e.g. the radiative transfer scheme (RTS) used and/or the inputs (e.g. meteorological fields) used in the RTS). © 2024 Copernicus Publications. All rights reserved.
BibTeX: @article{Pope2024a, author = {Pope, Richard J. and O'Connor, Fiona M. and Dalvi, Mohit and Kerridge, Brian J. and Siddans, Richard and Latter, Barry G. and Barret, Brice and Le Flochmoen, Eric and Boynard, Anne and Chipperfield, Martyn P. and Feng, Wuhu and Pimlott, Matilda A. and Dhomse, Sandip S. and Retscher, Christian and Wespes, Catherine and Rigby, Richard}, title = {Investigation of the impact of satellite vertical sensitivity on long-term retrieved lower-tropospheric ozone trends}, journal = {Atmospheric Chemistry and Physics}, year = {2024}, volume = {24}, number = {16}, pages = {9177 – 9195}, doi = {10.5194/acp-24-9177-2024} }
Pope RJ, Rap A, Pimlott MA, Barret B, Le Flochmoen E, Kerridge BJ, Siddans R, Latter BG, Ventress LJ, Boynard A, Retscher C, Feng W, Rigby R, Dhomse SS, Wespes C and Chipperfield MP (2024), "Quantifying the tropospheric ozone radiative effect and its temporal evolution in the satellite era", Atmospheric Chemistry and Physics. Vol. 24(6), pp. 3613 – 3626. [Abstract] [BibTeX] [DOI]
Abstract: Using state-of-the-art satellite ozone profile products, and a chemical transport model, we provide an updated estimate of the tropospheric ozone radiative effect (TO3RE) and observational constraint on its variability over the decade 2008-2017. Previous studies have shown the short-term (i.e. a few years) globally weighted average TO3RE to be 1.17 ± 0.03 W m-2. However, from our analysis, using decadal (2008-2017) ozone profile datasets from the Infrared Atmospheric Sounding Interferometer, average TO3RE ranges between 1.21 and 1.26 W m-2. Over this decade, the modelled and observational TO3RE linear trends show a negligible change (e.g. ± 0.1 % yr-1). Two model sensitivity experiments fixing emissions and meteorology to 1 year (i.e. start year - 2008) show that temporal changes in ozone precursor emissions (increasing contribution) and meteorological factors (decreasing contribution) have counteracting tendencies, leading to a negligible globally weighted average TO3RE trend. © Copyright:
BibTeX: @article{Pope2024, author = {Pope, Richard J. and Rap, Alexandru and Pimlott, Matilda A. and Barret, Brice and Le Flochmoen, Eric and Kerridge, Brian J. and Siddans, Richard and Latter, Barry G. and Ventress, Lucy J. and Boynard, Anne and Retscher, Christian and Feng, Wuhu and Rigby, Richard and Dhomse, Sandip S. and Wespes, Catherine and Chipperfield, Martyn P.}, title = {Quantifying the tropospheric ozone radiative effect and its temporal evolution in the satellite era}, journal = {Atmospheric Chemistry and Physics}, year = {2024}, volume = {24}, number = {6}, pages = {3613 – 3626}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-24-3613-2024} }
Schmitt T, Delnord M, Cauët E, Van Valckenborgh E and Van den Bulcke M (2024), "Contextual factors influencing the equitable implementation of precision medicine in routine cancer care in Belgium", European Journal of Public Health. Vol. 34(4), pp. 624 – 631. [Abstract] [BibTeX] [DOI]
Abstract: Background: Precision medicine represents a paradigm shift in health systems, moving from a one-size-fits-all approach to a more individualized form of care, spanning multiple scientific disciplines including drug discovery, genomics, and health communication. This study aims to explore the contextual factors influencing the equitable implementation of precision medicine in Belgium for incorporating precision medicine into routine cancer care within the Belgian health system. Methods: As part of a foresight study, our approach evaluates critical factors affecting the implementation of precision oncology. The study scrutinizes contextual, i.e. demographic, economic, societal, technological, environmental, and political/policy-related (DESTEP) factors, identified through a comprehensive literature review and validated by a multidisciplinary group at the Belgian Cancer Center, Sciensano. An expert survey further assesses the importance and likelihood of these factors, illuminating potential barriers and facilitators to implementation. Results: Based on the expert survey, five key elements (rising cancer rates, dedicated healthcare reimbursement budgets, increasing healthcare expenditures, advanced information technology solutions for data transfer, and demand for high-quality data) are expected to influence the equitable implementation of precision medicine in routine cancer care in Belgium in the future. Conclusions: This work contributes to the knowledge base on precision medicine in Belgium and public health foresight, exploring the implementation challenges and suggesting solutions with an emphasis on the importance of comparative analyses of health systems, evaluation of health technology assessment methods, and the exploration of ethical issues in data privacy and equity. © The Author(s) 2024. Published by Oxford University Press on behalf of the European Public Health Association.
BibTeX: @article{Schmitt2024a, author = {Schmitt, Tugce and Delnord, Marie and Cauët, Emilie and Van Valckenborgh, Els and Van den Bulcke, Marc}, title = {Contextual factors influencing the equitable implementation of precision medicine in routine cancer care in Belgium}, journal = {European Journal of Public Health}, year = {2024}, volume = {34}, number = {4}, pages = {624 – 631}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1093/eurpub/ckae055} }
Schmitt T, Poirel HA, Cauët E, Delnord M and Van den Bulcke M (2024), "Unlocking the genomic landscape: Results of the Beyond 1 Million Genomes (B1MG) pilot in Belgium towards Genomic Data Infrastructure (GDI)", Health Policy. Vol. 143 [Abstract] [BibTeX] [DOI]
Abstract: Genomic medicine has great potential to offer insights into how humans’ genetic variation can affect their health, prevention options and treatment responses. The Beyond 1 Million Genomes (B1MG) project was kicked off in 2020 with the aim of building a federated network of genomic data in Europe, in which Belgium took part as a piloting country. B1MG developed a framework to enable all interested countries to self-evaluate the level of maturity of national genomic medicine practices following a common matrix, called Maturity Level Model (MLM), that contained 49 indicators across eight domains: I. Governance and strategy; II. Investment and economic model; III. Ethics, legislation and policy; IV. Public awareness and acceptance; V. Workforce skills and organisation; VI. Clinical organisation, infrastructure and tools; VII. Clinical genomics guidelines and infrastructure; and VIII. Data management, standards and infrastructure. The ongoing Genomic Data Infrastructure (GDI) project aims to capitalise on the experience of B1MG piloting countries and their MLM results. In this paper, we present the qualitative and quantitative outcomes of B1MG MLM assessment in Belgium and discuss their relevance to GDI. The insights gained from this study can be helpful for steering future policy directions and interventions on genomics in Belgium and beyond. © 2024
BibTeX: @article{Schmitt2024, author = {Schmitt, Tugce and Poirel, Hélène A. and Cauët, Emilie and Delnord, Marie and Van den Bulcke, Marc}, title = {Unlocking the genomic landscape: Results of the Beyond 1 Million Genomes (B1MG) pilot in Belgium towards Genomic Data Infrastructure (GDI)}, journal = {Health Policy}, year = {2024}, volume = {143}, doi = {10.1016/j.healthpol.2024.105060} }
Song C, Yan S, Godefroid M, Bieroń J, Jönsson P, Gaigalas G, Ekman J, Zhang X, Chen C, Ning C and Si R (2024), "Isotope shifts in electron affinities and in binding energies of Pb and hyperfine structure of 207Pb−", Journal of Chemical Physics. Vol. 160(21) [Abstract] [BibTeX] [DOI]
Abstract: The isotope shifts in electron affinities of Pb were measured by Walter et al. [Phys. Rev. A 106, L010801 (2022)] to be −0.002(4) meV for 207-208Pb and −0.003(4) meV for 206-208Pb by scanning the threshold of the photodetachment channel Pb− ( S 3 / 2 ◦ 4 ) − Pb (3P0), while Chen and Ning reported 0.015(25) and −0.050(22) meV for the isotope shifts on the binding energies measured relative to 3P2 using the SEVI method [J. Chem. Phys. 145, 084303 (2016)]. Here we revisited these isotope shifts by using our second-generation SEVI spectrometer and obtained −0.001(15) meV for 207-208Pb and −0.001(14) meV for 206-208Pb, respectively. In order to aid the experiment by theory, we performed the first ab initio theoretical calculations of isotope shifts in electron affinities and binding energies of Pb, as well as the hyperfine structure of 207Pb−, by using the MCDHF and RCI methods. The isotope shifts in electron affinities of 207-208Pb and 206-208Pb are −0.0023(8) and −0.0037(13) meV for the 3P0 channel, respectively, in good agreement with Walter et al.’s measurements. The isotope shifts in binding energies relative to 3P1,2, −0.0015(8) and −0.0026(13) meV for 207-208Pb and 206-208Pb, respectively, are compatible with the present measurements. The hyperfine constant for the ground state of 207Pb− obtained by the present calculations, A ( S 3 / 2 ◦ 4 ) = − 1118 MHz, differs by a factor of 3 from the previous estimation by Bresteau et al. [J. Phys. B: At., Mol. Opt. Phys. 52, 065001 (2019)]. The reliability is supported by the good agreement between the theoretical and experimental hyperfine parameters of 209Bi. © 2024 Author(s).
BibTeX: @article{Song2024, author = {Song, C.X. and Yan, S.T. and Godefroid, M. and Bieroń, J. and Jönsson, P. and Gaigalas, G. and Ekman, J. and Zhang, X.M. and Chen, C.Y. and Ning, C.G. and Si, R.}, title = {Isotope shifts in electron affinities and in binding energies of Pb and hyperfine structure of 207Pb−}, journal = {Journal of Chemical Physics}, year = {2024}, volume = {160}, number = {21}, doi = {10.1063/5.0212299} }
Sun W, Tack F, Clarisse L, Schneider R, Stavrakou T and Van Roozendael M (2024), "Inferring Surface NO2 Over Western Europe: A Machine Learning Approach With Uncertainty Quantification", Journal of Geophysical Research: Atmospheres. Vol. 129(20) [Abstract] [BibTeX] [DOI]
Abstract: Nitrogen oxides (NOx = NO + NO2) are of great concern due to their impact on human health and the environment. In recent years, machine learning (ML) techniques have been widely used for surface NO2 estimation with rapid developments in computational power and big data. However, the uncertainties inherent to such retrievals are rarely studied. In this study, a novel ML framework has been developed, enhanced with uncertainty quantification techniques, to estimate surface NO2 and provide corresponding data-induced uncertainty. We apply the Boosting Ensemble Conformal Quantile Estimator (BEnCQE) model to infer surface NO2 concentrations over Western Europe at the daily scale and 1 km spatial resolution from May 2018 to December 2021. High NO2 mainly appears in urban areas, industrial areas, and roads. The space-based cross-validation shows that our model achieves accurate point estimates (r = 0.8, R2 = 0.64, root mean square error = 8.08 μg/m3) and reliable prediction intervals (coverage probability, PI-50%: 51.0%, PI-90%: 90.5%). Also, the model result agrees with the Copernicus Atmosphere Monitoring Service (CAMS) model. The quantile regression in our model enables us to understand the importance of predictors for different NO2 level estimations. Additionally, the uncertainty information reveals the extra potential exceedance of the World Health Organization (WHO) 2021 limit in some locations, which is undetectable by only point estimates. Meanwhile, the uncertainty quantification allows assessment of the model's robustness outside existing in-situ station measurements. It reveals challenges of NO2 estimation over urban and mountainous areas where NO2 is highly variable and heterogeneously distributed. © 2024 The Author(s).
BibTeX: @article{Sun2024, author = {Sun, Wenfu and Tack, Frederik and Clarisse, Lieven and Schneider, Rochelle and Stavrakou, Trissevgeni and Van Roozendael, Michel}, title = {Inferring Surface NO2 Over Western Europe: A Machine Learning Approach With Uncertainty Quantification}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2024}, volume = {129}, number = {20}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1029/2023JD040676} }
Tchana Betnga W, Hindle F, Manceron L, Vander Auwera J, Cuisset A, Mouret G, Bocquet R, Perrin A, Roy P and Kwabia Tchana F (2024), "A new instrumentation for simultaneous terahertz and mid-infrared spectroscopy in corrosive gaseous mixtures", Review of Scientific Instruments. Vol. 95(1) [Abstract] [BibTeX] [DOI]
Abstract: The correct interpretation of infrared (IR) observations of planetary atmospheres requires an accurate knowledge of temperature and partial and global pressures. Precise laboratory measurements of absorption intensities and line profiles, in the 200-350 K temperature range, are, therefore, critical. However, for gases only existing in complex chemical equilibria, such as nitrous or hypobromous acids, it is not possible to rely on absolute pressure measurements to measure absolute integrated optical absorption cross sections or IR line intensities. To overcome this difficulty, a novel dual-beam terahertz (THz)/mid-IR experimental setup has been developed, relying on the simultaneous use of two instruments. The setup involves a newly constructed temperature-controlled (200-350 K) cross-shaped absorption cell made of inert materials. The cell is traversed by the mid-IR beam from a high-resolution Fourier transform spectrometer using along a White-cell optical configuration providing absorption path lengths from 2.8 to 42 m and by a THz radiation beam (82.5 GHz to 1.1 THz), probing simultaneously the same gaseous sample. The THz channel records pure rotational lines of molecules for which the dipole moment was previously measured with high precision using Stark spectroscopy. This allows for a determination of the partial pressure in the gaseous mixture and enables absolute line intensities to be retrieved for the mid-IR range. This new instrument opens a new possibility for the retrieval of spectroscopic parameters for unstable molecules of atmospheric interest. The design and performance of the equipment are presented and illustrated by an example of simultaneous THz and mid-IR measurement on nitrous acid (HONO) equilibrium. © 2024 Author(s).
BibTeX: @article{TchanaBetnga2024, author = {Tchana Betnga, W. and Hindle, F. and Manceron, L. and Vander Auwera, J. and Cuisset, A. and Mouret, G. and Bocquet, R. and Perrin, A. and Roy, P. and Kwabia Tchana, F.}, title = {A new instrumentation for simultaneous terahertz and mid-infrared spectroscopy in corrosive gaseous mixtures}, journal = {Review of Scientific Instruments}, year = {2024}, volume = {95}, number = {1}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/5.0178449} }
Vandaele AC, Aoki S, Bauduin S, Daerden F, Fedorova A, Giuranna M, Korablev O, Lefèvre F, Määttänen A, Montmessin F, Patel MR, Smith M, Trompet L, Viscardy S, Willame Y and Yoshida N (2024), "Composition and Chemistry of the Martian Atmosphere as Observed by Mars Express and ExoMars Trace Gas Orbiter", Space Science Reviews. Vol. 220(7) [Abstract] [BibTeX] [DOI]
Abstract: The atmosphere of Mars has been studied for many years now by a long series of missions. The paper focuses on the results obtained by two of these that are led by European researchers overseen by the European Space Agency, i.e., Mars Express which was launched in 2003 and ExoMars Trace Gas Orbiter launched in 2016. Both missions are still providing high-quality data about the atmosphere of Mars, such as abundances of its key species – CO2, CO, H2O, O3 - playing an important role in the different cycles existing on the planet, as well as other trace gases – O2 (mixing ratio of 3.1 to 5.8 × 10−3 above 90 km), the recently discovered HCl (up to 4 ppbv below 30 km), and the elusive CH4 (stringent detection limit of 20 pptv). Some instruments are also sensitive enough to provide information on isotopologues of the key elements and have delivered for some of these the first and unique vertical profiles available today (δ13C and δ18O in CO2 and CO, D/H, δ17O and δ18O in water vapour). The paper retraces the history of the exploration of the Martian atmosphere putting the results from both missions in perspective. © The Author(s) 2024.
BibTeX: @article{Vandaele2024, author = {Vandaele, Ann C. and Aoki, Shohei and Bauduin, Sophie and Daerden, Frank and Fedorova, Anna and Giuranna, Marco and Korablev, Oleg and Lefèvre, Franck and Määttänen, Anni and Montmessin, Franck and Patel, Manish R. and Smith, Michael and Trompet, Loïc and Viscardy, Sébastien and Willame, Yannick and Yoshida, Nao}, title = {Composition and Chemistry of the Martian Atmosphere as Observed by Mars Express and ExoMars Trace Gas Orbiter}, journal = {Space Science Reviews}, year = {2024}, volume = {220}, number = {7}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1007/s11214-024-01109-7} }
Vernier J-P, Aubry TJ, Timmreck C, Schmidt A, Clarisse L, Prata F, Theys N, Prata AT, Mann G, Choi H, Carn S, Rigby R, Loughlin SC and Stevenson JA (2024), "The 2019 Raikoke eruption as a testbed used by the Volcano Response group for rapid assessment of volcanic atmospheric impacts", Atmospheric Chemistry and Physics. Vol. 24(10), pp. 5765 – 5782. [Abstract] [BibTeX] [DOI]
Abstract: The 21 June 2019 Raikoke eruption (48°N, 153°E) generated one of the largest amounts of sulfur emission to the stratosphere since the 1991 Mt. Pinatubo eruption. Satellite measurements indicate a consensus best estimate of 1.5Tg for the sulfur dioxide (SO2) injected at an altitude of around 14-15km. The peak Northern Hemisphere (NH) mean 525gnm stratospheric aerosol optical depth (SAOD) increased to 0.025, a factor of 3 higher than background levels. The Volcano Response (VolRes) initiative provided a platform for the community to share information about this eruption which significantly enhanced coordination efforts in the days after the eruption. A multi-platform satellite observation subgroup formed to prepare an initial report to present eruption parameters including SO2 emissions and their vertical distribution for the modeling community. It allowed us to make the first estimate of what would be the peak in SAOD 1 week after the eruption using a simple volcanic aerosol model. In this retrospective analysis, we show that revised volcanic SO2 injection profiles yield a higher peak injection of the SO2 mass. This highlights difficulties in accurately representing the vertical distribution for moderate SO2 explosive eruptions in the lowermost stratosphere due to limited vertical sensitivity of the current satellite sensors (±2 km accuracy and low horizontal resolution of lidar observations. We also show that the SO2 lifetime initially assumed in the simple aerosol model was overestimated by 66 %, pointing to challenges for simple models to capture how the life cycle of volcanic gases and aerosols depends on the SO2 injection magnitude, latitude, and height. Using a revised injection profile, modeling results indicate a peak NH monthly mean SAOD at 525 nm of 0.024, in excellent agreement with observations, associated with a global monthly mean radiative forcing of -0.17 W m-2 resulting in an annual global mean surface temperature anomaly of -0.028 K. Given the relatively small magnitude of the forcing, it is unlikely that the surface response can be dissociated from surface temperature variability. © 2024 Copernicus Publications. All rights reserved.
BibTeX: @article{Vernier2024, author = {Vernier, Jean-Paul and Aubry, Thomas J. and Timmreck, Claudia and Schmidt, Anja and Clarisse, Lieven and Prata, Fred and Theys, Nicolas and Prata, Andrew T. and Mann, Graham and Choi, Hyundeok and Carn, Simon and Rigby, Richard and Loughlin, Susan C. and Stevenson, John A.}, title = {The 2019 Raikoke eruption as a testbed used by the Volcano Response group for rapid assessment of volcanic atmospheric impacts}, journal = {Atmospheric Chemistry and Physics}, year = {2024}, volume = {24}, number = {10}, pages = {5765 – 5782}, doi = {10.5194/acp-24-5765-2024} }
Zeng Z-C, Franco B, Clarisse L, Lee L, Qi C and Lu F (2024), "Observing a Volatile Organic Compound From a Geostationary Infrared Sounder: HCOOH From FengYun-4B/GIIRS", Journal of Geophysical Research: Atmospheres. Vol. 129(19) [Abstract] [BibTeX] [DOI]
Abstract: Formic acid (HCOOH) is one of the most abundant volatile organic compounds (VOCs) in the Earth's atmosphere and an important source of atmospheric acidity. Here we present the first retrieval of HCOOH from a geostationary orbit using observations from the Geostationary Interferometric Infrared Sounder (GIIRS) on board FengYun-4B. The results from July 2022 to June 2023 show the monthly variation of the HCOOH distribution in Asia. In addition, we show that FY-4B/GIIRS effectively tracks HCOOH enhancements from wildfires both during the day and at night. Finally, inter-comparison with IASI HCOOH data shows good agreement, indicating that FY-4B/GIIRS observations have comparable sensitivity to IASI. This study is an important first step toward monitoring VOCs from geostationary infrared sounders, including the existing and future GIIRS on board the FY-4 series and the forthcoming European geostationary infrared sounder (IRS) on board Meteosat Third Generation (MTG). © 2024. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Zeng2024, author = {Zeng, Zhao-Cheng and Franco, Bruno and Clarisse, Lieven and Lee, Lu and Qi, Chengli and Lu, Feng}, title = {Observing a Volatile Organic Compound From a Geostationary Infrared Sounder: HCOOH From FengYun-4B/GIIRS}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2024}, volume = {129}, number = {19}, note = {All Open Access, Green Open Access}, doi = {10.1029/2024JD041352} }
Zhai S, Jacob DJ, Franco B, Clarisse L, Coheur P, Shah V, Bates KH, Lin H, Dang R, Sulprizio MP, Huey LG, Moore FL, Jaffe DA and Liao H (2024), "Transpacific Transport of Asian Peroxyacetyl Nitrate (PAN) Observed from Satellite: Implications for Ozone", Environmental Science and Technology. Vol. 58(22), pp. 9760 – 9769. [Abstract] [BibTeX] [DOI]
Abstract: Peroxyacetyl nitrate (PAN) is produced in the atmosphere by photochemical oxidation of non-methane volatile organic compounds in the presence of nitrogen oxides (NOx), and it can be transported over long distances at cold temperatures before decomposing thermally to release NOx in the remote troposphere. It is both a tracer and a precursor for transpacific ozone pollution transported from East Asia to North America. Here, we directly demonstrate this transport with PAN satellite observations from the infrared atmospheric sounding interferometer (IASI). We reprocess the IASI PAN retrievals by replacing the constant prior vertical profile with vertical shape factors from the GEOS-Chem model that capture the contrasting shapes observed from aircraft over South Korea (KORUS-AQ) and the North Pacific (ATom). The reprocessed IASI PAN observations show maximum transpacific transport of East Asian pollution in spring, with events over the Northeast Pacific offshore from the Western US associated in GEOS-Chem with elevated ozone in the lower free troposphere. However, these events increase surface ozone in the US by less than 1 ppbv because the East Asian pollution mainly remains offshore as it circulates the Pacific High. © 2024 The Authors. Published by American Chemical Society.
BibTeX: @article{Zhai2024, author = {Zhai, Shixian and Jacob, Daniel J. and Franco, Bruno and Clarisse, Lieven and Coheur, Pierre and Shah, Viral and Bates, Kelvin H. and Lin, Haipeng and Dang, Ruijun and Sulprizio, Melissa P. and Huey, L. Gregory and Moore, Fred L. and Jaffe, Daniel A. and Liao, Hong}, title = {Transpacific Transport of Asian Peroxyacetyl Nitrate (PAN) Observed from Satellite: Implications for Ozone}, journal = {Environmental Science and Technology}, year = {2024}, volume = {58}, number = {22}, pages = {9760 – 9769}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1021/acs.est.4c01980} }
Abeed R, Viatte C, Porter WC, Evangeliou N, Clerbaux C, Clarisse L, Van Damme M, Coheur P-F and Safieddine S (2023), "A roadmap to estimating agricultural ammonia volatilization over Europe using satellite observations and simulation data", Atmospheric Chemistry and Physics. Vol. 23(19), pp. 12505 – 12523. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) is one of the most important gases emitted from agricultural practices. It affects air quality and the overall climate and is in turn influenced by long-term climate trends as well as by short-term fluctuations in local and regional meteorology. Previous studies have established the capability of the Infrared Atmospheric Sounding Interferometer (IASI) series of instruments, aboard the Metop satellites, to measure ammonia from space since 2007. In this study, we explore the interactions between atmospheric ammonia, land and meteorological variability, and long-term climate trends in Europe. We investigate the emission potential (δsoil) of ammonia from the soil, which describes the soil-atmosphere ammonia exchange. δsoil is generally calculated in-field or in laboratory experiments; here, and for the first time, we investigate a method which assesses it remotely using satellite data, reanalysis data products, and model simulations. We focus on ammonia emission potential in March 2011, which marks the start of growing season in Europe. Our results show that δsoil ranges from 2 × 103 to 9.5 × 104 (dimensionless) in fertilized cropland, such as in the North European Plain, and is of the order of 10-102 in a non-fertilized soil (e.g., forest and grassland). These results agree with in-field measurements from the literature, suggesting that our method can be used in other seasons and regions in the world. However, some improvements are needed in the determination of mass transfer coefficient k (ms-1), which is a crucial parameter to derive δsoil. Using a climate model, we estimate the expected increase in ammonia columns by the end of the century based on the increase in skin temperature (Tskin), under two different climate scenarios. Ammonia columns are projected to increase by up to 50 %, particularly in eastern Europe, under the SSP2-4.5 scenario and might even double (increase of 100 %) under the SSP5-8.5 scenario. The increase in skin temperature is responsible for a formation of new hotspots of ammonia in Belarus, Ukraine, Hungary, Moldova, parts of Romania, and Switzerland. © 2023 Rimal Abeed et al.
BibTeX: @article{Abeed2023, author = {Abeed, Rimal and Viatte, Camille and Porter, William C. and Evangeliou, Nikolaos and Clerbaux, Cathy and Clarisse, Lieven and Van Damme, Martin and Coheur, Pierre-François and Safieddine, Sarah}, title = {A roadmap to estimating agricultural ammonia volatilization over Europe using satellite observations and simulation data}, journal = {Atmospheric Chemistry and Physics}, year = {2023}, volume = {23}, number = {19}, pages = {12505 – 12523}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-23-12505-2023} }
Aerts A, Jolly SW, Kockaert P, Gorza S-P, Auwera JV and Vaeck N (2023), "Modulated super-Gaussian laser pulse to populate a dark rovibrational state of acetylene", Journal of Chemical Physics. Vol. 159(8) [Abstract] [BibTeX] [DOI]
Abstract: A pulse-shaping technique in the mid-infrared spectral range based on pulses with a super-Gaussian temporal profile is considered for laser control. We show a realistic and efficient path to the population of a dark rovibrational state in acetylene (C2H2). The laser-induced dynamics in C2H2 are simulated using fully experimental structural parameters. Indeed, the rotation-vibration energy structure, including anharmonicities, is defined by the global spectroscopic Hamiltonian for the ground electronic state of C2H2 built from the extensive high-resolution spectroscopy studies on the molecule, transition dipole moments from intensities, and the effects of the (inelastic) collisions that are parameterized from line broadenings using the relaxation matrix [A. Aerts, J. Vander Auwera, and N. Vaeck, J. Chem. Phys. 154, 144308 (2021)]. The approach, based on an effective Hamiltonian, outperforms today’s ab initio computations both in terms of accuracy and computational cost for this class of molecules. With such accuracy, the Hamiltonian permits studying the inner mechanism of theoretical pulse shaping [A. Aerts et al., J. Chem. Phys. 156, 084302 (2022)] for laser quantum control. Here, the generated control pulse presents a number of interferences that take advantage of the control mechanism to populate the dark state. An experimental setup is proposed for in-laboratory investigation. © 2023 Author(s).
BibTeX: @article{Aerts2023, author = {Aerts, Antoine and Jolly, Spencer W. and Kockaert, Pascal and Gorza, Simon-Pierre and Auwera, Jean Vander and Vaeck, Nathalie}, title = {Modulated super-Gaussian laser pulse to populate a dark rovibrational state of acetylene}, journal = {Journal of Chemical Physics}, year = {2023}, volume = {159}, number = {8}, note = {All Open Access, Green Open Access}, doi = {10.1063/5.0160526} }
Ashani MN, Huang Q, Flowers AM, Brown A, Aerts A, Otero-De-la-Roza A and DiLabio GA (2023), "Accurate Potential Energy Surfaces Using Atom-Centered Potentials and Minimal High-Level Data", Journal of Physical Chemistry A. Vol. 127(38), pp. 8015 – 8024. [Abstract] [BibTeX] [DOI]
Abstract: We demonstrate that a Δ-density functional theory (Δ-DFT) approach based on atom-centered potentials (ACPs) represents a computationally inexpensive and accurate method for representing potential energy surfaces (PESs) for the HONO and HFCO molecules and vibrational frequencies derived therefrom. Using as few as 100 CCSD(T)-F12a reference energies, ACPs developed for use with B3LYP/def2-TZVPP are shown to produce PESs for HONO and HFCO with mean absolute errors of 27.7 and 5.8 cm-1, respectively. Application of the multiconfigurational time-dependent Hartree (MCTDH) method with ACP-corrected B3LYP/def2-TZVPP PESs produces vibrational frequencies for cis- and trans-HONO with mean absolute percent errors (MAPEs) of 0.8 and 1.1, compared to 0.8 obtained for the two isomers with CCSD(T)-F12a/cc-pVTZ-F12/MCTDH. For HFCO, the vibrational frequencies obtained using the present (Δ-DFT)/MCTDH approach give a MAPE of 0.1, which is the error obtained with CCSD(T)-F12a/cc-pVTZ-F12/MCTDH. The ACP approach is therefore successful in representing a PES calculated at a high level of theory (CCSD(T)-F12a) and a promising method for the development of a general protocol for the representation of accurate molecular PESs and the calculation of molecular properties from them. © 2023 American Chemical Society.
BibTeX: @article{Ashani2023, author = {Ashani, Mahsa Nazemi and Huang, Qinan and Flowers, A. Mackenzie and Brown, Alex and Aerts, Antoine and Otero-De-la-Roza, Alberto and DiLabio, Gino A.}, title = {Accurate Potential Energy Surfaces Using Atom-Centered Potentials and Minimal High-Level Data}, journal = {Journal of Physical Chemistry A}, year = {2023}, volume = {127}, number = {38}, pages = {8015 – 8024}, note = {All Open Access, Green Open Access}, doi = {10.1021/acs.jpca.3c04558} }
Beaudor M, Vuichard N, Lathiere J, Evangeliou N, Van Damme M, Clarisse L and Hauglustaine D (2023), "Global agricultural ammonia emissions simulated with the ORCHIDEE land surface model", Geoscientific Model Development. Vol. 16(3), pp. 1053 – 1081. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) is an important atmospheric constituent. It plays a role in air quality and climate through the formation of ammonium sulfate and ammonium nitrate particles. It has also an impact on ecosystems through deposition processes. About 85g% of NH3 global anthropogenic emissions are related to food and feed production and, in particular, to the use of mineral fertilizers and manure management. Most global chemistry transport models (CTMs) rely on bottom-up emission inventories, which are subject to significant uncertainties. In this study, we estimate emissions from livestock by developing a new module to calculate ammonia emissions from the whole agricultural sector (from housing and storage to grazing and fertilizer application) within the ORCHIDEE (Organising Carbon and Hydrology In Dynamic Ecosystems) global land surface model. We detail the approach used for quantifying livestock feed management, manure application, and indoor and soil emissions and subsequently evaluate the model performance. Our results reflect China, India, Africa, Latin America, the USA, and Europe as the main contributors to global NH3 emissions, accounting for 80g% of the total budget. The global calculated emissions reach 44gTgNyr-1 over the 2005-2015 period, which is within the range estimated by previous work. Key parameters (e.g., the pH of the manure, timing of N application, and atmospheric NH3 surface concentration) that drive the soil emissions have also been tested in order to assess the sensitivity of our model. Manure pH is the parameter to which modeled emissions are the most sensitive, with a 10g% change in emissions per percent change in pH. Even though we found an underestimation in our emissions over Europe (-26g%) and an overestimation in the USA (+56g%) compared with previous work, other hot spot regions are consistent. The calculated emission seasonality is in very good agreement with satellite-based emissions. These encouraging results prove the potential of coupling ORCHIDEE land-based emissions to CTMs, which are currently forced by bottom-up anthropogenic-centered inventories such as the CEDS (Community Emissions Data System). © Copyright:
BibTeX: @article{Beaudor2023, author = {Beaudor, Maureen and Vuichard, Nicolas and Lathiere, Juliette and Evangeliou, Nikolaos and Van Damme, Martin and Clarisse, Lieven and Hauglustaine, Didier}, title = {Global agricultural ammonia emissions simulated with the ORCHIDEE land surface model}, journal = {Geoscientific Model Development}, year = {2023}, volume = {16}, number = {3}, pages = {1053 – 1081}, note = {All Open Access, Gold Open Access}, doi = {10.5194/gmd-16-1053-2023} }
Bernath P, Dodangodage R and Liévin J (2023), "S-type Stars: Line List for the A2Π-X2Σ+ Band System of LaO", Astrophysical Journal. Vol. 953(2) [Abstract] [BibTeX] [DOI]
Abstract: LaO bands are found in the spectra of cool S-type stars. The bands of the A2Π-X2Σ+ transition with v ′ ≤ 3 and v″ ≤ 4 are rotationally analyzed, providing spectroscopic constants for the A2Π state. Line strengths are calculated using an ab initio transition dipole moment function, and radiative lifetimes for the A2Π state have also been computed. A line list for the A2Π-X2Σ+ transition of LaO is provided and can be used to determine LaO stellar abundances. © 2023. The Author(s). Published by the American Astronomical Society.
BibTeX: @article{Bernath2023, author = {Bernath, P.F. and Dodangodage, R. and Liévin, J.}, title = {S-type Stars: Line List for the A2Π-X2Σ+ Band System of LaO}, journal = {Astrophysical Journal}, year = {2023}, volume = {953}, number = {2}, note = {All Open Access, Gold Open Access}, doi = {10.3847/1538-4357/ace68a} }
Blake JS, Fletcher L, Orton G, Antuñano A, Roman M, Kasaba Y, Fujiyoshi T, Melin H, Bardet D, Sinclair J and Es-Sayeh M (2023), "Saturn's seasonal variability from four decades of ground-based mid-infrared observations", Icarus. Vol. 392 [Abstract] [BibTeX] [DOI]
Abstract: A multi-decade record of ground-based mid-infrared (7–25μm) images of Saturn is used to explore seasonal and non-seasonal variability in thermal emission over more than a Saturnian year (1984–2022). Thermal emission measured by 3-m and 8-m-class observatories (notably NASA's Infrared Telescope Facility, Subaru, and ESO's Very Large Telescope) compares favourably with synthetic images based on both Cassini-derived temperature records and the predictions of radiative climate models. We find that 8-m class facilities are capable of resolving thermal contrasts on the scale of Saturn's belts, zones, polar hexagon, and polar cyclones, superimposed onto large-scale seasonal asymmetries. Seasonal changes in brightness temperatures of ∼30 K in the stratosphere and ∼10 K in the upper troposphere are observed, as the northern and southern polar stratospheric vortices (NPSV and SPSV) form in spring and dissipate in autumn. The timings of the first appearance of the warm polar vortices is successfully reproduced by radiative climate models, confirming them to be radiative phenomena, albeit entrained within sharp boundaries influenced by dynamics. Axisymmetric thermal bands (4–5 per hemisphere) display temperature gradients that are strongly correlated with Saturn's zonal winds, indicating winds that decay in strength with altitude from the cloud-tops to the ∼1-mbar level, and implying meridional circulation cells in Saturn's upper troposphere and stratosphere forming the system of cool zones and warm belts. Saturn's thermal structure is largely repeatable from year to year (via comparison of infrared images in 1989 and 2018), with the exception of low-latitudes. Here we find evidence of inter-annual variations because the equatorial banding at 7.9μm is inconsistent with a ∼15-year period for Saturn's equatorial stratospheric oscillation, i.e., it is not strictly semi-annual. Either the oscillation has a longer period closer to ∼20 years, or its progression is naturally variable and interrupted by tropospheric meteorology (e.g., storms). Finally, observations between 2017–2022 extend the legacy of the Cassini mission, revealing the continued warming of the NPSV during northern summer in line with predictions of radiative climate models. © 2022 The Authors
BibTeX: @article{Blake2023, author = {Blake, James S.D. and Fletcher, L.N. and Orton, G.S. and Antuñano, A. and Roman, M.T. and Kasaba, Y. and Fujiyoshi, T. and Melin, H. and Bardet, D. and Sinclair, J.A. and Es-Sayeh, M.}, title = {Saturn's seasonal variability from four decades of ground-based mid-infrared observations}, journal = {Icarus}, year = {2023}, volume = {392}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.icarus.2022.115347} }
Bouillon M, Safieddine S and Clerbaux C (2023), "Sudden Stratospheric Warmings in the Northern Hemisphere Observed With IASI", Journal of Geophysical Research: Atmospheres. Vol. 128(17) [Abstract] [BibTeX] [DOI]
Abstract: Sudden Stratospheric Warming events (SSW) are extreme phenomena during which stratospheric temperature can increase by tens of degrees in a few days. They are due to the propagation and breaking of the planetary waves, leading to a perturbation of the polar vortex. SSWs also influence polar ozone concentrations and midlatitude weather. The Infrared Atmospheric Sounding Interferometers (IASI) monitor atmospheric composition and temperature globally since 2007, and they are ideal to observe the changes of temperature and ozone during SSWs. Since the launch of the first IASI, there have been several SSWs in the Northern Hemisphere, including eight major events that are investigated in this study. We find that during major SSWs, the temperature anomaly propagates from 10 hPa to the lower stratosphere and the maximum anomaly at 200 hPa is correlated to the maximum anomaly at 10 hPa. During these events, negative anomalies of temperature in Europe and Russia and positive anomalies in Canada and Greenland are often observed at 750 hPa. The cold air outbreaks that usually follow major SSWs are responsible for anomalies of −15 K. Finally, we look at the evolution of the total ozone column following major events. Major SSWs lead to higher springtime ozone concentrations and the ozone anomaly in March is correlated to the duration of the positive temperature anomaly at 10 hPa. These results show the potential of the IASI mission and its successors, IASI-New Generation, for the study of SSWs and their effects on weather and atmospheric composition. © 2023 The Authors.
BibTeX: @article{Bouillon2023, author = {Bouillon, Marie and Safieddine, Sarah and Clerbaux, Cathy}, title = {Sudden Stratospheric Warmings in the Northern Hemisphere Observed With IASI}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2023}, volume = {128}, number = {17}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1029/2023JD038692} }
Carvajal Gallego H, Deprince J, Godefroid M, Goriely S, Palmeri P and Quinet P (2023), "On the importance of using realistic partition functions in kilonova opacity calculations", European Physical Journal D. Vol. 77(5) [Abstract] [BibTeX] [DOI]
Abstract: Abstract: In the present work, we report an investigation on the importance of using realistic partition functions in the opacity calculations of lanthanide ions whether they are moderately or lowly ionized. In order to do this, atomic data for various moderately charged samarium (Sm V–XI) and lowly charged neodymium (Nd II–IV) ions were calculated by the pseudo-relativistic Hartree–Fock method (HFR) and then, used to compute the expansion opacities for conditions characterizing the ejecta of kilonovae observed as a result of neutron star mergers, with a particular attention given to the partition function computations. Graphical abstract: [Figure not available: see fulltext.] © 2023, The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature.
BibTeX: @article{CarvajalGallego2023, author = {Carvajal Gallego, Helena and Deprince, Jérôme and Godefroid, Michel and Goriely, Stéphane and Palmeri, Patrick and Quinet, Pascal}, title = {On the importance of using realistic partition functions in kilonova opacity calculations}, journal = {European Physical Journal D}, year = {2023}, volume = {77}, number = {5}, doi = {10.1140/epjd/s10053-023-00638-0} }
Ceamanos X, Coopman Q, George M, Riedi J, Parrington M and Clerbaux C (2023), "Remote sensing and model analysis of biomass burning smoke transported across the Atlantic during the 2020 Western US wildfire season", Scientific Reports. Vol. 13(1) [Abstract] [BibTeX] [DOI]
Abstract: Biomass burning is the main source of air pollution in several regions worldwide nowadays. This predominance is expected to increase in the upcoming years as a result of the rising number of devastating wildfires due to climate change. Harmful pollutants contained in the smoke emitted by fires can alter downwind air quality both locally and remotely as a consequence of the recurrent transport of biomass burning plumes across thousands of kilometers. Here, we demonstrate how observations of carbon monoxide and aerosol optical depth retrieved from polar orbiting and geostationary meteorological satellites can be used to study the long-range transport and evolution of smoke plumes. This is illustrated through the megafire events that occurred during summer 2020 in the Western United States and the transport of the emitted smoke across the Atlantic Ocean to Europe. Analyses from the Copernicus Atmosphere Monitoring Service, which combine satellite observations with an atmospheric model, are used for comparison across the region of study and along simulated air parcel trajectories. Lidar observation from spaceborne and ground-based instruments are used to verify consistency of passive observations. Results show the potential of joint satellite-model analysis to understand the emission, transport, and processing of smoke across the world. © 2023, Springer Nature Limited.
BibTeX: @article{Ceamanos2023, author = {Ceamanos, Xavier and Coopman, Quentin and George, Maya and Riedi, Jérôme and Parrington, Mark and Clerbaux, Cathy}, title = {Remote sensing and model analysis of biomass burning smoke transported across the Atlantic during the 2020 Western US wildfire season}, journal = {Scientific Reports}, year = {2023}, volume = {13}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.1038/s41598-023-39312-1} }
Clarisse L, Franco B, Van Damme M, Di Gioacchino T, Hadji-Lazaro J, Whitburn S, Noppen L, Hurtmans D, Clerbaux C and Coheur P (2023), "The IASI NH3 version 4 product: averaging kernels and improved consistency", Atmospheric Measurement Techniques. Vol. 16(21), pp. 5009 – 5028. [Abstract] [BibTeX] [DOI]
Abstract: Satellite measurements play an increasingly important role in the study of atmospheric ammonia (NH3). Here, we present version 4 of the Artificial Neural Network for IASI (ANNI; IASI: Infrared Atmospheric Sounding Interferometer) retrieval of NH3. The main change is the introduction of total column averaging kernels (AVKs), which can be used to undo the effect of the vertical profile shape assumption of the retrieval. While the main equations can be matched term for term with analogous ones used in UV/Vis retrievals for other minor absorbers, we derive the formalism from the ground up, as its applicability to thermal infrared measurements is non-trivial. A large number of other smaller changes were introduced in ANNI v4, most of which improve the consistency of the measurements across time and across the series of IASI instruments. This includes a more robust way of calculating the hyperspectral range index (HRI), explicitly accounting for long-term changes in CO2 in the HRI calculation and the use of a reprocessed cloud product that was specifically developed for climate applications. The NH3 distributions derived with ANNI v4 are very similar to the ones derived with v3, although values are about 10 %-20 % larger due to the improved setup of the HRI. We exclude further large biases of the same nature by showing the consistency between ANNI v4 derived NH3 columns with columns obtained with an optimal estimation approach. Finally, with v4, we revised the uncertainty budget and now report systematic uncertainty estimates alongside random uncertainties, allowing realistic mean uncertainties to be estimated. Copyright: © 2023 Lieven Clarisse et al.
BibTeX: @article{Clarisse2023, author = {Clarisse, Lieven and Franco, Bruno and Van Damme, Martin and Di Gioacchino, Tommaso and Hadji-Lazaro, Juliette and Whitburn, Simon and Noppen, Lara and Hurtmans, Daniel and Clerbaux, Cathy and Coheur, Pierre}, title = {The IASI NH3 version 4 product: averaging kernels and improved consistency}, journal = {Atmospheric Measurement Techniques}, year = {2023}, volume = {16}, number = {21}, pages = {5009 – 5028}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-16-5009-2023} }
Dang R, Jacob DJ, Zhai S, Coheur P, Clarisse L, Van Damme M, Pendergrass DC, Choi J-s, Park J-s, Liu Z and Liao H (2023), "Diagnosing the Sensitivity of Particulate Nitrate to Precursor Emissions Using Satellite Observations of Ammonia and Nitrogen Dioxide", Geophysical Research Letters. Vol. 50(24) [Abstract] [BibTeX] [DOI]
Abstract: Particulate nitrate is a major component of fine particulate matter (PM2.5). Its formation may be varyingly sensitive to emissions of ammonia (NH3), nitrogen oxides (NOx ≡ NO + NO2), and volatile organic compounds (VOCs), depending on local conditions. Diagnosing these sensitivities is critical for successful air quality management. Here, we show that satellite measurements of tropospheric NH3 and NO2 columns can be used as a quick indicator of the dominant sensitivity regime through the NH3/NO2 column ratio together with the NO2 column. We demonstrate the effectiveness of this indicator with the GEOS-Chem chemical transport model and define thresholds to separate the different sensitivity regimes. Applying the method to wintertime IASI and OMI observations in East Asia reveals that surface nitrate is dominantly VOC-sensitive in the southern North China Plain (NCP), NOx-sensitive in most of the East China Plain, and NH3-sensitive in the northern NCP, southern China, and Korea. © 2023. The Authors.
BibTeX: @article{Dang2023, author = {Dang, Ruijun and Jacob, Daniel J. and Zhai, Shixian and Coheur, Pierre and Clarisse, Lieven and Van Damme, Martin and Pendergrass, Drew C. and Choi, Jin-soo and Park, Jin-soo and Liu, Zirui and Liao, Hong}, title = {Diagnosing the Sensitivity of Particulate Nitrate to Precursor Emissions Using Satellite Observations of Ammonia and Nitrogen Dioxide}, journal = {Geophysical Research Letters}, year = {2023}, volume = {50}, number = {24}, note = {All Open Access, Gold Open Access}, doi = {10.1029/2023GL105761} }
De Longueville H, Clarisse L, Whitburn S, Clerbaux C, Lecomte G and Coheur P (2023), "Atmospheric trends of long-lived halogenated gases derived from 15 years of IASI measurements", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 311 [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric emissions of chlorofluorocarbons (CFCs), their hydrogenated derivatives (HCFCs, HFCs) and other long-lived halogen-containing substances perturb the chemical and radiative equilibrium of our atmosphere. A global network of ground-based stations (AGAGE) monitors the concentrations of most of these species. Supplementing these, upper tropospheric and stratospheric concentrations are available from satellite measurements of the ACE-FTS solar occultation sounder. Measurements derived from nadir viewing infrared sounders can potentially complement both observational datasets, offering extensive spatial coverage and temporal sampling. With a preferential sensitivity to the middle troposphere, they also cover the vertical altitude range that is not covered by other means. However, fluctuations in surface temperature and the concentration of interfering atmospheric constituents render the retrieval of halogenated species particularly challenging. Relying on previous work on spectral whitening, we present an unconstrained generalized least squares estimation retrieval methodology, which largely allows to overcome the problem of interference. We demonstrate that it can be used to retrieve monthly anomalies of all halogenated species previously observed in spectra from the Infrared Atmospheric Sounding Interferometer (IASI/Metop). Focussing on northern mid-latitudes, we derive the monthly concentrations of CFC-11, CFC-12, HCFC-22, HCFC-142b, HFC-134a, CF4, SF6 and CCl4 between 2008 and 2022. Trends are compared to the observations from AGAGE and ACE-FTS. A good match is obtained with both, with especially remarkable agreement in the linear trends for CF4, SF6 and HFC-134a, and in the non-linear trends of CFC-11 and HCFC-22. Large discrepancies and unexplained variations are seen in the time series of HCFC-142b, CFC-12 and CCl4, necessitating further optimization of the retrieval technique. The results demonstrate the potential of IASI and follow-up missions for establishing a unique long-term time series of the most important long-lived halogenated species. © 2023 The Author(s)
BibTeX: @article{DeLongueville2023, author = {De Longueville, Hélène and Clarisse, Lieven and Whitburn, Simon and Clerbaux, Cathy and Lecomte, Gilles and Coheur, Pierre}, title = {Atmospheric trends of long-lived halogenated gases derived from 15 years of IASI measurements}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2023}, volume = {311}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.jqsrt.2023.108755} }
Deguine A, Clarisse L, Herbin H and Petitprez D (2023), "Measuring Volcanic Ash with High-Spectral Resolution Infrared Sounders: Role of Refractive Indices", IEEE Geoscience and Remote Sensing Letters. Vol. 20 [Abstract] [BibTeX] [DOI]
Abstract: Airborne volcanic ash can be observed and quantified from hyperspectral infrared (IR) sounders. The retrieval process of physical quantities, such as particle radius and mass, depends critically on the assumed spectrally dependent complex refractive indices (CRIs) that are used. Traditionally, the Pollack et al. (1973) dataset was used almost exclusively. These indices are, however, based on measurements of rock slabs, and in recent years, two datasets have become available from laboratory measurements of ash in suspension, the Reed et al. (2018) and Deguine et al. (2020) datasets. Here, we compare the three datasets and quantify the extent to which each of them can be used to simulate satellite observed spectra of real volcanic ash plumes. We find that whereas the Pollack et al. indices perform worst throughout, the performance of the other two is comparable for andesitic and basaltic ash plumes. However, all three datasets have difficulty in reproducing the extinction minimum around 1250 cm-1. The Reed et al. indices in addition yield inconsistent results in the 800-850 cm-1 range. The Deguine et al. dataset is the only one, which can be used to reproduce the very large spectral signatures often observed with rhyolitic ash across the entire thermal IR window 750-1250 cm-1. In terms of retrieved quantities, the largest differences are seen for the radius, with the Deguine et al. dataset resulting in the smallest retrieved particle sizes. © 2004-2012 IEEE.
BibTeX: @article{Deguine2023, author = {Deguine, Alexandre and Clarisse, Lieven and Herbin, Herve and Petitprez, Denis}, title = {Measuring Volcanic Ash with High-Spectral Resolution Infrared Sounders: Role of Refractive Indices}, journal = {IEEE Geoscience and Remote Sensing Letters}, year = {2023}, volume = {20}, note = {All Open Access, Green Open Access}, doi = {10.1109/LGRS.2023.3261202} }
Deguine A, Petitprez D, Clarisse L, Deschutter L, Fontijn K and Herbin H (2023), "Retrieval of refractive indices of ten volcanic ash samples in the infrared, visible and ultraviolet spectral region", Journal of Aerosol Science. Vol. 167 [Abstract] [BibTeX] [DOI]
Abstract: Volcanic eruptions can emit large amounts of ash into the atmosphere, which can have significant impacts on infrastructure, human health, agriculture and air traffic. Remote sensing instruments can efficiently detect airborne ash plumes, and the measured spectra can be exploited to obtain information on the physical characteristics of ash (grain size distribution, concentration, optical depth). The key parameter on which all such satellite retrievals depend is the complex refractive index (CRI) which remains one of the largest sources of uncertainty in the retrieval process. Here we present a complementary dataset of refractive indices of volcanic ash to that published by Deguine et al. (2020), to cover a part of the major explosive eruptions occurred during the past 50 years. These CRIs were obtained using an innovative experimental methodology which consists in measuring simultaneously the extinction spectra in the IR and UV/visible domain and the size distribution of ash in suspension in a nitrogen flow. These experimental data are the main input to the retrieval process of CRI. The numerical routine uses Mie theory coupled with Kramers–Kronig relationship to retrieve the imaginary and the real part of the complex refractive index. This methodology has been successfully applied on samples collected from various eruptions and deposits in Indonesia (Kelud), Chile (Chaitén), Italy (Stromboli), Russia (Karymsky), Tanzania (Rungwe, Mount Meru), Ethiopia (Corbetti), Philippines (Taal, Pinatubo) and USA (Mount St. Helens). Significant variations of the real and imaginary part of the CRI are observed according to the chemical composition of the samples. Moreover, the sensitivity of the CRI to chemical composition and mineralogical structure (amorphous/crystalline fraction) has been investigated and shows a strong dependence of the CRI on these parameters. © 2022 Elsevier Ltd
BibTeX: @article{Deguine2023a, author = {Deguine, Alexandre and Petitprez, Denis and Clarisse, Lieven and Deschutter, Lise and Fontijn, Karen and Herbin, Hervé}, title = {Retrieval of refractive indices of ten volcanic ash samples in the infrared, visible and ultraviolet spectral region}, journal = {Journal of Aerosol Science}, year = {2023}, volume = {167}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jaerosci.2022.106100} }
Demaison J, Liévin J and Vogt N (2023), "Accurate equilibrium structures of some challenging molecules: FNO, ClNO, HONO, FNO2, and N2O", Journal of Molecular Spectroscopy. Vol. 394 [Abstract] [BibTeX] [DOI]
Abstract: It is sometimes difficult to determine the structure of some molecules because the optimization using standard ab initio methods (coupled-cluster with single, double, and perturbative triples [CCSD(T)] level) does not give the correct result and the experimental and semiexperimental methods are not accurate because the system of normal equations of the least-squares method is ill-conditioned. In such a case, it may be still possible to derive an accurate equilibrium structure in the following way: the experimental rotational constants are compared to those obtained at the CCSD(T) level, the latter being corrected to take into account the rovibrational correction (and, if necessary, the electronic correction). Extrapolating (or interpolating) the rotational constants calculated with different basis sets (e.g. cc-pwCVTZ and cc-pwCVQZ) towards the experimental values as a function of the bond lengths and angles permits to obtain an accurate equilibrium structure. This method is first tested on two molecules for which the multireference effects are important: O3 and HOON. It is then, applied to molecules with a weak N–X bond (HONO, FNO, ClNO, FNO2, and N2O) for which the single reference CCSD(T) method gives bonds that are too short. The results are compared to the experimental and semiexperimental equilibrium structures. As a further check, the structure of ClNO is calculated at the CCSDTQ level and the structures of FNO and ClNO are calculated at the MRCI-F12 level. From a comparison of the different results, it appears that the accuracy of the proposed method is better than 0.002 Å for the bond lengths and 0.3° for the angles. © 2023 Elsevier Inc.
BibTeX: @article{Demaison2023, author = {Demaison, Jean and Liévin, Jacques and Vogt, Natalja}, title = {Accurate equilibrium structures of some challenging molecules: FNO, ClNO, HONO, FNO2, and N2O}, journal = {Journal of Molecular Spectroscopy}, year = {2023}, volume = {394}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jms.2023.111788} }
Deprince J, Carvajal Gallego H, Godefroid M, Goriely S, Palmeri P and Quinet P (2023), "On the sensitivity of uranium opacity with respect to the atomic properties in the context of kilonova emission modeling", European Physical Journal D. Vol. 77(6) [Abstract] [BibTeX] [DOI]
Abstract: Abstract: In this study, the sensitivity of the opacities with respect to the atomic parameters is investigated in the case of weakly charged uranium ions. In order to do this, atomic data for U II and U III were calculated with the pseudo-relativistic Hartree–Fock method (HFR) and then, used to determine the expansion opacities for conditions characterizing the ejecta of kilonovae that follow neutron star mergers. In particular, we studied the sensitivity of the opacity with respect to the use of atomic data obtained considering several effects as the ionic core polarization and an adjustment procedure. Graphical abstract: [Figure not available: see fulltext.]. © 2023, The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature.
BibTeX: @article{Deprince2023, author = {Deprince, Jérôme and Carvajal Gallego, Helena and Godefroid, Michel and Goriely, Stéphane and Palmeri, Patrick and Quinet, Pascal}, title = {On the sensitivity of uranium opacity with respect to the atomic properties in the context of kilonova emission modeling}, journal = {European Physical Journal D}, year = {2023}, volume = {77}, number = {6}, doi = {10.1140/epjd/s10053-023-00671-z} }
Es-Sayeh M, Rodriguez S, Coutelier M, Rannou P, Bézard B, Maltagliati L, Cornet T, Grieger B, Karkoschka E, Le Mouélic S, Le Gall A, Neish C, MacKenzie S, Solomonidou A, Sotin C and Coustenis A (2023), "Updated Radiative Transfer Model for Titan in the Near-infrared Wavelength Range: Validation against Huygens Atmospheric and Surface Measurements and Application to the Cassini/VIMS Observations of the Dragonfly Landing Area", Planetary Science Journal. Vol. 4(3) [Abstract] [BibTeX] [DOI]
Abstract: We present an analysis of Titan data acquired by the Cassini Visual and Infrared Mapping Spectrometer (VIMS) at the landing site of the Dragonfly mission, using a new version of our radiative transfer model for Titan, with significant updates for the spectroscopic parameters of atmospheric gases and photochemical aerosols. Our updated radiative transfer model is validated against the in situ spectroscopic measurements of the Huygens probe during its descent and once landed. We confirm that aerosols with a fractal dimension of 2.3-2.4 provide the best fit to the observations. We apply our radiative transfer model to four VIMS data cubes over the Selk crater region including the Dragonfly landing and exploration areas, further validating our model by producing consistent aerosol population and surface albedo maps. These infrared albedo maps, further corrected from the photometry, enable us to study the Selk crater region in terms of surface composition, landscape formation, and evolution. Our results suggest that the Selk crater is in an intermediate state of degradation and that the mountainous terrains of the area (including the crater rim and ejecta) are likely to be dominated by fine grains of tholin-like sediment. This organic sediment would be transported to the lowlands (crater floor and surrounding plains), possibly with water ice particles, by rivers, and further deposited and processed to form the sand particles that feed the neighboring dune fields. These results provide information for the operational and scientific preparation of the Dragonfly mission, paving the way for future exploration of Titan’s surface composition and geology. © 2023. The Author(s). Published by the American Astronomical Society.
BibTeX: @article{EsSayeh2023, author = {Es-Sayeh, M. and Rodriguez, S. and Coutelier, M. and Rannou, P. and Bézard, B. and Maltagliati, L. and Cornet, T. and Grieger, B. and Karkoschka, E. and Le Mouélic, S. and Le Gall, A. and Neish, C. and MacKenzie, S. and Solomonidou, A. and Sotin, C. and Coustenis, A.}, title = {Updated Radiative Transfer Model for Titan in the Near-infrared Wavelength Range: Validation against Huygens Atmospheric and Surface Measurements and Application to the Cassini/VIMS Observations of the Dragonfly Landing Area}, journal = {Planetary Science Journal}, year = {2023}, volume = {4}, number = {3}, note = {All Open Access, Gold Open Access}, doi = {10.3847/PSJ/acbd37} }
Flörs A, Silva R, Deprince J, Carvajal Gallego H, Leck G, Shingles L, Martínez-Pinedo G, Sampaio J, Amaro P, Marques J, Goriely S, Quinet P, Palmeri P and Godefroid M (2023), "Opacities of singly and doubly ionized neodymium and uranium for kilonova emission modeling", Monthly Notices of the Royal Astronomical Society. Vol. 524(2), pp. 3083 – 3101. [Abstract] [BibTeX] [DOI]
Abstract: Even though the electromagnetic counterpart AT2017gfo to the binary neutron star merger GW170817 is powered by the radioactive decay of r-process nuclei, only few tentative identifications of light r-process elements have been made so far. One of the major limitations for the identification of heavy nuclei is incomplete or missing atomic data. While substantial progress has been made on lanthanide atomic data over the last few years, for actinides there has been less emphasis, with the first complete set of opacity data only recently published. We perform atomic structure calculations of neodymium (Z = 60) as well as the corresponding actinide uranium (Z = 92). Using two different codes [ FLEXIBLE ATOMIC CODE (FAC) and HARTREE-FOCK- RELATIVISTIC (HFR)] for the calculation of the atomic data, we investigate the accuracy of the calculated data (energy levels and electric dipole transitions) and their effect on kilonova opacities. For the FAC calculations, we optimize the local central potential and the number of included configurations and use a dedicated calibration technique to improve the agreement between theoretical and available experimental atomic energy levels (AELs). For ions with vast amounts of experimental data available, the presented opacities agree quite well with previous estimations. On the other hand, the optimization and calibration method cannot be used for ions with only few available AELs. For these cases, where no experimental nor benchmarked calculations are available, a large spread in the opacities estimated from the atomic data obtained with the various atomic structure codes is observed. We find that the opacity of uranium is almost double the neodymium opacity. © 2023 The Author(s).
BibTeX: @article{Floers2023, author = {Flörs, A. and Silva, R.F. and Deprince, J. and Carvajal Gallego, H. and Leck, G. and Shingles, L.J. and Martínez-Pinedo, G. and Sampaio, J.M. and Amaro, P. and Marques, J.P. and Goriely, S. and Quinet, P. and Palmeri, P. and Godefroid, M.}, title = {Opacities of singly and doubly ionized neodymium and uranium for kilonova emission modeling}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {2023}, volume = {524}, number = {2}, pages = {3083 – 3101}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1093/mnras/stad2053} }
Froese Fischer C and Godefroid M (2023), "Atomic Structure: Variational Wave Functions and Properties", Springer Handbooks. , pp. 309 – 330. [Abstract] [BibTeX] [DOI]
Abstract: This chapter describes variational methods for the determination of wave functions either in nonrelativistic (LS), quasi relativistic Breit–Pauli (LSJ), or Dirac (jj) theory. The emphasis is on Hartree–Fock and multiconfiguration Hartree–Fock theory with reference to similar Dirac theory. Although the underlying mathematics of the latter is technically different because of the properties of Dirac spinors, we draw parallels between the nonrelativistic and relativistic formulations that lay the foundation of, respectively, the Atomic Structure Package (ATSP) 1 ; 2 and the General Relativistic Atomic Structure Package (GRASP) 3 ; 4. Some results from the application of these multiconfiguration methods are presented for a number of atomic properties. Although framed entirely in terms of nonrelativistic calculations, the present chapter reveals a pattern that can be, and actually is, explored in the review article of variational theory 5 as in the following Chap. 23 on Relativistic Atomic Structure. © 2023, Springer Nature Switzerland AG.
BibTeX: @article{FroeseFischer2023, author = {Froese Fischer, Charlotte and Godefroid, Michel}, title = {Atomic Structure: Variational Wave Functions and Properties}, journal = {Springer Handbooks}, year = {2023}, pages = {309 – 330}, doi = {10.1007/978-3-030-73893-8_22} }
Gans B, Liévin J, Halvick P, Chen N, Boyé-Péronne S, Hartweg S, Garcia G and Loison J-C (2023), "Single-photon ionization of SiC in the gas phase: experimental and ab initio characterization of SiC+", Physical Chemistry Chemical Physics. Vol. 25(35), pp. 23568 – 23578. [Abstract] [BibTeX] [DOI]
Abstract: We report the first experimental observation of single-photon ionization transitions of the SiC radical between 8.0 and 11.0 eV performed on the DESIRS beamline at the SOLEIL synchrotron facility. The SiC radical, very difficult to synthesize in the gas phase, was produced through chemical reactions between CHx (x = 0-3) and SiHy (y = 0-3) in a continuous microwave discharge flow tube, the CHx and SiHy species being formed by successive hydrogen-atom abstractions induced by fluorine atoms on methane and silane, respectively. Mass-selected ion yield and photoelectron spectra were recorded as a function of photon energy using a double imaging photoelectron/photoion coincidence spectrometer. The photoelectron spectrum enables the first direct experimental determinations of the X+ 4Σ− ← X 3Π and 1+ 2Π ← X 3Π adiabatic ionization energies of SiC (8.978(10) eV and 10.216(24) eV, respectively). Calculated spectra based on Franck-Condon factors are compared with the experimental spectra. These spectra were obtained by solving the rovibrational Hamiltonian, using the potential energy curves calculated at the multireference single and double configuration interaction level with Davidson correction (MRCI + Q) and the aug-cc-pV5Z basis set. MRCI + Q calculations including the core and core-valence electron correlation were performed using the aug-cc-pCV6Z basis set to predict the spectroscopic properties of the six lowest electronic states of SiC+. Complete basis set extrapolations and relativistic energy corrections were also included in the determination of the energy differences characterizing the photoionization process. Using our experimental and theoretical results, we derived semi-experimental values for the five lowest ionization energies of SiC. © 2023 The Royal Society of Chemistry.
BibTeX: @article{Gans2023, author = {Gans, B. and Liévin, J. and Halvick, P. and Chen, N.L. and Boyé-Péronne, S. and Hartweg, S. and Garcia, G.A. and Loison, J.-C.}, title = {Single-photon ionization of SiC in the gas phase: experimental and ab initio characterization of SiC+}, journal = {Physical Chemistry Chemical Physics}, year = {2023}, volume = {25}, number = {35}, pages = {23568 – 23578}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1039/d3cp02775a} }
Glorieux R, Hays B, Bogomolov A, Herman M, Vanfleteren T, Moazzen-Ahmadi N and Lauzin C (2023), "Understanding the high-resolution spectral signature of the N2-H2O van der Waals complex in the 2OH stretch region", Journal of Chemical Physics. Vol. 158(22) [Abstract] [BibTeX] [DOI]
Abstract: We present the observation of the N2-H2O van der Waals complex in the 2OH stretch overtone region. The high-resolution jet cooled spectra were measured using a sensitive continuous wave cavity ringdown spectrometer. Several bands were observed and vibrationally assigned in terms of ν1, ν2, and ν3, the vibrational quantum numbers of the isolated H2O molecule, as ( ν 1 ′ ν 2 ′ ν 3 ′ ) ← ( ν 1 ″ ν 2 ″ ν 3 ″ ) = ( 200 ) ← ( 000 ) and (101) ← (000). A combination band involving the excitation of the in-plane bending motion of N2 and the (101) vibration of water is also reported. The spectra were analyzed using a set of four asymmetric top rotors, each associated with a nuclear spin isomer. Several local perturbations of the (101) vibrational state were observed. These perturbations were assigned to the presence of the nearby (200) vibrational state and to the combination of (200) with intermolecular modes. © 2023 Author(s).
BibTeX: @article{Glorieux2023, author = {Glorieux, R. and Hays, B.M. and Bogomolov, A.S. and Herman, M. and Vanfleteren, T. and Moazzen-Ahmadi, N. and Lauzin, C.}, title = {Understanding the high-resolution spectral signature of the N2-H2O van der Waals complex in the 2OH stretch region}, journal = {Journal of Chemical Physics}, year = {2023}, volume = {158}, number = {22}, doi = {10.1063/5.0150823} }
Honet A, Henrard L and Meunier V (2023), "Correlation effects on topological end-states in finite-size graphene nanoribbons in the GW approximation", Journal of Physics Condensed Matter. Vol. 35(48) [Abstract] [BibTeX] [DOI]
Abstract: Finite size armchair graphene nanoribbons (GNRs) of different families are theoretically studied using the Hubbard model in both mean-field and GW approximations, including spin correlation effects. It is shown that correlation primarily affect the properties of topological end states of the nanoribbons. A representative structure of each of the three GNR families is considered but the seven-atom width nanoribbon is studied in detail and compared to previously published experimental results, showing a clear improvement when correlations are included. Using isolated spin contributions to scanning tunneling microscopy (STM) simulations, spin-polarized measurements in STM are also suggested to help distinguish and highlight correlation effects. © 2023 The Author(s). Published by IOP Publishing Ltd.
BibTeX: @article{Honet2023a, author = {Honet, Antoine and Henrard, Luc and Meunier, Vincent}, title = {Correlation effects on topological end-states in finite-size graphene nanoribbons in the GW approximation}, journal = {Journal of Physics Condensed Matter}, year = {2023}, volume = {35}, number = {48}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1088/1361-648X/acf35f} }
Honet A, Henrard L and Meunier V (2023), "Mean-field approximation of the Fermi-Hubbard model expressed in a many-body basis", AIP Advances. Vol. 13(7) [Abstract] [BibTeX] [DOI]
Abstract: The effective independent-particle (mean-field) approximation of the Fermi-Hubbard Hamiltonian is described in a many-body basis to develop a formal comparison with the exact diagonalization of the full Fermi-Hubbard model using small atomic chain as test systems. This allows for the development of an intuitive understanding of the shortcomings of the mean-field approximation and how critical correlation effects are missed in this popular approach. The description in the many-body basis highlights a potential ambiguity related to the definition of the density of states. Specifically, satellite peaks are shown to emerge in the mean-field approximation, in departure from the common belief that they characterize correlation effects. The scheme emphasizes the importance of correlation and how different many-body corrections can improve the mean-field description. The pedagogical treatment is expected to make it possible for researchers to acquire an improved understanding of many-body effects as found in various areas related to the electronic properties of molecules and solids. © 2023 Author(s).
BibTeX: @article{Honet2023, author = {Honet, Antoine and Henrard, Luc and Meunier, Vincent}, title = {Mean-field approximation of the Fermi-Hubbard model expressed in a many-body basis}, journal = {AIP Advances}, year = {2023}, volume = {13}, number = {7}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.1063/5.0153076} }
Jönsson P, Gaigalas G, Fischer CF, Bieroń J, Grant IP, Brage T, Ekman J, Godefroid M, Grumer J, Li J and Li W (2023), "GRASP Manual for Users", Atoms. Vol. 11(4) [Abstract] [BibTeX] [DOI]
Abstract: grasp is a software package in Fortran 95, adapted to run in parallel under MPI, for research in atomic physics. The basic premise is that, given a wave function, any observed atomic property can be computed. Thus, the first step is always to determine a wave function. Different properties challenge the accuracy of the wave function in different ways. This software is distributed under the MIT Licence. © 2023 by the authors.
BibTeX: @article{Joensson2023, author = {Jönsson, Per and Gaigalas, Gediminas and Fischer, Charlotte Froese and Bieroń, Jacek and Grant, Ian P. and Brage, Tomas and Ekman, Jörgen and Godefroid, Michel and Grumer, Jon and Li, Jiguang and Li, Wenxian}, title = {GRASP Manual for Users}, journal = {Atoms}, year = {2023}, volume = {11}, number = {4}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atoms11040068} }
Jönsson P, Godefroid M, Gaigalas G, Ekman J, Grumer J, Li W, Li J, Brage T, Grant IP, Bieroń J and Fischer CF (2023), "An Introduction to Relativistic Theory as Implemented in GRASP", Atoms. Vol. 11(1) [Abstract] [BibTeX] [DOI]
Abstract: Computational atomic physics continues to play a crucial role in both increasing the understanding of fundamental physics (e.g., quantum electrodynamics and correlation) and producing atomic data for interpreting observations from large-scale research facilities ranging from fusion reactors to high-power laser systems, space-based telescopes and isotope separators. A number of different computational methods, each with their own strengths and weaknesses, is available to meet these tasks. Here, we review the relativistic multiconfiguration method as it applies to the General Relativistic Atomic Structure Package [grasp2018, C. Froese Fischer, G. Gaigalas, P. Jönsson, J. Bieroń, Comput. Phys. Commun. (2018). DOI: 10.1016/j.cpc.2018.10.032]. To illustrate the capacity of the package, examples of calculations of relevance for nuclear physics and astrophysics are presented. © 2022 by the authors.
BibTeX: @article{Joensson2023a, author = {Jönsson, Per and Godefroid, Michel and Gaigalas, Gediminas and Ekman, Jörgen and Grumer, Jon and Li, Wenxian and Li , Jiguang and Brage, Tomas and Grant, Ian P. and Bieroń, Jacek and Fischer, Charlotte Froese}, title = {An Introduction to Relativistic Theory as Implemented in GRASP}, journal = {Atoms}, year = {2023}, volume = {11}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atoms11010007} }
Lam L, George M, Gardoll S, Safieddine S, Whitburn S and Clerbaux C (2023), "Tropical Cyclone Detection from the Thermal Infrared Sensor IASI Data Using the Deep Learning Model YOLOv3", Atmosphere. Vol. 14(2) [Abstract] [BibTeX] [DOI]
Abstract: Tropical cyclone (TC) detection is essential to mitigate natural disasters, as TCs can cause significant damage to life, infrastructure and economy. In this study, we applied the deep learning object detection model YOLOv3 to detect TCs in the North Atlantic Basin, using data from the Thermal InfraRed (TIR) Atmospheric Sounding Interferometer (IASI) onboard the Metop satellites. IASI measures the outgoing TIR radiation of the Earth-Atmosphere. For the first time, we provide a proof of concept of the possibility of constructing images required by YOLOv3 from a TIR remote sensor that is not an imager. We constructed a dataset by selecting 50 IASI radiance channels and using them to create images, which we labeled by constructing bounding boxes around TCs using the hurricane database HURDAT2. We trained the YOLOv3 on two settings, first with three “best” selected channels, then using an autoencoder to exploit all 50 channels. We assessed its performance with the Average Precision (AP) metric at two different intersection over union (IoU) thresholds (0.1 and 0.5). The model achieved promising results with AP at IoU threshold 0.1 of 78.31%. Lower performance was achieved with IoU threshold 0.5 (31.05%), showing the model lacks precision regarding the size and position of the predicted boxes. Despite that, we show YOLOv3 demonstrates great potential for TC detection using TIR instruments data. © 2023 by the authors.
BibTeX: @article{Lam2023, author = {Lam, Lisa and George, Maya and Gardoll, Sébastien and Safieddine, Sarah and Whitburn, Simon and Clerbaux, Cathy}, title = {Tropical Cyclone Detection from the Thermal Infrared Sensor IASI Data Using the Deep Learning Model YOLOv3}, journal = {Atmosphere}, year = {2023}, volume = {14}, number = {2}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.3390/atmos14020215} }
Li Y, Jönsson P, Godefroid M, Gaigalas G, Bieroń J, Marques JP, Indelicato P and Chen C (2023), "Independently Optimized Orbital Sets in GRASP—The Case of Hyperfine Structure in Li I", Atoms. Vol. 11(1) [Abstract] [BibTeX] [DOI]
Abstract: In multiconfiguration Dirac–Hartree–Fock (MCDHF) calculations, there is a strong coupling between the localization of the orbital set and the configuration state function (CSF) expansion used to determine it. Furthermore, it is well known that an orbital set resulting from calculations, including CSFs describing core–core correlation and other effects, which aims to lower the weighted energies of a number of targeted states as much as possible, may be inadequate for building CSFs that account for correlation effects that are energetically unimportant but decisive for computed properties, e.g., hyperfine structures or transition rates. This inadequacy can be traced in irregular or oscillating convergence patterns of the computed properties as functions of the increasing orbital set. In order to alleviate the above problems, we propose a procedure in which the orbital set is obtained by merging several separately optimized, and mutually non-orthogonal, orbital sets. This computational strategy preserves the advantages of capturing electron correlation on the total energy through the variational MCDHF method and allows to target efficiently the correlation effects on the considered property. The orbital sets that are merged are successively orthogonalized against each other to retain orthonormality. The merged orbital set is used to build CSFs that efficiently lower the energy and also adequately account for the correlation effects that are important for the property. We apply the procedure to compute the hyperfine structure constants for the (Formula presented.) and (Formula presented.) states in (Formula presented.) Li and show that it leads to considerably improved convergence patterns with respect to the increasing orbital set compared to standard calculations based on a single orbital set, energy-optimized in the variational procedure. The perspectives of the new procedure are discussed in a broader context in the summary. © 2022 by the authors.
BibTeX: @article{Li2023a, author = {Li, Yanting and Jönsson, Per and Godefroid, Michel and Gaigalas, Gediminas and Bieroń, Jacek and Marques, José Pires and Indelicato, Paul and Chen, Chongyang}, title = {Independently Optimized Orbital Sets in GRASP—The Case of Hyperfine Structure in Li I}, journal = {Atoms}, year = {2023}, volume = {11}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atoms11010004} }
Li Y, Li J, Song C, Zhang C, Si R, Wang K, Godefroid M, Gaigalas G, Jönsson P and Chen C (2023), "Performance Tests and Improvements on the rmcdhf and rci Programs of GRASP", Atoms. Vol. 11(1) [Abstract] [BibTeX] [DOI]
Abstract: The latest published version of GRASP (General-purpose Relativistic Atomic Structure Package), i.e., GRASP2018, retains a few suboptimal subroutines/algorithms, which reflect the limited memory and file storage of computers available in the 1980s. Here we show how the efficiency of the relativistic self-consistent-field (SCF) procedure of the multiconfiguration-Dirac–Hartree–Fock (MCDHF) method and the relativistic configuration-interaction (RCI) calculations can be improved significantly. Compared with the original GRASP codes, the present modified version reduces the CPU times by factors of a few tens or more. The MPI performances for all the original and modified codes are carefully analyzed. Except for diagonalization, all computational processes show good MPI scaling. © 2023 by the authors.
BibTeX: @article{Li2023, author = {Li, Yanting and Li, Jinqing and Song, Changxian and Zhang, Chunyu and Si, Ran and Wang, Kai and Godefroid, Michel and Gaigalas, Gediminas and Jönsson, Per and Chen, Chongyang}, title = {Performance Tests and Improvements on the rmcdhf and rci Programs of GRASP}, journal = {Atoms}, year = {2023}, volume = {11}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atoms11010012} }
Li YT, Wang K, Si R, Godefroid M, Gaigalas G, Chen CY and Jönsson P (2023), "Reducing the computational load – atomic multiconfiguration calculations based on configuration state function generators", Computer Physics Communications. Vol. 283 [Abstract] [BibTeX] [DOI]
Abstract: In configuration interaction (CI) calculations the atomic wave functions are given as expansions over configuration state functions (CSFs) built on relativistic one-electron orbitals. The expansion coefficients of the configuration state functions are obtained by constructing and diagonalizing the Hamiltonian matrix. Here we show how a regrouping of the configuration state functions and the introduction of configuration state function generators (CSFGs) allow for a substantial reduction of the computational load in relativistic CI calculations. The computational methodology based on configuration state function generators, recently implemented in the General Relativistic Atomic Structure package (GRASP2018, Froese Fischer et al. (2019) [16]), is applied to a number of atomic systems and correlation models with increasing sets of one-electron orbitals. We demonstrate a reduction of the CPU time with factors between 10 and 14 for the largest CI calculations. The inclusion of the Breit interaction into the calculations is time consuming. By applying restrictions on the Breit integrals we show that it is possible to further reduce the CPU times with factors between 2 and 3, with negligible changes to the computed excitation energies. We also demonstrate that the introduction of configuration state function generators allows for efficient a priori condensation techniques, with reductions of the expansions sizes with factors between 1.5 and 2.5 and the CPU time with factors between 2.5 and 4.5, again with negligible changes to the excitation energies. In total we demonstrate reductions of the CPU time with factors up to 68 for CI calculations based on configuration state function generators, restrictions on the Breit integrals and with a priori condensed expansions compared to ordinary CI calculations without restrictions on the Breit integrals and with full expansions. Further perspectives of the new methodology based on configuration state function generators are given. © 2022
BibTeX: @article{Li2023b, author = {Li, Yan Ting and Wang, Kai and Si, Ran and Godefroid, Michel and Gaigalas, Gediminas and Chen, Chong Yang and Jönsson, Per}, title = {Reducing the computational load – atomic multiconfiguration calculations based on configuration state function generators}, journal = {Computer Physics Communications}, year = {2023}, volume = {283}, doi = {10.1016/j.cpc.2022.108562} }
Meurisse M, Catteau L, van Loenhout JAF, Braeye T, De Mot L, Serrien B, Blot K, Cauët E, Van Oyen H, Cuypers L, Robert A and Van Goethem N (2023), "Homologous and Heterologous Prime-Boost Vaccination: Impact on Clinical Severity of SARS-CoV-2 Omicron Infection among Hospitalized COVID-19 Patients in Belgium", Vaccines. Vol. 11(2) [Abstract] [BibTeX] [DOI]
Abstract: We investigated effectiveness of (1) mRNA booster vaccination versus primary vaccination only and (2) heterologous (viral vector–mRNA) versus homologous (mRNA–mRNA) prime-boost vaccination against severe outcomes of BA.1, BA.2, BA.4 or BA.5 Omicron infection (confirmed by whole genome sequencing) among hospitalized COVID-19 patients using observational data from national COVID-19 registries. In addition, it was investigated whether the difference between the heterologous and homologous prime-boost vaccination was homogenous across Omicron sub-lineages. Regression standardization (parametric g-formula) was used to estimate counterfactual risks for severe COVID-19 (combination of severity indicators), intensive care unit (ICU) admission, and in-hospital mortality under exposure to different vaccination schedules. The estimated risk for severe COVID-19 and in-hospital mortality was significantly lower with an mRNA booster vaccination as compared to only a primary vaccination schedule (RR = 0.59 [0.33; 0.85] and RR = 0.47 [0.15; 0.79], respectively). No significance difference was observed in the estimated risk for severe COVID-19, ICU admission and in-hospital mortality with a heterologous compared to a homologous prime-boost vaccination schedule, and this difference was not significantly modified by the Omicron sub-lineage. Our results support evidence that mRNA booster vaccination reduced the risk of severe COVID-19 disease during the Omicron-predominant period. © 2023 by the authors.
BibTeX: @article{Meurisse2023, author = {Meurisse, Marjan and Catteau, Lucy and van Loenhout, Joris A. F. and Braeye, Toon and De Mot, Laurane and Serrien, Ben and Blot, Koen and Cauët, Emilie and Van Oyen, Herman and Cuypers, Lize and Robert, Annie and Van Goethem, Nina}, title = {Homologous and Heterologous Prime-Boost Vaccination: Impact on Clinical Severity of SARS-CoV-2 Omicron Infection among Hospitalized COVID-19 Patients in Belgium}, journal = {Vaccines}, year = {2023}, volume = {11}, number = {2}, note = {All Open Access, Gold Open Access}, doi = {10.3390/vaccines11020378} }
Noppen L, Clarisse L, Tack F, Ruhtz T, Merlaud A, Van Damme M, Van Roozendael M, Schuettemeyer D and Coheur P (2023), "Constraining industrial ammonia emissions using hyperspectral infrared imaging", Remote Sensing of Environment. Vol. 291 [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric emissions of reactive nitrogen in the form of nitrogen dioxide (NO2) and ammonia (NH3) worsen air quality and upon deposition, dramatically affect the environment. Recent infrared satellite measurements have revealed that NH3 emitted by industries are an important and underestimated emission source. Yet, to assess these emissions, current satellite sounders are severely limited by their spatial resolution. In this paper, we analyse measurement data recorded in a series of imaging surveys that were conducted over industries in the Greater Berlin area (Germany). On board the aircraft were the Telops Hyper-Cam LW, targeting NH3 measurements in the longwave infrared at a resolution of 4 m and the SWING+ spectrometer targeting NO2 measurements in the UV–Vis at a resolution of 180 m. Two flights were carried out over German's largest production facility of synthetic NH3, urea and other fertilizers. In both cases, a large NH3 plume was observed originating from the factory. Using a Gaussian plume model to take into account plume rise and dispersion, coupled with well-established radiative transfer and inverse methods, we retrieve vertical column densities. From these, we calculate NH3 emission fluxes using the integrated mass enhancement and cross-sectional flux methods, yielding consistent emissions of the order of 2200 t yr−1 for both flights, assuming constant fluxes across the year. These estimates are about five times larger than those reported in the European Pollutant Release and Transfer Register (E-PRTR) for this plant. In the second campaign, a co-emitted NO2 plume was measured, likely related to the production of nitric acid at the plant. A third flight was carried out over an area comprising the cities of Staßfurt and Bernburg. Several small NH3 plumes were seen, one over a production facility of mineral wool insulation, one over a sugar factory and two over the soda ash plants in Staßfurt and Bernburg. A fifth and much larger plume was seen to originate from the sedimentation basins associated with the soda ash plant in Staßfurt, indicating rapid volatilization of ammonium rich effluents. We use the different measurement campaigns to simulate measurements of Nitrosat, a potential future satellite sounder dedicated to the sounding of reactive nitrogen at a resolution of 500 m. We demonstrate that such measurements would allow accurately constraining emissions in a single overpass, overcoming a number of important drawbacks of current satellite sounders. © 2023
BibTeX: @article{Noppen2023, author = {Noppen, Lara and Clarisse, Lieven and Tack, Frederik and Ruhtz, Thomas and Merlaud, Alexis and Van Damme, Martin and Van Roozendael, Michel and Schuettemeyer, Dirk and Coheur, Pierre}, title = {Constraining industrial ammonia emissions using hyperspectral infrared imaging}, journal = {Remote Sensing of Environment}, year = {2023}, volume = {291}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.rse.2023.113559} }
Ossohou M, Hickman JE, Clarisse L, Coheur P-F, Van Damme M, Adon M, Yoboué V, Gardrat E, Alvès MD and Galy-Lacaux C (2023), "Trends and seasonal variability in ammonia across major biomes in western and central Africa inferred from long-Term series of ground-based and satellite measurements", Atmospheric Chemistry and Physics. Vol. 23(16), pp. 9473 – 9494. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) is the most abundant alkaline component in the atmosphere. Changes in NH3 concentrations have important implications for atmospheric chemistry, air quality, and ecosystem integrity. We present a long-Term ammonia (NH3) assessment in the western and central African regions within the framework of the International Network to study Deposition and Atmospheric chemistry in Africa (INDAAF) programme. We analyse seasonal variations and trends in NH3 concentrations and total column densities along an African ecosystem transect spanning dry savannas in Banizoumbou, Niger, and Katibougou, Mali; wet savannas in Djougou, Benin, and Lamto, Cote d'Ivoire; and forests in Bomassa, Republic of the Congo, and Zoétélé, Cameroon. We use a 21-year record of observations (1998-2018) from INDAAF passive samplers and an 11-year record of observations (2008-2018) of atmospheric vertical column densities from the Infrared Atmospheric Sounding Interferometer (IASI) to evaluate NH3 ground-based concentrations and total column densities, respectively. Climatic data (air temperature, rainfall amount, and leaf area index), as well as ammonia emission data of biomass combustion from the fourth version of the Global Fire Emissions Database (GFED4) and anthropogenic sources from the Community Emissions Data System (CEDS), were compared with total NH3 concentrations and total columns over the same periods. Annual mean ground-based NH3 concentrations are around 5.7-5.8g€¯ppb in dry savannas, 3.5-4.7g€¯ppb in wet savannas, and 3.4-5.6g€¯ppb in forests. Annual IASI NH3 total column densities are 10.0-10.7g 1015gcm-2 in dry savanna, 16.0-20.9g 1015gcm-2 in wet savanna, and 12.4-13.8g 1015gcm-2 in forest stations. Non-parametric statistical Mann-Kendall trend tests applied to annual data show that ground-based NH3 concentrations increase at Bomassa (+2.56g yr-1) but decrease at Zoétélé (-2.95g yr-1) over the 21-year period. The 11-year period of IASI NH3 total column density measurements show yearly increasing trends at Katibougou (+3.46g yr-1), Djougou (+2.24g yr-1), and Zoétélé (+3.42g yr-1). From the outcome of our investigation, we conclude that air temperature, leaf area index, and rainfall combined with biomass burning, agricultural, and residential activities are the key drivers of atmospheric NH3 in the INDAAF stations. The results also show that the drivers of trends are (1) agriculture in the dry savanna of Katibougou; (2) air temperature and agriculture in the wet savanna of Djougou and Lamto; and (3) leaf area index, air temperature, residential, and agriculture in the forest of Bomassa. © 2023 Money Ossohou et al.
BibTeX: @article{Ossohou2023, author = {Ossohou, Money and Hickman, Jonathan Edward and Clarisse, Lieven and Coheur, Pierre-François and Van Damme, Martin and Adon, Marcellin and Yoboué, Véronique and Gardrat, Eric and Alvès, Maria Dias and Galy-Lacaux, Corinne}, title = {Trends and seasonal variability in ammonia across major biomes in western and central Africa inferred from long-Term series of ground-based and satellite measurements}, journal = {Atmospheric Chemistry and Physics}, year = {2023}, volume = {23}, number = {16}, pages = {9473 – 9494}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-23-9473-2023} }
Plattner P, Wood E, Al Ayoubi L, Beliuskina O, Bissell M, Blaum K, Campbell P, Cheal B, De Groote R, Devlin C, Eronen T, Filippin L, Garcia Ruiz R, Ge Z, Geldhof S, Gins W, Godefroid M, Heylen H, Hukkanen M, Imgram P, Jaries A, Jokinen A, Kanellakopoulos A, Kankainen A, Kaufmann S, König K, Koszorús Á, Kujanpää S, Lechner S, Malbrunot-Ettenauer S, Müller P, Mathieson R, Moore I, Nörtershäuser W, Nesterenko D, Neugart R, Neyens G, Ortiz-Cortes A, Penttilä H, Pohjalainen I, Raggio A, Reponen M, Rinta-Antila S, Rodríguez L, Romero J, Sánchez R, Sommer F, Stryjczyk M, Virtanen V, Xie L, Xu Z, Yang X and Yordanov D (2023), "Nuclear Charge Radius of Al 26m and Its Implication for Vud in the Quark Mixing Matrix", Physical Review Letters. Vol. 131(22) [Abstract] [BibTeX] [DOI]
Abstract: Collinear laser spectroscopy was performed on the isomer of the aluminium isotope Al26m. The measured isotope shift to Al27 in the 3s23p P3/2○2→3s24s S1/22 atomic transition enabled the first experimental determination of the nuclear charge radius of Al26m, resulting in Rc=3.130(15) fm. This differs by 4.5 standard deviations from the extrapolated value used to calculate the isospin-symmetry breaking corrections in the superallowed β decay of Al26m. Its corrected Ft value, important for the estimation of Vud in the Cabibbo-Kobayashi-Maskawa matrix, is thus shifted by 1 standard deviation to 3071.4(1.0) s. © 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
BibTeX: @article{Plattner2023, author = {Plattner, P. and Wood, E. and Al Ayoubi, L. and Beliuskina, O. and Bissell, M.L. and Blaum, K. and Campbell, P. and Cheal, B. and De Groote, R.P. and Devlin, C.S. and Eronen, T. and Filippin, L. and Garcia Ruiz, R.F. and Ge, Z. and Geldhof, S. and Gins, W. and Godefroid, M. and Heylen, H. and Hukkanen, M. and Imgram, P. and Jaries, A. and Jokinen, A. and Kanellakopoulos, A. and Kankainen, A. and Kaufmann, S. and König, K. and Koszorús, Á. and Kujanpää, S. and Lechner, S. and Malbrunot-Ettenauer, S. and Müller, P. and Mathieson, R. and Moore, I. and Nörtershäuser, W. and Nesterenko, D. and Neugart, R. and Neyens, G. and Ortiz-Cortes, A. and Penttilä, H. and Pohjalainen, I. and Raggio, A. and Reponen, M. and Rinta-Antila, S. and Rodríguez, L.V. and Romero, J. and Sánchez, R. and Sommer, F. and Stryjczyk, M. and Virtanen, V. and Xie, L. and Xu, Z.Y. and Yang, X.F. and Yordanov, D.T.}, title = {Nuclear Charge Radius of Al 26m and Its Implication for Vud in the Quark Mixing Matrix}, journal = {Physical Review Letters}, year = {2023}, volume = {131}, number = {22}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1103/PhysRevLett.131.222502} }
Richard C, Boudon V, Manceron L, Vander Auwera J, Vinatier S, Bézard B and Houelle M (2023), "Self and N2 collisional broadening of far-infrared methane lines at low-temperature with application to Titan", Icarus. Vol. 404 [Abstract] [BibTeX] [DOI]
Abstract: We report the measurement of broadening coefficients of pure rotational lines of methane at different pressure and temperature conditions. A total of 27 far-infrared spectra were recorded at the AILES beamline of the SOLEIL synchrotron at room-temperature, 200 K and 120 K, in a range of 10 to 800 mbar. Self and N2 broadening coefficients and temperature dependence exponents of methane pure rotational lines have been measured in the 73–136 cm−1 spectral range using multi-spectrum non-linear least squares fitting of Voigt profiles. These coefficients were used to model spectra of Titan that were compared to a selection of equatorial Cassini/CIRS spectra, showing a good agreement for a stratospheric methane mole fraction of (1.17 ± 0.08)%. © 2023 Elsevier Inc.
BibTeX: @article{Richard2023, author = {Richard, C. and Boudon, V. and Manceron, L. and Vander Auwera, J. and Vinatier, S. and Bézard, B. and Houelle, M.}, title = {Self and N2 collisional broadening of far-infrared methane lines at low-temperature with application to Titan}, journal = {Icarus}, year = {2023}, volume = {404}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.icarus.2023.115692} }
Ripak A, De Kreijger S, Sampaio RN, Vincent CA, Cauët É, Jabin I, Tambar UK, Elias B and Troian-Gautier L (2023), "Photosensitized activation of diazonium derivatives for C–B bond formation", Chem Catalysis. Vol. 3(2) [Abstract] [BibTeX] [DOI]
Abstract: Aryl diazonium salts are ubiquitous building blocks in chemistry, as they are useful radical precursors in organic synthesis as well as for the functionalization of solid materials. They can be reduced electrochemically or through a photo-induced electron transfer reaction. Here, we provide a detailed picture of the ground- and excited-state reactivity of a series of nine rare and earth-abundant photosensitizers with 13 aryl diazonium salts, which also included three macrocyclic calix[4]arene tetradiazonium salts. Nanosecond transient absorption spectroscopy confirmed the occurrence of excited-state electron transfer and was used to quantify cage-escape yields (i.e., the efficiency with which the formed radicals separate and escape the solvent cage). Cage-escape yields were large; they increased when the driving force for photo-induced electron transfer increased and also tracked with the C–N2+ bond cleavage propensity, among others. A photo-induced borylation reaction was then investigated with all the photosensitizers and proceeded with yields between 9% and 74%. © 2022 Elsevier Inc.
BibTeX: @article{Ripak2023, author = {Ripak, Alexia and De Kreijger, Simon and Sampaio, Renato N. and Vincent, Cooper A. and Cauët, Émilie and Jabin, Ivan and Tambar, Uttam K. and Elias, Benjamin and Troian-Gautier, Ludovic}, title = {Photosensitized activation of diazonium derivatives for C–B bond formation}, journal = {Chem Catalysis}, year = {2023}, volume = {3}, number = {2}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.checat.2022.100490} }
Viatte C, Guendouz N, Dufaux C, Hensen A, Swart D, Van Damme M, Clarisse L, Coheur P and Clerbaux C (2023), "Measurement report: Ammonia in Paris derived from ground-based open-path and satellite observations", Atmospheric Chemistry and Physics. Vol. 23(24), pp. 15253 – 15267. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) is an important air pollutant which, as a precursor of fine particulate matter, raises public health concerns. This study analyzes 2.5 years of NH3 observations derived from ground-based (miniDOAS; differential optical absorption spectroscopy) and satellite (IASI; Infrared Atmospheric Sounding Interferometer) remote sensing instruments to quantify, for the first time, temporal variabilities (from interannual to diurnal) in NH3 concentrations in Paris. The IASI and miniDOAS datasets are found to be in relatively good agreement (R>0.70) when atmospheric NH3 concentrations are high and driven by regional agricultural activities. Over the investigated period (January 2020–June 2022), NH3 average concentrations in Paris measured by the miniDOAS and IASI are 2.23 µg m−3 and 7.10 × 1015 molec. cm−2, respectively, which are lower than or equivalent to those documented in other urban areas. The seasonal and monthly variabilities in NH3 concentrations in Paris are driven by sporadic agricultural emissions influenced by meteorological conditions, with NH3 concentrations in spring up to 2 times higher than in other seasons. The potential source contribution function (PSCF) reveals that the close (100–200 km) east and northeast regions of Paris constitute the most important potential emission source areas of NH3 in the megacity. Weekly cycles of NH3 derived from satellite and ground-based observations show different ammonia sources in Paris. In spring, agriculture has a major influence on ammonia concentrations, and, in the other seasons, multi-platform observations suggest that ammonia is also controlled by traffic-related emissions. In Paris, the diurnal cycle of NH3 concentrations is very similar to the one of NO2, with morning enhancements coincident with intensified road traffic. NH3 evening enhancements synchronous with rush hours are also monitored in winter and fall. NH3 concentrations measured during the weekends are consistently lower than NH3 concentrations measured during weekdays in summer and fall. This is further evidence of a significant traffic source of NH3 in Paris. © Author(s) 2023. This work is distributed under the Creative Commons Attribution 4.0 License.
BibTeX: @article{Viatte2023, author = {Viatte, Camille and Guendouz, Nadir and Dufaux, Clarisse and Hensen, Arjan and Swart, Daan and Van Damme, Martin and Clarisse, Lieven and Coheur, Pierre and Clerbaux, Cathy}, title = {Measurement report: Ammonia in Paris derived from ground-based open-path and satellite observations}, journal = {Atmospheric Chemistry and Physics}, year = {2023}, volume = {23}, number = {24}, pages = {15253 – 15267}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-23-15253-2023} }
Vu Van A, Boynard A, Prunet P, Jolivet D, Lezeaux O, Henry P, Camy-Peyret C, Clarisse L, Franco B, Coheur P-F and Clerbaux C (2023), "Near-real-Time detection of unexpected atmospheric events using principal component analysis on the Infrared Atmospheric Sounding Interferometer (IASI) radiances", Atmospheric Measurement Techniques. Vol. 16(8), pp. 2107 – 2127. [Abstract] [BibTeX] [DOI]
Abstract: The three Infrared Atmospheric Sounding Interferometer (IASI) instruments on board the Metop family of satellites have been sounding the atmospheric composition since 2006. More than 30 atmospheric gases can be measured from the IASI radiance spectra, allowing the improvement of weather forecasting and the monitoring of atmospheric chemistry and climate variables. The early detection of extreme events such as fires, pollution episodes, volcanic eruptions, or industrial releases is key to take safety measures to protect the inhabitants and the environment in the impacted areas. With its near-real-Time observations and good horizontal coverage, IASI can contribute to the series of monitoring systems for the systematic and continuous detection of exceptional atmospheric events in order to support operational decisions. In this paper, we describe a new approach to the near-real-Time detection and characterization of unexpected events, which relies on the principal component analysis (PCA) of IASI radiance spectra. By analyzing both the IASI raw and compressed spectra, we applied a PCA-granule-based method on various past, well-documented extreme events such as volcanic eruptions, fires, anthropogenic pollution, and industrial accidents. We demonstrate that the method is well suited to the detection of spectral signatures for reactive and weakly absorbing gases, even for sporadic events. Consistent long-Term records are also generated for fire and volcanic events from the available IASI/Metop-B data record. The method is running continuously, delivering email alerts on a routine basis, using the near-real-Time IASI L1C radiance data. It is planned to be used as an online tool for the early and automatic detection of extreme events, which was not done before. © Copyright:
BibTeX: @article{VuVan2023, author = {Vu Van, Adrien and Boynard, Anne and Prunet, Pascal and Jolivet, Dominique and Lezeaux, Olivier and Henry, Patrice and Camy-Peyret, Claude and Clarisse, Lieven and Franco, Bruno and Coheur, Pierre-François and Clerbaux, Cathy}, title = {Near-real-Time detection of unexpected atmospheric events using principal component analysis on the Infrared Atmospheric Sounding Interferometer (IASI) radiances}, journal = {Atmospheric Measurement Techniques}, year = {2023}, volume = {16}, number = {8}, pages = {2107 – 2127}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-16-2107-2023} }
Wang R, Pan D, Guo X, Sun K, Clarisse L, Van Damme M, Coheur P-F, Clerbaux C, Puchalski M and Zondlo MA (2023), "Bridging the spatial gaps of the Ammonia Monitoring Network using satellite ammonia measurements", Atmospheric Chemistry and Physics. Vol. 23(20), pp. 13217 – 13234. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) is a key precursor to fine particulate matter (PM2.5) and a primary form of reactive nitrogen. The limited number of NH3 observations hinders the further understanding of its impacts on air quality, climate, and biodiversity. Currently, NH3 ground monitoring networks are few and sparse across most of the globe, and even in the most established networks, large spatial gaps exist between sites and only a few sites have records that span longer than a decade. Satellite NH3 observations can be used to discern trends and fill spatial gaps in networks, but many factors influence the syntheses of the vastly different spatiotemporal scales between surface network and satellite measurements. To this end, we intercompared surface NH3 data from the Ammonia Monitoring Network (AMoN) and satellite NH3 total columns from the Infrared Atmospheric Sounding Interferometer (IASI) in the contiguous United States (CONUS) and then performed trend analyses using both datasets. We explored the sensitivity of correlations between the two datasets to factors such as satellite data availability and distribution over the surface measurement period, as well as agreement within selected spatial and temporal windows. Given the short lifetime of atmospheric ammonia and consequently sharp gradients, smaller spatial windows show better agreement than larger ones except in areas of relatively uniform, low concentrations where large windows and more satellite measurements improve the signal-to-noise ratio. A critical factor in the comparison is having satellite measurements across most of the measurement period of the monitoring site. When IASI data are available for at least 80 % of the days of AMoN's 2-week sampling period within a 25 km spatial window of a given site, IASI NH3 column concentrations and the AMoN NH3 surface concentrations have a correlation of 0.74, demonstrating the feasibility of using satellite NH3 columns to bridge the spatial gaps existing in the surface network NH3 concentrations. Both IASI and AMoN show increasing NH3 concentrations across the CONUS (median: 6.8 %yr-1 versus 6.7 %yr-1) in the last decade (2008-2018), suggesting the NH3 will become a greater contributor to nitrogen deposition. NH3 trends at AMoN sites are correlated with IASI NH3 trends (r Combining double low line 0.66) and show similar spatial patterns, with the highest increases in the Midwest and eastern US. In spring and summer, increases in NH3 were larger than 10 %yr-1 in the eastern US and Midwest (cropland dominated) and the western US (pastureland dominated), respectively. NH3 hotspots are defined as regions where the IASI NH3 column is larger than the 95th percentile of the 11-year CONUS map (6.7 × 1015 molec.cm-2), they also experience increasing concentrations over time, with a median of NH3 trend of 4.7 %yr-1. IASI data show large NH3 increases in urban areas (8.1 %yr-1), including 8 of the top 10 most populous regions in the CONUS, where AMoN sites are sparse. A comparison between IASI NH3 concentration trends and state-level NH3 emission trends is then performed to reveal that positive correlations exist in states with strong agricultural NH3 emissions, while there are negative correlations in states with low NH3 emissions and large NOx emissions, suggesting the different roles of emission and partitioning in NH3 increases. The increases in NH3 could have detrimental effects on nearby eco-sensitive regions through nitrogen deposition and on aerosol chemistry in the densely populated urban areas, and therefore they should be carefully monitored and studied. © 2023 Rui Wang et al.
BibTeX: @article{Wang2023, author = {Wang, Rui and Pan, Da and Guo, Xuehui and Sun, Kang and Clarisse, Lieven and Van Damme, Martin and Coheur, Pierre-François and Clerbaux, Cathy and Puchalski, Melissa and Zondlo, Mark A.}, title = {Bridging the spatial gaps of the Ammonia Monitoring Network using satellite ammonia measurements}, journal = {Atmospheric Chemistry and Physics}, year = {2023}, volume = {23}, number = {20}, pages = {13217 – 13234}, doi = {10.5194/acp-23-13217-2023} }
Wizenberg T, Strong K, Jones D, Lutsch E, Mahieu E, Franco B and Clarisse L (2023), "Exceptional Wildfire Enhancements of PAN, C2H4, CH3OH, and HCOOH Over the Canadian High Arctic During August 2017", Journal of Geophysical Research: Atmospheres. Vol. 128(10) [Abstract] [BibTeX] [DOI]
Abstract: Extreme enhancements in the total columns of carbon monoxide (CO), peroxyacetyl nitrate (PAN), ethylene (C2H4), methanol (CH3OH), and formic acid (HCOOH) were observed over the Canadian high Arctic during the period of 17–22 August 2017 by a ground-based Fourier transform infrared (FTIR) spectrometer at Eureka, Nunavut (80.05°N, 86.42°W), and by the Infrared Atmospheric Sounding Interferometer (IASI) satellite instruments. These enhancements have been attributed to wildfires in British Columbia (BC) and the Northwest Territories (NWT) of Canada, and represent the largest short-term perturbations of PAN, C2H4, and HCOOH above ambient concentrations over the 14-year (2006–2020) Eureka time-series. Enhancement ratios, emission ratios, and emission factors relative to CO were calculated for all species for both FTIR and IASI observations. The C2H4 and HCOOH emission factors are significantly larger than previous studies, suggesting unusually high emissions from these fires. The wildfire plumes were also simulated using the GEOS-Chem model. Initial GEOS-Chem simulations displayed a severe under-estimation relative to observations for these fire plumes resulting from the injection height scheme of the model. Sensitivity tests highlighted that injection heights of 12.5 km for BC (based on previous studies) and 10 km for the NWT fires yielded the strongest correlations with ground-based measurements. Applying these injection heights to the model significantly improves the simulated plume transport and agreement with ground- and space-based observations. GEOS-Chem was also used to estimate the magnitude of secondary in-plume production of CH3OH and HCOOH; it was found to be an important component (∼18%) of the enhanced HCOOH columns at Eureka. © 2023. The Authors.
BibTeX: @article{Wizenberg2023, author = {Wizenberg, T. and Strong, K. and Jones, D.B.A. and Lutsch, E. and Mahieu, E. and Franco, B. and Clarisse, L.}, title = {Exceptional Wildfire Enhancements of PAN, C2H4, CH3OH, and HCOOH Over the Canadian High Arctic During August 2017}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2023}, volume = {128}, number = {10}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1029/2022JD038052} }
Zeng Z-C, Lee L, Qi C, Clarisse L and Van Damme M (2023), "Optimal estimation retrieval of tropospheric ammonia from the Geostationary Interferometric Infrared Sounder on board FengYun-4B", Atmospheric Measurement Techniques. Vol. 16(15), pp. 3693 – 3713. [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric ammonia (NH3) is a reactive nitrogen compound that pollutes our environment and threatens public health. Monitoring the spatial and temporal variations is important for quantifying its emissions and depositions and evaluating the strategies for managing anthropogenic sources of NH3. In this study, we present an NH3 retrieval algorithm based on the optimal estimation method for the Geostationary Interferometric Infrared Sounder (GIIRS) on board China's FengYun-4B satellite (FY-4B/GIIRS). In particular, we examine the information content based on the degree of freedom for signal (DOFS) in retrieving the diurnal NH3 in East Asia, with a focus on two source regions including the North China Plain and North India. Our retrieval is based on the FengYun Geostationary satellite Atmospheric Infrared Retrieval (FY-GeoAIR) algorithm and exploits the strong NH3 absorption window of 955-975ĝ€¯cm-1. Retrieval results using FY-4B/GIIRS spectra from July to December 2022 show that the DOFS for the majority ranges from 0 to 1.0, mainly depending on the thermal contrast (TC) defined as the temperature difference between the surface and the lowest atmospheric layer. Consistent with retrievals from low-Earth-orbit (LEO) infrared sounders, the detection sensitivity, as quantified by the averaging kernel (AK) matrix, peaks in the lowest 2ĝ€¯km atmospheric layers. The DOFS and TC are highly correlated, resulting in a typical "butterfly"shape. That is, the DOFS increases when TC becomes either more positive or more negative. The NH3 columns from FY-4B/GIIRS exhibit significant diurnal cycles that are consistent with the day-night gradient from the collocated IASI retrievals in the North China Plain and North India for the averages in July-August, September-October, and November-December, respectively. A collocated point-by-point intercomparison with the IASI NH3 dataset shows generally good agreement with a small systematic difference in the summer months that may be attributed to the slight difference in a priori profiles. This study demonstrates the capability of FY-4B/GIIRS in capturing the diurnal NH3 changes in East Asia, which will have the potential to improve regional and global air quality and climate research. © Copyright:
BibTeX: @article{Zeng2023, author = {Zeng, Zhao-Cheng and Lee, Lu and Qi, Chengli and Clarisse, Lieven and Van Damme, Martin}, title = {Optimal estimation retrieval of tropospheric ammonia from the Geostationary Interferometric Infrared Sounder on board FengYun-4B}, journal = {Atmospheric Measurement Techniques}, year = {2023}, volume = {16}, number = {15}, pages = {3693 – 3713}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-16-3693-2023} }
Aerts A, Brown A and Gatti F (2022), "Intramolecular vibrational redistribution in formic acid and its deuterated forms", Journal of Chemical Physics. Vol. 157(1) [Abstract] [BibTeX] [DOI]
Abstract: The intramolecular vibrational relaxation dynamics of formic acid and its deuterated isotopologues is simulated on the full-dimensional potential energy surface of Richter and Carbonnière [J. Chem. Phys. 148, 064303 (2018)] using the Heidelberg MCTDH package. We focus on couplings with the torsion vibrational modes close to the trans-cis isomerization coordinate from the dynamics of artificially excited vibrational mode overtones. The bright C-O stretch vibrational mode is coupled to the out-of-the plane torsion mode in HCOOH, where this coupling could be exploited for laser-induced trans-to-cis isomerization. Strong isotopic effects are observed: deuteration of the hydroxyl group, i.e., in HCOOD and DCOOD, destroys the C-O stretch to torsion mode coupling whereas in DCOOH, little to no effect is observed. © 2022 Author(s).
BibTeX: @article{Aerts2022a, author = {Aerts, Antoine and Brown, Alex and Gatti, Fabien}, title = {Intramolecular vibrational redistribution in formic acid and its deuterated forms}, journal = {Journal of Chemical Physics}, year = {2022}, volume = {157}, number = {1}, note = {All Open Access, Green Open Access}, doi = {10.1063/5.0098819} }
Aerts A, Kockaert P, Gorza S-P, Brown A, Vander Auwera J and Vaeck N (2022), "Laser control of a dark vibrational state of acetylene in the gas phase - Fourier transform pulse shaping constraints and effects of decoherence", Journal of Chemical Physics. Vol. 156(8) [Abstract] [BibTeX] [DOI]
Abstract: We propose a methodology to tackle the laser control of a non-stationary dark ro-vibrational state of acetylene (C2H2), given realistic experimental limitations in the 7.7 μm (1300 cm-1) region. Simulations are performed using the Lindblad master equation, where the so-called Lindblad parameters are used to describe the effect of the environment in the dilute gas phase. A phenomenological representation of the parameters is used, and they are extracted from high-resolution spectroscopy line broadening data. An effective Hamiltonian is used for the description of the system down to the rotational level close to experimental accuracy. The quality of both the Hamiltonian and Lindblad parameters is assessed by a comparison of a calculated infrared spectrum with the available experimental data. A single shaped laser pulse is used to perform the control, where elements of optics and pulse shaping using masks are introduced with emphasis on experimental limitations. The optimization procedure, based on gradients, explicitly takes into account the experimental constraints. Control performances are reported for shaping masks of increasing complexity. Although modest performances are obtained, mainly due to the strong pulse shaping constraints, we gain insights into the control mechanism. This work is the first step toward the conception of a realistic experiment that will allow for population characterization and manipulation of a non-stationary vibrational "dark"state. Effects of the collisions on the laser control in the dilute gas phase, leading to decoherence in the molecular system, are clearly shown. © 2022 Author(s).
BibTeX: @article{Aerts2022, author = {Aerts, Antoine and Kockaert, Pascal and Gorza, Simon-Pierre and Brown, Alex and Vander Auwera, Jean and Vaeck, Nathalie}, title = {Laser control of a dark vibrational state of acetylene in the gas phase - Fourier transform pulse shaping constraints and effects of decoherence}, journal = {Journal of Chemical Physics}, year = {2022}, volume = {156}, number = {8}, note = {All Open Access, Green Open Access}, doi = {10.1063/5.0080332} }
Aerts A, Schäfer MR and Brown A (2022), "Adaptive fitting of potential energy surfaces of small to medium-sized molecules in sum-of-product form: Application to vibrational spectroscopy", Journal of Chemical Physics. Vol. 156(16) [Abstract] [BibTeX] [DOI]
Abstract: A semi-automatic sampling and fitting procedure for generating sum-of-product (Born-Oppenheimer) potential energy surfaces based on a high-dimensional model representation is presented. The adaptive sampling procedure and subsequent fitting rely on energies only and can be used for re-fitting existing analytic potential energy surfaces in the sum-of-product form or for direct fits from ab initio computations. The method is tested by fitting ground electronic state potential energy surfaces for small to medium sized semi-rigid molecules, i.e., HFCO, HONO, and HCOOH, based on ab initio computations at the coupled-cluster single double and perturbative triples-F12/cc-pVTZ-F12 or MP2/aug-cc-pVTZ levels of theory. Vibrational eigenstates are computed using block improved relaxation in the Heidelberg multi-configurational time dependent Hartree package and compared to available experimental and theoretical data. The new potential energy surfaces are compared to the best ones currently available for these molecules in terms of accuracy, including resulting vibrational states, required number of sampling points, and number of fitting parameters. The present procedure leads to compact expansions and scales well with the number of dimensions for simple potentials such as single or double wells. © 2022 Author(s).
BibTeX: @article{Aerts2022b, author = {Aerts, Antoine and Schäfer, Moritz R. and Brown, Alex}, title = {Adaptive fitting of potential energy surfaces of small to medium-sized molecules in sum-of-product form: Application to vibrational spectroscopy}, journal = {Journal of Chemical Physics}, year = {2022}, volume = {156}, number = {16}, note = {All Open Access, Green Open Access}, doi = {10.1063/5.0089570} }
Beale CA, Paulot F, Randles CA, Wang R, Guo X, Clarisse L, Van Damme M, Coheur P-F, Clerbaux C, Shephard MW, Dammers E, Cady-Pereira K and Zondlo MA (2022), "Large sub-regional differences of ammonia seasonal patterns over India reveal inventory discrepancies", Environmental Research Letters. Vol. 17(10) [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) is a key precursor of haze particles and fine particulate matter (PM2.5) and its spatiotemporal variabilities are poorly constrained. In this study, we present measurements of NH3 over the Indian subcontinent region from the Infrared Atmospheric Sounder Interferometer (IASI) and Cross-track Infrared Sounder (CrIS) satellite instruments. This region exhibits a complex emission profile due to the number of varied sources, including crop burning, fossil fuel combustion, fertilizer application, livestock and industrial sources. Observations from the CrIS and IASI instruments are oversampled to a resolution of 0.02° × 0.02°. Five regions with distinct spatiotemporal NH3 profiles are determined using k-means clustering. Maximum NH3 columns are seen in July over the western India with column densities of 6.2 × 1017 mol cm−2 and 7.2 × 1017 mol cm−2 respectively for IASI and CrIS. The seasonality of measured NH3 columns show annual maxima occurring in spring in Eastern India and Bangladesh and in mid-summer for the western Indo-Gangetic plain. Our observational constraints suggest that the impact of local farming practices on NH3 emissions is not well captured in emission inventories such as Coupled Model Intercomparison Project Phase 6 (CMIP6), which exhibits peaks in the late spring and autumn. The spatial variability in the seasonal patterns of NH3 is also not captured by the single emissions profile used in CMIP6 for India. The high-resolution maps obtained from these measurements can be used to improve NH3 emission inventories in order to understand its sources for more accurate predictions of air quality in the Indian subcontinent. Our study points to the need for regionally specific emissions inventories for short-lived species such as NH3 that have heterogeneous emissions profiles due to specific agricultural practices and other emission source characteristics. © 2022 The Author(s). Published by IOP Publishing Ltd.
BibTeX: @article{Beale2022, author = {Beale, Christopher A. and Paulot, Fabien and Randles, Cynthia A. and Wang, Rui and Guo, Xuehui and Clarisse, Lieven and Van Damme, Martin and Coheur, Pierre-François and Clerbaux, Cathy and Shephard, Mark W. and Dammers, Enrico and Cady-Pereira, Karen and Zondlo, Mark A.}, title = {Large sub-regional differences of ammonia seasonal patterns over India reveal inventory discrepancies}, journal = {Environmental Research Letters}, year = {2022}, volume = {17}, number = {10}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1748-9326/ac881f} }
Bernath P, Dodangodage R and Liévin J (2022), "S-type Stars: LaO Line List for the B2ς+-X2ς+Band System", Astrophysical Journal. Vol. 933(1) [Abstract] [BibTeX] [DOI]
Abstract: LaO bands are a characteristic feature in the spectrum of cool S-type stars. La is made primarily by the s-process during the asymptotic giant branch phase of stellar evolution. The B2ς+-X2ς+ and A2Π-X2ς+ band systems can be used to determine the La abundances in cool S stars. The bands of the B2ς+-X2ς+ with v′ and v′′≤5 have been rotationally analyzed from an emission spectrum from a carbon furnace. Line strengths are calculated using an ab initio transition dipole function, corrected using experimental lifetimes. We provide a line list for the B2ς+-X2ς+ band system that can be used to determine La abundances. © 2022. The Author(s). Published by the American Astronomical Society.
BibTeX: @article{Bernath2022a, author = {Bernath, P.F. and Dodangodage, R. and Liévin, J.}, title = {S-type Stars: LaO Line List for the B2ς+-X2ς+Band System}, journal = {Astrophysical Journal}, year = {2022}, volume = {933}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.3847/1538-4357/ac731f} }
Bernath PF, Johnson RM and Liévin J (2022), "Line lists for X3Σ− and a1Δ vibration-rotation bands of SO", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 290 [Abstract] [BibTeX] [DOI]
Abstract: SO is found in several astronomical sources such as the atmospheres of Io and Venus. To complete our work on SO line lists, we used our previous fits for v = 0 to v = 6 for the X3Σ- state and v = 0–5 for the a1Δ state [JQSRT 272, 107772 (2021)] for line positions, and high-level ab initio calculations of electric dipole moments for line strengths for the vibration-rotation bands. LeRoy's RKR program was used to produce pointwise potential energy curves. N- and v-dependent dipole matrix elements were produced with LeRoy's LEVEL program and the final line lists were made with Western's PGOPHER program. All possible vibrational bands were calculated, and the line strengths included the Herman-Wallis effect caused by vibration-rotation interaction. © 2022
BibTeX: @article{Bernath2022, author = {Bernath, Peter F. and Johnson, Ryan M. and Liévin, Jacques}, title = {Line lists for X3Σ− and a1Δ vibration-rotation bands of SO}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2022}, volume = {290}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jqsrt.2022.108317} }
Bouillon M, Safieddine S, Whitburn S, Clarisse L, Aires F, Pellet V, Lezeaux O, Scott NA, Doutriaux-Boucher M and Clerbaux C (2022), "Time evolution of temperature profiles retrieved from 13 years of infrared atmospheric sounding interferometer (IASI) data using an artificial neural network", Atmospheric Measurement Techniques. Vol. 15(6), pp. 1779 – 1793. [Abstract] [BibTeX] [DOI]
Abstract: The three infrared atmospheric sounding interferometers (IASIs), launched in 2006, 2012, and 2018, are key instruments to weather forecasting, and most meteorological centres assimilate IASI nadir radiance data into atmospheric models to feed their forecasts. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) recently released a reprocessed homogeneous radiance record for the whole IASI observation period, from which 13 years (2008-2020) of temperature profiles can be obtained. In this work, atmospheric temperatures at different altitudes are retrieved from IASI radiances measured in the carbon dioxide absorption bands (654-800 and 2250-2400gcm-1) by selecting the channels that are the most sensitive to the temperature at different altitudes. We rely on an artificial neural network (ANN) to retrieve atmospheric temperatures from a selected set of IASI radiances. We trained the ANN with IASI radiances as input and the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis version 5 (ERA5) as output. The retrieved temperatures were validated with ERA5, with in situ radiosonde temperatures from the Analysed RadioSoundings Archive (ARSA) network and with EUMETSAT temperatures retrieved from IASI radiances using a different method. Between 750 and 7ghPa, where IASI is most sensitive to temperature, a good agreement is observed between the three datasets: the differences between IASI on one hand and ERA5, ARSA, or EUMETSAT on the other hand are usually less than 0.5gK at these altitudes. At 2ghPa, as the IASI sensitivity decreases, we found differences up to 2gK between IASI and the three validation datasets. We then computed atmospheric temperature linear trends from atmospheric temperatures between 750 and 2ghPa. We found that in the past 13 years, there is a general warming trend of the troposphere that is more important at the poles and at mid-latitudes (0.5gK/decade at mid-latitudes, 1gK/decade at the North Pole). The stratosphere is globally cooling on average, except at the South Pole as a result of the ozone layer recovery and a sudden stratospheric warming in 2019. The cooling is most pronounced in the equatorial upper stratosphere (-1gK/decade). This work shows that ANN can be a powerful and simple tool to retrieve IASI temperatures at different altitudes in the upper troposphere and in the stratosphere, allowing us to construct a homogeneous and consistent temperature data record adapted to trend analysis. © 2022 Copernicus GmbH. All rights reserved.
BibTeX: @article{Bouillon2022, author = {Bouillon, Marie and Safieddine, Sarah and Whitburn, Simon and Clarisse, Lieven and Aires, Filipe and Pellet, Victor and Lezeaux, Olivier and Scott, Noëlle A. and Doutriaux-Boucher, Marie and Clerbaux, Cathy}, title = {Time evolution of temperature profiles retrieved from 13 years of infrared atmospheric sounding interferometer (IASI) data using an artificial neural network}, journal = {Atmospheric Measurement Techniques}, year = {2022}, volume = {15}, number = {6}, pages = {1779 – 1793}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-15-1779-2022} }
Cacciani P, Čermák P, Vander Auwera J and Campargue A (2022), "The ammonia absorption spectrum between 3900 and 4700 cm−1", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 277 [Abstract] [BibTeX] [DOI]
Abstract: Room temperature absorption spectra of ammonia have been recorded by high-resolution Fourier transform spectroscopy in the range 3900-4700 cm–1 at four pressures (13, 46, 140, and 304 Pa). The investigated spectral region overlaps the important 2.3 µm atmospheric transparency window. 8419 absorption lines were retrieved from the recorded spectra. Line intensities range between 1 × 10−25 and 1.6 × 10−20 cm/molecule. The rovibrational assignments, relying on the position and intensity agreement with the C2018 theoretical line list (Coles et al. 2018), were validated by the systematic use of Lower State Combination Difference (LSCD) relations. 6052 transitions were assigned to 51 vibrational bands of the main isotopologue, 14NH3, and 625 transitions of the 15NH3 minor isotopologue were identified. Overall, the assigned transitions represent over 99.8% of the integrated absorption at room temperature in the region. The upper state empirical energy of a total of 2287 rovibrational levels of 14NH3 were derived. Among them, 1870 are newly reported. The achieved quality of the LSCD relations indicates that the accuracy of the derived energy levels is better than 0.001 cm−1. Comparison with the HITRAN2020 list shows that the present results will be valuable in improving the ammonia spectroscopic databases in the region, both in terms of completeness and accuracy of the line positions and line intensities. A recommended line list for ammonia in natural isotopic abundance is provided for the studied region. © 2021 Elsevier Ltd
BibTeX: @article{Cacciani2022, author = {Cacciani, P. and Čermák, P. and Vander Auwera, J. and Campargue, A.}, title = {The ammonia absorption spectrum between 3900 and 4700 cm−1}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2022}, volume = {277}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jqsrt.2021.107961} }
Cacciani P, Čermák P, Vander Auwera J and Campargue A (2022), "The ammonia absorption spectrum between 4700 and 5650 cm−1", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 292 [Abstract] [BibTeX] [DOI]
Abstract: Room temperature absorption spectra of ammonia were recorded by high-resolution Fourier transform spectroscopy in the 4700–5600 cm−1 range at four pressures (13, 46, 140, and 304 Pa). Additionally, we use an existing Kitt Peak spectrum to extend the analysis up to 5650 cm−1. In total, 9110 absorption lines with intensity ranging from 1×10−25 to 1.6×10−20 cm/molecule were retrieved, for the two principal isotopologues. Another Kitt Peak spectrum was used to identify 505 15NH3 transitions within the experimental line list. The rovibrational assignments of the 14NH3 lines relied on the position and intensity agreement with the C2018 theoretical line list (Coles et al. JQSRT 2018;219 199–212) and were validated by the systematic use of Lower State Combination Difference (LSCD) relations. In the process, a number of intensity transfer between nearby transitions were identified. Finally, 6562 transitions were assigned to 61 vibrational bands of the main isotopologue, 14NH3, representing 98.85% of the C2018 integrated absorption at room temperature in the region. The upper state empirical energy of a total of 2215 rovibrational levels of 14NH3 were derived. Most of them are newly reported. The comparison with the current HITRAN2020 list is discussed. A recommended line list for ammonia in natural isotopic abundance is provided for the studied region. © 2022 Elsevier Ltd
BibTeX: @article{Cacciani2022a, author = {Cacciani, P. and Čermák, P. and Vander Auwera, J. and Campargue, A.}, title = {The ammonia absorption spectrum between 4700 and 5650 cm−1}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2022}, volume = {292}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jqsrt.2022.108350} }
De Kreijger S, Schott O, Troian-Gautier L, Cauët E, Hanan GS and Elias B (2022), "Red Absorbing Cyclometalated Ir(III) Diimine Photosensitizers Competent for Hydrogen Photocatalysis", Inorganic Chemistry. Vol. 61(13), pp. 5245 – 5254. [Abstract] [BibTeX] [DOI]
Abstract: Two new cyclometalated Ir(III) diimine complexes were used as photosensitizers for homogeneous hydrogen evolution reaction (HER). These complexes were characterized by electrochemistry, ultraviolet-visible absorption, time-resolved and steady-state photoluminescence spectroscopy as well as by theoretical methods. The metal-ligand-to-ligand charge transfer character of their lowest excited state was shown to be competent for efficient H2photoproduction in the presence of [Co(dmgH)2(py)Cl] as the hydrogen evolution catalyst, triethanolamine as the sacrificial electron donor, and HBF4as the proton source. Under optimized experimental conditions, both complexes displayed HER over a period of more than 90 h, with turnover numbers reaching up to 11,650, 10,600, and 174 molH2molPS-1under blue-, green-, and red-light irradiation, respectively. Both complexes showed higher stability and efficiency vs HER than most of the previously described systems of the same kind. © 2022 American Chemical Society. All rights reserved.
BibTeX: @article{DeKreijger2022, author = {De Kreijger, Simon and Schott, Olivier and Troian-Gautier, Ludovic and Cauët, Emilie and Hanan, Garry S. and Elias, Benjamin}, title = {Red Absorbing Cyclometalated Ir(III) Diimine Photosensitizers Competent for Hydrogen Photocatalysis}, journal = {Inorganic Chemistry}, year = {2022}, volume = {61}, number = {13}, pages = {5245 – 5254}, doi = {10.1021/acs.inorgchem.1c03727} }
Demaison J and Liévin J (2022), "Accuracy of the equilibrium structure of sulphur dioxide", Molecular Physics. Vol. 120(15-16) [Abstract] [BibTeX] [DOI]
Abstract: The ground state rotational spectra of 12 different isotopologues of sulphur dioxide have been refitted in a consistent way and an accurate experimental cubic force field has been determined. The experimental, semi-experimental and ab initio equilibrium structures have been calculated and found in good agreement across themselves. Different approximations limiting the accuracy are discussed. In particular, the influence of centrifugal distortion is analysed. A method is proposed to estimate the higher-order rovibrational corrections (γ-constants). Although an accurate semi-experimental structure was obtained for 19 isotopologues, it was not possible to determine and account for the breakdown of the Born–Oppenheimer approximation. Finally, it was shown that the ab initio CCSDTQ level of theory was required to obtain a good agreement with the experimental structure. © 2021 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX: @article{Demaison2022, author = {Demaison, Jean and Liévin, Jacques}, title = {Accuracy of the equilibrium structure of sulphur dioxide}, journal = {Molecular Physics}, year = {2022}, volume = {120}, number = {15-16}, doi = {10.1080/00268976.2021.1950857} }
Fischer CF and Godefroid M (2022), "Variational Methods for Atoms and the Virial Theorem", Atoms. Vol. 10(4) [Abstract] [BibTeX] [DOI]
Abstract: In the case of the one-electron Dirac equation with a point nucleus, the virial theorem (VT) states that the ratio of the kinetic energy to potential energy is exactly -1, a ratio that can be an independent test of the accuracy of a computed solution. This paper studies the virial theorem for subshells of equivalent electrons and their interactions in many-electron atoms. This shows that the linear scaling of the dilation is achieved through the balancing of the contributions to the potential of an electron from inner and outer regions that some Slater integrals impose conditions on a single subshell, but others impose conditions between subshells. The latter slows the rate of convergence of the self-consistent field process in which radial functions are updated one at a time. Several cases are considered. Results are also extended to the nonrelativistic case. © 2022 by the authors.
BibTeX: @article{Fischer2022, author = {Fischer, Charlotte Froese and Godefroid, Michel}, title = {Variational Methods for Atoms and the Virial Theorem}, journal = {Atoms}, year = {2022}, volume = {10}, number = {4}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atoms10040110} }
Fortems-Cheiney A, Dufour G, Foret G, Siour G, Van Damme M, Coheur P-F, Clarisse L, Clerbaux C and Beekmann M (2022), "Understanding the Simulated Ammonia Increasing Trend from 2008 to 2015 over Europe with CHIMERE and Comparison with IASI Observations", Atmosphere. Vol. 13(7) [Abstract] [BibTeX] [DOI]
Abstract: The objective of this study is to assess and understand the NH3 recent trends and to identify the key components driving its concentrations. We have simulated the seasonal cycle, the interannual variability, and the trends in NH3 vertical column densities (VCD) from 2008 to 2015 over Europe, with the CHIMERE regional chemistry–transport model. We have also confronted the simulations against the Infrared Atmospheric Sounding Interferometer (IASI) satellite observations. IASI often shows a strong maximum in summer in addition to the spring peak, whereas CHIMERE only shows a slight peak in summer some years. This result could point to a misrepresentation of the temporal profile of the NH3 emissions, i.e., to missing emission sources during summertime either due to more than expected fertilizer use or to increased volatilization under warmer conditions. The simulated NH3 VCDs present an increasing trend over continental Europe (+2.7 ± 1.0 %/yr) but also at the national scale for Spain, Germany, UK, France, and Poland. Sensitivity tests indicate that these simulated positive trends are mainly due to (i) the trends in NH3 emissions, found heterogeneous in the EMEP NH3 emissions with strong disparities depending on the country, and (ii) the negative trends in NOx and SOx emissions. The impact of reductions in NO2 and SO2 emissions on NH3 concentrations should therefore be taken into account in future policies. This simulated NH3 VCD increase at the European scale is confirmed by IASI-v3R satellite observations in spring and summer, when ammonia emissions strongly contribute to the annual budget in accordance with crop requirements. Nevertheless, there are remaining differences about the significance and magnitude between the simulated and observed trends at the national scale, and it warrants further investigation. © 2022 by the authors.
BibTeX: @article{FortemsCheiney2022, author = {Fortems-Cheiney, Audrey and Dufour, Gaëlle and Foret, Gilles and Siour, Guillaume and Van Damme, Martin and Coheur, Pierre-François and Clarisse, Lieven and Clerbaux, Cathy and Beekmann, Matthias}, title = {Understanding the Simulated Ammonia Increasing Trend from 2008 to 2015 over Europe with CHIMERE and Comparison with IASI Observations}, journal = {Atmosphere}, year = {2022}, volume = {13}, number = {7}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.3390/atmos13071101} }
Franco B, Clarisse L, Van Damme M, Hadji-Lazaro J, Clerbaux C and Coheur P-F (2022), "Ethylene industrial emitters seen from space", Nature Communications. Vol. 13(1) [Abstract] [BibTeX] [DOI]
Abstract: Volatile organic compounds are emitted abundantly from a variety of natural and anthropogenic sources. However, in excess, they can severely degrade air quality. Their fluxes are currently poorly represented in inventories due to a lack of constraints from global measurements. Here, we track from space over 300 worldwide hotspots of ethylene, the most abundant industrially produced organic compound. We identify specific emitters associated with petrochemical clusters, steel plants, coal-related industries, and megacities. Satellite-derived fluxes reveal that the ethylene emissions of the industrial sources are underestimated or missing in the state-of-the-art Emission Database for Global Atmospheric Research (EDGAR) inventory. This work exposes global emission point-sources of a short-lived carbonated gas, complementing the ongoing large-scale efforts on the monitoring of inorganic pollutants. © 2022, The Author(s).
BibTeX: @article{Franco2022, author = {Franco, Bruno and Clarisse, Lieven and Van Damme, Martin and Hadji-Lazaro, Juliette and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Ethylene industrial emitters seen from space}, journal = {Nature Communications}, year = {2022}, volume = {13}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.1038/s41467-022-34098-8} }
Gordon I, Rothman L, Hargreaves R, Hashemi R, Karlovets E, Skinner F, Conway E, Hill C, Kochanov R, Tan Y, Wcisło P, Finenko A, Nelson K, Bernath P, Birk M, Boudon V, Campargue A, Chance K, Coustenis A, Drouin B, Flaud J, Gamache R, Hodges J, Jacquemart D, Mlawer E, Nikitin A, Perevalov V, Rotger M, Tennyson J, Toon G, Tran H, Tyuterev V, Adkins E, Baker A, Barbe A, Canè E, Császár A, Dudaryonok A, Egorov O, Fleisher A, Fleurbaey H, Foltynowicz A, Furtenbacher T, Harrison J, Hartmann J, Horneman V, Huang X, Karman T, Karns J, Kassi S, Kleiner I, Kofman V, Kwabia-Tchana F, Lavrentieva N, Lee T, Long D, Lukashevskaya A, Lyulin O, Makhnev V, Matt W, Massie S, Melosso M, Mikhailenko S, Mondelain D, Müller H, Naumenko O, Perrin A, Polyansky O, Raddaoui E, Raston P, Reed Z, Rey M, Richard C, Tóbiás R, Sadiek I, Schwenke D, Starikova E, Sung K, Tamassia F, Tashkun S, Vander Auwera J, Vasilenko I, Vigasin A, Villanueva G, Vispoel B, Wagner G, Yachmenev A and Yurchenko S (2022), "The HITRAN2020 molecular spectroscopic database", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 277 [Abstract] [BibTeX] [DOI]
Abstract: The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years). All five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH3F, GeH4, CS2, CH3I and NF3. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules. The HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition. © 2021 The Author(s)
BibTeX: @article{Gordon2022, author = {Gordon, I.E. and Rothman, L.S. and Hargreaves, R.J. and Hashemi, R. and Karlovets, E.V. and Skinner, F.M. and Conway, E.K. and Hill, C. and Kochanov, R.V. and Tan, Y. and Wcisło, P. and Finenko, A.A. and Nelson, K. and Bernath, P.F. and Birk, M. and Boudon, V. and Campargue, A. and Chance, K.V. and Coustenis, A. and Drouin, B.J. and Flaud, J.M. and Gamache, R.R. and Hodges, J.T. and Jacquemart, D. and Mlawer, E.J. and Nikitin, A.V. and Perevalov, V.I. and Rotger, M. and Tennyson, J. and Toon, G.C. and Tran, H. and Tyuterev, V.G. and Adkins, E.M. and Baker, A. and Barbe, A. and Canè, E. and Császár, A.G. and Dudaryonok, A. and Egorov, O. and Fleisher, A.J. and Fleurbaey, H. and Foltynowicz, A. and Furtenbacher, T. and Harrison, J.J. and Hartmann, J.M. and Horneman, V.M. and Huang, X. and Karman, T. and Karns, J. and Kassi, S. and Kleiner, I. and Kofman, V. and Kwabia-Tchana, F. and Lavrentieva, N.N. and Lee, T.J. and Long, D.A. and Lukashevskaya, A.A. and Lyulin, O.M. and Makhnev, V.Yu. and Matt, W. and Massie, S.T. and Melosso, M. and Mikhailenko, S.N. and Mondelain, D. and Müller, H.S.P. and Naumenko, O.V. and Perrin, A. and Polyansky, O.L. and Raddaoui, E. and Raston, P.L. and Reed, Z.D. and Rey, M. and Richard, C. and Tóbiás, R. and Sadiek, I. and Schwenke, D.W. and Starikova, E. and Sung, K. and Tamassia, F. and Tashkun, S.A. and Vander Auwera, J. and Vasilenko, I.A. and Vigasin, A.A. and Villanueva, G.L. and Vispoel, B. and Wagner, G. and Yachmenev, A. and Yurchenko, S.N.}, title = {The HITRAN2020 molecular spectroscopic database}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2022}, volume = {277}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.jqsrt.2021.107949} }
Herrera B, Bezanilla A, Blumenstock T, Dammers E, Hase F, Clarisse L, Magaldi A, Rivera C, Stremme W, Strong K, Viatte C, Van Damme M and Grutter M (2022), "Measurement report: Evolution and distribution of NH3over Mexico City from ground-based and satellite infrared spectroscopic measurements", Atmospheric Chemistry and Physics. Vol. 22(21), pp. 14119 – 14132. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) is the most abundant alkaline compound in the atmosphere, with consequences for the environment, human health, and radiative forcing. In urban environments, it is known to play a key role in the formation of secondary aerosols through its reactions with nitric and sulfuric acids. However, there are only a few studies about NH3 in Mexico City. In this work, atmospheric NH3 was measured over Mexico City between 2012 and 2020 by means of ground-based solar absorption spectroscopy using Fourier transform infrared (FTIR) spectrometers at two sites (urban and remote). Total columns of NH3 were retrieved from the FTIR spectra and compared with data obtained from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument. The diurnal variability of NH3 differs between the two FTIR stations and is strongly influenced by the urban sources. Most of the NH3 measured at the urban station is from local sources, while the NH3 observed at the remote site is most likely transported from the city and surrounding areas. The evolution of the boundary layer and the temperature play a significant role in the recorded seasonal and diurnal patterns of NH3. Although the vertical columns of NH3 are much larger at the urban station, the observed annual cycles are similar for both stations, with the largest values in the warm months, such as April and May. The IASI measurements underestimate the FTIR NH3 total columns by an average of 32.2±27.5 % but exhibit similar temporal variability. The NH3 spatial distribution from IASI shows the largest columns in the northeast part of the city. In general, NH3 total columns over Mexico City measured at the FTIR stations exhibited an average annual increase of 92±3.9×1013 molecules cm-2 yr-1 (urban, from 2012 to 2019) and 8.4±1.4×1013 molecules cm-2 yr-1 (remote, from 2012 to 2020), while IASI data within 20 km of the urban station exhibited an average annual increase of 38±7.6×1013 molecules cm-2 yr-1 from 2008 to 2018. Copyright © 2022 Beatriz Herrera et al.
BibTeX: @article{Herrera2022, author = {Herrera, Beatriz and Bezanilla, Alejandro and Blumenstock, Thomas and Dammers, Enrico and Hase, Frank and Clarisse, Lieven and Magaldi, Adolfo and Rivera, Claudia and Stremme, Wolfgang and Strong, Kimberly and Viatte, Camille and Van Damme, Martin and Grutter, Michel}, title = {Measurement report: Evolution and distribution of NH3over Mexico City from ground-based and satellite infrared spectroscopic measurements}, journal = {Atmospheric Chemistry and Physics}, year = {2022}, volume = {22}, number = {21}, pages = {14119 – 14132}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-22-14119-2022} }
Honet A, Henrard L and Meunier V (2022), "Exact and many-body perturbation solutions of the Hubbard model applied to linear chains", AIP Advances. Vol. 12(3) [Abstract] [BibTeX] [DOI]
Abstract: This study reports on the accuracy of the GW approximation for the treatment of the Hubbard model compared to exact diagonalization (ED) results. We consider not only global quantities, such as the total energy and the density of states, but also the spatial and spin symmetry of wavefunctions via the analysis of the local density of states. GW is part of the more general Green's function approach used to develop many-body approximations. We show that, for small linear chains, the GW approximation corrects the mean-field (MF) approach by reducing the total energy and the magnetization obtained from the MF approximation. The GW energy gap is in better agreement with ED, especially in systems of an even number of atoms where, in contrast to the MF approximation, no plateau is observed below the artificial predicted phase transition. In terms of density of states, the GW approximation induces quasi-particles and side satellite peaks via a splitting process of MF peaks. At the same time, GW slightly modifies the localization (e.g., edges or center) of states. We also use the GW approximation results in the context of Löwdin's symmetry dilemma and show that GW predicts an artificial paramagnetic-antiferromagnetic phase transition at a higher Hubbard parameter than MF does. © 2022 Author(s).
BibTeX: @article{Honet2022, author = {Honet, Antoine and Henrard, Luc and Meunier, Vincent}, title = {Exact and many-body perturbation solutions of the Hubbard model applied to linear chains}, journal = {AIP Advances}, year = {2022}, volume = {12}, number = {3}, note = {All Open Access, Gold Open Access}, doi = {10.1063/5.0082681} }
Koukouli M-E, Michailidis K, Hedelt P, Taylor IA, Inness A, Clarisse L, Balis D, Efremenko D, Loyola D, Grainger RG and Retscher C (2022), "Volcanic SO2layer height by TROPOMI/S5P: evaluation against IASI/MetOp and CALIOP/CALIPSO observations", Atmospheric Chemistry and Physics. Vol. 22(8), pp. 5665 – 5683. [Abstract] [BibTeX] [DOI]
Abstract: Volcanic eruptions eject large amounts of ash and trace gases such as sulfur dioxide (SO2) into the atmosphere. A significant difficulty in mitigating the impact of volcanic SO2 clouds on air traffic safety is that these gas emissions can be rapidly transported over long distances. The use of space-borne instruments enables the global monitoring of volcanic SO2 emissions in an economical and risk-free manner. Within the European Space Agency (ESA) Sentinel-5p+ Innovation project, the S5P SO2 layer height (S5P+I: SO2LH) activities led to the improvements of the retrieval algorithm and generation of the corresponding near real-time S5P SO2 LH products. These are currently operationally provided, in near real-time, by the German Aerospace Center (DLR) within the framework of the Innovative Products for Analyses of Atmospheric Composition (INPULS) project. The main aim of this paper is to present its extensive verification, accomplished within the S5P+I: SO2LH project, over major recent volcanic eruptions, against collocated space-borne measurements from the IASI/Metop and CALIOP/CALIPSO instruments as well as assess its impact on the forecasts provided by the Copernicus Atmospheric Monitoring Service (CAMS). The mean difference between S5P and IASI observations for the Raikoke 2019, the Nishinoshima 2020 and the La Soufrière-St Vincent 2021 eruptive periods is g-1/4 0.5 ± 3 km, while for the Taal 2020 eruption, a larger difference was found, between 3 ± 3 km and 4 ± 3 km. The comparison of the daily mean SO2 LH further demonstrates the capabilities of this near real-time product, with slopes between 0.8 and 1 and correlation coefficients ranging between 0.6 and 0.8. Comparisons between the S5P SO2 LH and the CALIOP/CALIPSO ash plumes revealed an expected bias at -2.5 ± 2 km, considering that the injected SO2 and ash plume locations do not always coincide over an eruption. Furthermore, the CAMS assimilation of the S5P SO2 LH product led to much improved model output against the non-assimilated IASI LH, with a mean difference of 1.5 ± 2 km, compared to the original CAMS analysis, and improved the geographical spread of the Raikoke volcanic plume following the eruptive days. © 2022 Maria-Elissavet Koukouli et al.
BibTeX: @article{Koukouli2022, author = {Koukouli, Maria-Elissavet and Michailidis, Konstantinos and Hedelt, Pascal and Taylor, Isabelle A. and Inness, Antje and Clarisse, Lieven and Balis, Dimitris and Efremenko, Dmitry and Loyola, Diego and Grainger, Roy G. and Retscher, Christian}, title = {Volcanic SO2layer height by TROPOMI/S5P: evaluation against IASI/MetOp and CALIOP/CALIPSO observations}, journal = {Atmospheric Chemistry and Physics}, year = {2022}, volume = {22}, number = {8}, pages = {5665 – 5683}, doi = {10.5194/acp-22-5665-2022} }
Li J, Gaigalas G, Bieroń J, Ekman J, Jönsson P, Godefroid M and Froese Fischer C (2022), "Re-Evaluation of the Nuclear Magnetic Octupole Moment of 209Bi", Atoms. Vol. 10(4) [Abstract] [BibTeX] [DOI]
Abstract: We modified the Hfs92 code of the GRASP package in order to describe the magnetic octupole hyperfine interaction. To illustrate the utility of the modified code, we carried out state-of-the-art calculations of the electronic factors of the magnetic octupole hyperfine interaction constants for levels in the ground configuration of the Bi atom. The nuclear magnetic octupole moment of the (Formula presented.) Bi isotope was extracted by combining old measurements of the hyperfine structures of (Formula presented.) [Hull, R.; Brink, G. Phys. Rev. A 1970, 1, 685] and (Formula presented.) [Landman, D.A.; Lurio, A. Phys. Rev. A 1970, 1, 1330] using the atomic-beam magnetic-resonance technique with our theoretical electronic factors. The present extracted octupole moment was consistent with all the available values but the one obtained in the single-particle nuclear shell model approximation. This observation supports the previous finding that nuclear many-body effects, such as the core polarization, significantly contribute to the nuclear magnetic octupole moment in the case of (Formula presented.) Bi. © 2022 by the authors.
BibTeX: @article{Li2022a, author = {Li, Jiguang and Gaigalas, Gediminas and Bieroń, Jacek and Ekman, Jörgen and Jönsson, Per and Godefroid, Michel and Froese Fischer, Charlotte}, title = {Re-Evaluation of the Nuclear Magnetic Octupole Moment of 209Bi}, journal = {Atoms}, year = {2022}, volume = {10}, number = {4}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atoms10040132} }
Li J, Zhang C, Del Zanna G, Jönsson P, Godefroid M, Gaigalas G, Rynkun P, Radziūte L, Wang K, Si R and Chen C (2022), "Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: C-like Ions from O iii to Mg vii", Astrophysical Journal, Supplement Series. Vol. 260(2) [Abstract] [BibTeX] [DOI]
Abstract: Large-scale multiconfiguration Dirac-Hartree-Fock calculations are provided for the n ≤ 5 states in C-like ions from O iii to Mg vii. Electron correlation effects are accounted for by using large configuration state function expansions, built from sets of orbitals with principal quantum numbers n ≤ 10. An accurate and complete data set of excitation energies, wavelengths, radiative transition parameters, and lifetimes is offered for the 156 (196, 215, 272, 318) lowest states of the 2s 22p 2, 2s2p 3, 2p 4, 2s 22p3s, 2s 22p3p, 2s 22p3d, 2s2p 23s, 2s2p 23p, 2s2p 23d, 2p 33s, 2p 33p, 2p 33d, 2s 22p4s, 2s 22p4p, 2s 22p4d, 2s 22p4f, 2s2p 24s, 2s2p 24p, 2s2p 24d, 2s2p 24f, 2s 22p5s, 2s 22p5p, 2s 22p5d, 2s 22p5f, and 2s 22p5g configurations in O iii (F iv, Ne v, Na vi, Mg vii). By comparing available experimental wavelengths with the MCDHF results, the previous line identifications for the n = 5, 4, 3 → n = 2 transitions of Na vi in the X-ray and EUV wavelength range are revised. For several previous identifications discrepancies are found, and tentative new (or revised) identifications are proposed. A consistent atomic data set including both energy and transition data with spectroscopic accuracy is provided for the lowest hundreds of states for C-like ions from O iii to Mg vii. © 2022. The Author(s). Published by the American Astronomical Society.
BibTeX: @article{Li2022, author = {Li, J.Q. and Zhang, C.Y. and Del Zanna, G. and Jönsson, P. and Godefroid, M. and Gaigalas, G. and Rynkun, P. and Radziūte, L. and Wang, K. and Si, R. and Chen, C.Y.}, title = {Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: C-like Ions from O iii to Mg vii}, journal = {Astrophysical Journal, Supplement Series}, year = {2022}, volume = {260}, number = {2}, note = {All Open Access, Gold Open Access}, doi = {10.3847/1538-4365/ac63ae} }
Luo Z, Zhang Y, Chen W, Van Damme M, Coheur P-F and Clarisse L (2022), "Estimating global ammonia (NH3) emissions based on IASI observations from 2008 to 2018", Atmospheric Chemistry and Physics. Vol. 22(15), pp. 10375 – 10388. [Abstract] [BibTeX] [DOI]
Abstract: Emissions of ammonia (NH3) to the atmosphere impact human health, climate, and ecosystems via their critical contributions to secondary aerosol formation. However, the estimation of NH3 emissions is associated with large uncertainties because of inadequate knowledge about agricultural sources. Here, we use satellite observations from the Infrared Atmospheric Sounding Interferometer (IASI) and simulations from the GEOS-Chem model to constrain global NH3 emissions over the period from 2008 to 2018. We update the prior NH3 emission fluxes with the ratio between biases in simulated NH3 concentrations and effective NH3 lifetimes against the loss of the NHx family. In contrast to the approximate factor of 2 discrepancies between top-down and bottom-up emissions found in previous studies, our method results in a global land NH3 emission of 78 (70-92)g Tgg a-1, which is g 1/430g % higher than the bottom-up estimates. Regionally, we find that the bottom-up inventory underestimates NH3 emissions over South America and tropical Africa by 60g %-70g %, indicating underrepresentation of agricultural sources in these regions. We find a good agreement within 10g % between bottom-up and top-down estimates over the US, Europe, and eastern China. Our results also show significant increases in NH3 emissions over India (13g % per decade), tropical Africa (33g % per decade), and South America (18g % per decade) during our study period, which is consistent with the intensifying agricultural activity in these regions in the past decade. We find that the inclusion of the sulfur dioxide (SO2) column observed by satellite is crucial for more accurate inference of NH3 emission trends over important source regions such as India and China where SO2 emissions have changed rapidly in recent years. © 2022 Copernicus GmbH. All rights reserved.
BibTeX: @article{Luo2022, author = {Luo, Zhenqi and Zhang, Yuzhong and Chen, Wei and Van Damme, Martin and Coheur, Pierre-François and Clarisse, Lieven}, title = {Estimating global ammonia (NH3) emissions based on IASI observations from 2008 to 2018}, journal = {Atmospheric Chemistry and Physics}, year = {2022}, volume = {22}, number = {15}, pages = {10375 – 10388}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-22-10375-2022} }
Meurisse M, Van Oyen H, Blot K, Catteau L, Serrien B, Klamer S, Cauët E, Robert A and Van Goethem N (2022), "Evaluating methodological approaches to assess the severity of infection with SARS-CoV-2 variants: scoping review and applications on Belgian COVID-19 data", BMC Infectious Diseases. Vol. 22(1) [Abstract] [BibTeX] [DOI]
Abstract: Background: Differences in the genetic material of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants may result in altered virulence characteristics. Assessing the disease severity caused by newly emerging variants is essential to estimate their impact on public health. However, causally inferring the intrinsic severity of infection with variants using observational data is a challenging process on which guidance is still limited. We describe potential limitations and biases that researchers are confronted with and evaluate different methodological approaches to study the severity of infection with SARS-CoV-2 variants. Methods: We reviewed the literature to identify limitations and potential biases in methods used to study the severity of infection with a particular variant. The impact of different methodological choices is illustrated by using real-world data of Belgian hospitalized COVID-19 patients. Results: We observed different ways of defining coronavirus disease 2019 (COVID-19) disease severity (e.g., admission to the hospital or intensive care unit versus the occurrence of severe complications or death) and exposure to a variant (e.g., linkage of the sequencing or genotyping result with the patient data through a unique identifier versus categorization of patients based on time periods). Different potential selection biases (e.g., overcontrol bias, endogenous selection bias, sample truncation bias) and factors fluctuating over time (e.g., medical expertise and therapeutic strategies, vaccination coverage and natural immunity, pressure on the healthcare system, affected population groups) according to the successive waves of COVID-19, dominated by different variants, were identified. Using data of Belgian hospitalized COVID-19 patients, we were able to document (i) the robustness of the analyses when using different variant exposure ascertainment methods, (ii) indications of the presence of selection bias and (iii) how important confounding variables are fluctuating over time. Conclusions: When estimating the unbiased marginal effect of SARS-CoV-2 variants on the severity of infection, different strategies can be used and different assumptions can be made, potentially leading to different conclusions. We propose four best practices to identify and reduce potential bias introduced by the study design, the data analysis approach, and the features of the underlying surveillance strategies and data infrastructure. © 2022, The Author(s).
BibTeX: @article{Meurisse2022, author = {Meurisse, Marjan and Van Oyen, Herman and Blot, Koen and Catteau, Lucy and Serrien, Ben and Klamer, Sofieke and Cauët, Emilie and Robert, Annie and Van Goethem, Nina}, title = {Evaluating methodological approaches to assess the severity of infection with SARS-CoV-2 variants: scoping review and applications on Belgian COVID-19 data}, journal = {BMC Infectious Diseases}, year = {2022}, volume = {22}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.1186/s12879-022-07777-6} }
Pan LL, Kinnison D, Liang Q, Chin M, Santee ML, Flemming J, Smith WP, Honomichl SB, Bresch JF, Lait LR, Zhu Y, Tilmes S, Colarco PR, Warner J, Vuvan A, Clerbaux C, Atlas EL, Newman PA, Thornberry T, Randel WJ and Toon OB (2022), "A Multimodel Investigation of Asian Summer Monsoon UTLS Transport Over the Western Pacific", Journal of Geophysical Research: Atmospheres. Vol. 127(24) [Abstract] [BibTeX] [DOI]
Abstract: The Asian summer monsoon (ASM) as a chemical transport system is investigated using a suite of models in preparation for an airborne field campaign over the Western Pacific. Results show that the dynamical process of anticyclone eddy shedding in the upper troposphere rapidly transports convectively uplifted Asian boundary layer air masses to the upper troposphere and lower stratosphere over the Western Pacific. The models show that the transported air masses contain significantly enhanced aerosol loading and a complex chemical mixture of trace gases that are relevant to ozone chemistry. The chemical forecast models consistently predict the occurrence of the shedding events, but the predicted concentrations of transported trace gases and aerosols often differ between models. The airborne measurements to be obtained in the field campaign are expected to help reduce the model uncertainties. Furthermore, the large-scale seasonal chemical structure of the monsoon system is obtained from modeled carbon monoxide, a tracer of the convective transport of pollutants, which provides a new perspective of the ASM circulation, complementing the dynamical characterization of the monsoon. © 2022. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Pan2022, author = {Pan, Laura L. and Kinnison, Douglas and Liang, Qing and Chin, Mian and Santee, Michelle L. and Flemming, Johannes and Smith, Warren P. and Honomichl, Shawn B. and Bresch, James F. and Lait, Leslie R. and Zhu, Yunqian and Tilmes, Simone and Colarco, Peter R. and Warner, Juying and Vuvan, Adrien and Clerbaux, Cathy and Atlas, Elliot L. and Newman, Paul A. and Thornberry, Troy and Randel, William J. and Toon, Owen B.}, title = {A Multimodel Investigation of Asian Summer Monsoon UTLS Transport Over the Western Pacific}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2022}, volume = {127}, number = {24}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2022JD037511} }
Pozzer A, Reifenberg SF, Kumar V, Franco B, Kohl M, Taraborrelli D, Gromov S, Ehrhart S, Jöckel P, Sander R, Fall V, Rosanka S, Karydis V, Akritidis D, Emmerichs T, Crippa M, Guizzardi D, Kaiser JW, Clarisse L, Kiendler-Scharr A, Tost H and Tsimpidi A (2022), "Simulation of organics in the atmosphere: evaluation of EMACv2.54 with the Mainz Organic Mechanism (MOM) coupled to the ORACLE (v1.0) submodel", Geoscientific Model Development. Vol. 15(6), pp. 2673 – 2710. [Abstract] [BibTeX] [DOI]
Abstract: An updated and expanded representation of organics in the chemistry general circulation model EMAC (ECHAM5/MESSy for Atmospheric Chemistry) has been evaluated. First, the comprehensive Mainz Organic Mechanism (MOM) in the submodel MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) was activated with explicit degradation of organic species up to five carbon atoms and a simplified mechanism for larger molecules. Second, the ORACLE submodel (version 1.0) now considers condensation on aerosols for all organics in the mechanism. Parameterizations for aerosol yields are used only for the lumped species that are not included in the explicit mechanism. The simultaneous usage of MOM and ORACLE allows an efficient estimation of not only the chemical degradation of the simulated volatile organic compounds but also the contribution of organics to the growth and fate of (organic) aerosol, with the complexity of the mechanism largely increased compared to EMAC simulations with more simplified chemistry. The model evaluation presented here reveals that the OH concentration is reproduced well globally, whereas significant biases for observed oxygenated organics are present. We also investigate the general properties of the aerosols and their composition, showing that the more sophisticated and process-oriented secondary aerosol formation does not degrade the good agreement of previous model configurations with observations at the surface, allowing further research in the field of gas-aerosol interactions. Copyright: © 2022 Andrea Pozzer et al.
BibTeX: @article{Pozzer2022, author = {Pozzer, Andrea and Reifenberg, Simon F. and Kumar, Vinod and Franco, Bruno and Kohl, Matthias and Taraborrelli, Domenico and Gromov, Sergey and Ehrhart, Sebastian and Jöckel, Patrick and Sander, Rolf and Fall, Veronica and Rosanka, Simon and Karydis, Vlassis and Akritidis, Dimitris and Emmerichs, Tamara and Crippa, Monica and Guizzardi, Diego and Kaiser, Johannes W. and Clarisse, Lieven and Kiendler-Scharr, Astrid and Tost, Holger and Tsimpidi, Alexandra}, title = {Simulation of organics in the atmosphere: evaluation of EMACv2.54 with the Mainz Organic Mechanism (MOM) coupled to the ORACLE (v1.0) submodel}, journal = {Geoscientific Model Development}, year = {2022}, volume = {15}, number = {6}, pages = {2673 – 2710}, note = {All Open Access, Gold Open Access}, doi = {10.5194/gmd-15-2673-2022} }
Safieddine S, Clerbaux C, Clarisse L, Whitburn S and Eltahir E (2022), "Present and future land surface and wet bulb temperatures in the Arabian Peninsula", Environmental Research Letters. Vol. 17(4) [Abstract] [BibTeX] [DOI]
Abstract: The Arabian Peninsula exhibits extreme hot summers and has one of the world's largest population growths. We use satellite observations and reanalysis as well as climate model projections to analyze morning and evening land surface temperatures (LSTs), to refer to processes at the surface, and wet bulb temperatures (WBTs) to measure human heat stress. We focus on three regions: the Persian Gulf and Gulf of Oman, the inland capital of Saudi Arabia, Riyadh and the irrigated agricultural region in Al-Jouf, Saudi Arabia. This study shows that the time of day is important when studying LST and WBT, with current and future WBT higher in the early summer evenings. It also shows that the effect of humidity brought from waterbodies or through irrigation can significantly increase heat stress. Over the coasts of the Peninsula, humidity decreases LST but increases heat stress via WBT values higher than 25 °C in the evening. Riyadh, located in the heart of the Peninsula has lower WBT of 15 °C-17.5 °C and LST reaching 42.5 °C. Irrigation in the Al-Jouf province decreases LST by up to 10° with respect to its surroundings, while it increases WBT by up to 2.5°. Climate projections over the Arabian Peninsula suggest that global efforts will determine the survivability in this region. The projected increase in LST and WBT are +6 °C and +4 °C, respectively, in the Persian Gulf and Riyadh by the end of the century, posing significant risks on human survivability in the Peninsula unless strict climate mitigation takes place. © 2022 The Author(s). Published by IOP Publishing Ltd.
BibTeX: @article{Safieddine2022, author = {Safieddine, S. and Clerbaux, C. and Clarisse, L. and Whitburn, S. and Eltahir, E.A.B.}, title = {Present and future land surface and wet bulb temperatures in the Arabian Peninsula}, journal = {Environmental Research Letters}, year = {2022}, volume = {17}, number = {4}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1748-9326/ac507c} }
Schiffmann S, Li J, Ekman J, Gaigalas G, Godefroid M, Jönsson P and Bieroń J (2022), "Relativistic radial electron density functions and natural orbitals from GRASP2018", Computer Physics Communications. Vol. 278 [Abstract] [BibTeX] [DOI]
Abstract: A new module, RDENSITY, of the GRASP2018 package [1] is presented for evaluating the radial electron density function of an atomic state described by a multiconfiguration Dirac-Hartree-Fock or configuration interaction wave function in the fully relativistic scheme. The present module is the relativistic version of DENSITY [2] that was developed for the ATSP2K package [3]. The calculation of the spin-angular factors entering in the expression of the expectation value of the density operator is performed using the angular momentum theory in orbital, spin, and quasispin spaces, adopting a generalized graphical technique [4]. The natural orbitals (NOs) are evaluated from the diagonalization of the density matrix, taking advantage of its κ-block structure. The features of the code are discussed in detail, focusing on the advantages and properties of the NOs and on the electron radial density picture as a mean for investigating electron correlation and relativistic effects. Program summary: Program title: RDENSITY CPC Library link to program files: https://doi.org/10.17632/4sdrf5kfzd.1 Licensing provisions: MIT license Programming language: FORTRAN 95 Nature of problem: This program determines the atomic electron radial density in the MCDHF approximation. It also evaluates the natural orbitals by diagonalizing the density matrix. Solution method: Building the density operator using second quantization - Spherical symmetry averaging - Evaluating the matrix elements of the one-body excitation operators in the configuration state function (CSF) space using the angular momentum theory in orbital, spin, and quasispin spaces. Additional comments including restrictions and unusual features: We evaluated the electron radial density and natural orbitals of the lowest states in Mg II. The MCDHF wave functions consisted of four non-interacting blocks and a total of 79 000 CSFs. The calculation took around 2 minutes using a computer with an Intel(R) Xeon(R) Gold 6148 processor @ 2.4 GHz. References: [1] GRASP2018 - A Fortran 95 version of the General Relativistic Atomic Structure Package, C. Froese Fischer, G. Gaigalas, P. Jönsson and J. Bieroń, Comput. Phys. Commun. 237 (2019) 184-187. [2] Multiconfiguration electron density function for the ATSP2K-package, A. Borgoo, O. Scharf, G. Gaigalas and M. Godefroid, Comput. Phys. Commun. 181 (2010) 426-439 [3] An MCHF atomic-structure package for large-scale calculations, C. Froese Fischer, G. Tachiev, G. Gaigalas, and M. Godefroid, Comput. Phys. Commun. 176 (2007) 559-579 [4] An efficient approach for spin-angular integrations in atomic structure calculations, G. Gaigalas, Z. Rudzikas, and C. Froese Fischer, J. Phys. B: At. Mol. Phys., 30 (1997) 3747-3771 © 2022
BibTeX: @article{Schiffmann2022, author = {Schiffmann, S. and Li, J.G. and Ekman, J. and Gaigalas, G. and Godefroid, M. and Jönsson, P. and Bieroń, J.}, title = {Relativistic radial electron density functions and natural orbitals from GRASP2018}, journal = {Computer Physics Communications}, year = {2022}, volume = {278}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.cpc.2022.108403} }
Sutcliffe B and Woolley RG (2022), "Is Chemistry Really Founded in Quantum Mechanics?", Synthese Library. Vol. 461, pp. 173 – 202. [Abstract] [BibTeX] [DOI]
Abstract: The solutions of the Schrödinger Coulomb Hamiltonian, in which the nuclei are fixed and identified, are discussed as providing a theoretical foundation for chemistry. It is shown that supportive relevant aspects of these clamped-nuclei solutions do not arise in solutions of the full problem; further, it is not, at present, possible to regard the clamped-nuclei Hamiltonian as an approximation to the full Hamiltonian. © 2022, Springer Nature Switzerland AG.
BibTeX: @article{Sutcliffe2022, author = {Sutcliffe, Brian and Woolley, R. Guy}, title = {Is Chemistry Really Founded in Quantum Mechanics?}, journal = {Synthese Library}, year = {2022}, volume = {461}, pages = {173 – 202}, doi = {10.1007/978-3-030-98373-4_8} }
Theys N, Lerot C, Brenot H, van Gent J, De Smedt I, Clarisse L, Burton M, Varnam M, Hayer C, Esse B and Van Roozendael M (2022), "Improved retrieval of SO2 plume height from TROPOMI using an iterative Covariance-Based Retrieval Algorithm", Atmospheric Measurement Techniques. Vol. 15(16), pp. 4801 – 4817. [Abstract] [BibTeX] [DOI]
Abstract: Knowledge of sulfur dioxide layer height (SO2 LH) is important to understand volcanic eruption processes, the climate impact of SO2 emissions and to mitigate volcanic risk for civil aviation. However, the estimation of SO2 LH from ground-based instruments is challenging in particular for rapidly evolving and sustained eruptions. Satellite wide-swath nadir observations have the advantage to cover large-scale plumes and the potential to provide key information on SO2 LH. In the ultraviolet, SO2 LH retrievals leverage the fact that, for large SO2 columns, the light path and its associated air mass factor (AMF) depends on the SO2 absorption (and therefore on the vertical distribution of SO2), and SO2 LH information can be obtained from the analysis of measured back-scattered radiances coupled with radiative transfer simulations. However, existing algorithms are mainly sensitive to SO2 LH for SO2 vertical columns of at least 20 DU. Here we develop a new SO2 LH algorithm and apply it to observations from the high-spatial-resolution TROPOspheric Monitoring Instrument (TROPOMI). It is based on an SO2 optical depth look-up table and an iterative approach. The strength of this scheme lies in the fact that it is a Covariance-Based Retrieval Algorithm (COBRA; Theys et al., 2021). This means that the SO2-free contribution of the measured optical depth is treated in an optimal way, resulting in an improvement of the SO2 LH sensitivity to SO2 columns as low as 5 DU, with a precision better than 2 km. We demonstrate the value of this new data through a number of examples and comparison with satellite plume height estimates (from IASI and CALIOP), and back-trajectory analyses. The comparisons indicate an SO2 LH accuracy of 1–2 km, except for some difficult observation conditions, in particular for optically thick ash plumes or partially SO2-filled scenes. © Author(s) 2022.
BibTeX: @article{Theys2022, author = {Theys, Nicolas and Lerot, Christophe and Brenot, Hugues and van Gent, Jeroen and De Smedt, Isabelle and Clarisse, Lieven and Burton, Mike and Varnam, Matthew and Hayer, Catherine and Esse, Benjamin and Van Roozendael, Michel}, title = {Improved retrieval of SO2 plume height from TROPOMI using an iterative Covariance-Based Retrieval Algorithm}, journal = {Atmospheric Measurement Techniques}, year = {2022}, volume = {15}, number = {16}, pages = {4801 – 4817}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-15-4801-2022} }
Tidiga M, Berthet G, Jégou F, Kloss C, Bègue N, Vernier J-P, Renard J-B, Bossolasco A, Clarisse L, Taha G, Portafaix T, Deshler T, Wienhold FG, Godin-Beekmann S, Payen G, Metzger J-M, Duflot V and Marquestaut N (2022), "Variability of the Aerosol Content in the Tropical Lower Stratosphere from 2013 to 2019: Evidence of Volcanic Eruption Impacts", Atmosphere. Vol. 13(2) [Abstract] [BibTeX] [DOI]
Abstract: This paper quantifies the tropical stratospheric aerosol content as impacted by volcanic events over the 2013–2019 period. We use global model simulations by the Whole Atmosphere Community Climate Model (WACCM) which is part of the Community Earth System Model version 1.0 (CESM1). WACCM is associated with the Community Aerosol and Radiation Model for Atmospheres (CARMA) sectional aerosol microphysics model which includes full sulphur chemical and microphysical cycles with no a priori assumption on particle size. Five main volcanic events (Kelud, Calbuco, Ambae, Raikoke and Ulawun) have been reported and are shown to have significantly influenced the stratospheric aerosol layer in the tropics, either through direct injection in this region or through transport from extra-tropical latitudes. Space-borne data as well as ground-based lidar and balloon-borne in situ observations are used to evaluate the model calculations in terms of aerosol content, vertical distribution, optical and microphysical properties, transport and residence time of the various volcanic plumes. Overall, zonal mean model results reproduce the occurrence and vertical extents of the plumes derived from satellite observations but shows some discrepancies for absolute values of extinction and of stratospheric aerosol optical depth (SAOD). Features of meridional transport of the plumes emitted from extra-tropical latitudes are captured by the model but simulated absolute values of SAOD differ from 6 to 200% among the various eruptions. Simulations tend to agree well with observed in situ vertical profiles for the Kelud and Calbuco plumes but this is likely to depend on the period for which comparison is done. Some explanations for the model– measurement discrepancies are discussed such as the inaccurate knowledge of the injection parameters and the presence of ash not accounted in the simulations. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
BibTeX: @article{Tidiga2022, author = {Tidiga, Mariam and Berthet, Gwenaël and Jégou, Fabrice and Kloss, Corinna and Bègue, Nelson and Vernier, Jean-Paul and Renard, Jean-Baptiste and Bossolasco, Adriana and Clarisse, Lieven and Taha, Ghassan and Portafaix, Thierry and Deshler, Terry and Wienhold, Frank G. and Godin-Beekmann, Sophie and Payen, Guillaume and Metzger, Jean-Marc and Duflot, Valentin and Marquestaut, Nicolas}, title = {Variability of the Aerosol Content in the Tropical Lower Stratosphere from 2013 to 2019: Evidence of Volcanic Eruption Impacts}, journal = {Atmosphere}, year = {2022}, volume = {13}, number = {2}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atmos13020250} }
Van Damme M, Clarisse L, Stavrakou T, Wichink Kruit R, Sellekaerts L, Viatte C, Clerbaux C and Coheur P-F (2022), "On the weekly cycle of atmospheric ammonia over European agricultural hotspots", Scientific Reports. Vol. 12(1) [Abstract] [BibTeX] [DOI]
Abstract: The presence of a weekly cycle in the abundance of an atmospheric constituent is a typical fingerprint for the anthropogenic nature of its emission sources. However, while ammonia is mainly emitted as a consequence of human activities, a weekly cycle has never been detected in its abundances at large scale. We expose here for the first time the presence of a weekend effect in the NH3 total columns measured by the IASI satellite sounder over the main agricultural source regions in Europe: northwestern Europe (Belgium-the Netherlands-northwest Germany), the Po Valley, Brittany, and, to a lesser extent, the Ebro Valley. A decrease of 15% relative to the weekly mean is seen on Sunday–Monday observations in northwestern Europe, as a result of reduced NH3 emissions over the weekend. This is confirmed by in situ NH3 concentration data from the National Air Quality Monitoring Network in the Netherlands, where an average reduction of 10% is found around midnight on Sunday. The identified weekend effect presents a strong seasonal variability, with two peaks, one in spring and one in summer, coinciding with the two main (manure) fertilization periods. In spring, a reduction on Sunday–Monday up to 53 and 26% is found in the NH3 satellite columns and in situ concentrations, respectively, as fertilization largely drives atmospheric NH3 abundances at this time of the year. © 2022, The Author(s).
BibTeX: @article{VanDamme2022, author = {Van Damme, Martin and Clarisse, Lieven and Stavrakou, Trissevgeni and Wichink Kruit, Roy and Sellekaerts, Louise and Viatte, Camille and Clerbaux, Cathy and Coheur, Pierre-François}, title = {On the weekly cycle of atmospheric ammonia over European agricultural hotspots}, journal = {Scientific Reports}, year = {2022}, volume = {12}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.1038/s41598-022-15836-w} }
Viatte C, Abeed R, Yamanouchi S, Porter WC, Safieddine S, Van Damme M, Clarisse L, Herrera B, Grutter M, Coheur P-F, Strong K and Clerbaux C (2022), "NH3 spatiotemporal variability over Paris, Mexico City, and Toronto, and its link to PM2.5 during pollution events", Atmospheric Chemistry and Physics. Vol. 22(19), pp. 12907 – 12922. [Abstract] [BibTeX] [DOI]
Abstract: Megacities can experience high levels of fine particulate matter (PM2.5) pollution linked to ammonia (NH3) mainly emitted from agricultural activities. Here, we investigate such pollution in the cities of Paris, Mexico, and Toronto, each of which have distinct emission sources, agricultural regulations, and topography. Ten years of measurements from the infrared atmospheric sounding interferometer (IASI) are used to assess the spatiotemporal NH3 variability over and around the three cities. In Europe and North America, we determine that temperature is associated with the increase in NH3 atmospheric concentrations with a coefficient of determination (r2) of 0.8 over agricultural areas. The variety of the NH3 sources (industry and agricultural) and the weaker temperature seasonal cycle in southern North America induce a lower correlation factor (r2Combining double low line0.5). The three regions are subject to long-range transport of NH3, as shown using HYSPLIT cluster back trajectories. The highest NH3 concentrations measured at the city scale are associated with air masses coming from the surrounding and north/northeast regions of Paris, the south/southwest areas of Toronto, and the southeast/southwest zones of Mexico City. Using NH3 and PM2.5 measurements derived from IASI and surface observations from 2008 to 2017, annually frequent pollution events are identified in the three cities. Wind roses reveal statistical patterns during these pollution events with dominant northeast/southwest directions in Paris and Mexico City, and the transboundary transport of pollutants from the United States in Toronto. To check how well chemistry transport models perform during pollution events, we evaluate simulations made using the GEOS-Chem model for March 2011. In these simulations we find that NH3 concentrations are underestimated overall, though day-to-day variability is well represented. PM2.5 is generally underestimated over Paris and Mexico City, but overestimated over Toronto. © Author(s) 2022.
BibTeX: @article{Viatte2022, author = {Viatte, Camille and Abeed, Rimal and Yamanouchi, Shoma and Porter, William C. and Safieddine, Sarah and Van Damme, Martin and Clarisse, Lieven and Herrera, Beatriz and Grutter, Michel and Coheur, Pierre-Francois and Strong, Kimberly and Clerbaux, Cathy}, title = {NH3 spatiotemporal variability over Paris, Mexico City, and Toronto, and its link to PM2.5 during pollution events}, journal = {Atmospheric Chemistry and Physics}, year = {2022}, volume = {22}, number = {19}, pages = {12907 – 12922}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-22-12907-2022} }
Vohra K, Marais EA, Bloss WJ, Schwartz J, Mickley LJ, Van Damme M, Clarisse L and Coheur P-F (2022), "Rapid rise in premature mortality due to anthropogenic air pollution in fast-growing tropical cities from 2005 to 2018", Science Advances. Vol. 8(14) [Abstract] [BibTeX] [DOI]
Abstract: Tropical cities are experiencing rapid growth but lack routine air pollution monitoring to develop prescient air quality policies. Here, we conduct targeted sampling of recent (2000s to 2010s) observations of air pollutants from space-based instruments over 46 fast-growing tropical cities. We quantify significant annual increases in nitrogen dioxide (NO2) (1 to 14%), ammonia (2 to 12%), and reactive volatile organic compounds (1 to 11%) in most cities, driven almost exclusively by emerging anthropogenic sources rather than traditional biomass burning. We estimate annual increases in urban population exposure to air pollutants of 1 to 18% for fine particles (PM2.5) and 2 to 23% for NO2 from 2005 to 2018 and attribute 180,000 (95% confidence interval: -230,000 to 590,000) additional premature deaths in 2018 (62% increase relative to 2005) to this increase in exposure. These cities are predicted to reach populations of up to 80 million people by 2100, so regulatory action targeting emerging anthropogenic sources is urgently needed. © 2022 The Authors.
BibTeX: @article{Vohra2022, author = {Vohra, Karn and Marais, Eloise A. and Bloss, William J. and Schwartz, Joel and Mickley, Loretta J. and Van Damme, Martin and Clarisse, Lieven and Coheur, Pierre-F.}, title = {Rapid rise in premature mortality due to anthropogenic air pollution in fast-growing tropical cities from 2005 to 2018}, journal = {Science Advances}, year = {2022}, volume = {8}, number = {14}, note = {All Open Access, Green Open Access}, doi = {10.1126/sciadv.abm4435} }
Wang W, Liu C, Clarisse L, Van Damme M, Coheur P-F, Xie Y, Shan C, Hu Q, Sun Y and Jones N (2022), "Ground-based measurements of atmospheric NH3 by Fourier transform infrared spectrometry at Hefei and comparisons with IASI data", Atmospheric Environment. Vol. 287 [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric ammonia (NH3) plays an important role in the formation of fine particulate matter, leading to severe environmental degradation and human health issues. In this work, ground-based Fourier transform infrared spectrometry (FTIR) observations are used to obtain the total columns of atmospheric NH3 at Hefei, China, from December 2016 to December 2020. After the presentation of the retrieval algorithm and uncertainty budget, we perform a spatio-temporal analysis of the dataset. Over the four years, NH3 columns have been increasing by 15.82% (2017–2018), 3.83% (2018–2019) and 3.68% (2019–2020). A clear seasonal cycle is observed, with the largest surface concentrations (12.93 ± 6.40 ppb) observed in June to August, and the lowest (4.08± 2.66 ppb) in November to January. The diurnal cycles of NH3 exhibit increased morning and afternoon concentrations. Interpretation of the diurnal cycles is difficult, however, the absence of a peak during rush hours, and the absence of correlation with CO and NO2 suggest that agriculture and not traffic is the main source of NH3 at Hefei. The polar plots of NH3 columns with wind and back trajectories of air masses calculated by the HYSPLIT model confirmed that agriculture was the dominant source of ammonia in four seasons, while urban anthropogenic emissions contributed to the high level of NH3 in summer over the Hefei site. We end this paper with a short validation exercise of NH3 columns retrieved from measurements of the IASI satellite data with the FTIR measurements over Hefei. Correlation coefficients (R) between the two datasets are 0.79 and 0.75 for IASI-A and IASI-B, with the slope of 0.96 and 1.10, respectively. The mean difference is −3.44 × 1015 and −3.96 × 1015 molec cm−2, with standard deviation of 7.16 × 1015 and 8.10 × 1015 molec cm−2, respectively. These results demonstrate the IASI and FTIR data, over Hefei, are in broad agreement. © 2022 The Authors
BibTeX: @article{Wang2022, author = {Wang, Wei and Liu, Cheng and Clarisse, Lieven and Van Damme, Martin and Coheur, Pierre-François and Xie, Yu and Shan, Changgong and Hu, Qihou and Sun, Youwen and Jones, Nicholas}, title = {Ground-based measurements of atmospheric NH3 by Fourier transform infrared spectrometry at Hefei and comparisons with IASI data}, journal = {Atmospheric Environment}, year = {2022}, volume = {287}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.atmosenv.2022.119256} }
Wespes C, Ronsmans G, Clarisse L, Solomon S, Hurtmans D, Clerbaux C and Coheur P-F (2022), "Polar stratospheric nitric acid depletion surveyed from a decadal dataset of IASI total columns", Atmospheric Chemistry and Physics. Vol. 22(16), pp. 10993 – 11007. [Abstract] [BibTeX] [DOI]
Abstract: In this paper, we exploit the first 10-year data record (2008–2017) of nitric acid (HNO3) total columns measured by the IASI-A/MetOp infrared sounder, characterized by an exceptional daily sampling and a good vertical sensitivity in the lower-to-mid stratosphere (around 50 hPa), to monitor the relationship between the temperature decrease and the observed HNO3 loss that occurs each year in the Antarctic stratosphere during the polar night. Since the HNO3 depletion results from the formation of polar stratospheric clouds (PSCs), which trigger the development of the ozone (O3) hole, its continuous monitoring is of high importance. We verify here, from the 10-year time evolution of HNO3 together with temperature (taken from reanalysis at 50 hPa), the recurrence of specific regimes in the annual cycle of IASI HNO3 and identify (for each year) the day and the 50 hPa temperature (“drop temperature”) corresponding to the onset of strong HNO3 depletion in the Antarctic winter. Although the measured HNO3 total column does not allow for the uptake of HNO3 by different types of PSC particles along the vertical profile to be differentiated, an average drop temperature of 194.2 ± 3.8 K, close to the nitric acid trihydrate (NAT) existence threshold (∼ 195 K at 50 hPa), is found in the region of potential vorticity lower than −10 × 10−5 K m2 kg−1 s−1 (similar to the 70–90◦ S equivalent latitude region during winter). The spatial distribution and interannual variability of the drop temperature are investigated and discussed. This paper highlights the capability of the IASI sounder to monitor the evolution of polar stratospheric HNO3, a key player in the processes involved in the depletion of stratospheric O3 © Author(s) 2022.
BibTeX: @article{Wespes2022, author = {Wespes, Catherine and Ronsmans, Gaetane and Clarisse, Lieven and Solomon, Susan and Hurtmans, Daniel and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Polar stratospheric nitric acid depletion surveyed from a decadal dataset of IASI total columns}, journal = {Atmospheric Chemistry and Physics}, year = {2022}, volume = {22}, number = {16}, pages = {10993 – 11007}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-22-10993-2022} }
Whitburn S, Clarisse L, Crapeau M, August T, Hultberg T, Coheur PF and Clerbaux C (2022), "A CO2-independent cloud mask from Infrared Atmospheric Sounding Interferometer (IASI) radiances for climate applications", Atmospheric Measurement Techniques. Vol. 15(22), pp. 6653 – 6668. [Abstract] [BibTeX] [DOI]
Abstract: With more than 15 years of continuous and consistent measurements, the Infrared Atmospheric Sounding Interferometer (IASI) radiance dataset is becoming a reference climate data record. To be exploited to its full potential, it requires a cloud filter that is accurate, unbiased over the full IASI life span and strict enough to be used in satellite data retrieval schemes. Here, we present a new cloud detection algorithm which combines (1) a high sensitivity, (2) a good consistency over the whole IASI time series and between the different copies of the instrument flying on board the suite of Metop satellites, and (3) simplicity in its parametrization. The method is based on a supervised neural network (NN) and relies, as input parameters, on the IASI radiance measurements only. The robustness of the cloud mask over time is ensured in particular by avoiding the IASI channels that are influenced by CO2, N2O, CH4, CFC-11 and CFC-12 absorption lines and those corresponding to the ν2 H2O absorption band. As a reference dataset for the training, version 6.5 of the operational IASI Level 2 (L2) cloud product is used. We provide different illustrations of the NN cloud product, including comparisons with other existing products. We find very good agreement overall with version 6.5 of the operational IASI L2 with an identical mean annual cloud amount and a pixel-by-pixel correspondence of about 87 %. The comparison with the other cloud products shows a good correspondence in the main cloud regimes but with sometimes large differences in the mean cloud amount (up to 10 %) due to the specificities of each of the different products. We also show the good capability of the NN product to differentiate clouds from dust plumes. Copyright © 2022 Simon Whitburn et al.
BibTeX: @article{Whitburn2022, author = {Whitburn, Simon and Clarisse, Lieven and Crapeau, Marc and August, Thomas and Hultberg, Tim and Coheur, Pierre François and Clerbaux, Cathy}, title = {A CO2-independent cloud mask from Infrared Atmospheric Sounding Interferometer (IASI) radiances for climate applications}, journal = {Atmospheric Measurement Techniques}, year = {2022}, volume = {15}, number = {22}, pages = {6653 – 6668}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-15-6653-2022} }
Wright CJ, Hindley NP, Alexander MJ, Barlow M, Hoffmann L, Mitchell CN, Prata F, Bouillon M, Carstens J, Clerbaux C, Osprey SM, Powell N, Randall CE and Yue J (2022), "Surface-to-space atmospheric waves from Hunga Tonga–Hunga Ha’apai eruption", Nature. Vol. 609(7928), pp. 741 – 746. [Abstract] [BibTeX] [DOI]
Abstract: The January 2022 Hunga Tonga–Hunga Ha’apai eruption was one of the most explosive volcanic events of the modern era1,2, producing a vertical plume that peaked more than 50 km above the Earth3. The initial explosion and subsequent plume triggered atmospheric waves that propagated around the world multiple times4. A global-scale wave response of this magnitude from a single source has not previously been observed. Here we show the details of this response, using a comprehensive set of satellite and ground-based observations to quantify it from surface to ionosphere. A broad spectrum of waves was triggered by the initial explosion, including Lamb waves5,6 propagating at phase speeds of 318.2 ± 6 m s−1 at surface level and between 308 ± 5 to 319 ± 4 m s−1 in the stratosphere, and gravity waves7 propagating at 238 ± 3 to 269 ± 3 m s−1 in the stratosphere. Gravity waves at sub-ionospheric heights have not previously been observed propagating at this speed or over the whole Earth from a single source8,9. Latent heat release from the plume remained the most significant individual gravity wave source worldwide for more than 12 h, producing circular wavefronts visible across the Pacific basin in satellite observations. A single source dominating such a large region is also unique in the observational record. The Hunga Tonga eruption represents a key natural experiment in how the atmosphere responds to a sudden point-source-driven state change, which will be of use for improving weather and climate models. © 2022, The Author(s).
BibTeX: @article{Wright2022, author = {Wright, Corwin J. and Hindley, Neil P. and Alexander, M. Joan and Barlow, Mathew and Hoffmann, Lars and Mitchell, Cathryn N. and Prata, Fred and Bouillon, Marie and Carstens, Justin and Clerbaux, Cathy and Osprey, Scott M. and Powell, Nick and Randall, Cora E. and Yue, Jia}, title = {Surface-to-space atmospheric waves from Hunga Tonga–Hunga Ha’apai eruption}, journal = {Nature}, year = {2022}, volume = {609}, number = {7928}, pages = {741 – 746}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1038/s41586-022-05012-5} }
Xu W, Zhao Y, Wen Z, Chang Y, Pan Y, Sun Y, Ma X, Sha Z, Li Z, Kang J, Liu L, Tang A, Wang K, Zhang Y, Guo Y, Zhang L, Sheng L, Zhang X, Gu B, Song Y, Van Damme M, Clarisse L, Coheur P-F, Collett JL, Goulding K, Zhang F, He K and Liu X (2022), "Increasing importance of ammonia emission abatement in PM2.5 pollution control", Science Bulletin. Vol. 67(17), pp. 1745 – 1749. [BibTeX] [DOI]
BibTeX: @article{Xu2022, author = {Xu, Wen and Zhao, Yuanhong and Wen, Zhang and Chang, Yunhua and Pan, Yuepeng and Sun, Yele and Ma, Xin and Sha, Zhipeng and Li, Ziyue and Kang, Jiahui and Liu, Lei and Tang, Aohan and Wang, Kai and Zhang, Ying and Guo, Yixin and Zhang, Lin and Sheng, Lifang and Zhang, Xiuming and Gu, Baojing and Song, Yu and Van Damme, Martin and Clarisse, Lieven and Coheur, Pierre-François and Collett, Jeffrey L. and Goulding, Keith and Zhang, Fusuo and He, Kebin and Liu, Xuejun}, title = {Increasing importance of ammonia emission abatement in PM2.5 pollution control}, journal = {Science Bulletin}, year = {2022}, volume = {67}, number = {17}, pages = {1745 – 1749}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.scib.2022.07.021} }
Zhang CY, Li JQ, Wang K, Si R, Godefroid M, Jönsson P, Xiao J, Gu MF and Chen CY (2022), "Benchmarking calculations of wavelengths and transition rates with spectroscopic accuracy for W xlviii through W lvi tungsten ions", Physical Review A. Vol. 105(2) [Abstract] [BibTeX] [DOI]
Abstract: Atomic properties of n=3 levels for W47+-W55+ ions (Z=74) are systematically calculated using two different and independent methods, namely, the second-order many-body perturbation theory and the multiconfiguration Dirac-Hartree-Fock method combined with the relativistic configuration interaction approach. Wavelengths and transition rates for electric-and magnetic-dipole transitions involving the n=3 levels of W47+-W55+ are calculated. In addition, we discuss in detail the importance of the valence and core-valence electron correlations, the Breit interaction, the higher-order frequency-dependent retardation correction, and the leading quantum electrodynamical corrections for transition wavelengths. Spectroscopic accuracy is achieved for the present calculated wavelengths, and most of them agree with experimental values within 0.05%. Our calculated wavelengths, combined with collisional radiative model simulations, are used to identify the yet unidentified 25 observed lines in the extremely complex spectrum between 27Å and 34Å measured by Lennartsson etal. [Phys. Rev. A 87, 062505 (2013)10.1103/PhysRevA.87.062505]. We provide additional data for 472 strong electric-dipole transitions in the wavelength range of 17-50 Å, and 185 strong magnetic-dipole transitions between 36Å and 4384Å, with a line intensity greater than 1photon/s. These can provide benchmark data for future experiments and theoretical calculations. © 2022 American Physical Society.
BibTeX: @article{Zhang2022, author = {Zhang, Chun Yu and Li, Jin Qing and Wang, Kai and Si, Ran and Godefroid, Michel and Jönsson, Per and Xiao, Jun and Gu, Ming Feng and Chen, Chong Yang}, title = {Benchmarking calculations of wavelengths and transition rates with spectroscopic accuracy for W xlviii through W lvi tungsten ions}, journal = {Physical Review A}, year = {2022}, volume = {105}, number = {2}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.105.022817} }
Abeed R, Clerbaux C, Clarisse L, van Damme M, Coheur P-F and Safieddine S (2021), "A space view of agricultural and industrial changes during the Syrian civil war", Elementa. Vol. 9(1) [Abstract] [BibTeX] [DOI]
Abstract: The agricultural sector in Syria was heavily affected by the civil war that started in 2011. We investigate the war’s impact on the country’s atmospheric ammonia (NH3) from 2008 to 2019, using measurements from the infrared atmospheric sounding interferometer instrument on board the Metop satellites. We examine the changes in NH3 close to a fertilizer industry, whose activities were suspended due to conflict-related events. We also explore the effect of war-induced land use/land cover changes on agriculture-emitted ammonia in north-east Syria that has witnessed battles between different groups. The interpretation of the changes in NH3 is supported by different datasets: visible satellite imagery to assess the effect on industrial activity, reanalysis data from the European center for medium-range weather forecasts to look at the effect of meteorology (temperature, wind speed, and precipitation), and land cover and burned area products from the moderate resolution imaging spectroradiometer (MODIS) to examine land use/land cover changes and fire events during the study period. We show that the NH3 columns are directly affected by the war. Periods of intense conflict are reflected in lower values over the industry reaching –17%, –47%, and –32% in 2013, 2014, and 2016, respectively, compared to the [2008–2012] average, and a decrease reaching –14% and –15% in the croplands’ area in northeast Syria during 2017 and 2018 (compared to 2011), respectively. Toward the end of the control of Islamic State in Iraq and Syria, an increase in atmospheric NH3 was accompanied by an increase in croplands’ area that reached up to þ35% in 2019 as compared to prewar (2011). This study shows the relevance of remote-sensing data of atmospheric composition in studying societal changes at a local and regional scale. © 2021 The Author(s).
BibTeX: @article{Abeed2021, author = {Abeed, Rimal and Clerbaux, Cathy and Clarisse, Lieven and van Damme, Martin and Coheur, Pierre-François and Safieddine, Sarah}, title = {A space view of agricultural and industrial changes during the Syrian civil war}, journal = {Elementa}, year = {2021}, volume = {9}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.1525/elementa.2021.000041} }
Aerts A, Vander Auwera J and Vaeck N (2021), "Lindblad parameters from high resolution spectroscopy to describe collision-induced rovibrational decoherence in the gas phase - Application to acetylene", Journal of Chemical Physics. Vol. 154(14) [Abstract] [BibTeX] [DOI]
Abstract: Within the framework of the Lindblad master equation, we propose a general methodology to describe the effects of the environment on a system in the dilute gas phase. The phenomenological parameters characterizing the transitions between rovibrational states of the system induced by collisions can be extracted from experimental transition kinetic constants, relying on energy gap fitting laws. As the availability of these kinds of experimental data can be limited, this work relied on experimental line broadening coefficients, however still using energy gap fitting laws. The 3 μm infrared spectral range of acetylene was chosen to illustrate the proposed approach. The method shows fair agreement with available experimental data while being computationally inexpensive. The results are discussed in the context of state laser quantum control. © 2021 Author(s).
BibTeX: @article{Aerts2021, author = {Aerts, Antoine and Vander Auwera, Jean and Vaeck, Nathalie}, title = {Lindblad parameters from high resolution spectroscopy to describe collision-induced rovibrational decoherence in the gas phase - Application to acetylene}, journal = {Journal of Chemical Physics}, year = {2021}, volume = {154}, number = {14}, note = {All Open Access, Green Open Access}, doi = {10.1063/5.0045275} }
Aydogan A, Bangle RE, Cadranel A, Turlington MD, Conroy DT, Cauët E, Singleton ML, Meyer GJ, Sampaio RN, Elias B and Troian-Gautier L (2021), "Accessing Photoredox Transformations with an Iron(III) Photosensitizer and Green Light", Journal of the American Chemical Society. Vol. 143(38), pp. 15661 – 15673. [Abstract] [BibTeX] [DOI]
Abstract: Efficient excited-state electron transfer between an iron(III) photosensitizer and organic electron donors was realized with green light irradiation. This advance was enabled by the use of the previously reported iron photosensitizer, [Fe(phtmeimb)2]+ (phtmeimb = phenyl[tris(3-methyl-imidazolin-2-ylidene)]borate, that exhibited long-lived and luminescent ligand-to-metal charge-transfer (LMCT) excited states. A benchmark dehalogenation reaction was investigated with yields that exceed 90% and an enhanced stability relative to the prototypical photosensitizer [Ru(bpy)3]2+. The initial catalytic step is electron transfer from an amine to the photoexcited iron sensitizer, which is shown to occur with a large cage-escape yield. For LMCT excited states, this reductive electron transfer is vectorial and may be a general advantage of Fe(III) photosensitizers. In-depth time-resolved spectroscopic methods, including transient absorption characterization from the ultraviolet to the infrared regions, provided a quantitative description of the catalytic mechanism with associated rate constants and yields. © 2021 American Chemical Society.
BibTeX: @article{Aydogan2021, author = {Aydogan, Akin and Bangle, Rachel E. and Cadranel, Alejandro and Turlington, Michael D. and Conroy, Daniel T. and Cauët, Emilie and Singleton, Michael L. and Meyer, Gerald J. and Sampaio, Renato N. and Elias, Benjamin and Troian-Gautier, Ludovic}, title = {Accessing Photoredox Transformations with an Iron(III) Photosensitizer and Green Light}, journal = {Journal of the American Chemical Society}, year = {2021}, volume = {143}, number = {38}, pages = {15661 – 15673}, note = {All Open Access, Green Open Access}, doi = {10.1021/jacs.1c06081} }
Aydogan A, Bangle RE, De Kreijger S, Dickenson JC, Singleton ML, Cauët E, Cadranel A, Meyer GJ, Elias B, Sampaio RN and Troian-Gautier L (2021), "Mechanistic investigation of a visible light mediated dehalogenation/cyclisation reaction using iron(iii), iridium(iii) and ruthenium(ii) photosensitizers", Catalysis Science and Technology. Vol. 11(24), pp. 8037 – 8051. [Abstract] [BibTeX] [DOI]
Abstract: The mechanism of a visible light-driven dehalogenation/cyclization reaction was investigated using ruthenium(ii), iridium(iii) and iron(iii) photosensitizers by means of steady-state photoluminescence, time-resolved infrared spectroscopy, and nanosecond/femtosecond transient absorption spectroscopy. The nature of the photosensitizer was found to influence the product distribution such that the dehalogenated, non-cyclized products were only detected for the iron photosensitizer. Strikingly, with the iron photosensitizer, large catalytic yields required a low dielectric solvent such as dichloromethane, consistent with a previous publication. This low dielectric solvent allowed ultrafast charge-separation to outcompete geminate charge recombination and improved cage escape efficiency. Further, the identification of reaction mechanisms unique to the iron, ruthenium, and iridium photosensitizer represents progress towards the long-sought goal of utilizing earth-abundant, first-row transition metals for emerging energy and environmental applications. © The Royal Society of Chemistry 2021.
BibTeX: @article{Aydogan2021a, author = {Aydogan, Akin and Bangle, Rachel E. and De Kreijger, Simon and Dickenson, John C. and Singleton, Michael L. and Cauët, Emilie and Cadranel, Alejandro and Meyer, Gerald J. and Elias, Benjamin and Sampaio, Renato N. and Troian-Gautier, Ludovic}, title = {Mechanistic investigation of a visible light mediated dehalogenation/cyclisation reaction using iron(iii), iridium(iii) and ruthenium(ii) photosensitizers}, journal = {Catalysis Science and Technology}, year = {2021}, volume = {11}, number = {24}, pages = {8037 – 8051}, doi = {10.1039/d1cy01771c} }
Barzakh A, Andreyev A, Raison C, Cubiss J, Van Duppen P, Péru S, Hilaire S, Goriely S, Andel B, Antalic S, Al Monthery M, Berengut J, Bieroń J, Bissell M, Borschevsky A, Chrysalidis K, Cocolios T, Day Goodacre T, Dognon J-P, Elantkowska M, Eliav E, Farooq-Smith G, Fedorov D, Fedosseev V, Gaffney L, Garcia Ruiz R, Godefroid M, Granados C, Harding R, Heinke R, Huyse M, Karls J, Larmonier P, Li J, Lynch K, Maison D, Marsh B, Molkanov P, Mosat P, Oleynichenko A, Panteleev V, Pyykkö P, Reitsma M, Rezynkina K, Rossel R, Rothe S, Ruczkowski J, Schiffmann S, Seiffert C, Seliverstov M, Sels S, Skripnikov L, Stryjczyk M, Studer D, Verlinde M, Wilman S and Zaitsevskii A (2021), "Large Shape Staggering in Neutron-Deficient Bi Isotopes", Physical Review Letters. Vol. 127(19) [Abstract] [BibTeX] [DOI]
Abstract: The changes in the mean-square charge radius (relative to Bi209), magnetic dipole, and electric quadrupole moments of Bi187,188,189,191 were measured using the in-source resonance-ionization spectroscopy technique at ISOLDE (CERN). A large staggering in radii was found in Bi187,188,189g, manifested by a sharp radius increase for the ground state of Bi188 relative to the neighboring Bi187,189g. A large isomer shift was also observed for Bi188m. Both effects happen at the same neutron number, N=105, where the shape staggering and a similar isomer shift were observed in the mercury isotopes. Experimental results are reproduced by mean-field calculations where the ground or isomeric states were identified by the blocked quasiparticle configuration compatible with the observed spin, parity, and magnetic moment. © 2021 authors.
BibTeX: @article{Barzakh2021, author = {Barzakh, A. and Andreyev, A.N. and Raison, C. and Cubiss, J.G. and Van Duppen, P. and Péru, S. and Hilaire, S. and Goriely, S. and Andel, B. and Antalic, S. and Al Monthery, M. and Berengut, J.C. and Bieroń, J. and Bissell, M.L. and Borschevsky, A. and Chrysalidis, K. and Cocolios, T.E. and Day Goodacre, T. and Dognon, J.-P. and Elantkowska, M. and Eliav, E. and Farooq-Smith, G.J. and Fedorov, D.V. and Fedosseev, V.N. and Gaffney, L.P. and Garcia Ruiz, R.F. and Godefroid, M. and Granados, C. and Harding, R.D. and Heinke, R. and Huyse, M. and Karls, J. and Larmonier, P. and Li, J.G. and Lynch, K.M. and Maison, D.E. and Marsh, B.A. and Molkanov, P. and Mosat, P. and Oleynichenko, A.V. and Panteleev, V. and Pyykkö, P. and Reitsma, M.L. and Rezynkina, K. and Rossel, R.E. and Rothe, S. and Ruczkowski, J. and Schiffmann, S. and Seiffert, C. and Seliverstov, M.D. and Sels, S. and Skripnikov, L.V. and Stryjczyk, M. and Studer, D. and Verlinde, M. and Wilman, S. and Zaitsevskii, A.V.}, title = {Large Shape Staggering in Neutron-Deficient Bi Isotopes}, journal = {Physical Review Letters}, year = {2021}, volume = {127}, number = {19}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1103/PhysRevLett.127.192501} }
Bauduin S, Giuranna M, Wolkenberg P, Nardi L, Daerden F, Bouche J, Wespes C, Lecomte G, Vandaele AC and Coheur P (2021), "Exploiting night-time averaged spectra from PFS/MEX shortwave channel. Part 1: Temperature retrieval from the CO2 ν3 band", Planetary and Space Science. Vol. 198 [Abstract] [BibTeX] [DOI]
Abstract: Nadir remote sensing of the night side of Mars is challenging, mainly due to the low signal-to-noise ratio of such observations. We show in a companion paper that the abundance of carbon monoxide (CO) during night can be retrieved from the observations of the Planetary Fourier Spectrometer (PFS). This requires, however, an accurate knowledge of the temperature profile, and especially of the night-time thermal inversions, to properly model the atmospheric emission. While the temperature profile is usually retrieved from the ν2 band of CO2 (centered at 667 cm−1), this work shows that, for averaged night-time PFS observations built from a large ensemble of spectra, the temperature profile can be retrieved from the more saturated ν3 band of CO2 (centered at 2349 cm−1). We show especially that, due to IFOV (instantaneous field-of-view) size differences and boresight offset between the longwave and shortwave channels of PFS, the temperature profile retrieved from the ν3 band is more consistent with the emission observed in the 1-0 band of CO (centered at 2143 cm−1), which is used in the second part paper. We provide a complete characterization of the retrieved temperature profiles in terms of error and vertical sensitivity. Using this, we show that using the ν3 CO2 band allows to properly constrain and characterize the thermal inversions encountered near the surface for most night-time observations. The resulting set of temperature profiles is essential for the retrieval of the night-time CO abundance that is presented in the companion paper. Beyond their usefulness for the night-time CO retrieval, we suggest with a last example that temperature profiles retrieved from the ν3 band of CO2 could be use more generally to study surface thermal inversions encountered at night. © 2021 Elsevier Ltd
BibTeX: @article{Bauduin2021, author = {Bauduin, Sophie and Giuranna, Marco and Wolkenberg, Paulina and Nardi, Luca and Daerden, Frank and Bouche, Jimmy and Wespes, Catherine and Lecomte, Gilles and Vandaele, Ann Carine and Coheur, Pierre}, title = {Exploiting night-time averaged spectra from PFS/MEX shortwave channel. Part 1: Temperature retrieval from the CO2 ν3 band}, journal = {Planetary and Space Science}, year = {2021}, volume = {198}, doi = {10.1016/j.pss.2021.105186} }
Bauduin S, Giuranna M, Wolkenberg P, Nardi L, Daerden F, Bouche J, Wespes C, Lecomte G, Vandaele AC and Coheur P (2021), "Exploiting night-time averaged spectra from PFS/MEX shortwave channel. Part 2: Near-surface CO retrievals", Planetary and Space Science. Vol. 199 [Abstract] [BibTeX] [DOI]
Abstract: Because of its important role in the Martian carbon cycle, carbon monoxide (CO) has been the subject of many measurements from ground and from space. Daytime measurements have been mostly exploited to measure the CO abundance because of their good signal-to-noise ratio, but night-time observations have not been documented yet. We demonstrate here the possibility of using PFS (Planetary Fourier Spectrometer) night-time observations to measure the Martian CO abundance. More particularly in this paper, we show that measuring CO during night with PFS can be achieved by averaging a large number of spectra to reach sufficient signal-to-noise. Furthermore, we show that the number of averaged spectra is not the only driving parameter for the detection of CO. High surface temperatures and high thermal contrast (negative in our case) are the two other conditions required for the measurement of the night-time CO abundance. Because of this, the retrievals are especially successful in the Southern Hemisphere during spring and summer when and where these two conditions are met. For night-time spectra with a positive detection, CO vertical profiles are successfully retrieved using the Optimal Estimation method and are characterized in terms of vertical sensitivity. Successful retrievals imply the use of accurate temperature profiles, and in particular an appropriate representation of the thermal inversion in the lower atmosphere. The temperature was obtained by using the relevant information from the CO2 ν3 band (Bauduin et al., 2020, this issue). A complete error budget of the retrieved CO profiles is also performed and includes different sources of uncertainty. Although the retrieved profiles are not resolved vertically, we show in particular that night-time PFS observations carry information mostly on the CO abundance for the 0–10 km altitude region, and thus provide a stronger constraint on the near-surface CO abundance compared to daytime observations. © 2021
BibTeX: @article{Bauduin2021a, author = {Bauduin, Sophie and Giuranna, Marco and Wolkenberg, Paulina and Nardi, Luca and Daerden, Frank and Bouche, Jimmy and Wespes, Catherine and Lecomte, Gilles and Vandaele, Ann Carine and Coheur, Pierre}, title = {Exploiting night-time averaged spectra from PFS/MEX shortwave channel. Part 2: Near-surface CO retrievals}, journal = {Planetary and Space Science}, year = {2021}, volume = {199}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.pss.2021.105188} }
Bègue N, Bencherif H, Jégou F, Vérèmes H, Khaykin S, Krysztofiak G, Portafaix T, Duflot V, Baron A, Berthet G, Kloss C, Payen G, Keckhut P, Coheur P-F, Clerbaux C, Smale D, Robinson J, Querel R and Smale P (2021), "Transport and variability of tropospheric ozone over oceania and southern pacific during the 2019–20 australian bushfires", Remote Sensing. Vol. 13(16) [Abstract] [BibTeX] [DOI]
Abstract: The present study contributes to the scientific effort for a better understanding of the potential of the Australian biomass burning events to influence tropospheric trace gas abundances at the regional scale. In order to exclude the influence of the long-range transport of ozone precursors from biomass burning plumes originating from Southern America and Africa, the analysis of the Australian smoke plume has been driven over the period December 2019 to January 2020. This study uses satellite (IASI, MLS, MODIS, CALIOP) and ground-based (sun-photometer, FTIR, ozone radiosondes) observations. The highest values of aerosol optical depth (AOD) and carbon monoxide total columns are observed over Southern and Central Australia. Transport is responsible for the spatial and temporal distributions of aerosols and carbon monoxide over Australia, and also the transport of the smoke plume outside the continent. The dispersion of the tropospheric smoke plume over Oceania and Southern Pacific extends from tropical to extratropical latitudes. Ozone radiosonde measurements performed at Samoa (14.4◦S, 170.6◦W) and Lauder (45.0◦S, 169.4◦E) indicate an increase in mid-tropospheric ozone (6–9 km) (from 10% to 43%) linked to the Australian biomass burning plume. This increase in mid-tropospheric ozone induced by the transport of the smoke plume was found to be consistent with MLS observations over the tropical and extratropical latitudes. The smoke plume over the Southern Pacific was organized as a stretchable anticyclonic rolling which impacted the ozone variability in the tropical and subtropical upper-troposphere over Oceania. This is corroborated by the ozone profile measurements at Samoa which exhibit an enhanced ozone layer (29%) in the upper-troposphere. Our results suggest that the transport of Australian biomass burning plumes have significantly impacted the vertical distribution of ozone in the mid-troposphere southern tropical to extratropical latitudes during the 2019–20 extreme Australian bushfires. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
BibTeX: @article{Begue2021, author = {Bègue, Nelson and Bencherif, Hassan and Jégou, Fabrice and Vérèmes, Hélène and Khaykin, Sergey and Krysztofiak, Gisèle and Portafaix, Thierry and Duflot, Valentin and Baron, Alexandre and Berthet, Gwenaël and Kloss, Corinna and Payen, Guillaume and Keckhut, Philippe and Coheur, Pierre-François and Clerbaux, Cathy and Smale, Dan and Robinson, John and Querel, Richard and Smale, Penny}, title = {Transport and variability of tropospheric ozone over oceania and southern pacific during the 2019–20 australian bushfires}, journal = {Remote Sensing}, year = {2021}, volume = {13}, number = {16}, note = {All Open Access, Gold Open Access}, doi = {10.3390/rs13163092} }
Bernath PF, Johnson R and Liévin J (2021), "Line lists for the b1Σ+-X3Σ− and a1Δ-X3Σ− transitions of SO", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 272 [Abstract] [BibTeX] [DOI]
Abstract: SO is found in many astronomical sources such as the atmospheres of Io and Venus. In order to create more complete line lists, we fit spectroscopic data on SO from the literature using PGOPHER. The fits covered v = 0 to v = 6 for the X3Σ−state, v = 0–5 for the a1Δ state and v = 0–2 for b1Σ+ state. LeRoy's RKR program was used to produce pointwise potential energy curves. High level ab initio calculations, including spin-orbit coupling, were carried out to obtain the electric transition dipole moment functions for the nominally forbidden b1Σ+-X3Σ−and a1Δ-X3Σ−transitions. The RKR potentials and transition dipole moment points were input into LeRoy's LEVEL program to calculate the transition dipole matrix elements for all possible b-X and a-X bands. For the b1Σ+-X3Σ−transition, the electric and magnetic transition dipole matrix elements were scaled using the experimental values obtained by Setzer et al. [J Mol Spectrosc 1999;198:163–174] for the 0–0 band. The transition dipole moment matrix elements were used in PGOPHER to produce our line lists for all possible bands of the b1Σ+-X3Σ−and a1Δ-X3Σ−transitions. © 2021 Elsevier Ltd
BibTeX: @article{Bernath2021, author = {Bernath, Peter F. and Johnson, Ryan and Liévin, Jacques}, title = {Line lists for the b1Σ+-X3Σ− and a1Δ-X3Σ− transitions of SO}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2021}, volume = {272}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jqsrt.2021.107772} }
Bogomolov A, Roucou A, Bejjani R, Herman M, Moazzen-Ahmadi N and Lauzin C (2021), "The rotationally resolved symmetric 2OH excitation in H2O-CO2 observed using pulsed supersonic expansion and CW-CRDS", Chemical Physics Letters. Vol. 774 [Abstract] [BibTeX] [DOI]
Abstract: The rovibrational band corresponding to a double excitation of the OH symmetric stretch of the H2O unit in the H2O-CO2 van der Waals complex has been recorded using CW-CRDS and a pulsed slit expansion seeded in He. The set-up is presented. The rotational analysis of this band is detailed and the results of the global fit of these data with those of the other 2OH excitation band and of the ground vibrational states are reported including data from the literature. The tunneling frequency and the vibrational predissociation lifetime are shown to decrease with vibrational excitation. © 2021
BibTeX: @article{Bogomolov2021, author = {Bogomolov, A.S. and Roucou, A. and Bejjani, R. and Herman, M. and Moazzen-Ahmadi, N. and Lauzin, C.}, title = {The rotationally resolved symmetric 2OH excitation in H2O-CO2 observed using pulsed supersonic expansion and CW-CRDS}, journal = {Chemical Physics Letters}, year = {2021}, volume = {774}, doi = {10.1016/j.cplett.2021.138606} }
Boualili FZ, Nemouchi M, Godefroid M and Jönsson P (2021), "Weak correlation and strong relativistic effects on the hyperfine interaction in fluorine", Physical Review A. Vol. 104(6) [Abstract] [BibTeX] [DOI]
Abstract: In previous work devoted to ab initio calculations of hyperfine-structure constants in nitrogen and fluorine atoms, we observed sizable relativistic effects, a priori unexpected for such light systems, that can even largely dominate over electron correlation. We observed that the atomic wave functions calculated in the Breit-Pauli approximation describe adequately the relevant atomic levels and hyperfine structures, even in cases for which a small relativistic LS-term mixing becomes crucial. In the present work we identify levels belonging to the spectroscopic terms 2p4(3P)3d2,4(P,D,F) of the fluorine atom, for which correlation effects on the hyperfine structures are small, but relativistic LS-term admixtures are decisive to correctly reproduce the experimental values. The Breit-Pauli analysis of the hyperfine matrix elements nails cases with large cancellation, either between LS pairs for individual hyperfine operators or between the orbital and the spin dipole contributions. Multiconfiguration Dirac-Hartree-Fock calculations are performed to support the Breit-Pauli analysis. © 2021 American Physical Society
BibTeX: @article{Boualili2021, author = {Boualili, Fatima Zahra and Nemouchi, Messaoud and Godefroid, Michel and Jönsson, Per}, title = {Weak correlation and strong relativistic effects on the hyperfine interaction in fluorine}, journal = {Physical Review A}, year = {2021}, volume = {104}, number = {6}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.104.062813} }
Bouche J, Coheur P-F, Giuranna M, Wolkenberg P, Nardi L, Amoroso M, Vandaele AC, Daerden F, Neary L and Bauduin S (2021), "Seasonal and Spatial Variability of Carbon Monoxide (CO) in the Martian Atmosphere From PFS/MEX Observations", Journal of Geophysical Research: Planets. Vol. 126(2) [Abstract] [BibTeX] [DOI]
Abstract: A subset of more than 100,000 nadir measurements covering more than 7 Martian years (MY 26–MY 33) recorded in the thermal part of the Short Wavelength Channel (SWC) from the Planetary Fourier Spectrometer (PFS) on board Mars Express is exploited to investigate the global distribution and the seasonal cycle of carbon monoxide (CO) on Mars. The retrieval of CO vertical profiles is successfully achieved using a methodology based on the optimal estimation but the low information content is such that we mainly discuss the variability in CO in terms of integrated columns (from the surface to 24 km) or the associated column-averaged mixing ratio. We find a strong seasonality in CO, especially at mid and high-latitudes, which confirms earlier work and the current knowledge of the CO2 condensation/sublimation cycles, as implemented for instance in the Global Environmental Multiscale (GEM) general circulation model for Mars, that we use as a basis for comparison. We report a general consistency between model and observation, with a tendency of the latter to provide lower CO volume mixing ratios (VMRs), except at low latitudes. The spatial distribution of the CO column-averaged VMR is obtained on a seasonal basis and investigated in terms of large-scale patterns but also local peculiarities. Finally, we show that the retrieved profiles systematically present strong CO vertical gradients close to the surface in mid- and equatorial latitudes, likely related to the vertical sensitivity of PFS rather than real near-surface CO enrichment. © 2021. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Bouche2021, author = {Bouche, Jimmy and Coheur, Pierre-François and Giuranna, Marco and Wolkenberg, Paulina and Nardi, Luca and Amoroso, Marilena and Vandaele, Ann Carine and Daerden, Frank and Neary, Lori and Bauduin, Sophie}, title = {Seasonal and Spatial Variability of Carbon Monoxide (CO) in the Martian Atmosphere From PFS/MEX Observations}, journal = {Journal of Geophysical Research: Planets}, year = {2021}, volume = {126}, number = {2}, note = {All Open Access, Green Open Access}, doi = {10.1029/2020JE006480} }
Bowen K, Hillenbrand P-M, Liévin J, Savin D and Urbain X (2021), "Dynamics of the isotope exchange reaction of D with H 3 +, H2D+, and D2H+", Journal of Chemical Physics. Vol. 154(8) [Abstract] [BibTeX] [DOI]
Abstract: We have measured the merged-beams rate coefficient for the titular isotope exchange reactions as a function of the relative collision energy in the range of ∼3 meV-10 eV. The results appear to scale with the number of available sites for deuteration. We have performed extensive theoretical calculations to characterize the zero-point energy corrected reaction path. Vibrationally adiabatic minimum energy paths were obtained using a combination of unrestricted quadratic configuration interaction of single and double excitations and internally contracted multireference configuration interaction calculations. The resulting barrier height, ranging from 68 meV to 89 meV, together with the various asymptotes that may be reached in the collision, was used in a classical over-the-barrier model. All competing endoergic reaction channels were taken into account using a flux reduction factor. This model reproduces all three experimental sets quite satisfactorily. In order to generate thermal rate coefficients down to 10 K, the internal excitation energy distribution of each H3+ isotopologue is evaluated level by level using available line lists and accurate spectroscopic parameters. Tunneling is accounted for by a direct inclusion of the exact quantum tunneling probability in the evaluation of the cross section. We derive a thermal rate coefficient of <1×10-12 cm3 s-1 for temperatures below 44 K, 86 K, and 139 K for the reaction of D with H3+, H2D+, and D2H+, respectively, with tunneling effects included. The derived thermal rate coefficients exceed the ring polymer molecular dynamics prediction of Bulut et al. [J. Phys. Chem. A 123, 8766 (2019)] at all temperatures. © 2021 Author(s).
BibTeX: @article{Bowen2021, author = {Bowen, K.P. and Hillenbrand, P.-M. and Liévin, J. and Savin, D.W. and Urbain, X.}, title = {Dynamics of the isotope exchange reaction of D with H 3 +, H2D+, and D2H+}, journal = {Journal of Chemical Physics}, year = {2021}, volume = {154}, number = {8}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1063/5.0038434} }
Brenot H, Theys N, Clarisse L, Van Gent J, Hurtmans DR, Vandenbussche S, Papagiannopoulos N, Mona L, Virtanen T, Uppstu A, Sofiev M, Bugliaro L, Vázquez-Navarro M, Hedelt P, Parks MM, Barsotti S, Coltelli M, Moreland W, Scollo S, Salerno G, Arnold-Arias D, Hirtl M, Peltonen T, Lahtinen J, Sievers K, Lipok F, Rüfenacht R, Haefele A, Hervo M, Wagenaar S, Som De Cerff W, De Laat J, Apituley A, Stammes P, Laffineur Q, Delcloo A, Lennart R, Rokitansky C-H, Vargas A, Kerschbaum M, Resch C, Zopp R, Plu M, Peuch V-H, Van Roozendael M and Wotawa G (2021), "EUNADICS-AV early warning system dedicated to supporting aviation in the case of a crisis from natural airborne hazards and radionuclide clouds", Natural Hazards and Earth System Sciences. Vol. 21(11), pp. 3367 – 3405. [Abstract] [BibTeX] [DOI]
Abstract: The purpose of the EUNADICS-AV (European Natural Airborne Disaster Information and Coordination System for Aviation) prototype early warning system (EWS) is to develop the combined use of harmonised data products from satellite, ground-based and in situ instruments to produce alerts of airborne hazards (volcanic, dust, smoke and radionuclide clouds), satisfying the requirement of aviation air traffic management (ATM) stakeholders (https://cordis.europa.eu/project/id/723986, last access: 5 November 2021). The alert products developed by the EUNADICS-AV EWS, i.e. near-real-time (NRT) observations, email notifications and netCDF (Network Common Data Form) alert data products (called NCAP files), have shown significant interest in using selective detection of natural airborne hazards from polar-orbiting satellites. The combination of several sensors inside a single global system demonstrates the advantage of using a triggered approach to obtain selective detection from observations, which cannot initially discriminate the different aerosol types. Satellite products from hyperspectral ultraviolet-visible (UV-vis) and infrared (IR) sensors (e.g. TROPOMI - TROPOspheric Monitoring Instrument - and IASI - Infrared Atmospheric Sounding Interferometer) and a broadband geostationary imager (Spinning Enhanced Visible and InfraRed Imager; SEVIRI) and retrievals from ground-based networks (e.g. EARLINET - European Aerosol Research Lidar Network, E-PROFILE and the regional network from volcano observatories) are combined by our system to create tailored alert products (e.g. selective ash detection, SO2 column and plume height, dust cloud, and smoke from wildfires). A total of 23 different alert products are implemented, using 1 geostationary and 13 polar-orbiting satellite platforms, 3 external existing service, and 2 EU and 2 regional ground-based networks. This allows for the identification and the tracking of extreme events. The EUNADICS-AV EWS has also shown the need to implement a future relay of radiological data (gamma dose rate and radionuclides concentrations in ground-level air) in the case of a nuclear accident. This highlights the interest of operating early warnings with the use of a homogenised dataset. For the four types of airborne hazard, the EUNADICS-AV EWS has demonstrated its capability to provide NRT alert data products to trigger data assimilation and dispersion modelling providing forecasts and inverse modelling for source term estimate. Not all of our alert data products (NCAP files) are publicly disseminated. Access to our alert products is currently restricted to key users (i.e. Volcanic Ash Advisory Centres, national meteorological services, the World Meteorological Organization, governments, volcano observatories and research collaborators), as these are considered pre-decisional products. On the other hand, thanks to the EUNADICS-AV-SACS (Support to Aviation Control Service) web interface (https://sacs.aeronomie.be, last access: 5 November 2021), the main part of the satellite observations used by the EUNADICS-AV EWS is shown in NRT, with public email notification of volcanic emission and delivery of tailored images and NCAP files. All of the ATM stakeholders (e.g. pilots, airlines and passengers) can access these alert products through this free channel. © Author(s) 2021.
BibTeX: @article{Brenot2021, author = {Brenot, Hugues and Theys, Nicolas and Clarisse, Lieven and Van Gent, Jeroen and Hurtmans, Daniel R. and Vandenbussche, Sophie and Papagiannopoulos, Nikolaos and Mona, Lucia and Virtanen, Timo and Uppstu, Andreas and Sofiev, Mikhail and Bugliaro, Luca and Vázquez-Navarro, Margarita and Hedelt, Pascal and Parks, Michelle Maree and Barsotti, Sara and Coltelli, Mauro and Moreland, William and Scollo, Simona and Salerno, Giuseppe and Arnold-Arias, Delia and Hirtl, Marcus and Peltonen, Tuomas and Lahtinen, Juhani and Sievers, Klaus and Lipok, Florian and Rüfenacht, Rolf and Haefele, Alexander and Hervo, Maxime and Wagenaar, Saskia and Som De Cerff, Wim and De Laat, Jos and Apituley, Arnoud and Stammes, Piet and Laffineur, Quentin and Delcloo, Andy and Lennart, Robertson and Rokitansky, Carl-Herbert and Vargas, Arturo and Kerschbaum, Markus and Resch, Christian and Zopp, Raimund and Plu, Matthieu and Peuch, Vincent-Henri and Van Roozendael, Michel and Wotawa, Gerhard}, title = {EUNADICS-AV early warning system dedicated to supporting aviation in the case of a crisis from natural airborne hazards and radionuclide clouds}, journal = {Natural Hazards and Earth System Sciences}, year = {2021}, volume = {21}, number = {11}, pages = {3367 – 3405}, note = {All Open Access, Gold Open Access}, doi = {10.5194/nhess-21-3367-2021} }
Buchholz RR, Worden HM, Park M, Francis G, Deeter MN, Edwards DP, Emmons LK, Gaubert B, Gille J, Martínez-Alonso S, Tang W, Kumar R, Drummond JR, Clerbaux C, George M, Coheur P-F, Hurtmans D, Bowman KW, Luo M, Payne VH, Worden JR, Chin M, Levy RC, Warner J, Wei Z and Kulawik SS (2021), "Air pollution trends measured from Terra: CO and AOD over industrial, fire-prone, and background regions", Remote Sensing of Environment. Vol. 256 [Abstract] [BibTeX] [DOI]
Abstract: Following past studies to quantify decadal trends in global carbon monoxide (CO) using satellite observations, we update estimates and find a CO trend in column amounts of about −0.50 % per year between 2002 to 2018, which is a deceleration compared to analyses performed on shorter records that found −1 % per year. Aerosols are co-emitted with CO from both fires and anthropogenic sources but with a shorter lifetime than CO. A combined trend analysis of CO and aerosol optical depth (AOD) measurements from space helps to diagnose the drivers of regional differences in the CO trend. We use the long-term records of CO from the Measurements of Pollution in the Troposphere (MOPITT) and AOD from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. Other satellite instruments measuring CO in the thermal infrared, AIRS, TES, IASI, and CrIS, show consistent hemispheric CO variability and corroborate results from the trend analysis performed with MOPITT CO. Trends are examined by hemisphere and in regions for 2002 to 2018, with uncertainties quantified. The CO and AOD records are split into two sub-periods (2002 to 2010 and 2010 to 2018) in order to assess trend changes over the 16 years. We focus on four major population centers: Northeast China, North India, Europe, and Eastern USA, as well as fire-prone regions in both hemispheres. In general, CO declines faster in the first half of the record compared to the second half, while AOD trends show more variability across regions. We find evidence of the atmospheric impact of air quality management policies. The large decline in CO found over Northeast China is initially associated with an improvement in combustion efficiency, with subsequent additional air quality improvements from 2010 onwards. Industrial regions with minimal emission control measures such as North India become more globally relevant as the global CO trend weakens. We also examine the CO trends in monthly percentile values to understand seasonal implications and find that local changes in biomass burning are sufficiently strong to counteract the global downward trend in atmospheric CO, particularly in late summer. © 2020 The Author(s)
BibTeX: @article{Buchholz2021, author = {Buchholz, Rebecca R. and Worden, Helen M. and Park, Mijeong and Francis, Gene and Deeter, Merritt N. and Edwards, David P. and Emmons, Louisa K. and Gaubert, Benjamin and Gille, John and Martínez-Alonso, Sara and Tang, Wenfu and Kumar, Rajesh and Drummond, James R. and Clerbaux, Cathy and George, Maya and Coheur, Pierre-François and Hurtmans, Daniel and Bowman, Kevin W. and Luo, Ming and Payne, Vivienne H. and Worden, John R. and Chin, Mian and Levy, Robert C. and Warner, Juying and Wei, Zigang and Kulawik, Susan S.}, title = {Air pollution trends measured from Terra: CO and AOD over industrial, fire-prone, and background regions}, journal = {Remote Sensing of Environment}, year = {2021}, volume = {256}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.rse.2020.112275} }
Cauët E, Vanhaegenborgh YJ, De Proft F and Geerlings P (2021), "Conceptual and Computational DFT-based In Silico Fragmentation Method for the Identification of Metabolite Mass Spectra", Chemistry-Methods. Vol. 1(2), pp. 101 – 115. [Abstract] [BibTeX] [DOI]
Abstract: Metabolomics is recognized as a crucial scientific domain, promising to advance our understanding of cell biology, physiology and medicine. Tandem mass spectrometry (MS/MS) has strong potential to elucidate the metabolites in complex biological samples and to become a standard tool complementing established techniques. However, despite its potential for answering many key questions, a major challenge in the use of tandem mass spectrometry for characterizing metabolites lies in a lack of computational tools for accurate annotation and structure identification allowing us to turn complex data into molecular knowledge. Chemo-informatics and related machine-learning in silico fragmentation tools have already been established and used for different classes of metabolites. For the classes of metabolites where existing chemo-informatics approaches produce insufficiently accurate predictions a supervised machine learning based strategy can be used to predict possible molecular structures from “unassigned” experimental tandem MS data. Here, we propose a new innovative in silico approach employing quantum mechanical (QM) methods in order to predict ion formation and subsequent fragmentation patterns of arbitrary small molecules and validate putative annotations of tandem mass spectrometry (MS) data. The focus is on the evaluation of a new conceptual density functional theory (CDFT) nuclear reactivity descriptor of the nuclear Fukui function type, that characterizes the forces that the atomic nuclei experience due to proton attachment and captures the onset of the change in the nuclear positions induced by it. A series of test compounds for which high quality experimental data exist and that were investigated before in a more approximate theoretical framework have been examined. The output of these calculations provides a list of the most probable molecular structures predicted to match the experimental tandem MS spectrum (“de novo metabolite identification”). © 2020 The Authors. Published by Wiley-VCH GmbH.
BibTeX: @article{Cauet2021, author = {Cauët, Emilie and Vanhaegenborgh, Yannick J. and De Proft, Frank and Geerlings, Paul}, title = {Conceptual and Computational DFT-based In Silico Fragmentation Method for the Identification of Metabolite Mass Spectra}, journal = {Chemistry-Methods}, year = {2021}, volume = {1}, number = {2}, pages = {101 – 115}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.1002/cmtd.202000047} }
Chang Y, Zhang Y-L, Kawichai S, Wang Q, Van Damme M, Clarisse L, Prapamontol T and Lehmann MF (2021), "Convergent evidence for the pervasive but limited contribution of biomass burning to atmospheric ammonia in peninsular Southeast Asia", Atmospheric Chemistry and Physics. Vol. 21(9), pp. 7187 – 7198. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) is an important agent involved in atmospheric chemistry and nitrogen cycling. Current estimates of NH3 emissions from biomass burning (BB) differ by more than a factor of 2, impeding a reliable assessment of their environmental consequences. Combining highresolution satellite observations of NH3 columns with network measurements of the concentration and stable nitrogen isotope composition (δ15N) of NH3, we present coherent estimates of the amount of NH3 derived from BB in the heartland of Southeast Asia, a tropical monsoon environment. Our results reveal a strong variability in atmospheric NH3 levels in time and space across different landscapes. All of the evidence on hand suggests that anthropogenic activities are the most important modulating control with respect to the observed patterns of NH3 distribution in the study area. Nisotope balance considerations revealed that during the intensive fire period, the atmospheric input from BB accounts for no more than 21 ± 5 % (1s) of the ambient NH3, even at the rural sites and in the proximity of burning areas. Our N-isotope-based assessment of the variation in the relative contribution of BB-derived NH3 is further validated independently through the measurements of particulate KC, a chemical tracer of BB. Our findings underscore that BB-induced NH3 emissions in tropical monsoon environments can be much lower than previously anticipated, with important implications for future modeling studies to better constrain the climate and air quality effects of wildfires. © 2021 Author(s).
BibTeX: @article{Chang2021, author = {Chang, Yunhua and Zhang, Yan-Lin and Kawichai, Sawaeng and Wang, Qian and Van Damme, Martin and Clarisse, Lieven and Prapamontol, Tippawan and Lehmann, Moritz F.}, title = {Convergent evidence for the pervasive but limited contribution of biomass burning to atmospheric ammonia in peninsular Southeast Asia}, journal = {Atmospheric Chemistry and Physics}, year = {2021}, volume = {21}, number = {9}, pages = {7187 – 7198}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-21-7187-2021} }
Chen Y, Shen H, Kaiser J, Hu Y, Capps SL, Zhao S, Hakami A, Shih J-S, Pavur GK, Turner MD, Henze DK, Resler J, Nenes A, Napelenok SL, Bash JO, Fahey KM, Carmichael GR, Chai T, Clarisse L, Coheur P-F, Van Damme M and Russell AG (2021), "High-resolution hybrid inversion of IASI ammonia columns to constrain US ammonia emissions using the CMAQ adjoint model", Atmospheric Chemistry and Physics. Vol. 21(3), pp. 2067 – 2082. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3/emissions have large impacts on air quality and nitrogen deposition, influencing human health and the well-being of sensitive ecosystems. Large uncertainties exist in the "bottom-up"NH3 emission inventories due to limited source information and a historical lack of measurements, hindering the assessment of NH3-related environmental impacts. The increasing capability of satellites to measure NH3 abundance and the development of modeling tools enable us to better constrain NH3 emission estimates at high spatial resolution. In this study, we constrain the NH3 emission estimates from the widely used 2011 National Emissions Inventory (2011 NEI) in the US using Infrared Atmospheric Sounding Interferometer NH3 column density measurements (IASI-NH3) gridded at a 36 km by 36 km horizontal resolution. With a hybrid inverse modeling approach, we use the Community Multiscale Air Quality Modeling System (CMAQ) and its multiphase adjoint model to optimize NH3 emission estimates in April, July, and October. Our optimized emission estimates suggest that the total NH3 emissions are biased low by 26 % in 2011 NEI in April with overestimation in the Midwest and underestimation in the Southern States. In July and October, the estimates from NEI agree well with the optimized emission estimates, despite a low bias in hotspot regions. Evaluation of the inversion performance using independent observations shows reduced underestimation in simulated ambient NH3 concentra tion in all 3 months and reduced underestimation in NHC 4 wet deposition in April. Implementing the optimized NH3 emission estimates improves the model performance in simulating PM2:5 concentration in the Midwest in April. The model results suggest that the estimated contribution of ammonium nitrate would be biased high in a priori NEI-based assessments. The higher emission estimates in this study also imply a higher ecological impact of nitrogen deposition originating from NH3 emissions. © 2021 Author(s).
BibTeX: @article{Chen2021, author = {Chen, Yilin and Shen, Huizhong and Kaiser, Jennifer and Hu, Yongtao and Capps, Shannon L. and Zhao, Shunliu and Hakami, Amir and Shih, Jhih-Shyang and Pavur, Gertrude K. and Turner, Matthew D. and Henze, Daven K. and Resler, Jaroslav and Nenes, Athanasios and Napelenok, Sergey L. and Bash, Jesse O. and Fahey, Kathleen M. and Carmichael, Gregory R. and Chai, Tianfeng and Clarisse, Lieven and Coheur, Pierre-François and Van Damme, Martin and Russell, Armistead G.}, title = {High-resolution hybrid inversion of IASI ammonia columns to constrain US ammonia emissions using the CMAQ adjoint model}, journal = {Atmospheric Chemistry and Physics}, year = {2021}, volume = {21}, number = {3}, pages = {2067 – 2082}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-21-2067-2021} }
Clarisse L, Van Damme M, Hurtmans D, Franco B, Clerbaux C and Coheur P-F (2021), "The Diel Cycle of NH3 Observed From the FY-4A Geostationary Interferometric Infrared Sounder (GIIRS)", Geophysical Research Letters. Vol. 48(14) [Abstract] [BibTeX] [DOI]
Abstract: Limiting excess atmospheric ammonia (NH3) is one of the great challenges for humanity in the 21st century but can only be achieved with adequate monitoring means in place. Here, we report the first NH3 measurements from the Geostationary Interferometric Infrared Sounder (GIIRS) onboard the Chinese FY-4A satellite. The instrument scans almost all of Asia 10 times per day. We show that GIIRS′ unprecedented temporal sampling can be exploited to measure diurnal and nocturnal variations of NH3 and demonstrate this on two case studies over Punjab and the North China Plain. Day–night variations are found to be almost absent in winter, but can reach a factor 2–3 in the warmer months. These case studies are very promising given the future landscape of geostationary sounders, but also show that improved knowledge on lower tropospheric air temperatures and the vertical profile of NH3 is key to better exploit their measurements. © 2021. The Authors.
BibTeX: @article{Clarisse2021, author = {Clarisse, Lieven and Van Damme, Martin and Hurtmans, Daniel and Franco, Bruno and Clerbaux, Cathy and Coheur, Pierre-François}, title = {The Diel Cycle of NH3 Observed From the FY-4A Geostationary Interferometric Infrared Sounder (GIIRS)}, journal = {Geophysical Research Letters}, year = {2021}, volume = {48}, number = {14}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1029/2021GL093010} }
Coheur P, Clarisse L, Hurtmans D, Franco B, van Damme M and Clerbaux C (2021), "Atmospheric composition applications with IASI and next-generation hyperspectral infrared sounders (IASI-NG and IRS)", International Geoscience and Remote Sensing Symposium (IGARSS). Vol. 2021-July, pp. 7858 – 7859. [BibTeX] [DOI]
BibTeX: @conference{Coheur2021, author = {Coheur, Pierre and Clarisse, Lieven and Hurtmans, Daniel and Franco, Bruno and van Damme, Martin and Clerbaux, Cathy}, title = {Atmospheric composition applications with IASI and next-generation hyperspectral infrared sounders (IASI-NG and IRS)}, journal = {International Geoscience and Remote Sensing Symposium (IGARSS)}, year = {2021}, volume = {2021-July}, pages = {7858 – 7859}, doi = {10.1109/IGARSS47720.2021.9553663} }
Corradini S, Guerrieri L, Brenot H, Clarisse L, Merucci L, Pardini F, Prata AJ, Realmuto VJ, Stelitano D and Theys N (2021), "Tropospheric volcanic so2 mass and flux retrievals from satellite. The etna december 2018 eruption", Remote Sensing. Vol. 13(11) [Abstract] [BibTeX] [DOI]
Abstract: The presence of volcanic clouds in the atmosphere affects air quality, the environment, climate, human health and aviation safety. The importance of the detection and retrieval of volcanic SO2 lies with risk mitigation as well as with the possibility of providing insights into the mechanisms that cause eruptions. Due to their intrinsic characteristics, satellite measurements have become an essential tool for volcanic monitoring. In recent years, several sensors, with different spectral, spatial and temporal resolutions, have been launched into orbit, significantly increasing the effectiveness of the estimation of the various parameters related to the state of volcanic activity. In this work, the SO2 total masses and fluxes were obtained from several satellite sounders—the geostationary (GEO) MSG-SEVIRI and the polar (LEO) Aqua/Terra-MODIS, NPP/NOAA20-VIIRS, Sentinel5p-TROPOMI, MetopA/MetopB-IASI and Aqua-AIRS—and compared to one another. As a test case, the Christmas 2018 Etna eruption was considered. The characteristics of the eruption (tropospheric with low ash content), the large amount of (simultaneously) available data and the different instrument types and SO2 columnar abundance retrieval strategies make this cross-comparison particularly relevant. Results show the higher sensitivity of TROPOMI and IASI and a general good agreement between the SO2 total masses and fluxes obtained from all the satellite instruments. The differences found are either related to inherent instrumental sensitivity or the assumed and/or calculated SO2 cloud height considered as input for the satellite retrievals. Results indicate also that, despite their low revisit time, the LEO sensors are able to provide information on SO2 flux over large time intervals. Finally, a complete error assessment on SO2 flux retrievals using SEVIRI data was realized by considering uncertainties in wind speed and SO2 abundance. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
BibTeX: @article{Corradini2021, author = {Corradini, Stefano and Guerrieri, Lorenzo and Brenot, Hugues and Clarisse, Lieven and Merucci, Luca and Pardini, Federica and Prata, Alfred J. and Realmuto, Vincent J. and Stelitano, Dario and Theys, Nicolas}, title = {Tropospheric volcanic so2 mass and flux retrievals from satellite. The etna december 2018 eruption}, journal = {Remote Sensing}, year = {2021}, volume = {13}, number = {11}, note = {All Open Access, Gold Open Access}, doi = {10.3390/rs13112225} }
De Longueville H, Clarisse L, Whitburn S, Franco B, Bauduin S, Clerbaux C, Camy-Peyret C and Coheur P-F (2021), "Identification of Short and Long-Lived Atmospheric Trace Gases From IASI Space Observations", Geophysical Research Letters. Vol. 48(5) [Abstract] [BibTeX] [DOI]
Abstract: In recent years, major progress has been made in measuring weakly absorbing atmospheric trace gases from high spectral resolution space observations. In this paper, we apply the so-called whitening transformation on spectra of the Infrared Atmospheric Sounding Interferometer, and show that it allows removing most of the climatological background from spectra, leaving a residual that contains those spectral signatures that depart from normality. These can subsequently be attributed to changes in the abundance of trace species. This is illustrated for two diverging cases: (1) a biomass burning plume from the 2019/2020 Australian bushfires, leading to the unambiguous identification of nine reactive trace gases, including a first observation of glycolaldehyde; (2) spectra observed a decade apart, from which changes in eight long-lived halogenated substances are identified; three of them never observed before by a nadir sounder. © 2021. American Geophysical Union. All Rights Reserved.
BibTeX: @article{DeLongueville2021, author = {De Longueville, Hélène and Clarisse, Lieven and Whitburn, Simon and Franco, Bruno and Bauduin, Sophie and Clerbaux, Cathy and Camy-Peyret, Claude and Coheur, Pierre-François}, title = {Identification of Short and Long-Lived Atmospheric Trace Gases From IASI Space Observations}, journal = {Geophysical Research Letters}, year = {2021}, volume = {48}, number = {5}, note = {All Open Access, Green Open Access}, doi = {10.1029/2020GL091742} }
Delahaye T, Armante R, Scott N, Jacquinet-Husson N, Chédin A, Crépeau L, Crevoisier C, Douet V, Perrin A, Barbe A, Boudon V, Campargue A, Coudert L, Ebert V, Flaud J-M, Gamache R, Jacquemart D, Jolly A, Kwabia Tchana F, Kyuberis A, Li G, Lyulin O, Manceron L, Mikhailenko S, Moazzen-Ahmadi N, Müller H, Naumenko O, Nikitin A, Perevalov V, Richard C, Starikova E, Tashkun S, Tyuterev V, Vander Auwera J, Vispoel B, Yachmenev A and Yurchenko S (2021), "The 2020 edition of the GEISA spectroscopic database", Journal of Molecular Spectroscopy. Vol. 380 [Abstract] [BibTeX] [DOI]
Abstract: This paper describes the 2020 release of the GEISA database (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information), developed and maintained at LMD since 1974. GEISA is the reference database for several current or planned Thermal and Short-Wave InfraRed (TIR and SWIR) space missions IASI (Infrared Atmospheric Sounding Interferometer), IASI-NG (IASI New Generation), MicroCarb (Carbon Dioxide Monitoring Mission), Merlin (MEthane Remote sensing LIdar missioN). It is actually a compilation of three databases: the “line parameters database”, the “cross-section sub-database” and the “microphysical and optical properties of atmospheric aerosols sub-database”. The new edition concerns only the line parameters dataset, with significant updates and additions implemented using the best available spectroscopic data. The GEISA-2020 line parameters database involves 58 molecules (145 isotopic species) and contains 6,746,987 entries, in the spectral range from 10−6 to 35877 cm−1. In this version, 23 molecules have been updated (with 10 new isotopic species) and 6 new molecules have been added (HONO, COFCl, CH3F, CH3I, RuO4, H2C3H2 (isomer of C3H4)) corresponding to 15 isotopic species. The compilation can be accessed through the AERIS data and services center for the atmosphere website (https://geisa.aeris-data.fr/), with the development of a powerful graphical tool and convenient searching, filtering, and plotting of data using modern technologies (PostgreSQL database, REST API, VueJS, Plotly). Based on four examples (H2O, O3, O2 and SF6), this paper also shows how the LMD in house validation algorithm SPARTE (Spectroscopic Parameters And Radiative Transfer Evaluation) helps to evaluate, correct, reject or defer the input of new spectroscopic data into GEISA and this, thanks to iterations with researchers from different communities (spectroscopy, radiative transfer). © 2021
BibTeX: @article{Delahaye2021, author = {Delahaye, T. and Armante, R. and Scott, N.A. and Jacquinet-Husson, N. and Chédin, A. and Crépeau, L. and Crevoisier, C. and Douet, V. and Perrin, A. and Barbe, A. and Boudon, V. and Campargue, A. and Coudert, L.H. and Ebert, V. and Flaud, J.-M. and Gamache, R.R. and Jacquemart, D. and Jolly, A. and Kwabia Tchana, F. and Kyuberis, A. and Li, G. and Lyulin, O.M. and Manceron, L. and Mikhailenko, S. and Moazzen-Ahmadi, N. and Müller, H.S.P. and Naumenko, O.V. and Nikitin, A. and Perevalov, V.I. and Richard, C. and Starikova, E. and Tashkun, S.A. and Tyuterev, Vl.G. and Vander Auwera, J. and Vispoel, B. and Yachmenev, A. and Yurchenko, S.}, title = {The 2020 edition of the GEISA spectroscopic database}, journal = {Journal of Molecular Spectroscopy}, year = {2021}, volume = {380}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jms.2021.111510} }
Evangeliou N, Balkanski Y, Eckhardt S, Cozic A, Van Damme M, Coheur P-F, Clarisse L, Shephard MW, Cady-Pereira KE and Hauglustaine D (2021), "10-year satellite-constrained fluxes of ammonia improve performance of chemistry transport models", Atmospheric Chemistry and Physics. Vol. 21(6), pp. 4431 – 4451. [Abstract] [BibTeX] [DOI]
Abstract: In recent years, ammonia emissions have been continuously increasing, being almost 4 times higher than in the 20th century. Although an important species, as its use as a fertilizer sustains human living, ammonia has major consequences for both humans and the environment because of its reactive gas-phase chemistry that makes it easily convertible to particles. Despite its pronounced importance, ammonia emissions are highly uncertain in most emission inventories. However, the great development of satellite remote sensing nowadays provides the opportunity for more targeted research on constraining ammonia emissions. Here, we used satellite measurements to calculate global ammonia emissions over the period 2008 2017. Then, the calculated ammonia emissions were fed to a chemistry transport model, and ammonia concentrations were simulated for the period 2008 2017. The simulated concentrations of ammonia were compared with ground measurements from Europe, North America and Southeastern Asia, as well as with satellite measurements. The satellite-constrained ammonia emissions represent global concentrations more accurately than state-of-theart emissions. Calculated fluxes in the North China Plain were seen to be more increased after 2015, which is not due to emission changes but due to changes in sulfate emissions that resulted in less ammonia neutralization and hence in larger atmospheric loads. Emissions over Europe were also twice as much as those in traditional datasets with dominant sources being industrial and agricultural applications. Four hot-spot regions of high ammonia emissions were seen in North America, which are characterized by high agricultural activity, such as animal breeding, animal farms and agricultural practices. South America is dominated by ammonia emissions from biomass burning, which causes a strong seasonality. In Southeastern Asia, ammonia emissions from fertilizer plants in China, Pakistan, India and Indonesia are the most important, while a strong seasonality was observed with a spring and late summer peak due to rice and wheat cultivation. Measurements of ammonia surface concentrations were better reproduced with satellite-constrained emissions, such as measurements from CrIS (Cross-track Infrared Sounder). © 2021 EDP Sciences. All rights reserved.
BibTeX: @article{Evangeliou2021, author = {Evangeliou, Nikolaos and Balkanski, Yves and Eckhardt, Sabine and Cozic, Anne and Van Damme, Martin and Coheur, Pierre-Francois and Clarisse, Lieven and Shephard, Mark W. and Cady-Pereira, Karen E. and Hauglustaine, DIdier}, title = {10-year satellite-constrained fluxes of ammonia improve performance of chemistry transport models}, journal = {Atmospheric Chemistry and Physics}, year = {2021}, volume = {21}, number = {6}, pages = {4431 – 4451}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-21-4431-2021} }
Farji A, Aroui H and Vander Auwera J (2021), "Air-induced collisional parameters in the ν3 band of methane", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 275 [Abstract] [BibTeX] [DOI]
Abstract: Air broadening and shift coefficients together with narrowing and first order line mixing parameters were measured for 166 lines belonging to J″ manifolds of the P (J″=2−11), Q (J″=1−12) and R (J″=0−11) branches of the ν3 band of 12CH4 near 3.3 μm. These measurements were carried out using a non-linear multispectrum least squares fitting technique. A hard collision Dicke narrowed line shape model including Rosenkranz line mixing was applied. Five high resolution Fourier transform spectra were recorded at room temperature, one at low pressure with pure methane and four at pressures up to 904 hPa with mixtures of methane and air. The measured parameters are compared with data available in the literature. © 2021 Elsevier Ltd
BibTeX: @article{Farji2021, author = {Farji, A. and Aroui, H. and Vander Auwera, J.}, title = {Air-induced collisional parameters in the ν3 band of methane}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2021}, volume = {275}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2021.107878} }
Franco B, Blumenstock T, Cho C, Clarisse L, Clerbaux C, Coheur P-F, De Mazière M, De Smedt I, Dorn H-P, Emmerichs T, Fuchs H, Gkatzelis G, Griffith D, Gromov S, Hannigan J, Hase F, Hohaus T, Jones N, Kerkweg A, Kiendler-Scharr A, Lutsch E, Mahieu E, Novelli A, Ortega I, Paton-Walsh C, Pommier M, Pozzer A, Reimer D, Rosanka S, Sander R, Schneider M, Strong K, Tillmann R, Van Roozendael M, Vereecken L, Vigouroux C, Wahner A and Taraborrelli D (2021), "Ubiquitous atmospheric production of organic acids mediated by cloud droplets", Nature. Vol. 593(7858), pp. 233 – 237. [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric acidity is increasingly determined by carbon dioxide and organic acids1–3. Among the latter, formic acid facilitates the nucleation of cloud droplets4 and contributes to the acidity of clouds and rainwater1,5. At present, chemistry–climate models greatly underestimate the atmospheric burden of formic acid, because key processes related to its sources and sinks remain poorly understood2,6–9. Here we present atmospheric chamber experiments that show that formaldehyde is efficiently converted to gaseous formic acid via a multiphase pathway that involves its hydrated form, methanediol. In warm cloud droplets, methanediol undergoes fast outgassing but slow dehydration. Using a chemistry–climate model, we estimate that the gas-phase oxidation of methanediol produces up to four times more formic acid than all other known chemical sources combined. Our findings reconcile model predictions and measurements of formic acid abundance. The additional formic acid burden increases atmospheric acidity by reducing the pH of clouds and rainwater by up to 0.3. The diol mechanism presented here probably applies to other aldehydes and may help to explain the high atmospheric levels of other organic acids that affect aerosol growth and cloud evolution. © 2021, The Author(s).
BibTeX: @article{Franco2021, author = {Franco, B. and Blumenstock, T. and Cho, C. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and De Mazière, M. and De Smedt, I. and Dorn, H.-P. and Emmerichs, T. and Fuchs, H. and Gkatzelis, G. and Griffith, D.W.T. and Gromov, S. and Hannigan, J.W. and Hase, F. and Hohaus, T. and Jones, N. and Kerkweg, A. and Kiendler-Scharr, A. and Lutsch, E. and Mahieu, E. and Novelli, A. and Ortega, I. and Paton-Walsh, C. and Pommier, M. and Pozzer, A. and Reimer, D. and Rosanka, S. and Sander, R. and Schneider, M. and Strong, K. and Tillmann, R. and Van Roozendael, M. and Vereecken, L. and Vigouroux, C. and Wahner, A. and Taraborrelli, D.}, title = {Ubiquitous atmospheric production of organic acids mediated by cloud droplets}, journal = {Nature}, year = {2021}, volume = {593}, number = {7858}, pages = {233 – 237}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1038/s41586-021-03462-x} }
Glorieux R, Lauzin C, Barclay A, Herman M and Moazzen-Ahmadi N (2021), "Spectroscopic study of the tunneling dynamics in N2-water observed in the O-D stretch region", Journal of Chemical Physics. Vol. 155(17) [Abstract] [BibTeX] [DOI]
Abstract: The O-D stretch rovibrational spectra of N2-D2O and N2-DOH were measured and analyzed. A combination band involving the in-plane N2 bending vibration was also observed. These bands were recorded using a pulsed-slit supersonic jet expansion and a mid-infrared tunable optical parametric oscillator. The spectra were analyzed by considering the feasible tunneling motions, and transitions were fitted to independent asymmetric rotors for each tunneling state. The rotational constants of the four tunneling components of N2-D2O were retrieved for the excited vibrational states. A two order of magnitude increase in the tunneling splittings is observed for the asymmetric O-D stretch (ν3 in D2O) excitation compared to the symmetric stretch (ν1 in D2O) and to the ground vibrational state. This last finding indicates that the ν3 vibrational state is likely perturbed by a combination state that includes ν1. Finally, the observation of a local perturbation in the ν3 vibrational band, affecting the positions of few rovibrational levels, provides an experimental lower limit of the dissociation energy of the complex, D0 > 120 cm-1. © 2021 Author(s).
BibTeX: @article{Glorieux2021, author = {Glorieux, R. and Lauzin, C. and Barclay, A.J. and Herman, M. and Moazzen-Ahmadi, N.}, title = {Spectroscopic study of the tunneling dynamics in N2-water observed in the O-D stretch region}, journal = {Journal of Chemical Physics}, year = {2021}, volume = {155}, number = {17}, doi = {10.1063/5.0071732} }
Guo X, Wang R, Pan D, Zondlo MA, Clarisse L, Van Damme M, Whitburn S, Coheur P-F, Clerbaux C, Franco B, Golston LM, Wendt L, Sun K, Tao L, Miller D, Mikoviny T, Müller M, Wisthaler A, Tevlin AG, Murphy JG, Nowak JB, Roscioli JR, Volkamer R, Kille N, Neuman JA, Eilerman SJ, Crawford JH, Yacovitch TI, Barrick JD and Scarino AJ (2021), "Validation of IASI Satellite Ammonia Observations at the Pixel Scale Using In Situ Vertical Profiles", Journal of Geophysical Research: Atmospheres. Vol. 126(9) [Abstract] [BibTeX] [DOI]
Abstract: Satellite ammonia (NH3) observations provide unprecedented insights into NH3 emissions, spatiotemporal variabilities and trends, but validation with in situ measurements remains lacking. Here, total columns from the Infrared Atmospheric Sounding Interferometer (IASI) were intercompared to boundary layer NH3 profiles derived from aircraft- and surface-based measurements primarily in Colorado, USA, in the summer of 2014. IASI-NH3 version 3 near real-time data set compared well to in situ derived columns (windows ±15 km around centroid, ±1 h around overpass time) with a correlation of 0.58, a slope of 0.78 ± 0.14 and an intercept of 2.1 × 1015±1.5 × 1015 molecules cm−2. Agreement degrades at larger spatiotemporal windows, consistent with the short atmospheric lifetime of NH3. We also examined IASI version 3R data, which relies on temperature retrievals from the ERA Reanalysis, and a third product generated using aircraft-measured temperature profiles. The overall agreement improves slightly for both cases, and neither is biased within their combined measurement errors. Thus, spatiotemporal averaging of IASI over large windows can be used to reduce retrieval noise. Nonetheless, sampling artifacts of airborne NH3 instruments result in significant uncertainties of the in situ-derived columns. For example, large validation differences exist between ascent and descent profiles, and the assumptions of the free tropospheric NH3 profiles used above the aircraft ceiling significantly impact the validation. Because short-lived species like NH3 largely reside within the boundary layer with complex vertical structures, more comprehensive validation is needed across a wide range of environments. More accurate and widespread in situ NH3 data sets are therefore required for improved validations of satellite products. © 2021. The Authors.
BibTeX: @article{Guo2021, author = {Guo, Xuehui and Wang, Rui and Pan, Da and Zondlo, Mark A. and Clarisse, Lieven and Van Damme, Martin and Whitburn, Simon and Coheur, Pierre-François and Clerbaux, Cathy and Franco, Bruno and Golston, Levi M. and Wendt, Lars and Sun, Kang and Tao, Lei and Miller, David and Mikoviny, Tomas and Müller, Markus and Wisthaler, Armin and Tevlin, Alexandra G. and Murphy, Jennifer G. and Nowak, John B. and Roscioli, Joseph R. and Volkamer, Rainer and Kille, Natalie and Neuman, J. Andrew and Eilerman, Scott J. and Crawford, James H. and Yacovitch, Tara I. and Barrick, John D. and Scarino, Amy Jo}, title = {Validation of IASI Satellite Ammonia Observations at the Pixel Scale Using In Situ Vertical Profiles}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2021}, volume = {126}, number = {9}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1029/2020JD033475} }
Heylen H, Devlin C, Gins W, Bissell M, Blaum K, Cheal B, Filippin L, Ruiz RFG, Godefroid M, Gorges C, Holt J, Kanellakopoulos A, Kaufmann S, Koszorús Á, König K, Malbrunot-Ettenauer S, Miyagi T, Neugart R, Neyens G, Nörtershäuser W, Sánchez R, Sommer F, Rodríguez L, Xie L, Xu Z, Yang X and Yordanov D (2021), "High-resolution laser spectroscopy of Al 27-32", Physical Review C. Vol. 103(1) [Abstract] [BibTeX] [DOI]
Abstract: Hyperfine spectra of Al27-32 (Z=13) have been measured at the ISOLDE-CERN facility via collinear laser spectroscopy using the 3s23p2P3/2o→3s24s2S1/2 atomic transition. For the first time, mean-square charge radii of radioactive aluminum isotopes have been determined alongside the previously unknown magnetic dipole moment of Al29 and electric quadrupole moments of Al29,30. A potentially reduced charge radius at N=19 may suggest an effect of the N=20 shell closure, which is visible in the Al chain, contrary to other isotopic chains in the sd shell. The experimental results are compared with theoretical calculations in the framework of the valence-space in-medium similarity renormalization group using multiple sets of two-and three-nucleon forces from chiral effective field theory. While the trend of experimental magnetic dipole and electric quadrupole moments is well reproduced, the absolute values are underestimated by theory, which is consistent with earlier studies. Moreover, both the scale and trend of the charge radii appear to be very sensitive to the chosen interaction. © 2021 authors.
BibTeX: @article{Heylen2021, author = {Heylen, H. and Devlin, C.S. and Gins, W. and Bissell, M.L. and Blaum, K. and Cheal, B. and Filippin, L. and Ruiz, R. F. Garcia and Godefroid, M. and Gorges, C. and Holt, J.D. and Kanellakopoulos, A. and Kaufmann, S. and Koszorús, Á. and König, K. and Malbrunot-Ettenauer, S. and Miyagi, T. and Neugart, R. and Neyens, G. and Nörtershäuser, W. and Sánchez, R. and Sommer, F. and Rodríguez, L.V. and Xie, L. and Xu, Z.Y. and Yang, X.F. and Yordanov, D.T.}, title = {High-resolution laser spectroscopy of Al 27-32}, journal = {Physical Review C}, year = {2021}, volume = {103}, number = {1}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1103/PhysRevC.103.014318} }
Hickman JE, Andela N, Dammers E, Clarisse L, Coheur P-F, Van Damme M, Di Vittorio CA, Ossohou M, Galy-Lacaux C, Tsigaridis K and Bauer SE (2021), "Changes in biomass burning, wetland extent, or agriculture drive atmospheric NH3 trends in select African regions", Atmospheric Chemistry and Physics. Vol. 21(21), pp. 16277 – 16291. [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric ammonia (NH3) is a precursor to fine particulate matter and a source of nitrogen (N) deposition that can adversely affect ecosystem health. The main sources of NH3 - agriculture and biomass burning - are undergoing are or expected to undergo substantial changes in Africa. Although evidence of increasing NH3 over parts of Africa has been observed, the mechanisms behind these trends are not well understood. Here we use observations of atmospheric NH3 vertical column densities (VCDs) from the Infrared Atmospheric Sounding Interferometer (IASI) along with other satellite observations of the land surface and atmosphere to evaluate how NH3 concentrations have changed over Africa from 2008 through 2018, and what has caused those changes. In West Africa NH3 VCDs are observed to increase during the late dry season, with increases of over 6 % yr-1 in Nigeria during February and March (p<0.01). These positive trends are associated with increasing burned area and CO trends during these months, likely related to agricultural preparation. Increases are also observed in the Lake Victoria basin region, where they are associated with expanding agricultural area. In contrast, NH3 VCDs declined over the Sudd wetlands in South Sudan by over 1.5 % yr-1, though not significantly (pCombining double low line0.28). Annual maxima in NH3 VCDs in South Sudan occur during February through May and are associated with the drying of temporarily flooded wetland soils, which favor emissions of NH3. The change in mean NH3 VCDs over the Sudd is strongly correlated with variation in wetland extent in the Sudd: in years when more area remained flooded during the dry season, NH3 VCDs were lower (rCombining double low line0.64, p<0.05). Relationships between biomass burning and NH3 may be observed when evaluating national-scale statistics: countries with the highest rates of increasing NH3 VCDs also had high rates of growth in CO VCDs; burned area displayed a similar pattern, though not significantly. Livestock numbers were also higher in countries with intermediate or high rates of NH3 VCD growth. Fertilizer use in Africa is currently low but growing; implementing practices that can limit NH3 losses from fertilizer as agriculture is intensified may help mitigate impacts on health and ecosystems. ©
BibTeX: @article{Hickman2021a, author = {Hickman, Jonathan E. and Andela, Niels and Dammers, Enrico and Clarisse, Lieven and Coheur, Pierre-François and Van Damme, Martin and Di Vittorio, Courtney A. and Ossohou, Money and Galy-Lacaux, Corinne and Tsigaridis, Kostas and Bauer, Susanne E.}, title = {Changes in biomass burning, wetland extent, or agriculture drive atmospheric NH3 trends in select African regions}, journal = {Atmospheric Chemistry and Physics}, year = {2021}, volume = {21}, number = {21}, pages = {16277 – 16291}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-21-16277-2021} }
Hickman JE, Andela N, Tsigaridis K, Galy-Lacaux C, Ossohou M, Dammers E, Van Damme M, Clarisse L and Bauer SE (2021), "Continental and Ecoregion-Specific Drivers of Atmospheric NO2 and NH3 Seasonality Over Africa Revealed by Satellite Observations", Global Biogeochemical Cycles. Vol. 35(8) [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) and nitrogen oxides (NOx: nitrogen dioxide [NO2] + nitric oxide [NO]) play important roles in atmospheric chemistry. Throughout most of Africa, emissions of these gases are predominantly from soils and biomass burning. Here we use observations of tropospheric NO2 vertical column densities (VCDs) from the Ozone Monitoring Instrument from 2005 through 2017 and atmospheric NH3 VCDs from the Infrared Atmospheric Sounding Interferometer from 2008 through 2017 to evaluate seasonal variation of NO2 and NH3 VCDs across Africa and in seven African ecoregions. In regions where mean annual precipitation (MAP) is under 500 mm yr−1, we find that NO2 and NH3 VCDs are positively related to monthly precipitation, and where MAP is between 500 and 1,750 mm yr−1 or higher, NO2 VCDs are negatively related to monthly precipitation. In dry ecoregions, temperature and precipitation were important predictors of NH3 and NO2 VCDs, likely related to variation in soil emissions. In mesic ecoregions, monthly NO2 VCDs were strongly related to burned area, suggesting that biomass burning drives seasonality. NH3 VCDs in mesic ecoregions were positively related to both monthly temperature and monthly carbon monoxide (CO) VCDs, suggesting that a mixture of soil and biomass burning emissions influenced NH3 seasonality. In northern mesic ecoregions, monthly temperature explained most of the variance in monthly NH3 VCDs, suggesting that soil sources, including animal excreta, determined NH3 seasonality. In southern mesic ecoregions, monthly CO VCDs explained more variation in NH3 VCDs than temperature, suggesting that biomass burning may have greater influence over NH3 seasonality. © 2021. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Hickman2021, author = {Hickman, Jonathan E. and Andela, Niels and Tsigaridis, Kostas and Galy-Lacaux, Corinne and Ossohou, Money and Dammers, Enrico and Van Damme, Martin and Clarisse, Lieven and Bauer, Susanne E.}, title = {Continental and Ecoregion-Specific Drivers of Atmospheric NO2 and NH3 Seasonality Over Africa Revealed by Satellite Observations}, journal = {Global Biogeochemical Cycles}, year = {2021}, volume = {35}, number = {8}, note = {All Open Access, Green Open Access}, doi = {10.1029/2020GB006916} }
Honet A, Henrard L and Meunier V (2021), "Semi-empirical many-body formalism of optical absorption in nanosystems and molecules", Carbon Trends. Vol. 4 [Abstract] [BibTeX] [DOI]
Abstract: A computationally efficient Green's function approach is developed to evaluate the optical properties of nanostructures within a semi-empirical Hubbard model. A GW formalism is applied on top of a tight-binding and mean-field approach. The use of the GW approximation includes key parts of the many-body physics that govern the optical response of nanostructures and molecules subjected to an external electromagnetic field and that is not included in the mean-field approximation. Such description of the electron-electron correlation yields computed spectra that compare significantly better with experiment for a subset of polycyclic aromatic hydrocarbons (PAHs) considered for illustrative purpose. More generally, the method is applicable to any structure whose electronic properties can be described in first approximation within a mean-field approach and is amenable for high-throughput studies aimed at screening materials with desired optical properties. © 2021 The Authors
BibTeX: @article{Honet2021, author = {Honet, Antoine and Henrard, Luc and Meunier, Vincent}, title = {Semi-empirical many-body formalism of optical absorption in nanosystems and molecules}, journal = {Carbon Trends}, year = {2021}, volume = {4}, note = {All Open Access, Gold Open Access}, doi = {10.1016/j.cartre.2021.100073} }
Ikeda K, Tanimoto H, Sugita T, Akiyoshi H, Clerbaux C and Coheur P-F (2021), "Model and Satellite Analysis of Transport of Asian Anthropogenic Pollution to the Arctic: Siberian and Pacific Pathways and Their Meteorological Controls", Journal of Geophysical Research: Atmospheres. Vol. 126(7) [Abstract] [BibTeX] [DOI]
Abstract: We made comprehensive analyses of long-range transport episodes of air pollutants from East Asia to the Arctic and associated meteorological conditions. While our main focus was black carbon (BC) as its transport to the Arctic has attracted great attention, carbon monoxide (CO) was also diagnosed as a species co-emitted with BC and as a tracer of long-range transport. We used satellite observations by the Infrared Atmospheric Sounding Interferometer (IASI) and a newly implemented BC tagged-tracer simulation using a global chemical transport model, GEOS-Chem. Temporal variations of IASI-CO column over the Pacific Arctic (160–200°E, 60–80°N) showed that episodic increases occurred several times in each season. For the period of 2007–2011, 11 strong events (6 in spring, 3 in autumn, and 2 in winter) caused by the long-range transport from East Asia were identified. Two transport pathways from East Asia to the Arctic were found: over Siberia and the Sea of Okhotsk, and over the North Pacific. In the pathway over Siberia and the Sea of Okhotsk, the pollutants were transported northeastward from China mainly through the Sea of Okhotsk and East Siberia. The low pressures passing from East Siberia to the Sea of Okhotsk played important roles in the transport in the lower troposphere and uplifting to the middle troposphere. In the pathway over the North Pacific, the pollutants were transported eastward from the Asian continent and subsequent northward transport took place over the North Pacific. The poleward transport occurred west of the high pressure that stayed around the Bering Sea. © 2021. The Authors.
BibTeX: @article{Ikeda2021, author = {Ikeda, Kohei and Tanimoto, Hiroshi and Sugita, Takafumi and Akiyoshi, Hideharu and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Model and Satellite Analysis of Transport of Asian Anthropogenic Pollution to the Arctic: Siberian and Pacific Pathways and Their Meteorological Controls}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2021}, volume = {126}, number = {7}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1029/2020JD033459} }
Lentz C, Marcélis L, Troian-Gautier L, Robeyns K, Cauët E and Elias B (2021), "Excited-state behavior and photoinduced electron transfer of pH-sensitive Ir(III) complexes with cyclometallation (C/N–) ratios between 0/6 and 3/3", Journal of Photochemistry and Photobiology A: Chemistry. Vol. 405 [Abstract] [BibTeX] [DOI]
Abstract: The first coordination sphere of Ir(III) 2,2′-bipyridine / 2-phenylpyridine complexes can be tuned to achieve either C– or N–chelation in ratios that range between 0/6 and 3/3. Of particular interest is the synthesis of Ir(III) complexes bearing a 2,2′-bipyridine ligand coordinated in a N,C3 pattern, leaving an exposed pyridine moiety, accessible for acid-base chemistry or coordination to a second transition metal center. The protonated forms of these “rolled-over” Ir(III) complexes were isolated in a straight-forward procedure using trifluoroacetic acid. The photophysical, photochemical and electrochemical properties of both the protonated and unprotonated Ir(III) complexes were investigated by steady-state and time-resolved spectroscopies, as well as by density functional theory calculations. The nature of the excited states was shown to depend on both the ligand coordination pattern and protonation state of the complex. In addition, the unprotonated and protonated analogues were efficiently quenched by hydroquinone and benzoquinone in acetonitrile with quenching rate constants close to the solvent diffusion limit. The results presented herein have direct implications for proton sensitive photoredox chemistry and the development of photo-acids and photo-bases. © 2020 Elsevier B.V.
BibTeX: @article{Lentz2021, author = {Lentz, Cédric and Marcélis, Lionel and Troian-Gautier, Ludovic and Robeyns, Koen and Cauët, Emilie and Elias, Benjamin}, title = {Excited-state behavior and photoinduced electron transfer of pH-sensitive Ir(III) complexes with cyclometallation (C/N–) ratios between 0/6 and 3/3}, journal = {Journal of Photochemistry and Photobiology A: Chemistry}, year = {2021}, volume = {405}, doi = {10.1016/j.jphotochem.2020.112957} }
Leroux K, Guillemin J-C and Krim L (2021), "Hydrogenation of glycolaldehyde to ethylene glycol at 10 K", Monthly Notices of the Royal Astronomical Society. Vol. 507(2), pp. 2632 – 2642. [Abstract] [BibTeX] [DOI]
Abstract: Glycolaldehyde, the simplest sugar, is a complex organic molecule detected in many regions of the interstellar medium (ISM). Although its synthetic routes are fairly well known and consistent with many laboratory studies, queries still arise about its reactivity and its role in the complex chemistry of the ISM. This study shows the surface and bulk hydrogenation of glycolaldehyde at 10 K in order to confirm or invalidate the astrophysical models which suggest that CHOCH2OH would be a precursor of ethylene glycol through hydrogenation processes occurring on the surface of interstellar dust grains. By coupling IR spectroscopy and mass spectrometry, we show that the formation of HOCH2CH2OH from CHOCH2OH + H solid state reaction occurs, supporting the existence of a chemical link between these two organics in the ISM. This work suggests that while CHO + CH2OH and CH2OH + CH2OH radical recombination would lead to CHOCH2OH and HOCH2CH2OH, respectively, the presence of H-atoms in the ISM would be a secondary source to favour ethylene glycol over glycolaldehyde. These results are in good agreement with different astronomical observations which show simultaneous detections of glycolaldehyde and ethylene glycol with an abundance ratio HOCH2CH2OH/CHOCH2OH ranged between 1 and 15. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.
BibTeX: @article{Leroux2021b, author = {Leroux, Killian and Guillemin, Jean-Claude and Krim, Lahouari}, title = {Hydrogenation of glycolaldehyde to ethylene glycol at 10 K}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {2021}, volume = {507}, number = {2}, pages = {2632 – 2642}, note = {All Open Access, Green Open Access}, doi = {10.1093/mnras/stab2267} }
Leroux K, Guillemin J-C and Krim L (2021), "Organic residues in astrophysical ice analogues: Thermal processing of hydrogenated glyoxal ices under interstellar conditions", Monthly Notices of the Royal Astronomical Society. Vol. 504(2), pp. 2181 – 2189. [Abstract] [BibTeX] [DOI]
Abstract: Organic residues are considered as part of the chemical composition of the interstellar dust grains. They are formed under the extreme conditions of the interstellar medium and play an important role in exobiology. They may contain pre-biotic organic species such as amino acids, constituents of proteins and building blocks of DNA and RNA, key elements of life. By investigating the formation of organic residues in an astrophysical context, many groups have been focusing in the UV irradiation and subsequent warm-up of astrophysical ice analogues. This aims to suggest that organic residues are mainly formed in regions of molecular clouds exposed to UV light or cosmic rays. This study shows an organic residue formation involving glyoxal ice and H atoms. While the hydrogenation of glyoxal at 10 K leads mainly to small molecules such as CO and H2CO and CH3OH, we show that the heating of the hydrogenated ice in the 10-300 K temperature range leads to solid residues whose structure is similar to that of glycolaldehyde but they remain stable in solid phase at 300 K and atmospheric pressure. The analysis of the IR data shows that the organic residues formed through the thermal processing of CHOCHO + H reaction would be a mixture of hydroxypyruvaldehyde and methyl glyoxylate, two solid organics whose formation starts with an H-abstraction from glyoxal to form CHOCO• radical which recombines to •CH2OH and •OCH3 radicals. These latter may be formed and trapped in glyoxal ice as secondary products from H2CO + H secondary reaction. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.
BibTeX: @article{Leroux2021, author = {Leroux, Killian and Guillemin, Jean-Claude and Krim, Lahouari}, title = {Organic residues in astrophysical ice analogues: Thermal processing of hydrogenated glyoxal ices under interstellar conditions}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {2021}, volume = {504}, number = {2}, pages = {2181 – 2189}, note = {All Open Access, Green Open Access}, doi = {10.1093/mnras/stab951} }
Leroux K and Krim L (2021), "Thermal and photochemical study of CH3OH and CH3OH-O2astrophysical ices", Monthly Notices of the Royal Astronomical Society. Vol. 500(1), pp. 1188 – 1200. [Abstract] [BibTeX] [DOI]
Abstract: Methanol, which is one of the most abundant organic molecules in the interstellar medium, plays an important role in the complex grain surface chemistry that is believed to be a source of many organic compounds. Under energetic processing such as ultraviolet (UV) photons or cosmic rays, methanol may decompose into CH4, CO2, CO, HCO, H2CO, CH3O and CH2OH, which in turn lead to complex organic molecules such as CH3OCHO, CHOCH2OH and HOCH2CH2OH through radical recombination reactions. However, although molecular oxygen and its detection, abundance and role in the interstellar medium have been the subject of many debates, few experiments on the oxidation of organic compounds have been carried out under interstellar conditions. The present study shows the behaviour of solid methanol when treated by UV light and thermal processing in oxygen-rich environments. Methanol has been irradiated in the absence and presence of O2 at different concentrations in order to study how oxidized complex organic molecules may form and also to investigate the O-insertion reaction in the C-H bound to form methanediol HOCH2OH through a CH3OH + O(1D) solid-state reaction. The adding of O2 in the thermal and photochemical reaction of solid methanol leads to the formation of O3, H2O and HO2, in addition to three main organics, HCOOH, CHOCHO and HOCH2OH. We show that in an O2-rich environment, species such as CO, CH4, HCO, CH3OH and CHOCH2OH are oxidized into CO2, CH3OH, HC(O)OO, HOCH2OH and CHOCHO, respectively, while HCOOH might be formed through the H2CO + O(3P) ? (OH + HCO)cage ? HCOOH hydrogen-Abstraction reaction. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
BibTeX: @article{Leroux2021a, author = {Leroux, Killian and Krim, Lahouari}, title = {Thermal and photochemical study of CH3OH and CH3OH-O2astrophysical ices}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {2021}, volume = {500}, number = {1}, pages = {1188 – 1200}, doi = {10.1093/mnras/staa3205} }
Loubet B, Baisnée D, Cazaunau M, Fortems-Cheiney A, Ciuraru R, Clerbaux C, Doussin J-F, Dufour G, Focsa C, George C, Gros V, Hassouna M, Jaffrezo J-L, Kammer J, Laville P, Mellouki A, Millet M, Petitprez D, Quivet E, Redon N, Sarda-Esteve R, Sauvage S, Uzu G, Villenave É and Zannoni N (2021), "Measuring Air Pollutant Concentrations and Fluxes", Agriculture and Air Quality: Investigating, Assessing and Managing. , pp. 119 – 157. [Abstract] [BibTeX] [DOI]
Abstract: Estimating agriculture’s contribution to air pollution and global warming is needed to understand and limit its impacts on the environment and climate. It is equally important to estimate the capacity of agricultural practices to mitigate these emissions and to characterize atmospheric deposition and the impacts of air pollutants on agroecosystems. This chapter presents methods for measuring air pollutant concentrations, their fluxes at the soil-vegetation-atmosphere interface, and emissions from livestock facilities. Methods for measuring air concentrations are described with a focus on compounds emitted from or impacting agriculture (including forests): ammonia, nitrogen oxides, pesticides, volatile organic compounds including methane, abiotic and biotic particles, and ozone. The main methods for measuring emission and deposition fluxes of air pollutants between terrestrial surfaces, especially agroecosystems, and the atmosphere are described with a specific focus on the eddy covariance method as well as on emissions from livestock buildings. Then the general principles of source apportionment methods for estimating emissions spatial variability are presented. To address the questions on atmospheric chemistry, the methods used for measuring the reactivity of atmospheric compounds are presented. Finally, an insight is given on the developments of measurement methodologies to address new compounds and improve the sensors’ sensitivity and response time as well as provide estimates of spatial variability of concentrations and fluxes at larger scales. © Springer Nature B.V. 2020.
BibTeX: @book{Loubet2021, author = {Loubet, Benjamin and Baisnée, Dominique and Cazaunau, Mathieu and Fortems-Cheiney, Audrey and Ciuraru, Raluca and Clerbaux, Cathy and Doussin, Jean-François and Dufour, Gaëlle and Focsa, Cristian and George, Christian and Gros, Valérie and Hassouna, Mélynda and Jaffrezo, Jean-Luc and Kammer, Julien and Laville, Patricia and Mellouki, Abdelwahid and Millet, Maurice and Petitprez, Denis and Quivet, Etienne and Redon, Nathalie and Sarda-Esteve, Roland and Sauvage, Stéphane and Uzu, Gaëlle and Villenave, Éric and Zannoni, Nora}, title = {Measuring Air Pollutant Concentrations and Fluxes}, journal = {Agriculture and Air Quality: Investigating, Assessing and Managing}, year = {2021}, pages = {119 – 157}, doi = {10.1007/978-94-024-2058-6_6} }
Mahieu E, Fischer EV, Franco B, Palm M, Wizenberg T, Smale D, Clarisse L, Clerbaux C, Coheur P-F, Hannigan JW, Lutsch E, Notholt J, Cantos IP, Prignon M, Servais C and Strong K (2021), "First retrievals of peroxyacetyl nitrate (PAN) from ground-based FTIR solar spectra recorded at remote sites, comparison with model and satellite data", Elementa. Vol. 9(1) [Abstract] [BibTeX] [DOI]
Abstract: Peroxyacetyl nitrate (PAN) is the main tropospheric reservoir of NOx (NO þ NO2). Its lifetime can reach several months in the upper cold troposphere. This enables the long-range transport of NOx radicals, under the form of PAN, far from the regions of emission. The subsequent release of NOx through the PAN thermal decomposition leads to the efficient formation of tropospheric ozone (O3), with important consequences for tropospheric oxidative capacity and air quality. The chemical properties of PAN have stimulated the progressive development of remote-sensing products by the satellite community, and recent additions open the prospect for the production of decadal and near-global time series. These products will provide new constraints on the distribution and evolution of this key trace gas in the Earth's atmosphere, but they will also require reliable measurements for validation and characterization of performance. We present an approach that has been developed to retrieve PAN total columns from ground-based high-resolution solar absorption Fourier transform infrared (FTIR) spectra. This strategy is applied to observations recorded at remote FTIR stations of the Network for the Detection of Atmospheric Composition Change (NDACC). The resulting data sets are compared with total column time series derived from IASI (Infrared Atmospheric Sounding Interferometer) satellite observations and to a global chemical transport model. The results are discussed in terms of their overall consistency, mutual agreement, and seasonal cycles. Noticeable is the fact that the FTIR data point to substantial deficiencies in the global model simulation over high latitudes, a poorly sampled region, with an underestimation of the PAN columns during spring, at the peak of the seasonal cycle. Finally, we suggest avenues for development that should make it possible to limit intra- or intersite biases and extend the retrieval of PAN to other NDACC stations that are more affected by water vapor interferences. Copyright: © 2021 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See http://creativecommons.org/licenses/by/4.0/.
BibTeX: @article{Mahieu2021, author = {Mahieu, Emmanuel and Fischer, Emily V. and Franco, Bruno and Palm, Mathias and Wizenberg, Tyler and Smale, Dan and Clarisse, Lieven and Clerbaux, Cathy and Coheur, Pierre-François and Hannigan, James W. and Lutsch, Erik and Notholt, Justus and Cantos, Irene Pardo and Prignon, Maxime and Servais, Christian and Strong, Kimberly}, title = {First retrievals of peroxyacetyl nitrate (PAN) from ground-based FTIR solar spectra recorded at remote sites, comparison with model and satellite data}, journal = {Elementa}, year = {2021}, volume = {9}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.1525/elementa.2021.00027} }
Maldonado-Pacheco G, García-Reynoso JA, Stremme W, Ruiz-Suárez LG, García-Yee JS, Clerbaux C and Coheur P-F (2021), "Carbon monoxide emissions assessment by using satellite and modeling data: Central Mexico case study", Atmosfera. Vol. 34(2), pp. 157 – 170. [Abstract] [BibTeX] [DOI]
Abstract: This paper quantifies and reduces the differences in emissions from the 2008 inventory with respect to the real ones through the use of satellite observations and modeling. Carbon monoxide column comparisons from the Infrared Atmospheric Sounding Interferometer (IASI) satellite data were made against columns obtained from the WRF-Chem model, during February 2011. The analysis was carried out at the satellite passage local time (approximately 10:00 LT) over Mexico City. The 2008 National Emissions Inventory generated by the Mexican Ministry of Environment and Natural Resources was utilized. An inversion method was applied to the modeled and observed column data. With the above, scaling factors were obtained for five regions and the concentration from the model domain boundaries, which were used to update the emissions. These were used in modeling and the result was compared with surface measurements. For Mexico City and the Metropolitan Area, a scaling factor equal to 0.43 was obtained when using the 2008 emissions inventory; for Toluca, Morelos and Puebla, a less than one factor was estimated, while for Hidalgo and the concentration from model boundaries it was close to two. The model performance was improved by an increment in the agreement index and a reduction on the mean square error when the updated CO emissions were used. © 2021 Universidad Nacional Autónoma de México, Centro de Ciencias de la Atmósfera. This is an open access article under the CC BY-NC License (http://creativecommons.org/licenses/by-nc/4.0/).
BibTeX: @article{MaldonadoPacheco2021, author = {Maldonado-Pacheco, Gilberto and García-Reynoso, José Agustín and Stremme, Wolfgang and Ruiz-Suárez, Luis Gerardo and García-Yee, José Santos and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Carbon monoxide emissions assessment by using satellite and modeling data: Central Mexico case study}, journal = {Atmosfera}, year = {2021}, volume = {34}, number = {2}, pages = {157 – 170}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.20937/ATM.52696} }
Marais EA, Pandey AK, Van Damme M, Clarisse L, Coheur P-F, Shephard MW, Cady-Pereira KE, Misselbrook T, Zhu L, Luo G and Yu F (2021), "UK Ammonia Emissions Estimated With Satellite Observations and GEOS-Chem", Journal of Geophysical Research: Atmospheres. Vol. 126(18) [Abstract] [BibTeX] [DOI]
Abstract: Agricultural emissions of ammonia (NH3) impact air quality, human health, and the vitality of aquatic and terrestrial ecosystems. In the UK, there are few direct policies regulating anthropogenic NH3 emissions and development of sustainable mitigation measures necessitates reliable emissions estimates. Here, we use observations of column densities of NH3 from two space-based sensors (IASI and CrIS) with the GEOS-Chem model to derive top-down NH3 emissions for the UK at fine spatial (∼10 km) and time (monthly) scales. We focus on March-September when there is adequate spectral signal to reliably retrieve NH3. We estimate total emissions of 272 Gg from IASI and 389 Gg from CrIS. Bottom-up emissions are 27% less than IASI and 49% less than CrIS. There are also differences in seasonality. Top-down and bottom-up emissions agree on a spring April peak due to fertilizer and manure application, but there is also a comparable summer July peak in the top-down emissions that is not in the bottom-up emissions and appears to be associated with dairy cattle farming. We estimate relative errors in the top-down emissions of 11%–36% for IASI and 9%–27% for CrIS, dominated by column density retrieval errors. The bottom-up versus top-down emissions discrepancies estimated in this work impact model predictions of the environmental damage caused by NH3 emissions and warrant further investigation. © 2021. The Authors.
BibTeX: @article{Marais2021, author = {Marais, Eloise A. and Pandey, Alok K. and Van Damme, Martin and Clarisse, Lieven and Coheur, Pierre-François and Shephard, Mark W. and Cady-Pereira, Karen E. and Misselbrook, Tom and Zhu, Lei and Luo, Gan and Yu, Fangqun}, title = {UK Ammonia Emissions Estimated With Satellite Observations and GEOS-Chem}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2021}, volume = {126}, number = {18}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1029/2021JD035237} }
Papoulia A, Schiffmann S, Bieroń J, Gaigalas G, Godefroid M, Harman Z, Jönsson P, Oreshkina NS, Pyykkö P and Tupitsyn II (2021), "Ab initio electronic factors of the A and B hyperfine structure constants for the 5s25p6s P1o 1,3 states in Sn i", Physical Review A. Vol. 103(2) [Abstract] [BibTeX] [DOI]
Abstract: Large-scale ab initio calculations of the electronic contribution to the electric quadrupole hyperfine constant B were performed for the 5s25p6s1,3P1o excited states of neutral tin. To probe the sensitivity of B to different electron correlation effects, three sets of variational multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction calculations employing different strategies were carried out. In addition, a fourth set of calculations was based on the configuration interaction Dirac-Fock-Sturm theory. For the 5s25p6sP1o1 state, the final value of B/Q=703(50) MHz/b differs by 0.4% from the one recently used by Yordanov et al. [Commun. Phys. 3, 107 (2020)10.1038/s42005-020-0348-9] to extract the nuclear quadrupole moments Q for tin isotopes in the range Sn117-131 from collinear laser spectroscopy measurements. Efforts were made to provide a realistic theoretical uncertainty for the final B/Q value of the 5s25p6sP1o1 state based on statistical principles and on correlation with the electronic contribution to the magnetic dipole hyperfine constant A. © 2021 American Physical Society.
BibTeX: @article{Papoulia2021, author = {Papoulia, Asimina and Schiffmann, Sacha and Bieroń, Jacek and Gaigalas, Gediminas and Godefroid, Michel and Harman, Zoltán and Jönsson, Per and Oreshkina, Natalia S. and Pyykkö, Pekka and Tupitsyn, Ilya I.}, title = {Ab initio electronic factors of the A and B hyperfine structure constants for the 5s25p6s P1o 1,3 states in Sn i}, journal = {Physical Review A}, year = {2021}, volume = {103}, number = {2}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.103.022815} }
Parracho AC, Safieddine S, Lezeaux O, Clarisse L, Whitburn S, George M, Prunet P and Clerbaux C (2021), "IASI-Derived Sea Surface Temperature Data Set for Climate Studies", Earth and Space Science. Vol. 8(5) [Abstract] [BibTeX] [DOI]
Abstract: Sea surface temperature (SST) is an essential climate variable, that is directly used in climate monitoring. Although satellite measurements can offer continuous global coverage, obtaining a long-term homogeneous satellite-derived SST data set suitable for climate studies based on a single instrument is still a challenge. In this work, we assess a homogeneous SST data set derived from reprocessed Infrared Atmospheric Sounding Interferometer (IASI) level-1 (L1C) radiance data. The SST is computed using Planck's Law and simple atmospheric corrections. We assess the data set using the ERA5 reanalysis and the EUMETSAT-released IASI level-2 SST product. Over the entire period, the reprocessed IASI SST shows a mean global difference with ERA5 close to zero, a mean absolute bias under 0.5°C, with a SD of difference around 0.3°C and a correlation coefficient over 0.99. In addition, the reprocessed data set shows a stable bias and SD, which is an advantage for climate studies. The interannual variability and trends were compared with other SST data sets: ERA5, Hadley Centre's SST (HadISST), and NOAA's Optimal Interpolation SST Analysis (OISSTv2). We found that the reprocessed SST data set is able to capture the patterns of interannual variability well, showing the same areas of high interannual variability (>1.5°C), including over the tropical Pacific in January corresponding to the El Niño Southern Oscillation. Although the period studied is relatively short, we demonstrate that the IASI data set reproduces the same trend patterns found in the other data sets (i.e., cooling trend in the North Atlantic, warming trend over the Mediterranean). © 2021. The Authors. Earth and Space Science published by Wiley Periodicals LLC on behalf of American Geophysical Union.
BibTeX: @article{Parracho2021, author = {Parracho, Ana C. and Safieddine, Sarah and Lezeaux, Olivier and Clarisse, Lieven and Whitburn, Simon and George, Maya and Prunet, Pascal and Clerbaux, Cathy}, title = {IASI-Derived Sea Surface Temperature Data Set for Climate Studies}, journal = {Earth and Space Science}, year = {2021}, volume = {8}, number = {5}, note = {All Open Access, Gold Open Access}, doi = {10.1029/2020EA001427} }
Pawar PV, Ghude SD, Jena C, Móring A, Sutton MA, Kulkarni S, Mani Lal D, Surendran D, Van Damme M, Clarisse L, Coheur P-F, Liu X, Govardhan G, Xu W, Jiang J and Kumar Adhya T (2021), "Analysis of atmospheric ammonia over South and East Asia based on the MOZART-4 model and its comparison with satellite and surface observations", Atmospheric Chemistry and Physics. Vol. 21(8), pp. 6389 – 6409. [Abstract] [BibTeX] [DOI]
Abstract: Limited availability of atmospheric ammonia (NHspan classCombining double low line"inline-formula"3/span) observations limits our understanding of controls on its spatial and temporal variability and its interactions with the ecosystem. Here we used the Model for Ozone and Related chemical Tracers version 4 (MOZART-4) global chemistry transport model and the Hemispheric Transport of Air Pollution version 2 (HTAP-v2) emission inventory to simulate global NHspan classCombining double low line"inline-formula"3/span distribution for the year 2010. We presented a first comparison of the model with monthly averaged satellite distributions and limited ground-based observations available across South Asia. The MOZART-4 simulations over South Asia and East Asia were evaluated with the NHspan classCombining double low line"inline-formula"3/span retrievals obtained from the Infrared Atmospheric Sounding Interferometer (IASI) satellite and 69 ground-based monitoring stations for air quality across South Asia and 32 ground-based monitoring stations from the Nationwide Nitrogen Deposition Monitoring Network (NNDMN) of China. We identified the northern region of India (Indo-Gangetic Plain, IGP) as a hotspot for NHspan classCombining double low line"inline-formula"3/span in Asia, both using the model and satellite observations. In general, a close agreement was found between yearly averaged NHspan classCombining double low line"inline-formula"3/span total columns simulated by the model and IASI satellite measurements over the IGP, South Asia (span classCombining double low line"inline-formula"ir/iCombining double low line0.81/span), and the North China Plain (NCP), East Asia (span classCombining double low line"inline-formula"ir/iCombining double low line0.90/span). However, the MOZART-4-simulated NHspan classCombining double low line"inline-formula"3/span column was substantially higher over South Asia than East Asia, as compared with the IASI retrievals, which show smaller differences. Model-simulated surface NHspan classCombining double low line"inline-formula"3/span concentrations indicated smaller concentrations in all seasons than surface NHspan classCombining double low line"inline-formula"3/span measured by the ground-based observations over South and East Asia, although uncertainties remain in the available surface NHspan classCombining double low line"inline-formula"3/span measurements. Overall, the comparison of East Asia and South Asia using both MOZART-4 model and satellite observations showed smaller NHspan classCombining double low line"inline-formula"3/span columns in East Asia compared with South Asia for comparable emissions, indicating rapid dissipation of NHspan classCombining double low line"inline-formula"3/span due to secondary aerosol formation, which can be explained by larger emissions of acidic precursor gases in East Asia./. © 2021 Royal Society of Chemistry. All rights reserved.
BibTeX: @article{Pawar2021, author = {Pawar, Pooja V. and Ghude, Sachin D. and Jena, Chinmay and Móring, Andrea and Sutton, Mark A. and Kulkarni, Santosh and Mani Lal, Deen and Surendran, Divya and Van Damme, Martin and Clarisse, Lieven and Coheur, Pierre-Francois and Liu, Xuejun and Govardhan, Gaurav and Xu, Wen and Jiang, Jize and Kumar Adhya, Tapan}, title = {Analysis of atmospheric ammonia over South and East Asia based on the MOZART-4 model and its comparison with satellite and surface observations}, journal = {Atmospheric Chemistry and Physics}, year = {2021}, volume = {21}, number = {8}, pages = {6389 – 6409}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-21-6389-2021} }
Richard C, Boudon V, Rizopoulos A, Vander Auwera J and Kwabia Tchana F (2021), "Line positions and intensities for the ν2/ν4 bands of 5 isotopologues of germane near 11.5 µm", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 260 [Abstract] [BibTeX] [DOI]
Abstract: Germane is a tetrahedral molecule found in trace abundance in giant gas planets like Jupiter and Saturn. We have recently provided a database of calculated lines of the stretching fundamental bands in the 2100 cm−1 region that is of high interest for planetology (https://vamdc.icb.cnrs.fr/PHP/GeH4.php). It is now necessary to study many rovibrational levels, including the lowest ones, in order to access the hot bands and thus to improve the model of the spectral region of interest for Jupiter, especially in the framework of the ongoing Juno mission. We present here a complete analysis and modeling of line positions and intensities in the ν2/ν4 bending dyad region near 900 cm−1 for all five germane isotopologues in natural abundance. Thanks to the high symmetry of the molecule, we use the tensorial formalism and group theory methods developed in the Dijon group, that allows us to provide a set of effective Hamiltonian and dipole parameters. The present study also leads to a refined value of the Ge–H equilibrium bond length of 1.51714(25) Å. Finally, new calculated germane lines were derived and injected in the GeCaSDa database. © 2020 Elsevier Ltd
BibTeX: @article{Richard2021, author = {Richard, C. and Boudon, V. and Rizopoulos, A. and Vander Auwera, J. and Kwabia Tchana, F.}, title = {Line positions and intensities for the ν2/ν4 bands of 5 isotopologues of germane near 11.5 µm}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2021}, volume = {260}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jqsrt.2020.107474} }
Rosanka S, Franco B, Clarisse L, Coheur P-F, Pozzer A, Wahner A and Taraborrelli D (2021), "The impact of organic pollutants from Indonesian peatland fires on the tropospheric and lower stratospheric composition", Atmospheric Chemistry and Physics. Vol. 21(14), pp. 11257 – 11288. [Abstract] [BibTeX] [DOI]
Abstract: The particularly strong dry season in Indonesia in 2015, caused by an exceptionally strong El Niño, led to severe peatland fires resulting in high volatile organic compound (VOC) biomass burning emissions. At the same time, the developing Asian monsoon anticyclone (ASMA) and the general upward transport in the Intertropical Convergence Zone (ITCZ) efficiently transported the resulting primary and secondary pollutants to the upper troposphere and lower stratosphere (UTLS). In this study, we assess the importance of these VOC emissions for the composition of the lower troposphere and the UTLS and investigate the effect of in-cloud oxygenated VOC (OVOC) oxidation during such a strong pollution event. This is achieved by performing multiple chemistry simulations using the global atmospheric model ECHAM/MESSy (EMAC). By comparing modelled columns of the biomass burning marker hydrogen cyanide (HCN) and carbon monoxide (CO) to spaceborne measurements from the Infrared Atmospheric Sounding Interferometer (IASI), we find that EMAC properly captures the exceptional strength of the Indonesian fires. In the lower troposphere, the increase in VOC levels is higher in Indonesia compared to other biomass burning regions. This has a direct impact on the oxidation capacity, resulting in the largest regional reduction in the hydroxyl radical (OH) and nitrogen oxides (NOx). While an increase in ozone (O3) is predicted close to the peatland fires, simulated O3 decreases in eastern Indonesia due to particularly high phenol concentrations. In the ASMA and the ITCZ, the upward transport leads to elevated VOC concentrations in the lower stratosphere, which results in the reduction of OH and NOx and the increase in the hydroperoxyl radical (HO2). In addition, the degradation of VOC emissions from the Indonesian fires becomes a major source of lower stratospheric nitrate radicals (NO3), which increase by up to 20ĝ€¯%. Enhanced phenol levels in the upper troposphere result in a 20ĝ€¯% increase in the contribution of phenoxy radicals to the chemical destruction of O3, which is predicted to be as large as 40ĝ€¯% of the total chemical O3 loss in the UTLS. In the months following the fires, this loss propagates into the lower stratosphere and potentially contributes to the variability of lower stratospheric O3 observed by satellite retrievals. The Indonesian peatland fires regularly occur during El Niño years, and the largest perturbations of radical concentrations in the lower stratosphere are predicted for particularly strong El Niño years. By activating the detailed in-cloud OVOC oxidation scheme Jülich Aqueous-phase Mechanism of Organic Chemistry (JAMOC), we find that the predicted changes are dampened. Global models that neglect in-cloud OVOC oxidation tend to overestimate the impact of such extreme pollution events on the atmospheric composition. © 2021 Copernicus GmbH. All rights reserved.
BibTeX: @article{Rosanka2021a, author = {Rosanka, Simon and Franco, Bruno and Clarisse, Lieven and Coheur, Pierre-François and Pozzer, Andrea and Wahner, Andreas and Taraborrelli, Domenico}, title = {The impact of organic pollutants from Indonesian peatland fires on the tropospheric and lower stratospheric composition}, journal = {Atmospheric Chemistry and Physics}, year = {2021}, volume = {21}, number = {14}, pages = {11257 – 11288}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-21-11257-2021} }
Rosanka S, Sander R, Franco B, Wespes C, Wahner A and Taraborrelli D (2021), "Oxidation of low-molecular-weight organic compounds in cloud droplets: Global impact on tropospheric oxidants", Atmospheric Chemistry and Physics. Vol. 21(12), pp. 9909 – 9930. [Abstract] [BibTeX] [DOI]
Abstract: In liquid cloud droplets, superoxide anion (O2(aq)-) is known to quickly consume ozone (O3(aq)), which is relatively insoluble. The significance of this reaction as a tropospheric O3 sink is sensitive to the abundance of O2(aq)- and therefore to the production of its main precursor, the hydroperoxyl radical (HO2(aq)). The aqueous-phase oxidation of oxygenated volatile organic compounds (OVOCs) is the major source of HO2(aq) in cloud droplets. Hence, the lack of explicit aqueous-phase chemical kinetics in global atmospheric models leads to a general underestimation of clouds as O3 sinks. In this study, the importance of in-cloud OVOC oxidation for tropospheric composition is assessed by using the Chemistry As A Boxmodel Application (CAABA) and the global ECHAM/MESSy Atmospheric Chemistry (EMAC) model, which are both capable of explicitly representing the relevant chemical transformations. For this analysis, three different in-cloud oxidation mechanisms are employed: (1) one including the basic oxidation of SO2(aq) by O3(aq) and H2O2(aq), which thus represents the capabilities of most global models; (2) the more advanced standard EMAC mechanism, which includes inorganic chemistry and simplified degradation of methane oxidation products; and (3) the detailed in-cloud OVOC oxidation scheme Jülich Aqueous-phase Mechanism of Organic Chemistry (JAMOC). By using EMAC, the global impact of each mechanism is assessed focusing mainly on tropospheric volatile organic compounds (VOCs), HOx (HOxCombining double low lineOH+HO2), and O3. This is achieved by performing a detailed HOx and O3 budget analysis in the gas and aqueous phase. The resulting changes are evaluated against O3 and methanol (CH3OH) satellite observations from the Infrared Atmospheric Sounding Interferometer (IASI) for 2015. In general, the explicit in-cloud oxidation leads to an overall reduction in predicted OVOC levels and reduces EMAC's overestimation of some OVOCs in the tropics. The in-cloud OVOC oxidation shifts the HO2 production from the gas to the aqueous phase. As a result, the O3 budget is perturbed with scavenging being enhanced and the gas-phase chemical losses being reduced. With the simplified in-cloud chemistry, about 13Tgyr-1 of O3 is scavenged, which increases to 336Tgyr-1 when JAMOC is used. The highest O3 reduction of 12% is predicted in the upper troposphere-lower stratosphere (UTLS). These changes in the free troposphere significantly reduce the modelled tropospheric ozone columns, which are known to be generally overestimated by EMAC and other global atmospheric models. © 2021 Simon Rosanka et al.
BibTeX: @article{Rosanka2021, author = {Rosanka, Simon and Sander, Rolf and Franco, Bruno and Wespes, Catherine and Wahner, Andreas and Taraborrelli, Domenico}, title = {Oxidation of low-molecular-weight organic compounds in cloud droplets: Global impact on tropospheric oxidants}, journal = {Atmospheric Chemistry and Physics}, year = {2021}, volume = {21}, number = {12}, pages = {9909 – 9930}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-21-9909-2021} }
Safieddine S, George M, Clarisse L, Whitburn S and Clerbaux C (2021), "Skin temperature from IASI: Extreme events and urban heat islands monitoring", Optics InfoBase Conference Papers. [Abstract] [BibTeX]
Abstract: In this work, we investigate the skin temperature product from IASI to look at local changes at the city and regional scales and to assess temperature over a period of 13 years. © 2021 The Author(s).
BibTeX: @conference{Safieddine2021, author = {Safieddine, Sarah and George, Maya and Clarisse, Lieven and Whitburn, Simon and Clerbaux, Cathy}, title = {Skin temperature from IASI: Extreme events and urban heat islands monitoring}, journal = {Optics InfoBase Conference Papers}, year = {2021} }
Schiffmann S and Godefroid M (2021), "Electronic isotope shift factors for the Ir 5d76s24F9/2→(odd,J=9/2) line at 247.587 nm", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 258 [Abstract] [BibTeX] [DOI]
Abstract: We present the theoretical calculations of the electronic isotope shift factors of the 5d76s24F9/2→(odd,J=9/2) line at 247.587 nm, that were recently used to extract nuclear mean square radii and nuclear deformations of iridium isotopes [Mukai et al. (2020)]. The fully relativistic multiconfiguration Dirac-Hartree-Fock method and the relativistic configuration interaction method were used to perform the atomic structure calculations. Additional properties such as the sharing rule, Landé g factors or phase tracking were employed to ensure an adequate description of the targeted odd level. © 2020 Elsevier Ltd
BibTeX: @article{Schiffmann2021, author = {Schiffmann, Sacha and Godefroid, Michel}, title = {Electronic isotope shift factors for the Ir 5d76s24F9/2→(odd,J=9/2) line at 247.587 nm}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2021}, volume = {258}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2020.107332} }
Shetye S, Van Eck S, Jorissen A, Goriely S, Siess L, Van Winckel H, Plez B, Godefroid M and Wallerstein G (2021), "S stars and s-process in the Gaia era: II. Constraining the luminosity of the third dredge-up with Tc-rich S stars", Astronomy and Astrophysics. Vol. 650 [Abstract] [BibTeX] [DOI]
Abstract: Context. S stars are late-type giants that are transition objects between M-type stars and carbon stars on the asymptotic giant branch (AGB). They are classified into two types: intrinsic or extrinsic, based on the presence or absence of technetium (Tc). The Tc-rich or intrinsic S stars are thermally pulsing (TP-)AGB stars internally producing s-process elements (including Tc) that are brought to their surface via the third dredge-up (TDU). The Tc-poor or extrinsic S stars gained their s-process overabundances via the accretion of s-process-rich material from an AGB companion that has since turned into a dim white dwarf. Aims. Our goal is to investigate the evolutionary status of Tc-rich S stars by locating them in a Hertzsprung-Russell (HR) diagram using the results of Gaia Early Data Release 3 (EDR3). We combine the current sample of 13 Tc-rich stars with our previous studies of 10 Tc-rich stars to determine the observational onset of the TDU in the metallicity range [-0.7; 0]. We also compare our abundance determinations with dedicated AGB nucleosynthesis predictions. Methods. We derived the stellar parameters using an iterative tool that combines HERMES high-resolution spectra, accurate Gaia EDR3 parallaxes, stellar evolution models, and tailored MARCS model atmospheres for S-type stars. Using these stellar parameters, we determined the heavy-element abundances by line synthesis. Results. In the HR diagram, the intrinsic S stars are located at higher luminosities than the predicted onset of the TDU. These findings are consistent with Tc-rich S stars being genuine TP-AGB stars. The comparison of the derived s-process abundance profiles of our intrinsic S stars with the nucleosynthesis predictions provide an overall good agreement. Stars with highest [s/Fe] tend to have the highest C/O ratios. © 2021 ESO.
BibTeX: @article{Shetye2021, author = {Shetye, Shreeya and Van Eck, Sophie and Jorissen, Alain and Goriely, Stephane and Siess, Lionel and Van Winckel, Hans and Plez, Bertrand and Godefroid, Michel and Wallerstein, George}, title = {S stars and s-process in the Gaia era: II. Constraining the luminosity of the third dredge-up with Tc-rich S stars}, journal = {Astronomy and Astrophysics}, year = {2021}, volume = {650}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1051/0004-6361/202040207} }
Si R, Schiffmann S, Wang K, Chen CY and Godefroid M (2021), "Ab initio multiconfiguration Dirac-Hartree-Fock calculations of the in and Tl electron affinities and their isotope shifts", Physical Review A. Vol. 104(1) [Abstract] [BibTeX] [DOI]
Abstract: We report multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction calculations on the thallium (Tl) electron affinity, as well as on the excited energy levels arising from the ground configuration of Tl-. The results are compared with the available experimental values and further validated by extending the study to its homologous, lighter element, indium (In), belonging to group 13 (III.A) of the Periodic Table. The calculated electron affinities of In and Tl, 383.4 and 322.8 meV, agree with the latest measurements by within 1%. Three bound states 3P0,1,2 are confirmed in the 5s25p2 configuration of In-, while only the ground state 3P0 is bound in the 6s26p2 configuration of Tl-. The isotope shifts on the In and Tl electron affinities are also estimated. The E2 and M1 intraconfiguration radiative transition rates within 5s25p2 3P0,1,2 of In- are used to calculate the radiative lifetimes of the metastable 3P1,2 levels. © 2021 American Physical Society.
BibTeX: @article{Si2021, author = {Si, Ran and Schiffmann, Sacha and Wang, Kai and Chen, Chong Yang and Godefroid, Michel}, title = {Ab initio multiconfiguration Dirac-Hartree-Fock calculations of the in and Tl electron affinities and their isotope shifts}, journal = {Physical Review A}, year = {2021}, volume = {104}, number = {1}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.104.012802} }
Song C, Zhang C, Wang K, Si R, Godefroid M, Jönsson P, Dang W, Zhao X, Yan J and Chen C (2021), "Extended calculations with spectroscopic accuracy: Energy levels and radiative rates for O-like ions between Ar XI and Cr XVII", Atomic Data and Nuclear Data Tables. Vol. 138 [Abstract] [BibTeX] [DOI]
Abstract: Using the multiconfiguration Dirac–Hartree–Fock and the relativistic configuration interaction methods, a consistent set of transition energies and radiative transition data for the main states of the 2s22p4, 2s2p5, 2p6, 2s22p33s, 2s22p33p, 2s22p33d, 2s2p43s, 2s2p43p, and 2s2p43d configurations in O-like Ions between Ar XI (Z=18) and Cr XVII (Z=24) is provided. Our data set is compared with the NIST compiled values and previous calculations. The data are accurate enough for identification and deblending of new emission lines from hot astrophysical and laboratory plasmas. The amount of data of high accuracy is significantly increased for the n=3 states of several O-like ions, where experimental data are very scarce. © 2020 Elsevier Inc.
BibTeX: @article{Song2021, author = {Song, C.X. and Zhang, C.Y. and Wang, K. and Si, R. and Godefroid, M. and Jönsson, P. and Dang, W. and Zhao, X.H. and Yan, J. and Chen, C.Y.}, title = {Extended calculations with spectroscopic accuracy: Energy levels and radiative rates for O-like ions between Ar XI and Cr XVII}, journal = {Atomic Data and Nuclear Data Tables}, year = {2021}, volume = {138}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.adt.2020.101377} }
Stavrakou T, Müller J-F, Bauwens M, Doumbia T, Elguindi N, Darras S, Granier C, De Smedt I, Lerot C, Van Roozendael M, Franco B, Clarisse L, Clerbaux C, Coheur P-F, Liu Y, Wang T, Shi X, Gaubert B, Tilmes S and Brasseur G (2021), "Atmospheric impacts of COVID-19 on NOx and VOC levels over China based on TROPOMI and IASI satellite data and modeling", Atmosphere. Vol. 12(8) [Abstract] [BibTeX] [DOI]
Abstract: China was the first country to undergo large-scale lockdowns in response to the pandemic in early 2020 and a progressive return to normalization after April 2020. Spaceborne observations of atmospheric nitrogen dioxide (NO2) and oxygenated volatile organic compounds (OVOCs), including formaldehyde (HCHO), glyoxal (CHOCHO), and peroxyacetyl nitrate (PAN), reveal important changes over China in 2020, relative to 2019, in response to the pandemic-induced shutdown and the subsequent drop in pollutant emissions. In February, at the peak of the shutdown, the observed declines in OVOC levels were generally weaker (less than 20%) compared to the observed NO2 reductions (-40%). In May 2020, the observations reveal moderate decreases in NO2 (-15%) and PAN (-21%), small changes in CHOCHO (-3%) and HCHO (6%). Model simulations using the regional model MAGRITTEv1.1 with anthropogenic emissions accounting for the reductions due to the pandemic explain to a large extent the observed changes in lockdown-affected regions. The model results suggest that meteorological variability accounts for a minor but non-negligible part ( -5%) of the observed changes for NO2, whereas it is negligible for CHOCHO but plays a more substantial role for HCHO and PAN, especially in May. The interannual variability of biogenic and biomass burning emissions also contribute to the observed variations, explaining e.g., the important column increases of NO2 and OVOCs in February 2020, relative to 2019. These changes are well captured by the model simulations. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
BibTeX: @article{Stavrakou2021, author = {Stavrakou, Trissevgeni and Müller, Jean-François and Bauwens, Maite and Doumbia, Thierno and Elguindi, Nellie and Darras, Sabine and Granier, Claire and De Smedt, Isabelle and Lerot, Christophe and Van Roozendael, Michel and Franco, Bruno and Clarisse, Lieven and Clerbaux, Cathy and Coheur, Pierre-François and Liu, Yiming and Wang, Tao and Shi, Xiaoqin and Gaubert, Benjamin and Tilmes, Simone and Brasseur, Guy}, title = {Atmospheric impacts of COVID-19 on NOx and VOC levels over China based on TROPOMI and IASI satellite data and modeling}, journal = {Atmosphere}, year = {2021}, volume = {12}, number = {8}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atmos12080946} }
Sutcliffe B (2021), "Treating nuclei in molecules with quantum mechanical respect", Theoretical Chemistry Accounts. Vol. 140(3) [Abstract] [BibTeX] [DOI]
Abstract: An examination is made of how nuclear motion ought to be considered in solutions to the eigenvalue problem for the full Coulomb Hamiltonian and the role played by the usual clamped-nuclei electronic Hamiltonian in the construction of such solutions. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.
BibTeX: @article{Sutcliffe2021, author = {Sutcliffe, Brian}, title = {Treating nuclei in molecules with quantum mechanical respect}, journal = {Theoretical Chemistry Accounts}, year = {2021}, volume = {140}, number = {3}, doi = {10.1007/s00214-021-02722-3} }
Theys N, Fioletov V, Li C, De Smedt I, Lerot C, Mclinden C, Krotkov N, Griffin D, Clarisse L, Hedelt P, Loyola D, Wagner T, Kumar V, Innes A, Ribas R, Hendrick F, Vlietinck J, Brenot H and Van Roozendael M (2021), "A sulfur dioxide Covariance-Based Retrieval Algorithm (COBRA): application to TROPOMI reveals new emission sources", Atmospheric Chemistry and Physics. Vol. 21(22), pp. 16727 – 16744. [Abstract] [BibTeX] [DOI]
Abstract: Sensitive and accurate detection of sulfur dioxide (SO2) from space is important for monitoring and estimating global sulfur emissions. Inspired by detection methods applied in the thermal infrared, we present here a new scheme to retrieve SO2 columns from satellite observations of ultraviolet back-scattered radiances. The retrieval is based on a measurement error covariance matrix to fully represent the SO2-free radiance variability, so that the SO2 slant column density is the only retrieved parameter of the algorithm. We demonstrate this approach, named COBRA, on measurements from the TROPOspheric Monitoring Instrument (TROPOMI) aboard the Sentinel-5 Precursor (S-5P) satellite. We show that the method reduces significantly both the noise and biases present in the current TROPOMI operational DOAS SO2 retrievals. The performance of this technique is also benchmarked against that of the principal component algorithm (PCA) approach. We find that the quality of the data is similar and even slightly better with the proposed COBRA approach. The ability of the algorithm to retrieve SO2 accurately is further supported by comparison with ground-based observations. We illustrate the great sensitivity of the method with a high-resolution global SO2 map, considering 2.5 years of TROPOMI data. In addition to the known sources, we detect many new SO2 emission hotspots worldwide. For the largest sources, we use the COBRA data to estimate SO2 emission rates. Results are comparable to other recently published TROPOMI-based SO2 emissions estimates, but the associated uncertainties are significantly lower than with the operational data. Next, for a limited number of weak sources, we demonstrate the potential of our data for quantifying SO2 emissions with a detection limit of about 8 kt yr-1, a factor of 4 better than the emissions derived from the Ozone Monitoring Instrument (OMI). We anticipate that the systematic use of our TROPOMI COBRA SO2 column data set at a global scale will allow missing sources to be identified and quantified and help improve SO2 emission inventories. © 2021 Nicolas Theys et al.
BibTeX: @article{Theys2021, author = {Theys, Nicolas and Fioletov, Vitali and Li, Can and De Smedt, Isabelle and Lerot, Christophe and Mclinden, Chris and Krotkov, Nickolay and Griffin, Debora and Clarisse, Lieven and Hedelt, Pascal and Loyola, Diego and Wagner, Thomas and Kumar, Vinod and Innes, Antje and Ribas, Roberto and Hendrick, François and Vlietinck, Jonas and Brenot, Hugues and Van Roozendael, Michel}, title = {A sulfur dioxide Covariance-Based Retrieval Algorithm (COBRA): application to TROPOMI reveals new emission sources}, journal = {Atmospheric Chemistry and Physics}, year = {2021}, volume = {21}, number = {22}, pages = {16727 – 16744}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-21-16727-2021} }
Van Damme M, Clarisse L, Franco B, Sutton MA, Erisman JW, Wichink Kruit R, Van Zanten M, Whitburn S, Hadji-Lazaro J, Hurtmans D, Clerbaux C and Coheur P-Fo (2021), "Global, regional and national trends of atmospheric ammonia derived from a decadal (2008-2018) satellite record", Environmental Research Letters. Vol. 16(5) [Abstract] [BibTeX] [DOI]
Abstract: Excess atmospheric ammonia (NH3) leads to deleterious effects on biodiversity, ecosystems, air quality and health, and it is therefore essential to monitor its budget and temporal evolution. Hyperspectral infrared satellite sounders provide daily NH3 observations at global scale for over a decade. Here we use the version 3 of the Infrared Atmospheric Sounding Interferometer (IASI) NH3 dataset to derive global, regional and national trends from 2008 to 2018. We find a worldwide increase of 12.8 ± 1.3 % over this 11-year period, driven by large increases in east Asia (5.80 ± 0.61% increase per year), western and central Africa (2.58 ± 0.23 % yr-1), North America (2.40 ± 0.45 % yr-1) and western and southern Europe (1.90 ± 0.43 % yr-1). These are also seen in the Indo-Gangetic Plain, while the southwestern part of India exhibits decreasing trends. Reported national trends are analyzed in the light of changing anthropogenic and pyrogenic NH3 emissions, meteorological conditions and the impact of sulfur and nitrogen oxides emissions, which alter the atmospheric lifetime of NH3. We end with a short case study dedicated to the Netherlands and the 'Dutch Nitrogen crisis' of 2019. © 2021 The Author(s). Published by IOP Publishing Ltd.
BibTeX: @article{VanDamme2021, author = {Van Damme, Martin and Clarisse, Lieven and Franco, Bruno and Sutton, Mark A and Erisman, Jan Willem and Wichink Kruit, Roy and Van Zanten, Margreet and Whitburn, Simon and Hadji-Lazaro, Juliette and Hurtmans, Daniel and Clerbaux, Cathy and Coheur, Pierre-Fran ois}, title = {Global, regional and national trends of atmospheric ammonia derived from a decadal (2008-2018) satellite record}, journal = {Environmental Research Letters}, year = {2021}, volume = {16}, number = {5}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1748-9326/abd5e0} }
Viatte C, Petit J-E, Yamanouchi S, Van Damme M, Doucerain C, Germain-Piaulenne E, Gros V, Favez O, Clarisse L, Coheur P-F, Strong K and Clerbaux C (2021), "Ammonia and pm2.5 air pollution in paris during the 2020 covid lockdown", Atmosphere. Vol. 12(2), pp. 1 – 18. [Abstract] [BibTeX] [DOI]
Abstract: During the COVID-19 pandemic, the lockdown reduced anthropogenic emissions of NO2 in Paris. NO2 concentrations recorded in 2020 were the lowest they have been in the past 5 years. Despite these low-NO2 levels, Paris experienced PM2.5 pollution episodes, which were investigated here based on multi-species and multi-platform measurements. Ammonia (NH3 ) measurements over Paris, derived from a mini-DOAS (differential optical absorption spectroscopy) instrument and the Infrared Atmospheric Sounding Interferometer (IASI) satellite, revealed simultaneous enhancements during the spring PM2.5 pollution episodes. Using the IASI maps and the FLEXPART model, we show that long-range transport had a statistically significant influence on the degradation of air quality in Paris. In addition, concentrations of ammonium (NH4+ ) and PM2.5 were strongly correlated for all episodes observed in springtime 2020, suggesting that transport of NH3 drove a large component of the PM2.5 pollution over Paris. We found that NH3 was not the limiting factor for the formation of ammonium nitrate (NH4 NO3 ), and we suggest that the conversion of ammonia to ammonium may have been the essential driver. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
BibTeX: @article{Viatte2021, author = {Viatte, Camille and Petit, Jean-Eudes and Yamanouchi, Shoma and Van Damme, Martin and Doucerain, Carole and Germain-Piaulenne, Emeric and Gros, Valérie and Favez, Olivier and Clarisse, Lieven and Coheur, Pierre-Francois and Strong, Kimberly and Clerbaux, Cathy}, title = {Ammonia and pm2.5 air pollution in paris during the 2020 covid lockdown}, journal = {Atmosphere}, year = {2021}, volume = {12}, number = {2}, pages = {1 – 18}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atmos12020160} }
Vohra K, Marais E, Suckra S, Kramer L, Bloss W, Sahu R, Gaur A, Tripathi S, Van Damme M, Clarisse L and Coheur PF (2021), "Long-Term trends in air quality in major cities in the UK and India: A view from space", Atmospheric Chemistry and Physics. Vol. 21(8), pp. 6275 – 6296. [Abstract] [BibTeX] [DOI]
Abstract: Air quality networks in cities can be costly and inconsistent and typically monitor a few pollutants. Spacebased instruments provide global coverage spanning more than a decade to determine trends in air quality, augmenting surface networks. Here we target cities in the UK (London and Birmingham) and India (Delhi and Kanpur) and use observations of nitrogen dioxide (NO2) from the Ozone Monitoring Instrument (OMI), ammonia (NH3) from the Infrared Atmospheric Sounding Interferometer (IASI), formaldehyde (HCHO) from OMI as a proxy for non-methane volatile organic compounds (NMVOCs), and aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) for PM2:5. We assess the skill of these products at reproducing monthly variability in surface concentrations of air pollutants where available. We find temporal consistency between column and surface NO2 in cities in the UK and India (R D0.5 0.7) and NH3 at two of three rural sites in the UK (R D0.5 0.7) but not between AOD and surface PM2:5 (R 0.4). MODIS AOD is consistent with AERONET at sites in the UK and India (R 0.8) and reproduces a significant decline in surface PM2:5 in London (2.7%a1) and Birmingham (3.7%a1) since 2009. We derive long-Term trends in the four cities for 2005 2018 from OMI and MODIS and for 2008 2018 from IASI. Trends of all pollutants are positive in Delhi, suggesting no air quality improvements there, despite the roll-out of controls on industrial and transport sectors. Kanpur, identified by the WHO as the most polluted city in the world in 2018, experiences a significant and substantial (3.1%a1) increase in PM2:5. The decline of NO2, NH3, and PM2:5 in London and Birmingham is likely due in large part to emissions controls on vehicles. Trends are significant only for NO2 and PM2:5. Reactive NMVOCs decline in Birmingham, but the trend is not significant. There is a recent (2012 2018) steep (9%a1) increase in reactive NMVOCs in London. The cause for this rapid increase is uncertain but may reflect the increased contribution of oxygenated volatile organic compounds (VOCs) from household products, the food and beverage industry, and domestic wood burning, with implications for the formation of ozone in a VOC-limited city. © 2021 Copernicus GmbH. All rights reserved.
BibTeX: @article{Vohra2021, author = {Vohra, Karn and Marais, Eloise and Suckra, Shannen and Kramer, Louisa and Bloss, William and Sahu, Ravi and Gaur, Abhishek and Tripathi, Sachchida and Van Damme, Martin and Clarisse, Lieven and Coheur, Pierre F.}, title = {Long-Term trends in air quality in major cities in the UK and India: A view from space}, journal = {Atmospheric Chemistry and Physics}, year = {2021}, volume = {21}, number = {8}, pages = {6275 – 6296}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-21-6275-2021} }
Wang R, Guo X, Pan D, Kelly JT, Bash JO, Sun K, Paulot F, Clarisse L, Van Damme M, Whitburn S, Coheur P-F, Clerbaux C and Zondlo MA (2021), "Monthly Patterns of Ammonia Over the Contiguous United States at 2-km Resolution", Geophysical Research Letters. Vol. 48(5) [Abstract] [BibTeX] [DOI]
Abstract: Monthly, high-resolution (∼2 km) ammonia (NH3) column maps from the Infrared Atmospheric Sounding Interferometer (IASI) were developed across the contiguous United States and adjacent areas. Ammonia hotspots (95th percentile of the column distribution) were highly localized with a characteristic length scale of 12 km and median area of 152 km2. Five seasonality clusters were identified with k-means++ clustering. The Midwest and eastern United States had a broad, spring maximum of NH3 (67% of hotspots in this cluster). The western United States, in contrast, showed a narrower midsummer peak (32% of hotspots). IASI spatiotemporal clustering was consistent with those from the Ammonia Monitoring Network. CMAQ and GFDL-AM3 modeled NH3 columns have some success replicating the seasonal patterns but did not capture the regional differences. The high spatial-resolution monthly NH3 maps serve as a constraint for model simulations and as a guide for the placement of future, ground-based network sites. © 2020. The Authors.
BibTeX: @article{Wang2021, author = {Wang, Rui and Guo, Xuehui and Pan, Da and Kelly, James T. and Bash, Jesse O. and Sun, Kang and Paulot, Fabien and Clarisse, Lieven and Van Damme, Martin and Whitburn, Simon and Coheur, Pierre-François and Clerbaux, Cathy and Zondlo, Mark A.}, title = {Monthly Patterns of Ammonia Over the Contiguous United States at 2-km Resolution}, journal = {Geophysical Research Letters}, year = {2021}, volume = {48}, number = {5}, note = {All Open Access, Green Open Access}, doi = {10.1029/2020GL090579} }
Whitburn S, Clarisse L, Bouillon M, Safieddine S, George M, Dewitte S, De Longueville H, Coheur P-F and Clerbaux C (2021), "Trends in spectrally resolved outgoing longwave radiation from 10 years of satellite measurements", npj Climate and Atmospheric Science. Vol. 4(1) [Abstract] [BibTeX] [DOI]
Abstract: In recent years, the interest has grown in satellite-derived hyperspectral radiance measurements for assessing the individual impact of climate drivers and their cascade of feedbacks on the outgoing longwave radiation (OLR). In this paper, we use 10 years (2008–2017) of reprocessed radiances from the infrared atmospheric sounding interferometer (IASI) to evaluate the linear trends in clear-sky spectrally resolved OLR (SOLR) in the range [645–2300] cm−1. Spatial inhomogeneities are observed in most of the analyzed spectral regions. These mostly reflected the natural variability of the atmospheric temperature and composition but long-term changes in greenhouse gases concentrations are also highlighted. In particular, the increase of atmospheric CO2 and CH4 led to significant negative trends in the SOLR of −0.05 to −0.3% per year in the spectral region corresponding to the ν2 and the ν3 CO2 and in the ν4 CH4 band. Most of the trends associated with the natural variability of the OLR can be related to the El Niño/Southern Oscillation activity and its teleconnections in the studied period. This is the case for the channels most affected by the temperature variations of the surface and the first layers of the atmosphere but also for the channels corresponding to the ν2 H2O and the ν3 O3 bands. © 2021, The Author(s).
BibTeX: @article{Whitburn2021, author = {Whitburn, Simon and Clarisse, Lieven and Bouillon, Marie and Safieddine, Sarah and George, Maya and Dewitte, Steven and De Longueville, Hélène and Coheur, Pierre-François and Clerbaux, Cathy}, title = {Trends in spectrally resolved outgoing longwave radiation from 10 years of satellite measurements}, journal = {npj Climate and Atmospheric Science}, year = {2021}, volume = {4}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.1038/s41612-021-00205-7} }
Yamanouchi S, Viatte C, Strong K, Lutsch E, Jones DB, Clerbaux C, Van Damme M, Clarisse L and Coheur P-F (2021), "Multiscale observations of NH3 around Toronto, Canada", Atmospheric Measurement Techniques. Vol. 14(2), pp. 905 – 921. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) is a major source of nitrates in the atmosphere and a major source of fine particulate matter. As such, there have been increasing efforts to measure the atmospheric abundance of NH3 and its spatial and temporal variability. In this study, long-Term measurements of NH3 derived from multiscale datasets are examined. These NH3 datasets include 16 years of total column measurements using Fourier transform infrared (FTIR) spectroscopy, 3 years of surface in situ measurements, and 10 years of total column measurements from the Infrared Atmospheric Sounding Interferometer (IASI). The datasets were used to quantify NH3 temporal variability over Toronto, Canada. The multiscale datasets were also compared to assess the representativeness of the FTIR measurements. All three time series showed positive trends in NH3 over Toronto: 3.34-0.89 %/yr from 2002 to 2018 in the FTIR columns, 8.88-5.08 %/yr from 2013 to 2017 in the surface in situ data, and 8.38-1.54 %/yr from 2008 to 2018 in the IASI columns. To assess the representative scale of the FTIR NH3 columns, correlations between the datasets were examined. The best correlation between FTIR and IASI was obtained with coincidence criteria of-25 km and-20 min, with r D 0:73 and a slope of 1.14-0.06. Additionally, FTIR column and in situ measurements were standardized and correlated. Comparison of 24 d averages and monthly averages resulted in correlation coefficients of r D 0:72 and r D 0:75, respectively, although correlation without averaging to reduce high-frequency variability led to a poorer correlation, with r D 0:39. The GEOS-Chem model, run at 22.5 resolution, was compared to FTIR and IASI to assess model performance and investigate the correlation of observational data and model output, both with local column measurements (FTIR) and measurements on a regional scale (IASI). Comparisons on a regional scale (a domain spanning 35 to 53-N and 93.75 to 63.75-W) resulted in r D 0:57 and thus a coefficient of determination, which is indicative of the predictive capacity of the model, of r2 D 0:33, but comparing a single model grid point against the FTIR resulted in a poorer correlation, with r2 D 0:13, indicating that a finer spatial resolution is needed for modeling NH3. © 2021 BMJ Publishing Group. All rights reserved.
BibTeX: @article{Yamanouchi2021, author = {Yamanouchi, Shoma and Viatte, Camille and Strong, Kimberly and Lutsch, Erik and Jones, Dylan B.A. and Clerbaux, Cathy and Van Damme, Martin and Clarisse, Lieven and Coheur, Pierre-Francois}, title = {Multiscale observations of NH3 around Toronto, Canada}, journal = {Atmospheric Measurement Techniques}, year = {2021}, volume = {14}, number = {2}, pages = {905 – 921}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-14-905-2021} }
Zhang CY, Wang K, Si R, Godefroid M, Jönsson P, Xiao J, Gu MF and Chen CY (2021), "Benchmarking calculations with spectroscopic accuracy of level energies and wavelengths in W LVII–W LXII tungsten ions", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 269 [Abstract] [BibTeX] [DOI]
Abstract: Atomic properties of n=3 states of the W56+ - W61+ ions are systematically investigated through two state-of-the-art methods, namely, the second-order many-body perturbation theory, and the multi-configuration Dirac–Hartree–Fock method combined with the relativistic configuration interaction approach. The contributions of valence-valence and core-valence electron correlations, the Breit interaction, the higher-order retardation correction beyond the Breit interaction through the transverse photon interaction, and the quantum electrodynamical corrections to the excitation energies are studied in detail. The excitation energies and wavelengths obtained with the two methods agree with each other within ≈0.01%. The present results achieve spectroscopic accuracy and provide a benchmark test for various applications and other theoretical calculations of W56+ - W61+ ions. They will assist spectroscopists in their assignment and direct identification of observed lines in complex spectra. © 2021 Elsevier Ltd
BibTeX: @article{Zhang2021, author = {Zhang, Chun Yu and Wang, Kai and Si, Ran and Godefroid, Michel and Jönsson, Per and Xiao, Jun and Gu, Ming Feng and Chen, Chong Yang}, title = {Benchmarking calculations with spectroscopic accuracy of level energies and wavelengths in W LVII–W LXII tungsten ions}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2021}, volume = {269}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2021.107650} }
Zhang X, Del Zanna G, Wang K, Rynkun P, Jönsson P, Godefroid M, Gaigalas G, Radžiūtė L, Ma L, Si R, Xiao J, Chen Z, Yan J, Wu Y and Chen C (2021), "Benchmarking Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: Si-like Ions from Cr xi to Zn xvii", Astrophysical Journal, Supplement Series. Vol. 257(2) [Abstract] [BibTeX] [DOI]
Abstract: The multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction methods are used to provide excitation energies, lifetimes, and radiative transition data for the 604 (699, 702, 704, 704, 704, and 699) lowest levels of the 3s 23p 2, 3s3p 3, 3s 23p3d, 3p 4, 3s3p 23d, 3s 23d 2, 3p 33d, 3s3p3d 2, 3s3d 3, 3p3d 3, 3p 23d 2, 3s 23p4s, 3s 23p4p, 3s 23p4d, 3s 23p4f, 3s3p 24s, 3s3p 24p, 3s3p 24d, 3s3p 24f, 3s 23d4s, 3s 23d4p, 3p 34s, 3p 34p, 3s3p3d4s, 3s 23p5s, and 3s 23p5p configurations in Cr xi, (Mn xii, Fe xiii, Co xiv, Ni xv, Cu xvi, and Zn xvii). Previous line identifications of Fe xiii and Ni xv in the EUV and X-ray wavelength ranges are reviewed by comprehensively comparing the MCDHF theoretical results with available experimental data. Many recent identifications of Fe xiii and Ni xv lines are confirmed, and several new identifications for these two ions are proposed. A consistent atomic data set with spectroscopic accuracy is provided for the lowest hundreds of levels for Si-like ions of iron-group elements of astrophysical interest, for which experimental values are scarce. The uncertainty estimation method suggested by Kramida, applied to the comparison of the length and velocity line strength values, is used for ranking the transition data. The correlation of the latter with the gauge dependency patterns of the line strengths is investigated. © 2021. The American Astronomical Society. All rights reserved..
BibTeX: @article{Zhang2021a, author = {Zhang, X.H. and Del Zanna, G. and Wang, K. and Rynkun, P. and Jönsson, P. and Godefroid, M. and Gaigalas, G. and Radžiūtė, L. and Ma, L.H. and Si, R. and Xiao, J. and Chen, Z.B. and Yan, J. and Wu, Y. and Chen, C.Y.}, title = {Benchmarking Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: Si-like Ions from Cr xi to Zn xvii}, journal = {Astrophysical Journal, Supplement Series}, year = {2021}, volume = {257}, number = {2}, note = {All Open Access, Bronze Open Access}, doi = {10.3847/1538-4365/ac2a3f} }
Zobov N, Bertin T, Vander Auwera J, Civiš S, Knížek A, Ferus M, Ovsyannikov RI, Makhnev VY, Tennyson J and Polyansky OL (2021), "The spectrum of ammonia near 0.793 μm", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 273 [Abstract] [BibTeX] [DOI]
Abstract: Two sets of NH3 absorption spectra covering the 0.793 μm region are recorded using two Bruker IFS 125 HR Fourier transform spectrometers. Three unapodized absorption spectra are recorded in Brussels over the range 11000−14500 cm−1 and the positions and intensities of 1114 ammonia lines observed in the 12491−12810 cm−1 region are measured using a multi-spectrum least squares fitting algorithm. 367 additional lines are identified in an ammonia absorption spectrum recorded in two steps at the J. Heyrovsky Institute of Physical Chemistry in Prague, using two different interference filters covering the 12000−12500 and 12400−13000 cm−1 ranges. The 1481 measured ammonia lines are analyzed using an empirical line list computed using variational nuclear motion calculations and ground state combination differences. Transitions are assigned to vibrational states with 4νNH stretching excitation (v1+v3=4). 278 out of the 1481 measured lines are assigned to 300 transitions and 119 upper state energy levels are derived from the frequencies of the assigned transitions. © 2021 The Authors
BibTeX: @article{Zobov2021, author = {Zobov, N.F. and Bertin, T. and Vander Auwera, J. and Civiš, S. and Knížek, A. and Ferus, M. and Ovsyannikov, Roman I. and Makhnev, Vladimir Yu. and Tennyson, Jonathan and Polyansky, Oleg L.}, title = {The spectrum of ammonia near 0.793 μm}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2021}, volume = {273}, doi = {10.1016/j.jqsrt.2021.107838} }
Aerts A, Carbonnière P, Richter F and Brown A (2020), "Vibrational states of deuterated trans - And cis -formic acid: DCOOH, HCOOD, and DCOOD", Journal of Chemical Physics. Vol. 152(2) [Abstract] [BibTeX] [DOI]
Abstract: The vibrational eigenenergies of the deuterated forms of formic acid (DCOOD, HCOOD, and DCOOH) have been computed using the block-improved relaxation method, as implemented in the Heidelberg multiconfiguration time-dependent Hartree package on a previously published potential energy surface [F. Richter and P. Carbonnière, J. Chem. Phys. 148, 064303 (2018)] generated at the CCSD(T)-F12a/aug-cc-pVTZ-F12 level of theory. Fundamental, combination band, and overtone transition frequencies of the trans isomer were computed up to ∼3000 cm-1 with respect to the zero point energy, and assignments were determined by visualization of the reduced densities. Root mean square deviations of computed fundamental transition frequencies with experimentally available gas-phase measurements are 8, 7, and 3 cm-1 for trans-DCOOD, trans-HCOOD, and trans-DCOOH, respectively. The fundamental transition frequencies are provided for the cis isomer of all deuterated forms; experimental measurements of these frequencies for the deuterated cis isotopologues are not yet available, and the present work may guide their identification. © 2020 Author(s).
BibTeX: @article{Aerts2020, author = {Aerts, Antoine and Carbonnière, P. and Richter, F. and Brown, Alex}, title = {Vibrational states of deuterated trans - And cis -formic acid: DCOOH, HCOOD, and DCOOD}, journal = {Journal of Chemical Physics}, year = {2020}, volume = {152}, number = {2}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.5135571} }
Aprà E, Bylaska E, De Jong W, Govind N, Kowalski K, Straatsma T, Valiev M, Van Dam H, Alexeev Y, Anchell J, Anisimov V, Aquino F, Atta-Fynn R, Autschbach J, Bauman N, Becca J, Bernholdt D, Bhaskaran-Nair K, Bogatko S, Borowski P, Boschen J, Brabec J, Bruner A, Cauët E, Chen Y, Chuev G, Cramer C, Daily J, Deegan M, Dunning T, Dupuis M, Dyall K, Fann G, Fischer S, Fonari A, Früchtl H, Gagliardi L, Garza J, Gawande N, Ghosh S, Glaesemann K, Götz A, Hammond J, Helms V, Hermes E, Hirao K, Hirata S, Jacquelin M, Jensen L, Johnson B, Jónsson H, Kendall R, Klemm M, Kobayashi R, Konkov V, Krishnamoorthy S, Krishnan M, Lin Z, Lins R, Littlefield R, Logsdail A, Lopata K, Ma W, Marenich A, Martin Del Campo J, Mejia-Rodriguez D, Moore J, Mullin J, Nakajima T, Nascimento D, Nichols J, Nichols P, Nieplocha J, Otero-De-La-Roza A, Palmer B, Panyala A, Pirojsirikul T, Peng B, Peverati R, Pittner J, Pollack L, Richard R, Sadayappan P, Schatz G, Shelton W, Silverstein D, Smith D, Soares T, Song D, Swart M, Taylor H, Thomas G, Tipparaju V, Truhlar D, Tsemekhman K, Van Voorhis T, Vázquez-Mayagoitia A, Verma P, Villa O, Vishnu A, Vogiatzis K, Wang D, Weare J, Williamson M, Windus T, Woliński K, Wong A, Wu Q, Yang C, Yu Q, Zacharias M, Zhang Z, Zhao Y and Harrison R (2020), "NWChem: Past, present, and future", Journal of Chemical Physics. Vol. 152(18) [Abstract] [BibTeX] [DOI]
Abstract: Specialized computational chemistry packages have permanently reshaped the landscape of chemical and materials science by providing tools to support and guide experimental efforts and for the prediction of atomistic and electronic properties. In this regard, electronic structure packages have played a special role by using first-principle-driven methodologies to model complex chemical and materials processes. Over the past few decades, the rapid development of computing technologies and the tremendous increase in computational power have offered a unique chance to study complex transformations using sophisticated and predictive many-body techniques that describe correlated behavior of electrons in molecular and condensed phase systems at different levels of theory. In enabling these simulations, novel parallel algorithms have been able to take advantage of computational resources to address the polynomial scaling of electronic structure methods. In this paper, we briefly review the NWChem computational chemistry suite, including its history, design principles, parallel tools, current capabilities, outreach, and outlook. © 2020 U.S. Government.
BibTeX: @article{Apra2020, author = {Aprà, E. and Bylaska, E.J. and De Jong, W.A. and Govind, N. and Kowalski, K. and Straatsma, T.P. and Valiev, M. and Van Dam, H.J.J. and Alexeev, Y. and Anchell, J. and Anisimov, V. and Aquino, F.W. and Atta-Fynn, R. and Autschbach, J. and Bauman, N.P. and Becca, J.C. and Bernholdt, D.E. and Bhaskaran-Nair, K. and Bogatko, S. and Borowski, P. and Boschen, J. and Brabec, J. and Bruner, A. and Cauët, E. and Chen, Y. and Chuev, G.N. and Cramer, C.J. and Daily, J. and Deegan, M.J.O. and Dunning, T.H. and Dupuis, M. and Dyall, K.G. and Fann, G.I. and Fischer, S.A. and Fonari, A. and Früchtl, H. and Gagliardi, L. and Garza, J. and Gawande, N. and Ghosh, S. and Glaesemann, K. and Götz, A.W. and Hammond, J. and Helms, V. and Hermes, E.D. and Hirao, K. and Hirata, S. and Jacquelin, M. and Jensen, L. and Johnson, B.G. and Jónsson, H. and Kendall, R.A. and Klemm, M. and Kobayashi, R. and Konkov, V. and Krishnamoorthy, S. and Krishnan, M. and Lin, Z. and Lins, R.D. and Littlefield, R.J. and Logsdail, A.J. and Lopata, K. and Ma, W. and Marenich, A.V. and Martin Del Campo, J. and Mejia-Rodriguez, D. and Moore, J.E. and Mullin, J.M. and Nakajima, T. and Nascimento, D.R. and Nichols, J.A. and Nichols, P.J. and Nieplocha, J. and Otero-De-La-Roza, A. and Palmer, B. and Panyala, A. and Pirojsirikul, T. and Peng, B. and Peverati, R. and Pittner, J. and Pollack, L. and Richard, R.M. and Sadayappan, P. and Schatz, G.C. and Shelton, W.A. and Silverstein, D.W. and Smith, D.M.A. and Soares, T.A. and Song, D. and Swart, M. and Taylor, H.L. and Thomas, G.S. and Tipparaju, V. and Truhlar, D.G. and Tsemekhman, K. and Van Voorhis, T. and Vázquez-Mayagoitia, A. and Verma, P. and Villa, O. and Vishnu, A. and Vogiatzis, K.D. and Wang, D. and Weare, J.H. and Williamson, M.J. and Windus, T.L. and Woliński, K. and Wong, A.T. and Wu, Q. and Yang, C. and Yu, Q. and Zacharias, M. and Zhang, Z. and Zhao, Y. and Harrison, R.J.}, title = {NWChem: Past, present, and future}, journal = {Journal of Chemical Physics}, year = {2020}, volume = {152}, number = {18}, note = {All Open Access, Green Open Access}, doi = {10.1063/5.0004997} }
Bencherif H, Bègue N, Pinheiro DK, du Preez DJ, Cadet J-M, Lopes FJdS, Shikwambana L, Landulfo E, Vescovini T, Labuschagne C, Silva JJ, Anabor V, Coheur P-F, Mbatha N, Hadji-Lazaro J, Sivakumar V and Clerbaux C (2020), "Investigating the long-range transport of aerosol plumes following the amazon fires (August 2019): A multi-instrumental approach from ground-based and satellite observations", Remote Sensing. Vol. 12(22), pp. 1 – 18. [Abstract] [BibTeX] [DOI]
Abstract: Despite a number of studies on biomass burning (BB) emissions in the atmosphere, observation of the associated aerosols and pollutants requires continuous efforts. Brazil, and more broadly Latin America, is one of the most important seasonal sources of BB, particularly in the Amazon region. Uncertainty about aerosol loading in the source regions is a limiting factor in terms of understanding the role of aerosols in climate modelling. In the present work, we investigated the Amazon BB episode that occurred during August 2019 and made the international headlines, especially when the smoke plumes plunged distant cities such as São Paulo into darkness. Here, we used satellite and ground-based observations at different locations to investigate the long-range transport of aerosol plumes generated by the Amazon fires during the study period. The monitoring of BB activity was carried out using fire related pixel count from the moderate resolution imaging spectroradiometer (MODIS) onboard the Aqua and Terra platforms, while the distribution of carbon monoxide (CO) concentrations and total columns were obtained from the infrared atmospheric sounding interferometer (IASI) onboard the METOP-A and METOP-B satellites. In addition, AERONET sun-photometers as well as the MODIS instrument made aerosol optical depth (AOD) measurements over the study region. Our datasets are consistent with each other and highlight AOD and CO variations and long-range transport of the fire plume from the source regions in the Amazon basin. We used the Lagrangian transport model FLEXPART (FLEXible PARTicle) to simulate backward dispersion, which showed good agreement with satellite and ground measurements observed over the study area. The increase in Rossby wave activity during the 2019 austral winter the Southern Hemisphere may have contributed to increasing the efficiency of large-scale transport of aerosol plumes generated by the Amazon fires during the study period. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
BibTeX: @article{Bencherif2020, author = {Bencherif, Hassan and Bègue, Nelson and Pinheiro, Damaris Kirsch and du Preez, David Jean and Cadet, Jean-Maurice and Lopes, Fábio Juliano da Silva and Shikwambana, Lerato and Landulfo, Eduardo and Vescovini, Thomas and Labuschagne, Casper and Silva, Jonatan João and Anabor, Vagner and Coheur, Pierre-François and Mbatha, Nkanyiso and Hadji-Lazaro, Juliette and Sivakumar, Venkataraman and Clerbaux, Cathy}, title = {Investigating the long-range transport of aerosol plumes following the amazon fires (August 2019): A multi-instrumental approach from ground-based and satellite observations}, journal = {Remote Sensing}, year = {2020}, volume = {12}, number = {22}, pages = {1 – 18}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.3390/rs12223846} }
Bouillon M, Safieddine S, Hadji-Lazaro J, Whitburn S, Clarisse L, Doutriaux-Boucher M, Coppens D, August T, Jacquette E and Clerbaux C (2020), "Ten-year assessment of IASI radiance and temperature", Remote Sensing. Vol. 12(15) [Abstract] [BibTeX] [DOI]
Abstract: The Infrared Atmospheric Sounding Interferometers (IASIs) are three instruments flying on board the Metop satellites, launched in 2006 (IASI-A), 2012 (IASI-B), and 2018 (IASI-C). They measure infrared radiance from the Earth and atmosphere system, from which the atmospheric composition and temperature can be retrieved using dedicated algorithms, forming the Level 2 (L2) product. The operational near real-time processing of IASI data is conducted by the EUropean organisation for the exploitation of METeorological SATellites (EUMETSAT). It has improved over time, but due to IASI's large data flow, the whole dataset has not yet been reprocessed backwards. A necessary step that must be completed before initiating this reprocessing is to uniformize the IASI radiance record (Level 1C), which has also changed with time due to various instrumental and software modifications. In 2019, EUMETSAT released a reprocessed IASI-A 2007-2017 radiance dataset that is consistent with both the L1C product generated after 2017 and with IASI-B. First, this study aimed to assess the changes in radiance associated with this update by comparing the operational and reprocessed datasets. The differences in the brightness temperature ranged from 0.02 K at 700 cm-1 to 0.1 K at 2200 cm-1. Additionally, two major updates in 2010 and 2013 were seen to have the largest impact. Then, we investigated the effects on the retrieved temperatures due to successive upgrades to the Level 2 processing chain. We compared IASI L2 with ERA5 reanalysis temperatures. We found differences of 5-10 K at the surface and between 1 and 5 K in the atmosphere. These differences decreased abruptly after the release of the IASI L2 processor version 6 in 2014. These results suggest that it is not recommended to use the IASI inhomogeneous temperature products for trend analysis, both for temperature and trace gas trends. © 2020 by the authors.
BibTeX: @article{Bouillon2020, author = {Bouillon, Marie and Safieddine, Sarah and Hadji-Lazaro, Juliette and Whitburn, Simon and Clarisse, Lieven and Doutriaux-Boucher, Marie and Coppens, Dorothée and August, Thomas and Jacquette, Elsa and Clerbaux, Cathy}, title = {Ten-year assessment of IASI radiance and temperature}, journal = {Remote Sensing}, year = {2020}, volume = {12}, number = {15}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.3390/RS12152393} }
Bowen K, Hillenbrand P-M, Liévin J, Urbain X and Savin D (2020), "Astrophysically motivated laboratory measurements of deuterium reacting with isotopologues of H+3", Proceedings of the International Astronomical Union. , pp. 114 – 115. [Abstract] [BibTeX] [DOI]
Abstract: H2D+ and D2H+ are important chemical tracers of prestellar cores due to their pure rotational spectra that can be excited at the ∼ 20 K temperature of these environments. The use of these molecules as probes of prestellar cores requires understanding the chemistry that forms and destroys these molecules. Of the eight key reactions that have been identified (Albertsson et al. 2013), five are thought to be well understood. The remaining three are the isotope exchange reactions of atomic D with H+ 3 , H2D+, and D2H+. Semi-classical results differ from the classical Langevin calculations by an order of magnitude (Moyano et al. 2004). To resolve this discrepancy, we have carried out laboratory measurements for these three reactions. Absolute cross sections were measured using a dual-source, merged fast-beams apparatus for relative collision energies between ∼ 10 meV to ∼ 10 eV (Hillenbrand et al. 2019). A semi-empirical model was developed incorporating high level quantum mechanical ab initio calculations for the zero-point-energycorrected potential energy barrier in order to generate thermal rate coefficients for astrochemical models. Based on our studies, we find that these three reactions proceed too slowly at prestellar core temperatures to play a significant role in the deuteration of H+ 3 isotopologues. © International Astronomical Union 2020.
BibTeX: @article{Bowen2020, author = {Bowen, K.P. and Hillenbrand, P.-M. and Liévin, J. and Urbain, X. and Savin, D.W.}, title = {Astrophysically motivated laboratory measurements of deuterium reacting with isotopologues of H+3}, journal = {Proceedings of the International Astronomical Union}, year = {2020}, pages = {114 – 115}, doi = {10.1017/S1743921319006471} }
Brenot H, Theys N, Lerot C, Van Gent J, Van Roozendael M, Wilson S, Clarkson R, Clarisse L, Hyman DM, Pavolonis MJ, Biondi R, Tournigand P-Y, Corradini S, Salerno G, Durant A, Bannister D and Sievers K (2020), "Volcanic SO2 +eight SWIM 6ervice OPAS KTN Engage Catalyst funded project", SESAR Innovation Days. [Abstract] [BibTeX]
Abstract: Volcanic ash and related gas cause a major risk for air traffic. To mitigate this risk and to improve situational awareness for ATM, information about the height of SO2 plume is critical. This study presents a new SWIM Yellow Profile service, so called OPAS, with the aim of providing early warnings of volcanic SO2 height from three satellite instruments (TROPOMI, IASI-A and IASI-B) with an accuracy of 1-2 km. This study describes our TROPOMI SO2 height algorithm with a validation using synthetic data, a comparison with external observations, and highlights the potential impact of flying through an SO2 cloud from the point of view of an engine constructor (Rolls-Royce) directly in relation with airlines and ATM. The SO2 height alert from TROPOMI for the recent eruption of Nishinoshima volcano in June – July 2020, illustrates the interest of OPAS service in support of volcanic SO2 plume avoidance by commercial airplanes. © 2020 IADIS. All rights reserved.
BibTeX: @conference{Brenot2020, author = {Brenot, Hugues and Theys, Nicolas and Lerot, Christophe and Van Gent, Jeroen and Van Roozendael, Michel and Wilson, Scott and Clarkson, Rory and Clarisse, Lieven and Hyman, Dave M. and Pavolonis, Michael J. and Biondi, Riccardo and Tournigand, Pierre-Yves and Corradini, Stefano and Salerno, Giuseppe and Durant, Adam and Bannister, Daniel and Sievers, Klaus}, title = {Volcanic SO2 +eight SWIM 6ervice OPAS KTN Engage Catalyst funded project}, journal = {SESAR Innovation Days}, year = {2020} }
Chang Y, Clarisse L, Van Damme M, Tao Y, Zou Z, Dore AJ and Collett JL (2020), "Ammonia Emissions from Mudflats of River, Lake, and Sea", ACS Earth and Space Chemistry. Vol. 4(4), pp. 614 – 619. [Abstract] [BibTeX] [DOI]
Abstract: Whether mudflats are an important source of atmospheric ammonia (NH3) remains an open question, despite the fact that over half of the world's population live within 3 km of surface water bodies. Here, we established three sites (lake, river, and sea) that are representative of tide-influenced mudflats across the Yangtze Delta in eastern China. Online field measurements of NH3 and auxiliary hydrometeorological parameters were simultaneously performed over a 9 month period. Surprisingly, the average NH3 concentrations measured at these locations are as low as regional background levels. No pulses of increased NH3 were found at these sites when mudflats were exposed due to receding water levels. High atmospheric NH3 concentrations are persistently associated with high temperatures, but their geographical origins have no overlap with the locations of water bodies. The potential mechanism is also discussed. Collectively, we provide the first direct observational evidence concerning mudflat as a source of NH3 © 2020 American Chemical Society.
BibTeX: @article{Chang2020, author = {Chang, Yunhua and Clarisse, Lieven and Van Damme, Martin and Tao, Ye and Zou, Zhong and Dore, Anthony J. and Collett, Jeffrey L.}, title = {Ammonia Emissions from Mudflats of River, Lake, and Sea}, journal = {ACS Earth and Space Chemistry}, year = {2020}, volume = {4}, number = {4}, pages = {614 – 619}, doi = {10.1021/acsearthspacechem.0c00017} }
Deguine A, Petitprez D, Clarisse L, Guđmundsson S, Outes V, Villarosa G and Herbin H (2020), "Complex refractive index of volcanic ash aerosol in the infrared, visible, and ultraviolet", Applied Optics. Vol. 59(4), pp. 884 – 895. [Abstract] [BibTeX] [DOI]
Abstract: Very fine silicate-rich volcanic ash, generated by explosive volcanic eruptions, can efficiently be traced downwind with infrared satellite sounders. Their measurements can also be used to derive physical parameters, such as optical depths and effective radii. However, one of the key requirements for accurate retrievals is a good knowledge of the complex refractive index (CRI) of the ash under investigation. In the past, the vast majority of the studies used the CRIs from Pollack et al. [Icarus 19, 372 (1973)], which are based on measurements of thin slices of volcanic rock, and therefore are not representative for airborne volcanic ash particles. Here, we report measurements of the CRI of volcanic ash in suspension, generated from samples collected from recent high-impact eruptions in Chile (Puyehue-Cordón Caulle, Calbuco, and Chaitén), Iceland (Eyjafjallajökull and Grímsvötn), and Italy (Etna). The samples cover a wide range of SiO2 content (46% to 76%) as confirmed by an X-ray fluorescence analysis. In the experimental setup, volcanic ash was suspended in nitrogen through mechanical agitation. Extinction spectra were recorded in the infrared, visible, and ultraviolet spectral regions. The particle size distribution within the airflow was also recorded. An iterative algorithm allowed us to obtain fully consistent CRIs for the six samples, compatible with the observed extinction spectra and the Kramers–Krönig relations. While a good agreement is found with other recently reported CRIs in the UV/Vis, larger differences are found in the longwave infrared spectral region. © 2020 Optical Society of America.
BibTeX: @article{Deguine2020, author = {Deguine, Alexandre and Petitprez, Denis and Clarisse, Lieven and Guđmundsson, Snævarr and Outes, Valeria and Villarosa, Gustavo and Herbin, Hervé}, title = {Complex refractive index of volcanic ash aerosol in the infrared, visible, and ultraviolet}, journal = {Applied Optics}, year = {2020}, volume = {59}, number = {4}, pages = {884 – 895}, note = {All Open Access, Green Open Access}, doi = {10.1364/AO.59.000884} }
Du Preez DJ, Bencherif H, Bègue N, Clarisse L, Hoffman RF and Wright CY (2020), "Investigating the large-scale transport of a volcanic plume and the impact on a secondary site", Atmosphere. Vol. 11(5) [Abstract] [BibTeX] [DOI]
Abstract: Volcanic plumes can be transported across vast distances and can have an impact on solar ultraviolet radiation (UVR) reaching the surface due to the scattering and absorption caused by aerosols. The dispersion of the volcanic plume from the Puyehue-Cordon Caulle volcanic complex (PCCVC) eruption was investigated to determine the effect on aerosol loading at Cape Point, South Africa. The eruption occurred on 4 June 2011 and resulted in a plume reaching a height of between 9 and 12 km and was dispersed across the Southern Hemisphere. Satellite sulphur dioxide (SO2) observations and a dispersion model showed low concentrations of SO2 at the secondary site. However, satellite observations of volcanic ash and ground-based aerosol measurements did show increases between 10 and 20 June 2011 at the secondary site. Furthermore, there was good agreement with the dispersion model results and observations from satellites with most of the plume located between latitudes 40°-60° South. © 2020 by the authors.
BibTeX: @article{DuPreez2020, author = {Du Preez, David Jean and Bencherif, Hassan and Bègue, Nelson and Clarisse, Lieven and Hoffman, Rebecca F. and Wright, Caradee Yael}, title = {Investigating the large-scale transport of a volcanic plume and the impact on a secondary site}, journal = {Atmosphere}, year = {2020}, volume = {11}, number = {5}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.3390/atmos11050548} }
Elias B, Cerfontaine S, Troian-Gautier L, Wehlin SAM, Loiseau F and Cauët E (2020), "Tuning the excited-state deactivation pathways of dinuclear ruthenium(ii) 2,2′-bipyridine complexes through bridging ligand design", Dalton Transactions. Vol. 49(24), pp. 8096 – 8106. [Abstract] [BibTeX] [DOI]
Abstract: A detailed photophysical investigation of two dinuclear ruthenium(ii) complexes is reported. The two metallic centers were coordinated to a bis-2,2′-bipyridine bridging ligand, connected either through the para (Lp, Dp) or the meta position (Lm, Dm). The results obtained herein were compared to the prototypical [Ru(bpy)3]2+ parent compound. The formation of dinuclear complexes was accompanied by the expected increase in molar absorption coefficients, i.e. 12 000 M-1 cm-1, 17 000 M-1 cm-1, and 22 000 M-1 cm-1 at the lowest energy MLCTmax transition for [Ru(bpy)3]2+, Dm and Dp respectively. The Lp bridging ligand resulted in a ruthenium(ii) dinuclear complex that absorbed more visible light, and had a longer-lived and more delocalized excited-state compared to a complex with the Lm bridging ligand. Variable temperature measurements provided valuable information about activation energies to the uppermost 3MLCT state and the metal-centered (3MC) state, often accompanied by irreversible ligand-loss chemistry. At 298 K, 48% of [Ru(bpy)3]2+∗ excited-state underwent deactivation through the 3MC state, whereas this deactivation pathway remained practically unpopulated (<0.5%) in both dinuclear complexes. This journal is © The Royal Society of Chemistry.
BibTeX: @article{Elias2020, author = {Elias, Benjamin and Cerfontaine, Simon and Troian-Gautier, Ludovic and Wehlin, Sara A. M. and Loiseau, Frédérique and Cauët, Emilie}, title = {Tuning the excited-state deactivation pathways of dinuclear ruthenium(ii) 2,2′-bipyridine complexes through bridging ligand design}, journal = {Dalton Transactions}, year = {2020}, volume = {49}, number = {24}, pages = {8096 – 8106}, doi = {10.1039/d0dt01216e} }
Fortems-Cheiney A, Dufour G, Dufossé K, Couvidat F, Gilliot J-M, Siour G, Beekmann M, Foret G, Meleux F, Clarisse L, Coheur P-F, Van Damme M, Clerbaux C and Génermont S (2020), "Do alternative inventories converge on the spatiotemporal representation of spring ammonia emissions in France", Atmospheric Chemistry and Physics. Vol. 20(21), pp. 13481 – 13495. [Abstract] [BibTeX] [DOI]
Abstract: Agriculture is the main source of ammonia (NH3) in France, an important gaseous precursor of atmospheric particulate matter (PM). National and global emission inventories are known to have difficulty representing the large spatial and temporal variability inherent to atmospheric NH3. In this study, we compare NH3 emissions in France during spring 2011 from one reference inventory, the TNO inventory, and two alternative inventories that account in different manners for both the spatial and temporal variabilities of the emissions: (i) the NH3SAT satellite-derived inventory based on IASI NH3 columns and (ii) the CADASTRE-CIT inventory that combines NH3 emissions due to nitrogen fertilization calculated with the mechanistic model VOLT'AIR on the database of the CADASTRE_NH3 framework and other source emissions from the CITEPA. The total spring budgets, from March to May 2011, at the national level are higher when calculated with both alternative inventories than with the reference, the difference being more marked with CADASTRE-CIT. NH3SAT and CADASTRE-CIT inventories both yield to large NH3 spring emissions due to fertilization on soils with high pH in the northeastern part of France (65 and 135 ktNH3, respectively, vs. 48 ktNH3 for TNO-GEN), while soil properties are not accounted for by the TNO-GEN methodology. For the other parts of France, the differences are smaller. The timing of fertilization and associated ammonia emissions is closely related to the nitrogen requirements and hence the phenological stage of the crops, and therefore to the crop year's specific weather conditions. Maximum emissions are observed in March for 2011 for some regions for both alternative inventories, while April is the period with maximum emissions for the reference inventory regardless of the region or the year. Comparing the inventories at finer temporal resolutions, typically at daily scale, large differences are found. The convergence of alternative, independent and complementary methods on the spatiotemporal representation of the spring NH3 emissions, particularly over areas where the contribution of mineral fertilizer spreading to the spring budget is strong, encourages further developments in both prospective complementary directions, as this will help improve national NH3 emission inventories. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License.
BibTeX: @article{FortemsCheiney2020, author = {Fortems-Cheiney, Audrey and Dufour, Gaelle and Dufossé, Karine and Couvidat, Florian and Gilliot, Jean-Marc and Siour, Guillaume and Beekmann, Matthias and Foret, Gilles and Meleux, Frederik and Clarisse, Lieven and Coheur, Pierre-Francois and Van Damme, Martin and Clerbaux, Cathy and Génermont, Sophie}, title = {Do alternative inventories converge on the spatiotemporal representation of spring ammonia emissions in France}, journal = {Atmospheric Chemistry and Physics}, year = {2020}, volume = {20}, number = {21}, pages = {13481 – 13495}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-20-13481-2020} }
Franco B, Clarisse L, Stavrakou T, Müller J-F, Taraborrelli D, Hadji-Lazaro J, Hannigan J, Hase F, Hurtmans D, Jones N, Lutsch E, Mahieu E, Ortega I, Schneider M, Strong K, Vigouroux C, Clerbaux C and Coheur P-F (2020), "Spaceborne Measurements of Formic and Acetic Acids: A Global View of the Regional Sources", Geophysical Research Letters. Vol. 47(4) [Abstract] [BibTeX] [DOI]
Abstract: Formic (HCOOH) and acetic acids (CH3COOH) are the most abundant carboxylic acids in the Earth's atmosphere and key compounds to aqueous-phase chemistry. Here we present the first distributions of CH3COOH retrieved from the 2007–2018 satellite observations of the nadir-looking infrared atmospheric sounding interferometer (IASI), using a neural network-based retrieval approach. A joint analysis with the IASI HCOOH product reveals that the two species exhibit similar distributions, seasonality, and atmospheric burden, pointing to major common sources. We show that their abundance is highly correlated to isoprene and monoterpenes emissions, as well as to biomass burning. Over Africa, evidence is provided that residual smoldering combustion might be a major driver of the HCOOH and CH3COOH seasonality. Earlier seasonal enhancement of HCOOH at Northern Hemisphere middle and high latitudes and late seasonal secondary peaks of CH3COOH in the tropics suggest that sources and production pathways specific to each species are also at play. ©2020. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Franco2020, author = {Franco, B. and Clarisse, L. and Stavrakou, T. and Müller, J.-F. and Taraborrelli, D. and Hadji-Lazaro, J. and Hannigan, J.W. and Hase, F. and Hurtmans, D. and Jones, N. and Lutsch, E. and Mahieu, E. and Ortega, I. and Schneider, M. and Strong, K. and Vigouroux, C. and Clerbaux, C. and Coheur, P.-F.}, title = {Spaceborne Measurements of Formic and Acetic Acids: A Global View of the Regional Sources}, journal = {Geophysical Research Letters}, year = {2020}, volume = {47}, number = {4}, note = {All Open Access, Green Open Access}, doi = {10.1029/2019GL086239} }
Friedrich M, Beutner E, Reuvers H, Smeekes S, Urbain J-P, Bader W, Franco B, Lejeune B and Mahieu E (2020), "A statistical analysis of time trends in atmospheric ethane", Climatic Change. Vol. 162(1), pp. 105 – 125. [Abstract] [BibTeX] [DOI]
Abstract: Ethane is the most abundant non-methane hydrocarbon in the Earth’s atmosphere and an important precursor of tropospheric ozone through various chemical pathways. Ethane is also an indirect greenhouse gas (global warming potential), influencing the atmospheric lifetime of methane through the consumption of the hydroxyl radical (OH). Understanding the development of trends and identifying trend reversals in atmospheric ethane is therefore crucial. Our dataset consists of four series of daily ethane columns. As with many other decadal time series, our data are characterized by autocorrelation, heteroskedasticity, and seasonal effects. Additionally, missing observations due to instrument failure or unfavorable measurement conditions are common in such series. The goal of this paper is therefore to analyze trends in atmospheric ethane with statistical tools that correctly address these data features. We present selected methods designed for the analysis of time trends and trend reversals. We consider bootstrap inference on broken linear trends and smoothly varying nonlinear trends. In particular, for the broken trend model, we propose a bootstrap method for inference on the break location and the corresponding changes in slope. For the smooth trend model, we construct simultaneous confidence bands around the nonparametrically estimated trend. Our autoregressive wild bootstrap approach, combined with a seasonal filter, is able to handle all issues mentioned above (we provide R code for all proposed methods on https://www.stephansmeekes.nl/code.). © 2020, The Author(s).
BibTeX: @article{Friedrich2020, author = {Friedrich, Marina and Beutner, Eric and Reuvers, Hanno and Smeekes, Stephan and Urbain, Jean-Pierre and Bader, Whitney and Franco, Bruno and Lejeune, Bernard and Mahieu, Emmanuel}, title = {A statistical analysis of time trends in atmospheric ethane}, journal = {Climatic Change}, year = {2020}, volume = {162}, number = {1}, pages = {105 – 125}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1007/s10584-020-02806-2} }
Gamrath S, Godefroid M, Palmeri P, Quinet P and Wang K (2020), "Spectral line list of potential cosmochronological interest deduced from new calculations of radiative transition rates in singly ionized thorium (Th II)", Monthly Notices of the Royal Astronomical Society. Vol. 496(4), pp. 4507 – 4516. [Abstract] [BibTeX] [DOI]
Abstract: In this work, we report a list of 91 strong Th II spectral lines in the visible wavelength region that could be used as cosmochronometers in future investigations to determine stellar ages from thorium radioactive decay. This list was established on the basis of a pseudo-relativistic Hartree-Fock model including core-polarization corrections (HFR+CPOL) allowing us to compute the corresponding radiative decay parameters, the latter being found to be in good overall agreement with the most accurate experimental data when available. Besides this semi-empirical approach, the fully relativistic ab initio multiconfiguration Dirac-Hartree-Fock (MCDHF) method was attempted, showing large discrepancies with both the present HFR+CPOL and the most recent experimental oscillator strengths, although the calculated wavelengths from theoretical energy levels agreed with observed spectral line wavelengths within 2.4 per cent. © 2020 The Author(s).
BibTeX: @article{Gamrath2020, author = {Gamrath, S. and Godefroid, M.R. and Palmeri, P. and Quinet, P. and Wang, K.}, title = {Spectral line list of potential cosmochronological interest deduced from new calculations of radiative transition rates in singly ionized thorium (Th II)}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {2020}, volume = {496}, number = {4}, pages = {4507 – 4516}, doi = {10.1093/mnras/staa1740} }
Jiang J, Du Z, Liévin J and Field RW (2020), "One-colour (∼220 nm) resonance-enhanced (S1 − S0) multi-photon dissociation of acetylene: probe of the C2 A 1 Π u − X 1 Σ+ g band by frequency-modulation spectroscopy", Molecular Physics. Vol. 118(15) [Abstract] [BibTeX] [DOI]
Abstract: In a recent paper, we demonstrated that one-colour (∼220 nm), resonance-enhanced (S (Formula presented.) S (Formula presented.)), photodissociation of acetylene generates strong (Formula presented.) Swan band ((Formula presented.)) and (Formula presented.) Deslandres-d'Azambuja band ((Formula presented.)) fluorescence, and long-lived (>3 µs) fluorescence from an electronically-excited (Formula presented.) H (Formula presented.) species. It was not known whether the (Formula presented.) and (Formula presented.) states are also directly populated in this process. In this work, multiple vibration-rotation transitions between the (Formula presented.) -state v = 2 and the X-state v = 0 level are examined by time-resolved frequency-modulation (FM) spectroscopy. The photolysis laser wavelength is tuned into resonance at the one-photon level with S (Formula presented.) S (Formula presented.) transitions that populate individual rotational levels of the S (Formula presented.) -conformer (Formula presented.), (Formula presented.), and (Formula presented.) vibrational states. By comparing the phase of the FM signals from the (Formula presented.) transitions with that from the Rb D (Formula presented.) -line absorption transition, we determine that, for all of the probed A−X transitions, the X-state level is more populated than the A-state level. We propose that the acetylene S (Formula presented.) level is excited by the second photon to an acetylene dissociation precursor state, which undergoes sequential C-H bond-breaking to produce the (Formula presented.) state. The dissociation precursor is assigned as the (Formula presented.) valence state, which correlates to a doubly-excited configuration, (Formula presented.), at linear geometry. Based on the rotational distributions of the (Formula presented.) -state fragments, we believe that at least one of the transition states involved in the photolysis via S (Formula presented.) has a larger CC-H bend-angle for the departing H-atom than that involved in the S (Formula presented.) and (Formula presented.) photolysis. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX: @article{Jiang2020, author = {Jiang, Jun and Du, Zhenhui and Liévin, Jacques and Field, Robert W.}, title = {One-colour (∼220 nm) resonance-enhanced (S1 − S0) multi-photon dissociation of acetylene: probe of the C2 A 1 Π u − X 1 Σ+ g band by frequency-modulation spectroscopy}, journal = {Molecular Physics}, year = {2020}, volume = {118}, number = {15}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268976.2020.1724340} }
Jonusas M, Leroux K and Krim L (2020), "N + H surface reaction under interstellar conditions: Does the NH/NH2/NH3 distribution depend on N/H ratio?", Journal of Molecular Structure. Vol. 1220 [Abstract] [BibTeX] [DOI]
Abstract: Astronomical observations have already reported that the abundances of NH, NH2, and NH3 cannot be explained with gas phase chemistry modeling and depend strongly on the environment where these three N-hydrides have been detected. Consequently, dust grains may play a crucial role in the formation of these species through surface reactions. We have investigated the formation of NH, NH2 and NH3 through N→+HNH→+HNH2→+HNH3 solid state reaction at 3 and 10 K, in different environments. The N2–H2 gas binary mixture is then plasma activated and the resulting gas from the microwave discharge made of H, H2, N, N2 and NH3 is deposited onto the surface of the sample holder maintained at 3 and 10 K. We show that, while at 10 K, NH, NH2 and NH3 have been detected in different abundance distributions, at 3 K the NH and NH2 radicals have not observed and the low amount of NH3 present in our solid samples comes from the N2–H2 plasma discharge. This is the first experimental study showing all the steps leading to ammonia formation, by detecting the final reaction product NH3 and the two reaction intermediates NH and NH2. In addition to support the idea of NH and NH2 formation on interstellar dust grains, we show that the environment where the reaction takes place plays an important role in the formation and stabilization of these two reactive unsaturated N-hydride radicals. We emphasize that NH and NH2 are detected only if there are enough nitrogen molecules in the solid samples to isolate them from reacting, otherwise, directly exposed to H-atoms they turn into stable saturated species such as NH3 and NH3-aggregates. © 2020 Elsevier B.V.
BibTeX: @article{Jonusas2020, author = {Jonusas, Mindaugas and Leroux, Killian and Krim, Lahouari}, title = {N + H surface reaction under interstellar conditions: Does the NH/NH2/NH3 distribution depend on N/H ratio?}, journal = {Journal of Molecular Structure}, year = {2020}, volume = {1220}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.molstruc.2020.128736} }
Kas M, Liévin J, Vaeck N and Loreau J (2020), "Cold collisions of C2- with Li and Rb atoms in hybrid traps", Journal of Physics: Conference Series. Vol. 1412(6) [Abstract] [BibTeX] [DOI]
Abstract: We present a theoretical investigation of reactive and non-reactive collisions of Li and Rb atoms with C2- molecular anions at low temperatures in the context of sympathetic cooling in hybrid trap experiments. Based on accurate potential energy surfaces for the singlet and triplet states of the Li-C2- and Rb-C2- systems, we show that the associative electronic detachment reaction is inefficient but that it occurs with a large rate for collisions involving excited states of either Li/Rb or C2-. We also investigate rotationally inelastic collisions in order to explore the cooling of the translational and rotational degrees of freedom of C2- in hybrid ion-atom traps. The effect of micromotion is taken into account by considering Tsallis distributions of collision energies. We show that the translational cooling occurs much more rapidly than rotational cooling and that the presence of excited atoms leads to losses of anions on a timescale comparable to that of rotational cooling. © Published under licence by IOP Publishing Ltd.
BibTeX: @conference{Kas2020, author = {Kas, Milaim and Liévin, Jacques and Vaeck, Nathalie and Loreau, Jérôme}, title = {Cold collisions of C2- with Li and Rb atoms in hybrid traps}, journal = {Journal of Physics: Conference Series}, year = {2020}, volume = {1412}, number = {6}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/1412/6/062003} }
Kuttippurath J, Singh A, Dash S, Mallick N, Clerbaux C, Van Damme M, Clarisse L, Coheur P-F, Raj S, Abbhishek K and Varikoden H (2020), "Record high levels of atmospheric ammonia over India: Spatial and temporal analyses", Science of the Total Environment. Vol. 740 [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric ammonia (NH3) is an alkaline gas and a prominent constituent of the nitrogen cycle that adversely affects ecosystems at higher concentrations. It is a pollutant, which influences all three spheres such as haze formation in the atmosphere, soil acidification in the lithosphere, and eutrophication in water bodies. Atmospheric NH3 reacts with sulfur (SOx) and nitrogen (NOx) oxides to form aerosols, which eventually affect human health and climate. Here, we present the seasonal and inter-annual variability of atmospheric NH3 over India in 2008–2016 using the IASI (Infrared Atmospheric Sounding Interferometer) satellite observations. We find that Indo-Gangetic Plains (IGP) is one of the largest and rapidly growing NH3 hotspots of the world, with a growth rate of +1.2% yr−1 in summer (June–August: Kharif season), due to intense agricultural activities and presence of many fertilizer industries there. However, our analyses show insignificant decreasing trends in annual NH3 of about −0.8% yr−1 in all India, about −0.4% yr−1 in IGP, and −1.0% yr−1 in the rest of India. Ammonia is positively correlated with total fertilizer consumption (r = 0.75) and temperature (r = 0.5) since high temperature favors volatilization, and is anti-correlated with total precipitation (r = from −0.2, but −0.8 in the Rabi season: October–February) as wet deposition helps removal of atmospheric NH3. This study, henceforth, suggests the need for better fertilization practices and viable strategies to curb emissions, to alleviate the adverse health effects and negative impacts on the ecosystem in the region. On the other hand, the overall decreasing trend in atmospheric NH3 over India shows the positive actions, and commitment to the national missions and action plans to reduce atmospheric pollution and changes in climate. © 2020 Elsevier B.V.
BibTeX: @article{Kuttippurath2020, author = {Kuttippurath, J. and Singh, A. and Dash, S.P. and Mallick, N. and Clerbaux, C. and Van Damme, M. and Clarisse, L. and Coheur, P.-F. and Raj, S. and Abbhishek, K. and Varikoden, H.}, title = {Record high levels of atmospheric ammonia over India: Spatial and temporal analyses}, journal = {Science of the Total Environment}, year = {2020}, volume = {740}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.scitotenv.2020.139986} }
Lauzin C, Imbreckx A, Foldes T, Vanfleteren T, Moazzen-Ahmadi N and Herman M (2020), "High-resolution spectroscopic study of the H2O–CO2 van der Waals complex in the 2OH overtone range", Molecular Physics. Vol. 118(11) [Abstract] [BibTeX] [DOI]
Abstract: The jet-cooled spectrum ((Formula presented.) K) of the H (Formula presented.) O–CO (Formula presented.) van der Waals complex has been recorded in the 1.4 μm region by cavity ring-down spectroscopy. Two b-type vibrational bands have been observed and analysed. The rotational assignment has been achieved using a different asymmetric rotor Hamiltonian for each nuclear spin species, accounting for the internal rotation of the H (Formula presented.) O and CO (Formula presented.) units. The band at 7247 cm (Formula presented.) is assigned to (101) in terms of the ((Formula presented.)) vibrational quantum number of the H (Formula presented.) O monomer. The band at 7238 cm (Formula presented.) is assigned to (200) + an intermolecular mode ((Formula presented.)) excited in the complex. Vibration-rotation constants are provided for the excited states. The symmetry of the wavefunction, the effect of vibrational excitation on the tunnelling dynamics and the vibrational assignment are discussed. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX: @article{Lauzin2020, author = {Lauzin, C. and Imbreckx, A.C. and Foldes, T. and Vanfleteren, T. and Moazzen-Ahmadi, N. and Herman, M.}, title = {High-resolution spectroscopic study of the H2O–CO2 van der Waals complex in the 2OH overtone range}, journal = {Molecular Physics}, year = {2020}, volume = {118}, number = {11}, doi = {10.1080/00268976.2019.1706776} }
Leifer I, Melton C, Tratt DM, Buckland KN, Chang CS, Clarisse L, Franklin M, Hall JL, Brian Leen J, Lundquist T, Van Damme M, Vigil S and Whitburn S (2020), "Estimating exposure to hydrogen sulfide from animal husbandry operations using satellite ammonia as a proxy: Methodology demonstration", Science of the Total Environment. Vol. 709 [Abstract] [BibTeX] [DOI]
Abstract: Husbandry trace gases that have climate change implications such as carbon dioxide (CO2), methane (CH4) and ammonia (NH3) can be quantified through remote sensing; however, many husbandry gases with health implications such as hydrogen sulfide (H2S), cannot. This pilot study demonstrates an approach to derive H2S concentrations by coupling in situ and remote sensing data. Using AMOG (AutoMObile trace Gas) Surveyor, a mobile air quality and meteorology laboratory, we measured in situ concentrations of CH4, CO2, NH3, H2S, and wind at a southern California university research dairy. Emissions were 0.13, 1.93, 0.022 and 0.0064 Gg yr−1; emission factors (EF) were 422, 6333, 74, and 21 kg cow−1 yr−1, respectively, for the 306 head herd. Contributing to these strong EF were spillway emissions from a grate between the main cowshed and the waste lagoon identified in airborne remote sensing data acquired by the hyperspectral thermal infrared imager, Mako. NH3 emissions from the Chino Dairy Complex, also in southern California, were calculated from Infrared Atmospheric Sounding Interferometer (IASI) satellite data for 2008–2017 using average morning winds, yielding a flushing time of 2.7 h, and 8.9 Gg yr−1. The ratio of EF(H2S) to EF(NH3) for the research dairy from AMOG data were applied to IASI NH3 emissions to derive H2S exposure concentration maps for the Chino area, which ranged to 10–30 ppb H2S for many populated areas. Combining remote sensing with in situ concentrations of multiple emitted gases can allow derivation of emissions at the sub-facility, facility, and larger scales, providing spatial and temporal coverage that can translate into exposure estimates for use in epidemiology studies and regulation development. Furthermore, with high fidelity information at the sub-facility level we can identify best practices and opportunities to sustainably and holistically reduce husbandry emissions. © 2019 Elsevier B.V.
BibTeX: @article{Leifer2020, author = {Leifer, Ira and Melton, Christopher and Tratt, David M. and Buckland, Kerry N. and Chang, Clement S. and Clarisse, Lieven and Franklin, Meredith and Hall, Jeffrey L. and Brian Leen, J. and Lundquist, Tryg and Van Damme, Martin and Vigil, Sam and Whitburn, Simon}, title = {Estimating exposure to hydrogen sulfide from animal husbandry operations using satellite ammonia as a proxy: Methodology demonstration}, journal = {Science of the Total Environment}, year = {2020}, volume = {709}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.scitotenv.2019.134508} }
Leroux K, Guillemin J-C and Krim L (2020), "Solid-state formation of CO and H2CO via the CHOCHO + H reaction", Monthly Notices of the Royal Astronomical Society. Vol. 491(1), pp. 289 – 301. [Abstract] [BibTeX] [DOI]
Abstract: Glycolaldehyde (CHOCH2OH) and ethylene glycol (HOCH2CH2OH) are among many complex organic molecules detected in the interstellar medium (ISM). Astrophysical models proposed very often that the formation of these compounds would be directly linked to the hydrogenation of glyoxal (CHOCHO), a potential precursor which is not yet detected in the ISM. We have performed, in this work, surface and bulk hydrogenations of solid CHOCHO under ISM conditions in order to confirm or invalidate the astrophysical modelling of glyoxal transformation. Our results show that the hydrogenation of glyoxal does not lead to the formation of detectable amounts of heavier organic molecules such as glycolaldehyde and ethylene glycol but rather to lighter CO-bearing species such as CO, H2CO, and CO-H2CO, a reaction intermediate resulting from an H-addition-elimination process on CHOCHO and where CO is linked to H2CO. The solid phase formation of such a reaction intermediate has been confirmed through the neon matrix isolation of CO-H2CO species. Additionally, the CHOCHO + H solid-state reaction might also lead to the production of CH3OH formed under our experimental conditions as a secondary product resulting from the hydrogenation of formaldehyde. © 2019 The Author(s)
BibTeX: @article{Leroux2020, author = {Leroux, Killian and Guillemin, Jean-Claude and Krim, Lahouari}, title = {Solid-state formation of CO and H2CO via the CHOCHO + H reaction}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {2020}, volume = {491}, number = {1}, pages = {289 – 301}, note = {All Open Access, Green Open Access}, doi = {10.1093/mnras/stz3051} }
Lopez T, Clarisse L, Schwaiger H, Van Eaton A, Loewen M, Fee D, Lyons J, Wallace K, Searcy C, Wech A, Haney M, Schneider D and Graham N (2020), "Constraints on eruption processes and event masses for the 2016–2017 eruption of Bogoslof volcano, Alaska, through evaluation of IASI satellite SO2 masses and complementary datasets", Bulletin of Volcanology. Vol. 82(2) [Abstract] [BibTeX] [DOI]
Abstract: Bogoslof volcano, Alaska, experienced at least 70 explosive eruptions between 12 December 2016 and 31 August 2017. Due to its remote location and limited local monitoring network, this eruption was monitored and characterized primarily using remote geophysical and satellite techniques. SO2 emissions from Bogoslof were persistently detected by the Infrared Atmospheric Sounding Interferometer (IASI) satellite sensors. Of Bogoslof’s 70 explosive events, 50% produced measurable SO2 masses ranging from 0.1 to 21.5 kt, with a median and standard deviation of 0.7 ± 4.0 kt SO2, respectively. Here, we compare IASI-derived SO2 masses from Bogoslof events to complementary geophysical datasets to provide insights into eruption source processes, namely the degree of seawater scrubbing of water-soluble SO2 and variations in magma flux. Correlations with the number of lightning strokes and infrasound energy are expected to indicate magma-flux as a controlling process, while correlations with infrasound frequency index are expected to indicate variations in vent-water content as a controlling factor. These comparisons suggest that the measured SO2 masses are primarily a function of eruption magnitude (degassed magma mass) and that scrubbing of SO2 emissions by vent seawater may have exerted a minor effect on the observed SO2 masses. SO2 masses were combined with petrologic constraints on melt inclusion and matrix glass S concentrations to calculate degassed magma masses and volumes. The cumulative SO2-derived degassed magma mass and estimated volume (dense-rock equivalent) for the full Bogoslof eruption were found to be 2.8 × 1010 kg and 9.3 × 106 m3, respectively. When individual event masses are compared against event masses calculated using an empirical plume-height method, a strong correlation is found (R2 = 0.83), with better than order-of-magnitude agreement in most cases. These estimates of eruption masses provide useful information on the magnitude, behavior, and associated hazards of the 2016–2017 eruption, and potentially future unrest at Bogoslof volcano. © 2020, International Association of Volcanology & Chemistry of the Earth's Interior.
BibTeX: @article{Lopez2020, author = {Lopez, Taryn and Clarisse, Lieven and Schwaiger, Hans and Van Eaton, Alexa and Loewen, Matthew and Fee, David and Lyons, John and Wallace, Kristi and Searcy, Cheryl and Wech, Aaron and Haney, Matthew and Schneider, David and Graham, Nathan}, title = {Constraints on eruption processes and event masses for the 2016–2017 eruption of Bogoslof volcano, Alaska, through evaluation of IASI satellite SO2 masses and complementary datasets}, journal = {Bulletin of Volcanology}, year = {2020}, volume = {82}, number = {2}, doi = {10.1007/s00445-019-1348-z} }
Mukai M, Hirayama Y, Watanabe Y, Schiffmann S, Ekman J, Godefroid M, Schury P, Kakiguchi Y, Oyaizu M, Wada M, Jeong S, Moon J, Park J, Ishiyama H, Kimura S, Ueno H, Ahmed M, Ozawa A, Watanabe H, Kanaya S and Miyatake H (2020), "In-gas-cell laser resonance ionization spectroscopy of Ir 196,197,198", Physical Review C. Vol. 102(5) [Abstract] [BibTeX] [DOI]
Abstract: Hyperfine structure (HFS) measurements of neutron-rich iridium isotopes Ir196,197,198 (Z=77,N=119-121) were performed via in-gas-cell laser resonance ionization spectroscopy at the KEK Isotope Separation System. Magnetic dipole moments μ and isotope shifts were determined from the HFS spectra. The variation of mean-square charge radii and quadrupole deformation parameters of these isotopes were evaluated from the isotope shifts. The μ value of Ir197 agreed with a theoretical value based on the strong coupling model, and the Ir nucleus was interpreted as prolately deformed by the theoretical calculations. The μ values of Ir196,198 were also compared with semiempirical values calculated based on the strong coupling model. From the comparison, we can suggest the possible spin values of Iπ=1,2- for Ir196 and Iπ=1- for Ir198. © 2020 American Physical Society.
BibTeX: @article{Mukai2020, author = {Mukai, M. and Hirayama, Y. and Watanabe, Y.X. and Schiffmann, S. and Ekman, J. and Godefroid, M. and Schury, P. and Kakiguchi, Y. and Oyaizu, M. and Wada, M. and Jeong, S.C. and Moon, J.Y. and Park, J.H. and Ishiyama, H. and Kimura, S. and Ueno, H. and Ahmed, M. and Ozawa, A. and Watanabe, H. and Kanaya, S. and Miyatake, H.}, title = {In-gas-cell laser resonance ionization spectroscopy of Ir 196,197,198}, journal = {Physical Review C}, year = {2020}, volume = {102}, number = {5}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevC.102.054307} }
Safieddine S, Bouillon M, Paracho A-C, Jumelet J, Tencé F, Pazmino A, Goutail F, Wespes C, Bekki S, Boynard A, Hadji-Lazaro J, Coheur P-F, Hurtmans D and Clerbaux C (2020), "Antarctic Ozone Enhancement During the 2019 Sudden Stratospheric Warming Event", Geophysical Research Letters. Vol. 47(14) [Abstract] [BibTeX] [DOI]
Abstract: We analyze the 2019 sudden stratospheric warming event that occurred in the Southern Hemisphere through its impact on the Antarctic ozone. Using temperature, ozone, and nitric acid data from the Infrared Atmospheric Sounding Interferometer (IASI), our results show that the average increase in stratospheric temperature reached a maximum of 34.4° on 20 September in the [60–90]°S latitude range when compared to the past 3 years. Dynamical parameters suggest a locally reversed and weakened zonal winds and a shift in the location of the polar jet vortex. This led to air masses mixing, to a reduced polar stratospheric clouds formation detected at a ground station, and as such to lower ozone and nitric acid depletion. 2019 total ozone columns for the months of September, October, and November were on average higher by 29%, 28%, and 26%, respectively, when compared to the 11-year average of the same months. ©2020. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Safieddine2020a, author = {Safieddine, Sarah and Bouillon, Marie and Paracho, Ana-Claudia and Jumelet, Julien and Tencé, Florent and Pazmino, Andrea and Goutail, Florence and Wespes, Catherine and Bekki, Slimane and Boynard, Anne and Hadji-Lazaro, Juliette and Coheur, Pierre-François and Hurtmans, Daniel and Clerbaux, Cathy}, title = {Antarctic Ozone Enhancement During the 2019 Sudden Stratospheric Warming Event}, journal = {Geophysical Research Letters}, year = {2020}, volume = {47}, number = {14}, note = {All Open Access, Green Open Access}, doi = {10.1029/2020GL087810} }
Safieddine S, Parracho AC, George M, Aires F, Pellet V, Clarisse L, Whitburn S, Lezeaux O, Thépaut J-N, Hersbach H, Radnoti G, Goettsche F, Martin M, Doutriaux-Boucher M, Coppens D, August T, Zhou DK and Clerbaux C (2020), "Artificial neural networks to retrieve land and sea skin temperature from IASI", Remote Sensing. Vol. 12(17) [Abstract] [BibTeX] [DOI]
Abstract: Surface skin temperature (Tskin) derived from infrared remote sensors mounted on board satellites provides a continuous observation of Earth's surface and allows the monitoring of global temperature change relevant to climate trends. In this study, we present a fast retrieval method for retrieving Tskin based on an artificial neural network (ANN) from a set of spectral channels selected from the Infrared Atmospheric Sounding Interferometer (IASI) using the information theory/entropy reduction technique. Our IASI Tskin product (i.e., TANN) is evaluated against Tskin from EUMETSAT Level 2 product, ECMWF Reanalysis (ERA5), SEVIRI observations, and ground in situ measurements. Good correlations between IASI TANN and the Tskin from other datasets are shown by their statistic data, such as a mean bias and standard deviation (i.e., [bias, STDE]) of [0.55, 1.86 °C], [0.19, 2.10 °C], [-1.5, 3.56 °C], from EUMETSAT IASI L-2 product, ERA5, and SEVIRI. When compared to ground station data, we found that all datasets did not achieve the needed accuracy at several months of the year, and better results were achieved at nighttime. Therefore, comparison with ground-based measurements should be done with care to achieve the ±2 °C accuracy needed, by choosing, for example, a validation site near the station location. On average, this accuracy is achieved, in particular at night, leading to the ability to construct a robust Tskin dataset suitable for Tskin long-term spatio-temporal variability and trend analysis. © 2020 by the authors.
BibTeX: @article{Safieddine2020, author = {Safieddine, Sarah and Parracho, Ana Claudia and George, Maya and Aires, Filipe and Pellet, Victor and Clarisse, Lieven and Whitburn, Simon and Lezeaux, Olivier and Thépaut, Jean-Noël and Hersbach, Hans and Radnoti, Gabor and Goettsche, Frank and Martin, Maria and Doutriaux-Boucher, Marie and Coppens, Dorothée and August, Thomas and Zhou, Daniel K. and Clerbaux, Cathy}, title = {Artificial neural networks to retrieve land and sea skin temperature from IASI}, journal = {Remote Sensing}, year = {2020}, volume = {12}, number = {17}, note = {All Open Access, Gold Open Access}, doi = {10.3390/RS12172777} }
Schiffmann S, Filippin L, Baye D and Godefroid M (2020), "POLALMM: A program to compute polarizabilities for nominal one-electron systems using the Lagrange-mesh method", Computer Physics Communications. Vol. 256 [Abstract] [BibTeX] [DOI]
Abstract: We present a program to compute polarizabilities of nominal one-electron systems using the Lagrange-mesh method (LMM) (Baye, 2015), that was used by Filippin et al., (2018). A semiempirical-core-potential approach is implemented, ultimately solving a Dirac-like equation by diagonalizing the corresponding Hamiltonian matrix. In order to build the core potential, the core orbitals are obtained from independent calculations using the GRASP2018 package (Fischer et al., 2019). Therefore we provide an easy-to-use interface between the GRASP2018 package and the LMM complete finite basis, allowing to switch easily from one one-electron basis to the other. Program summary: Program Title: POLALMM CPC Library link to program files: http://dx.doi.org/10.17632/6mw5gdwfkt.1 Licensing provisions: MIT license Programming language: Fortran90 Nature of problem: Determination of the dipole and quadrupole polarizabilities. Solution method: We combine a semiempirical-core-potential approach with the numerical Lagrange-mesh method to solve a Dirac-like one-electron equation [2]. The building of the core potential requires the prior knowledge of core orbitals provided by GRASP [3]. Two free parameters are optimized by fitting the computed single-electron valence energies to their experimental reference value. References: [1] The Lagrange-mesh method, D. Baye, Phys. Rep. 565 (2015) 1-107 [2] Relativistic semiempirical-core-potential calculations in Ca+, Ba+ and Sr+ ions on Lagrange meshes, L. Filippin, S. Schiffmann, J. Dohet-Eraly, D. Baye and M. Godefroid, Phys. Rev. A 97 (2018) 012506 [3] GRASP2018 - A Fortran 95 version of the General Relativistic Atomic Structure Package, C. Froese Fischer, G. Gaigalas, P. Jönsson and J. Bieroń, Comput. Phys. Commun. 237 (2019) 184-187 © 2020 Elsevier B.V.
BibTeX: @article{Schiffmann2020, author = {Schiffmann, Sacha and Filippin, Livio and Baye, Daniel and Godefroid, Michel}, title = {POLALMM: A program to compute polarizabilities for nominal one-electron systems using the Lagrange-mesh method}, journal = {Computer Physics Communications}, year = {2020}, volume = {256}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.cpc.2020.107452} }
Schiffmann S, Godefroid M, Ekman J, Jönsson P and Fischer CF (2020), "Natural orbitals in multiconfiguration calculations of hyperfine-structure parameters", Physical Review A. Vol. 101(6) [Abstract] [BibTeX] [DOI]
Abstract: We are reinvestigating the hyperfine structure of sodium using a fully relativistic multiconfiguration approach. In the fully relativistic approach, the computational strategy somewhat differs from the original nonrelativistic counterpart used by P. Jönsson, Phys. Rev. A 53, 4021 (1996)PLRAAN1050-294710.1103/PhysRevA.53.4021. Numerical instabilities force us to use a layer-by-layer approach that has some broad unexpected effects. Core correlation is found to be significant and therefore should be described in an adequate orbital basis. The natural-orbital basis provides an interesting alternative to the orbital basis from the layer-by-layer approach, allowing us to overcome some deficits of the latter, giving rise to magnetic dipole hyperfine structure constant values, in excellent agreement with observations. Effort is made to assess the reliability of the natural-orbital bases and to illustrate their efficiency. © 2020 American Physical Society
BibTeX: @article{Schiffmann2020a, author = {Schiffmann, Sacha and Godefroid, Michel and Ekman, Jörgen and Jönsson, Per and Fischer, Charlotte Froese}, title = {Natural orbitals in multiconfiguration calculations of hyperfine-structure parameters}, journal = {Physical Review A}, year = {2020}, volume = {101}, number = {6}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.101.062510} }
Song C, Wang K, Del Zanna G, Jönsson P, Si R, Godefroid M, Gaigalas G, Radžiūtė L, Rynkun P, Zhao X, Yan J and Chen C (2020), "Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: N = 4 Levels in P-like Ions from Mn Xi to Ni XIV", Astrophysical Journal, Supplement Series. Vol. 247(2) [Abstract] [BibTeX] [DOI]
Abstract: Using the multiconfiguration Dirac-Hartree-Fock and the relativistic configuration interaction methods, a consistent set of transition energies and radiative transition data for the lowest 546 (623, 701, and 745) states of the 3p43, 3s3p23d2, 3s3p33, 3s3p4, 3s23d33, 3s23p23d, 3s23p24d, 3s23p24s, 3p33d2, 3p5, 3s3p3d3, 3s3p33d, 3s3p34s, 3s23p3d2, 3s23p24p, and 3s23p3 configurations in Mn xi (Fe xii, Co xiii, and Ni xiv) is provided. The comparison between calculated excitation energies for the n = 4 states and available experimental values for Fe xii indicate that the calculations are highly accurate, with uncertainties of only a few hundred cm-1. Lines from these states are prominent in the soft X-rays. With the present calculations, several recent new identifications are confirmed. Other identifications involving 3p24d levels in Fe xii that were found to be questionable are discussed and a few new assignments are recommended. As some n = 4 states of the other ions also show large discrepancies between experimental and calculated energies, we reassess their identification. The present study provides highly accurate atomic data for the n = 4 states of P-like ions of astrophysical interest, for which experimental data are scarce. © 2020. The American Astronomical Society. All rights reserved.
BibTeX: @article{Song2020, author = {Song, C.X. and Wang, K. and Del Zanna, G. and Jönsson, P. and Si, R. and Godefroid, M. and Gaigalas, G. and Radžiūtė, L. and Rynkun, P. and Zhao, X.H. and Yan, J. and Chen, C.Y.}, title = {Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: N = 4 Levels in P-like Ions from Mn Xi to Ni XIV}, journal = {Astrophysical Journal, Supplement Series}, year = {2020}, volume = {247}, number = {2}, note = {All Open Access, Bronze Open Access}, doi = {10.3847/1538-4365/ab7cc6} }
Theys N, Volkamer R, Müller J-F, Zarzana K, Kille N, Clarisse L, De Smedt I, Lerot C, Finkenzeller H, Hendrick F, Koenig T, Lee C, Knote C, Yu H and Van Roozendael M (2020), "Global nitrous acid emissions and levels of regional oxidants enhanced by wildfires", Nature Geoscience. Vol. 13(10), pp. 681 – 686. [Abstract] [BibTeX] [DOI]
Abstract: Nitrous acid (HONO) is a precursor of the hydroxyl radical in the atmosphere, which controls the degradation of greenhouse gases, contributes to photochemical smog and ozone production, and influences air quality. Although biomass burning is known to contribute substantially to global aerosols and reactive gas emissions, pyrogenic contributions to HONO emissions are poorly constrained and often omitted in models. Here we present a global survey of TROPOMI/Sentinel-5 Precursor satellite sounder observations and show that HONO emissions are consistently enhanced in fresh wildfire plumes. Comparing major ecosystems (savanna, grassland, shrubland and tropical and extratropical forests), we found that the enhancement ratios of HONO to nitrogen dioxide varied systematically with biome type, with the lowest in savannas and grasslands and highest in extratropical evergreen forests. Supported by airborne measurements, we demonstrate that previous assessments underestimate pyrogenic HONO emissions by a factor of 2–4 across all ecosystem types. We estimate that HONO emissions are responsible for two-thirds of the hydroxyl radical production in fresh wildfire plumes worldwide and act to accelerate oxidative plume chemistry and ozone production. Our findings suggest that pyrogenic HONO emissions have a substantial impact on atmospheric composition, which enhances regional ozone levels by up to 7 ppbv. © 2020, The Author(s), under exclusive licence to Springer Nature Limited.
BibTeX: @article{Theys2020, author = {Theys, N. and Volkamer, R. and Müller, J.-F. and Zarzana, K.J. and Kille, N. and Clarisse, L. and De Smedt, I. and Lerot, C. and Finkenzeller, H. and Hendrick, F. and Koenig, T.K. and Lee, C.F. and Knote, C. and Yu, H. and Van Roozendael, M.}, title = {Global nitrous acid emissions and levels of regional oxidants enhanced by wildfires}, journal = {Nature Geoscience}, year = {2020}, volume = {13}, number = {10}, pages = {681 – 686}, doi = {10.1038/s41561-020-0637-7} }
Tournigand P-Y, Cigala V, Lasota E, Hammouti M, Clarisse L, Brenot H, Prata F, Kirchengast G, Steiner AK and Biondi R (2020), "A multi-sensor satellite-based archive of the largest SO2volcanic eruptions since 2006", Earth System Science Data. Vol. 12(4), pp. 3139 – 3159. [Abstract] [BibTeX] [DOI]
Abstract: We present a multi-sensor archive collecting spatial and temporal information about volcanic SO2 clouds generated by the 11 largest eruptions of this century. The detection and monitoring of volcanic clouds are an important topic for aviation management, climate issues and weather forecasts. Several studies focusing on single eruptive events exist, but no archive available at the moment combines quantitative data from as many instruments. We archived and collocated the SO2 vertical column density estimations from three different satellite instruments (AIRS, IASI and GOME-2), atmospheric parameters as vertical profiles from the Global Navigation Satellite Systems (GNSS) Radio Occultations (RO), and the cloud-top height and aerosol type from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Additionally, we provide information about the cloud-top height from three different algorithms and the atmospheric anomaly due to the presence of the cloud. The dataset is gathering 206 d of SO2 data, collocated with 44 180 backscatter profiles and 64 764 radio occultation profiles. The modular structure of the archive allows an easy collocation of the datasets according to the users' needs, and the cross-comparison of the datasets shows different consistency of the parameters estimated with different sensors and algorithms, according to the sensitivity and resolution of the instruments. The data described here are published with a DOI at https://doi.org/10.5880/fidgeo.2020.016 (Tournigand et al., 2020a). © 2020 Author(s).
BibTeX: @article{Tournigand2020a, author = {Tournigand, Pierre-Yves and Cigala, Valeria and Lasota, Elzbieta and Hammouti, Mohammed and Clarisse, Lieven and Brenot, Hugues and Prata, Fred and Kirchengast, Gottfried and Steiner, Andrea K. and Biondi, Riccardo}, title = {A multi-sensor satellite-based archive of the largest SO2volcanic eruptions since 2006}, journal = {Earth System Science Data}, year = {2020}, volume = {12}, number = {4}, pages = {3139 – 3159}, note = {All Open Access, Gold Open Access}, doi = {10.5194/essd-12-3139-2020} }
Tournigand P-Y, Cigala V, Prata AJ, Steiner AK, Kirchengast G, Brenot H, Clarisse L and Biondi R (2020), "The 2015 Calbuco Volcanic Cloud Detection Using GNSS Radio Occultation and Satellite Lidar", International Geoscience and Remote Sensing Symposium (IGARSS). , pp. 6834 – 6837. [Abstract] [BibTeX] [DOI]
Abstract: Explosive volcanic eruptions can generate ash and gas clouds rising to the stratosphere and dispersing on a global scale. Such volcanic features are at the origin of many hazards including aircraft engine damages, ash fallouts and health threats. It is thus crucial, to mitigate such hazards, to monitor volcanic clouds dispersion and altitude. In this study, we use the Global Navigation Satellite System (GNSS) Radio Occultation (RO) technique to assess the volcanic cloud altitude resulting from the 2015 Calbuco's eruption. We find volcanic cloud altitude estimations based on RO data in good agreement with the collocated Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) and the Infrared Atmospheric Sounding Interferometer (IASI). The preliminary results of this study confirm that automatized RO profiles processing has great potential in the field of volcanic clouds monitoring. © 2020 IEEE.
BibTeX: @conference{Tournigand2020, author = {Tournigand, Pierre-Yves and Cigala, Valeria and Prata, Alfredo J. and Steiner, Andrea K. and Kirchengast, Gottfried and Brenot, Hugues and Clarisse, Lieven and Biondi, Riccardo}, title = {The 2015 Calbuco Volcanic Cloud Detection Using GNSS Radio Occultation and Satellite Lidar}, journal = {International Geoscience and Remote Sensing Symposium (IGARSS)}, year = {2020}, pages = {6834 – 6837}, doi = {10.1109/IGARSS39084.2020.9323356} }
Turquety S, Menut L, Siour G, Mailler S, Hadji-Lazaro J, George M, Clerbaux C, Hurtmans D and Coheur P-F (2020), "APIFLAME v2.0 biomass burning emissions model: Impact of refined input parameters on atmospheric concentration in Portugal in summer 2016", Geoscientific Model Development. Vol. 13(7), pp. 2981 – 3009. [Abstract] [BibTeX] [DOI]
Abstract: Biomass burning emissions are a major source of trace gases and aerosols. Wildfires being highly variable in time and space, calculating emissions requires a numerical tool able to estimate fluxes at the kilometer scale and with an hourly time step. Here, the APIFLAME model version 2.0 is presented. It is structured to be modular in terms of input databases and processing methods. The main evolution compared to version 1.0 is the possibility of merging burned area and fire radiative power (FRP) satellite observations to modulate the temporal variations of fire emissions and to integrate small fires that may not be detected in the burned area product. Accounting for possible missed detection due to small fire results in an increase in burned area ranging from ∼5% in Africa and Australia to ∼30% in North America on average over the 2013-2017 time period based on the Moderate-Resolution Imaging Spectroradiometer (MODIS) Collection 6 fire products. An illustration for the case of southwestern Europe during the summer of 2016, marked by large wildfires in Portugal, is presented. Emissions calculated using different possible configurations of APIFLAME show a dispersion of 80% on average over the domain during the largest wildfires (8-14 August 2016), which can be considered as an estimate of uncertainty of emissions. The main sources of uncertainty studied, by order of importance, are the emission factors, the calculation of the burned area, and the vegetation attribution. The aerosol (PM10) and carbon monoxide (CO) concentrations simulated with the CHIMERE regional chemistry transport model (CTM) are consistent with observations (good timing for the beginning and end of the events, ±1d for the timing of the peak values) but tend to be overestimated compared to observations at surface stations. On the contrary, vertically integrated concentrations tend to be underestimated compared to satellite observations of total column CO by the Infrared Atmospheric Sounding Interferometer (IASI) instrument and aerosol optical depth (AOD) by MODIS. This underestimate is lower close to the fire region (5%-40% for AOD depending on the configuration and 8%-18% for total CO) but rapidly increases downwind. For all comparisons, better agreement is achieved when emissions are injected higher into the free troposphere using a vertical profile as estimated from observations of aerosol plume height by the Multi-angle Imaging SpectroRadiometer (MISR) satellite instrument (injection up to 4km). Comparisons of aerosol layer heights to observations by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) show that some parts of the plume may still be transported at too low an altitude. The comparisons of the different CTM simulations to observations point to uncertainties not only on emissions (total mass and daily variability) but also on the simulation of their transport with the CTM and mixing with other sources. Considering the uncertainty of the emission injection profile and of the modeling of the transport of these dense plumes, it is difficult to fully validate emissions through comparisons between model simulations and atmospheric observations. © Author(s) 2020.
BibTeX: @article{Turquety2020, author = {Turquety, Solène and Menut, Laurent and Siour, Guillaume and Mailler, Sylvain and Hadji-Lazaro, Juliette and George, Maya and Clerbaux, Cathy and Hurtmans, Daniel and Coheur, Pierre-François}, title = {APIFLAME v2.0 biomass burning emissions model: Impact of refined input parameters on atmospheric concentration in Portugal in summer 2016}, journal = {Geoscientific Model Development}, year = {2020}, volume = {13}, number = {7}, pages = {2981 – 3009}, note = {All Open Access, Gold Open Access}, doi = {10.5194/gmd-13-2981-2020} }
Urbain X, De Ruette N, Dochain A, Launoy T, Nascimento R, Kaminska M, Stockett M, Loreau J, Liévin J, Vaeck N, Thomas R, Schmidt H and Cederquist H (2020), "Merged beam studies of mutual neutralization at subthermal collision energies", Journal of Physics: Conference Series. Vol. 1412(6) [Abstract] [BibTeX] [DOI]
Abstract: We have measured the kinetic energy distributions for the mutual neutralization of a large ensemble of atomic anions and cations. Ions are accelerated to equal velocities in a merged beam setup, enabling measurements at collision energies as low as 5 meV. Three-dimensional momentum imaging is performed with two position sensitive detectors located several meters downstream from the few centimeter long region where the beams overlap. An unprecedented resolution in the kinetic energy release (KER) spectra allows us to identify the states of both reactants and products down to their fine structure. Knowing the angular distribution of the products in the laboratory and center-of-mass frame, allows for total, partial, and differential cross sections to be retrieved. © Published under licence by IOP Publishing Ltd.
BibTeX: @conference{Urbain2020, author = {Urbain, X. and De Ruette, N. and Dochain, A. and Launoy, T. and Nascimento, R.F. and Kaminska, M. and Stockett, M.H. and Loreau, J. and Liévin, J. and Vaeck, N. and Thomas, R.D. and Schmidt, H.T. and Cederquist, H.}, title = {Merged beam studies of mutual neutralization at subthermal collision energies}, journal = {Journal of Physics: Conference Series}, year = {2020}, volume = {1412}, number = {6}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/1412/6/062009} }
Van Gent J, Brenot H, Theys N, Clarisse L, Wilson S, Clarkson R and Van Roozendael M (2020), "Prototyping of a Multi-Hazard Early Warning System for Aviation and Development of NRT Alert Products within the EUNADICS-AV and OPAS Projects", International Geoscience and Remote Sensing Symposium (IGARSS). , pp. 6859 – 6862. [Abstract] [BibTeX] [DOI]
Abstract: The eruption of the Eyjafjöll volcano in 2010 has shown that aviation can be very vulnerable to natural disasters. Although such events are rare, the consequences for aviation can be enormous, on both the economic and human scale. Nowadays many techniques are available to measure hazards to aviation, yet there is still no Europe wide warning system for this kind of disasters. The EUNADICS-AV project aimed at filling this gap, by providing fast information to the aviation community. In addition, the ongoing Engage-KTN OPAS projects involves the development of an algorithm for the retrieval of the height of sulfur dioxide (SO2) plumes, a proxy for the presence of volcanic ash. This paper reports on the major contributions to these two projects: the development of an early warning system, the SO2 layer height developments, and the creation of standardized alert products. © 2020 IEEE.
BibTeX: @conference{VanGent2020, author = {Van Gent, Jeroen and Brenot, Hugues and Theys, Nicolas and Clarisse, Lieven and Wilson, Scott and Clarkson, Rory and Van Roozendael, Michel}, title = {Prototyping of a Multi-Hazard Early Warning System for Aviation and Development of NRT Alert Products within the EUNADICS-AV and OPAS Projects}, journal = {International Geoscience and Remote Sensing Symposium (IGARSS)}, year = {2020}, pages = {6859 – 6862}, doi = {10.1109/IGARSS39084.2020.9324335} }
Viatte C, Clerbaux C, Maes C, Daniel P, Garello R, Safieddine S and Ardhuin F (2020), "Air Pollution and Sea Pollution Seen from Space", Surveys in Geophysics. Vol. 41(6), pp. 1583 – 1609. [Abstract] [BibTeX] [DOI]
Abstract: Air pollution and sea pollution are both impacting human health and all the natural environments on Earth. These complex interactions in the biosphere are becoming better known and understood. Major progress has been made in recent past years for understanding their societal and environmental impacts, thanks to remote sensors placed aboard satellites. This paper describes the state of the art of what is known about air pollution and focuses on specific aspects of marine pollution, which all benefit from the improved knowledge of the small-scale eddy field in the oceans. Examples of recent findings are shown, based on the global observing system (both remote and in situ) with standardized protocols for monitoring emerging environmental threats at the global scale. © 2020, The Author(s).
BibTeX: @article{Viatte2020, author = {Viatte, Camille and Clerbaux, Cathy and Maes, Christophe and Daniel, Pierre and Garello, René and Safieddine, Sarah and Ardhuin, Fabrice}, title = {Air Pollution and Sea Pollution Seen from Space}, journal = {Surveys in Geophysics}, year = {2020}, volume = {41}, number = {6}, pages = {1583 – 1609}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1007/s10712-020-09599-0} }
Viatte C, Wang T, Van Damme M, Dammers E, Meleux F, Clarisse L, Shephard MW, Whitburn S, François Coheur P, Cady-Pereira KE and Clerbaux C (2020), "Atmospheric ammonia variability and link with particulate matter formation: A case study over the Paris area", Atmospheric Chemistry and Physics. Vol. 20(1), pp. 577 – 596. [Abstract] [BibTeX] [DOI]
Abstract: The Paris megacity experiences frequent particulate matter (i.e.PM2:5, particulate matter with a diameter less than 2.5 μm) pollution episodes in spring (March.April). At this time of the year, large numbers of the particles consist of ammonium sulfate and nitrate which are formed from ammonia (NH3) released during fertilizer spreading practices and transported from the surrounding areas to Paris. There is still limited knowledge of the emission sources around Paris, their magnitude, and their seasonality. Using space-borne NH3 observation records of 10 years (2008.2017) and 5 years (2013.2017) provided by the Infrared Atmospheric Sounding Interferometer (IASI) and the Cross-Track Infrared Sounder (CrIS) instrument, regional patterns of NH3 variabilities (seasonal and interannual) are derived. Observations reveal identical high seasonal variability with three major NH3 hotspots found from March to August. The high interannual variability is discussed with respect to atmospheric total precipitation and temperature. A detailed analysis of the seasonal cycle is performed using both IASI and CrIS instrument data, together with outputs from the CHIMERE atmospheric model. For 2014 and 2015, the CHIMERE model shows coefficients of determination of 0.58 and 0.18 when compared to IASI and CrIS, respectively. With respect to spatial variability, the CHIMERE monthly NH3 concentrations in spring show a slight underrepresentation over Belgium and the United Kingdom and an overrepresentation in agricultural areas in the French Brittany.Pays de la Loire and Plateau du Jura region, as well as in northern Switzerland. In addition, PM2.5 concentrations derived from the CHIMERE model have been evaluated against surface measurements from the Airparif network over Paris, with which agreement was found (r2 = 0.56) with however an underestimation during spring pollution events. Using HYSPLIT cluster analysis of back trajectories, we show that NH3 total columns measured in spring over Paris are enhanced when air masses originate from the north-east (e.g. the Netherlands and Belgium), highlighting the importance of long-range transport in the NH3 budget over Paris. Variability in NH3 in the north-east region is likely to impact NH3 concentrations in the Parisian region since the crosscorrelation function is above 0.3 (at lag=0 and 1 d). Finally, we quantify the key meteorological parameters driving the specific conditions important for the formation of PM2.5 from NH3 in the Ile-de-France region in spring. Datadriven results based on surface PM2.5 measurements from the Airparif network and IASI NH3 measurements show that a combination of the factors such as a low boundary layer of ∼ 500 m, a relatively low temperature of 5 °C, a high relative humidity of 70 %, and wind from the north-east contributes to a positive PM2.5 and NH3 correlation. © 2020 Author(s).
BibTeX: @article{Viatte2020a, author = {Viatte, Camille and Wang, Tianze and Van Damme, Martin and Dammers, Enrico and Meleux, Frederik and Clarisse, Lieven and Shephard, Mark W. and Whitburn, Simon and François Coheur, Pierre and Cady-Pereira, Karen E. and Clerbaux, Cathy}, title = {Atmospheric ammonia variability and link with particulate matter formation: A case study over the Paris area}, journal = {Atmospheric Chemistry and Physics}, year = {2020}, volume = {20}, number = {1}, pages = {577 – 596}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-20-577-2020} }
Wang K, Jönsson P, Del Zanna G, Godefroid M, Chen Z, Chen C and Yan J (2020), "Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: Cl-like Ions from Cr viii to Zn xiv", Astrophysical Journal, Supplement Series. Vol. 246(1) [Abstract] [BibTeX] [DOI]
Abstract: We use the multiconfiguration Dirac-Hartree-Fock (MCDHF) method combined with the relativistic configuration interaction approach (GRASP2K) to provide a consistent set of transition energies and radiative transition data for the lower n = 3 states in all Cl-like ions of astrophysical importance, from Cr viii to Zn xiv. We also provide excitation energies calculated for Fe x using the many-body perturbation theory (MBPT, implemented within FAC). The comparison of the present MCDHF results with MBPT and with the available experimental energies indicates that the theoretical excitation energies are highly accurate, with uncertainties of only a few hundred cm-1. Detailed comparisons for Fe x and Ni xii highlight discrepancies in the experimental energies found in the literature. Several new identifications are proposed. © 2019. The American Astronomical Society. All rights reserved.
BibTeX: @article{Wang2020, author = {Wang, K. and Jönsson, P. and Del Zanna, G. and Godefroid, M. and Chen, Z.B. and Chen, C.Y. and Yan, J.}, title = {Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: Cl-like Ions from Cr viii to Zn xiv}, journal = {Astrophysical Journal, Supplement Series}, year = {2020}, volume = {246}, number = {1}, note = {All Open Access, Bronze Open Access}, doi = {10.3847/1538-4365/ab5530} }
Whitburn S, Clarisse L, Bauduin S, George M, Hurtmans D, Safieddine S, Coheur PF and Clerbaux C (2020), "Spectrally resolved fluxes from IASI data: Retrieval algorithm for clear-sky measurements", Journal of Climate. Vol. 33(16), pp. 6971 – 6988. [Abstract] [BibTeX] [DOI]
Abstract: Space-based measurements of the outgoing longwave radiation (OLR) are essential for the study of Earth's climate system. While the CERES instrument provides accurate measurements of this quantity, its measurements are not spectrally resolved. Here we present a high-resolution OLR product (sampled at 0.25 cm21), derived from measurements of the IASI satellite sounder. The applied methodology relies on precalculated angular distribution models (ADMs). These are usually calculated for tens to hundreds of different scene types (characterized by surface and atmosphere parameters). To guarantee accurate results in the range 645-2300 cm21 covered by IASI, we constructed ADMs for over 140 000 scenes. These were selected from one year of CAMS reanalysis data. A dissimilarity-based selection algorithm was applied to choose scenes as different from each other as possible, thereby maximizing the performance on real data, while keeping the number of scenes manageable. A comparison of the IASI OLR integrated over the 645-2300 cm21 range was performed with the longwave broadband OLR products from CERES and the AIRS instrument. The latter are systematically higher due to the contribution of the far infrared to the total IR spectral range, but as expected exhibit generally high spatial correlations with the IASI OLR, except for some areas in the tropical region. We also compared the IASI OLR against the spectrally resolved OLR derived from AIRS. A good agreement was found above 1200 cm21 while AIRS OLR appeared to be systematically higher in the atmospheric window region, likely related to differences in overpass time or to the use of a different cloud detection algorithm. © 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).
BibTeX: @article{Whitburn2020, author = {Whitburn, Simon and Clarisse, Lieven and Bauduin, Sophie and George, Maya and Hurtmans, Daniel and Safieddine, Sarah and Coheur, Pierre François and Clerbaux, Cathy}, title = {Spectrally resolved fluxes from IASI data: Retrieval algorithm for clear-sky measurements}, journal = {Journal of Climate}, year = {2020}, volume = {33}, number = {16}, pages = {6971 – 6988}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1175/JCLI-D-19-0523.1} }
Yordanov DT, Rodríguez LV, Balabanski DL, Bieroń J, Bissell ML, Blaum K, Cheal B, Ekman J, Gaigalas G, Garcia Ruiz RF, Georgiev G, Gins W, Godefroid MR, Gorges C, Harman Z, Heylen H, Jönsson P, Kanellakopoulos A, Kaufmann S, Keitel CH, Lagaki V, Lechner S, Maaß B, Malbrunot-Ettenauer S, Nazarewicz W, Neugart R, Neyens G, Nörtershäuser W, Oreshkina NS, Papoulia A, Pyykkö P, Reinhard P-G, Sailer S, Sánchez R, Schiffmann S, Schmidt S, Wehner L, Wraith C, Xie L, Xu Z and Yang X (2020), "Structural trends in atomic nuclei from laser spectroscopy of tin", Communications Physics. Vol. 3(1) [Abstract] [BibTeX] [DOI]
Abstract: Tin is the chemical element with the largest number of stable isotopes. Its complete proton shell, comparable with the closed electron shells in the chemically inert noble gases, is not a mere precursor to extended stability; since the protons carry the nuclear charge, their spatial arrangement also drives the nuclear electromagnetism. We report high-precision measurements of the electromagnetic moments and isomeric differences in charge radii between the lowest 1/2+, 3/2+, and 11/2− states in 117–131Sn, obtained by collinear laser spectroscopy. Supported by state-of-the-art atomic-structure calculations, the data accurately show a considerable attenuation of the quadrupole moments in the closed-shell tin isotopes relative to those of cadmium, with two protons less. Linear and quadratic mass-dependent trends are observed. While microscopic density functional theory explains the global behaviour of the measured quantities, interpretation of the local patterns demands higher-fidelity modelling. © 2020, The Author(s).
BibTeX: @article{Yordanov2020, author = {Yordanov, Deyan T. and Rodríguez, Liss V. and Balabanski, Dimiter L. and Bieroń, Jacek and Bissell, Mark L. and Blaum, Klaus and Cheal, Bradley and Ekman, Jörgen and Gaigalas, Gediminas and Garcia Ruiz, Ronald F. and Georgiev, Georgi and Gins, Wouter and Godefroid, Michel R. and Gorges, Christian and Harman, Zoltán and Heylen, Hanne and Jönsson, Per and Kanellakopoulos, Anastasios and Kaufmann, Simon and Keitel, Christoph H. and Lagaki, Varvara and Lechner, Simon and Maaß, Bernhard and Malbrunot-Ettenauer, Stephan and Nazarewicz, Witold and Neugart, Rainer and Neyens, Gerda and Nörtershäuser, Wilfried and Oreshkina, Natalia S. and Papoulia, Asimina and Pyykkö, Pekka and Reinhard, Paul-Gerhard and Sailer, Stefan and Sánchez, Rodolfo and Schiffmann, Sacha and Schmidt, Stefan and Wehner, Laura and Wraith, Calvin and Xie, Liang and Xu, Zhengyu and Yang, Xiaofei}, title = {Structural trends in atomic nuclei from laser spectroscopy of tin}, journal = {Communications Physics}, year = {2020}, volume = {3}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.1038/s42005-020-0348-9} }
Zhang CY, Wang K, Godefroid M, Jönsson P, Si R and Chen CY (2020), "Benchmarking calculations with spectroscopic accuracy of excitation energies and wavelengths in sulfur-like tungsten", Physical Review A. Vol. 101(3) [Abstract] [BibTeX] [DOI]
Abstract: Atomic properties of S-like W are evaluated through a state-of-the-art method, namely, the multiconfiguration Dirac-Hartree-Fock method combined with the relativistic configuration-interaction approach. The level energies, wavelengths, and transition parameters involving the 88 lowest levels of W58+ (W lix) are calculated. We discuss in detail the relative importance of the valence-and core-valence electron correlation effects, the Breit interaction, the higher-order retardation correction beyond the Breit interaction through the transverse photon interaction, and the quantum electrodynamical corrections. The present level energies are highly accurate, with uncertainties close to what can be achieved from spectroscopy. As such, they provide benchmark tests for other theoretical calculations of S-like W and should assist the spectroscopists in their assignment and identification of observed lines in complex spectra. © 2020 American Physical Society.
BibTeX: @article{Zhang2020, author = {Zhang, Chun Yu and Wang, Kai and Godefroid, Michel and Jönsson, Per and Si, Ran and Chen, Chong Yang}, title = {Benchmarking calculations with spectroscopic accuracy of excitation energies and wavelengths in sulfur-like tungsten}, journal = {Physical Review A}, year = {2020}, volume = {101}, number = {3}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.101.032509} }
Zhang X, Jones D, Keller M, Jiang Z, Bourassa AE, Degenstein D and Clerbaux C (2020), "Global CO Emission Estimates Inferred from Assimilation of MOPITT CO, Together with Observations of O3, NO2, HNO3, and HCHO", Springer Proceedings in Complexity. , pp. 219 – 224. [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric carbon monoxide (CO) emissions estimated from inverse modeling analyses exhibit large uncertainties, due, in part, to discrepancies in the tropospheric chemistry in atmospheric models. We attempt to reduce the uncertainties in CO emission estimates by constraining the modeled abundance of ozone (O3), nitrogen dioxide (NO2), nitric acid (HNO3), and formaldehyde (HCHO), which are constituents that play a key role in tropospheric chemistry. Using the GEOS-Chem four-dimensional variational (4D-Var) data assimilation system, we estimate CO emissions by assimilating observations of CO from the Measurement of Pollution In the Troposphere (MOPITT) and the Infrared Atmospheric Sounding Interferometer (IASI), together with observations of O3 from the Optical Spectrograph and InfraRed Imager System (OSIRIS) and IASI, NO2 and HCHO from the Ozone Monitoring Instrument (OMI), and HNO3 from the Microwave Limb Sounder (MLS). Although our focus is on quantifying CO emission estimates, we also infer surface emissions of nitrogen oxides (NOx = NO + NO2) and isoprene. Our results reveal that this multiple species chemical data assimilation produces a chemical consistent state that effectively adjusts the CO–O3–OH coupling in the model. The O3-induced changes in OH are particularly large in the tropics. We show that the analysis results in a tropospheric chemical state that is better constrained. Our experiments also evaluate the inferred CO emission estimates from major anthropogenic, biomass burning and biogenic sources. © Springer Nature Switzerland AG 2020.
BibTeX: @conference{Zhang2020a, author = {Zhang, Xuesong and Jones, Dylan and Keller, Martin and Jiang, Zhe and Bourassa, Adam E. and Degenstein, D.A. and Clerbaux, Cathy}, title = {Global CO Emission Estimates Inferred from Assimilation of MOPITT CO, Together with Observations of O3, NO2, HNO3, and HCHO}, journal = {Springer Proceedings in Complexity}, year = {2020}, pages = {219 – 224}, doi = {10.1007/978-3-030-22055-6_34} }
Aerts A and Brown A (2019), "A revised nuclear quadrupole moment for aluminum: Theoretical nuclear quadrupole coupling constants of aluminum compounds", Journal of Chemical Physics. Vol. 150(22) [Abstract] [BibTeX] [DOI]
Abstract: The nuclear quadrupole moment of aluminum (27Al) has been re-evaluated by determining the electric field gradients at this nucleus for AlF and AlCl using the coupled cluster method with single, double, and perturbative triple excitations [CCSD(T)]/aug-cc-pwCVXZ (X = T and Q) accounting for both vibrational averaging and core-core/core-valence electron correlation and then comparing to the experimentally measured nuclear quadrupole coupling constants (NQCCs). The new recommended value is Q(27Al) = 148.2 ± 0.5 mb, which can be compared to the previous value of 146.6 ± 1 mb. Using the new value of the nuclear quadrupole moment, the accuracy is assessed for several computational approaches [i.e., Hartree-Fock, Møller-Plesset perturbation theory to the second order, quadratic configuration interaction with single and double excitations, CCSD, CCSD(T), and density functional theory (DFT) with the B3LYP, PBE0, and M06-2X functionals] and basis sets (the aug-cc-pVXZ and aug-cc-pwCVXZ families) for determining the nuclear quadruple coupling constants for AlCN, AlNC, AlSH, AlOH, and AlCCH, where experimental measurements are available. From the results at equilibrium geometries of the polyatomic molecules, it has been determined that (i) the CCSD(T)/aug-cc-pwCVXZ approach is needed to obtain results within 4% of the experimental measurements, (ii) typical DFT values are only within 10%-15% of the experimental measurements, and (iii) the aug-cc-pVXZ family of basis sets is not recommended for computing the electric field gradients at aluminum. The present results also suggest that the NQCC for AlOH should be remeasured. Using the recommended CCSD(T)/aug-cc-pwCVXZ approach, the equilibrium geometries and corresponding NQCCs for AlCH3 and AlCCCN were determined, and the NQCCs are in excellent agreement with previously reported experimental values. © 2019 Author(s).
BibTeX: @article{Aerts2019, author = {Aerts, Antoine and Brown, Alex}, title = {A revised nuclear quadrupole moment for aluminum: Theoretical nuclear quadrupole coupling constants of aluminum compounds}, journal = {Journal of Chemical Physics}, year = {2019}, volume = {150}, number = {22}, doi = {10.1063/1.5097151} }
Aoki S, Vandaele AC, Daerden F, Villanueva G, Liuzzi G, Thomas I, Erwin J, Trompet L, Robert S, Neary L, Viscardy S, Clancy R, Smith M, Lopez-Valverde M, Hill B, Ristic B, Patel M, Bellucci G, López-Moreno J-J, Alonso-Rodrigo G, Altieri F, Bauduin S, Bolsée D, Carrozzo G, Cloutis E, Crismani M, Da Pieve F, D’aversa E, Depiesse C, Etiope G, Fedorova AA, Funke B, Fussen D, Garcia-Comas M, Geminale A, Gérard J-C, Giuranna M, Gkouvelis L, Gonzalez-Galindo F, Holmes J, Hubert B, Ignatiev NI, Kaminski J, Karatekin O, Kasaba Y, Kass D, Kleinböhl A, Lanciano O, Lefèvre F, Lewis S, López-Puertas M, Mahieux A, Mason J, Mege D, Mumma MJ, Nakagawa H, Neefs E, Novak RE, Oliva F, Piccialli A, Renotte E, Ritter B, Schmidt F, Schneider N, Sindoni G, Teanby NA, Thiemann E, Trokhimovskiy A, Auwera JV, Whiteway J, Wilquet V, Willame Y, Wolff MJ, Wolkenberg P, Yelle R, Del Moral Beatriz A, Barzin P, Beeckman B, Benmoussa A, Berkenbosch S, Biondi D, Bonnewijn S, Candini GP, Clairquin R, Cubas J, Giordanengo B, Gissot S, Gomez A, Hathi B, Jeronimo Zafra J, Leese M, Maes J, Mazy E, Mazzoli A, Meseguer J, Morales R, Orban A, Pastor-Morales M, Perez-Grande I, Queirolo C, Rodriguez Gomez J, Saggin B, Samain V, Sanz Andres A, Sanz R, Simar J-F and Thibert T (2019), "Water Vapor Vertical Profiles on Mars in Dust Storms Observed by TGO/NOMAD", Journal of Geophysical Research: Planets. Vol. 124(12), pp. 3482 – 3497. [Abstract] [BibTeX] [DOI]
Abstract: It has been suggested that dust storms efficiently transport water vapor from the near-surface to the middle atmosphere on Mars. Knowledge of the water vapor vertical profile during dust storms is important to understand water escape. During Martian Year 34, two dust storms occurred on Mars: a global dust storm (June to mid-September 2018) and a regional storm (January 2019). Here we present water vapor vertical profiles in the periods of the two dust storms (Ls = 162–260° and Ls = 298–345°) from the solar occultation measurements by Nadir and Occultation for Mars Discovery (NOMAD) onboard ExoMars Trace Gas Orbiter (TGO). We show a significant increase of water vapor abundance in the middle atmosphere (40–100 km) during the global dust storm. The water enhancement rapidly occurs following the onset of the storm (Ls 190°) and has a peak at the most active period (Ls 200°). Water vapor reaches very high altitudes (up to 100 km) with a volume mixing ratio of 50 ppm. The water vapor abundance in the middle atmosphere shows high values consistently at 60°S-60°N at the growth phase of the dust storm (Ls = 195°–220°), and peaks at latitudes greater than 60°S at the decay phase (Ls = 220°–260°). This is explained by the seasonal change of meridional circulation: from equinoctial Hadley circulation (two cells) to the solstitial one (a single pole-to-pole cell). We also find a conspicuous increase of water vapor density in the middle atmosphere at the period of the regional dust storm (Ls = 322–327°), in particular at latitudes greater than 60°S. ©2019. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Aoki2019, author = {Aoki, S. and Vandaele, Ann Carine and Daerden, F. and Villanueva, G.L. and Liuzzi, G. and Thomas, I.R. and Erwin, J.T. and Trompet, L. and Robert, S. and Neary, L. and Viscardy, S. and Clancy, R.T. and Smith, M.D. and Lopez-Valverde, M.A. and Hill, B. and Ristic, B. and Patel, M.R. and Bellucci, G. and López-Moreno, J.-J. and Alonso-Rodrigo, Gustavo and Altieri, Francesca and Bauduin, Sophie and Bolsée, David and Carrozzo, Giacomo and Cloutis, Edward and Crismani, Matteo and Da Pieve, Fabiana and D’aversa, Emiliano and Depiesse, Cédric and Etiope, Giuseppe and Fedorova, Anna A. and Funke, Bernd and Fussen, Didier and Garcia-Comas, Maia and Geminale, Anna and Gérard, Jean-Claude and Giuranna, Marco and Gkouvelis, Leo and Gonzalez-Galindo, Francisco and Holmes, James and Hubert, Benoît and Ignatiev, Nicolay I. and Kaminski, Jacek and Karatekin, Ozgur and Kasaba, Yasumasa and Kass, David and Kleinböhl, Armin and Lanciano, Orietta and Lefèvre, Franck and Lewis, Stephen and López-Puertas, Manuel and Mahieux, Arnaud and Mason, Jon and Mege, Daniel and Mumma, Michael J. and Nakagawa, Hiromu and Neefs, Eddy and Novak, Robert E. and Oliva, Fabrizio and Piccialli, Arianna and Renotte, Etienne and Ritter, Birgit and Schmidt, Frédéric and Schneider, Nick and Sindoni, Giuseppe and Teanby, Nicholas A. and Thiemann, Ed and Trokhimovskiy, Alexander and Auwera, Jean Vander and Whiteway, James and Wilquet, Valerie and Willame, Yannick and Wolff, Michael J. and Wolkenberg, Paulina and Yelle, Roger and Del Moral Beatriz, Aparicio and Barzin, Pascal and Beeckman, Bram and Benmoussa, Ali and Berkenbosch, Sophie and Biondi, David and Bonnewijn, Sabrina and Candini, Gian Paolo and Clairquin, Roland and Cubas, Javier and Giordanengo, Boris and Gissot, Samuel and Gomez, Alejandro and Hathi, Brijen and Jeronimo Zafra, Jose and Leese, Mark and Maes, Jeroen and Mazy, Emmanuel and Mazzoli, Alexandra and Meseguer, Jose and Morales, Rafael and Orban, Anne and Pastor-Morales, M. and Perez-Grande, Isabel and Queirolo, Claudio and Rodriguez Gomez, Julio and Saggin, Bortolino and Samain, Valérie and Sanz Andres, Angel and Sanz, Rosario and Simar, Juan-Felipe and Thibert, Tanguy}, title = {Water Vapor Vertical Profiles on Mars in Dust Storms Observed by TGO/NOMAD}, journal = {Journal of Geophysical Research: Planets}, year = {2019}, volume = {124}, number = {12}, pages = {3482 – 3497}, note = {All Open Access, Green Open Access}, doi = {10.1029/2019JE006109} }
Attafi Y, Galalou S, Kwabia Tchana F, Vander Auwera J, Ben Hassen A, Aroui H, Perrin A, Manceron L and Doizi D (2019), "Oxygen broadening and shift coefficients in the ν6 band of methyl iodide (12CH3I) at room temperature", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 239 [Abstract] [BibTeX] [DOI]
Abstract: In this study we report the high-resolution measurements of oxygen pressure- broadening and pressure-induced shift coefficients for rovibrational transitions in the ν6 band of methyl iodide (12CH3I), centered at 892.918 cm–1. The results were obtained by analyzing fourteen high-resolution room temperature laboratory absorption spectra with a mono-spectrum non-linear least squares fitting of Voigt profiles. The data were recorded with the Bruker IF125HR Fourier transform spectrometer located at the LISA facility in Créteil, using a White type cell with a path length of 564.9 cm and total pressures up to 295 hPa. The measured oxygen-broadening coefficients range from 0.0648 to 0.1207 cm–1atm–1 at 295 K. The measured shift coefficients were all negative and varied between −0.00044 and −0.04984 cm–1atm–1. The average accuracy on the measured O2-broadening coefficients and pressure shift coefficients was estimated to about 4% and 11%, respectively. The O2-broadening coefficients obtained in the present work are compared with values reported in the literature for the ν5 band of CH3I, showing a satisfactory agreement with an average difference of about 8%. The shift coefficients are compared with values reported in the literature for the ν6 band of CH3F-Ar system, exhibiting the same order of magnitude and trend. The J and K rotational dependences of the O2-broadening coefficients have been observed and the latter modeled using empirical polynomial expansions. On average, the empirical expression reproduces the measured O2-broadening coefficients to within 3%. Using the measured broadening coefficients of the CH3I-O2 and CH3I-N2 [Attafi et al., J Quant Spectrosc Radiat Transf 231 (2019) 1–8] systems, we produced CH3I-air broadening coefficients, ranging from 0.0783 to 0.1385 cm–1atm–1 at 295 K. The present results and the data already available should be valuable not only for predicting the CH3I infrared spectrum in the atmosphere, but also for verifying theoretical calculations of pressure-broadening and pressure-shift coefficients in the ν6 region of methyl iodide spectra. © 2019
BibTeX: @article{Attafi2019, author = {Attafi, Y. and Galalou, S. and Kwabia Tchana, F. and Vander Auwera, J. and Ben Hassen, A. and Aroui, H. and Perrin, A. and Manceron, L. and Doizi, D.}, title = {Oxygen broadening and shift coefficients in the ν6 band of methyl iodide (12CH3I) at room temperature}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2019}, volume = {239}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jqsrt.2019.106679} }
Boichu M, Favez O, Riffault V, Petit J-E, Zhang Y, Brogniez C, Sciare J, Chiapello I, Clarisse L, Zhang S, Pujol-Söhne N, Tison E, Delbarre H and Goloub P (2019), "Large-scale particulate air pollution and chemical fingerprint of volcanic sulfate aerosols from the 2014-2015 Holuhraun flood lava eruption of Bárdarbunga volcano (Iceland)", Atmospheric Chemistry and Physics. Vol. 19(22), pp. 14253 – 14287. [Abstract] [BibTeX] [DOI]
Abstract: Volcanic sulfate aerosols play a key role in air quality and climate. However, the rate of oxidation of sulfur dioxide (SO2) precursor gas to sulfate aerosols (SO2-4 ) in volcanic plumes is poorly known, especially in the troposphere. Here we determine the chemical speciation as well as the intensity and temporal persistence of the impact on air quality of sulfate aerosols from the 2014-2015 Holuhraun flood lava eruption of Icelandic volcano Bárdarbunga. To do so, we jointly analyse a set of SO2 observations from satellite (OMPS and IASI) and ground-level measurements from air quality monitoring stations together with high temporal resolution mass spectrometry measurements of an Aerosol Chemical Speciation Monitor (ACSM) performed far from the volcanic source. We explore month/year long ACSM data in France from stations in contrasting environments, close and far from industrial sulfur-rich activities. We demonstrate that volcanic sulfate aerosols exhibit a distinct chemical signature in urban/rural conditions, with NO3 : SO4 mass concentration ratios lower than for non-volcanic background aerosols. These results are supported by thermodynamic simulations of aerosol composition, using the ISORROPIA II model, which show that ammonium sulfate aerosols are preferentially formed at a high concentration of sulfate, leading to a decrease in the production of particulate ammonium nitrate. Such a chemical signature is however more difficult to identify at heavily polluted industrial sites due to a high level of background noise in sulfur. Nevertheless, aged volcanic sulfates can be distinguished from freshly emitted industrial sulfates according to their contrasting degree of anion neutralization. Combining AERONET (AErosol RObotic NETwork) sunphotometric data with ACSM observations, we also show a long persistence over weeks of pollution in volcanic sulfate aerosols, while SO2 pollution disappears in a few days at most. Finally, gathering 6-month long datasets from 27 sulfur monitoring stations of the EMEP (European Monitoring and Evaluation Programme) network allows us to demonstrate a much broader large-scale European pollution, in both SO2 and SO4, associated with the Holuhraun eruption, from Scandinavia to France. While widespread SO2 anomalies, with ground-level mass concentrations far exceeding background values, almost entirely result from the volcanic source, the origin of sulfate aerosols is more complex. Using a multi-site concentration-weighted trajectory analysis, emissions from the Holuhraun eruption are shown to be one of the main sources of SO4 at all EMEP sites across Europe and can be distinguished from anthropogenic emissions from eastern Europe but also from Great Britain. A wide variability in SO2 : SO4 mass concentration ratios, ranging from 0.8 to 8.0, is shown at several stations geographically dispersed at thousands of kilometres from the eruption site. Despite this apparent spatial complexity, we demonstrate that these mass oxidation ratios can be explained by a simple linear dependency on the age of the plume, with a SO2-to-SO4 oxidation rate of 0.23 h-1. Most current studies generally focus on SO2, an unambiguous and more readily measured marker of the volcanic plume. However, the long persistence of the chemical fingerprint of volcanic sulfate aerosols at continental scale, as shown for the Holuhraun eruption here, casts light on the impact of tropospheric eruptions and passive degassing activities on air quality, health, atmospheric chemistry and climate. © 2019 Author(s).
BibTeX: @article{Boichu2019, author = {Boichu, Marie and Favez, Olivier and Riffault, Véronique and Petit, Jean-Eudes and Zhang, Yunjiang and Brogniez, Colette and Sciare, Jean and Chiapello, Isabelle and Clarisse, Lieven and Zhang, Shouwen and Pujol-Söhne, Nathalie and Tison, Emmanuel and Delbarre, Hervé and Goloub, Philippe}, title = {Large-scale particulate air pollution and chemical fingerprint of volcanic sulfate aerosols from the 2014-2015 Holuhraun flood lava eruption of Bárdarbunga volcano (Iceland)}, journal = {Atmospheric Chemistry and Physics}, year = {2019}, volume = {19}, number = {22}, pages = {14253 – 14287}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-19-14253-2019} }
Bouche J, Bauduin S, Giuranna M, Robert S, Aoki S, Vandaele AC, Erwin JT, Daerden F, Wolkenberg P and Coheur P-F (2019), "Retrieval and characterization of carbon monoxide (CO) vertical profiles in the Martian atmosphere from observations of PFS/MEX", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 238 [Abstract] [BibTeX] [DOI]
Abstract: The knowledge of the carbon monoxide (CO) abundance on Mars is essential in order to assess the processes driving the carbon cycle on the planet. Solar occultation measurements provide vertically-resolved measurements of CO from a few kilometers to higher altitudes and can be complemented by nadir measurements to enhance the spatial coverage of observations and the monitoring of the near-surface layer. Up to now, in the shortwave, CO retrievals from nadir observations have, however, mostly been performed on mean spectra and only total column abundances have been obtained. In this work we explore the possibility of exploiting nadir measurements from the Planetary Fourier Spectrometer (PFS) in the 1–0 band of CO (centered at 2143 cm−1) to retrieve vertical profiles of that species on individual measurement. The retrievals are performed for a set of 16 selected PFS spectra with reasonable signal-to-noise ratios by applying the Optimal Estimation Method (OEM) with appropriate constraints, built from model simulations of the Martian atmosphere. The retrieved profiles are characterized in terms of vertical sensitivity and errors. We demonstrate, in particular, that the PFS nadir measurements carry information mostly on the CO column below 15 km, with a maximum sensitivity to the near-surface atmosphere. These measurements allow to substantially reduce the prior uncertainty on the CO abundance in this altitude range, with an estimated total retrieval error on the column-averaged volume mixing ratio (VMR) around 10%. We show that the set of retrieved VMRs are in the range of values reported from other instruments. The retrieved VMRs also capture well the known spatial and seasonal CO variability, which is promising in the perspective of better exploiting the exceptional set of PFS observations on Mars. © 2019 Elsevier Ltd
BibTeX: @article{Bouche2019, author = {Bouche, Jimmy and Bauduin, Sophie and Giuranna, Marco and Robert, Séverine and Aoki, Shohei and Vandaele, Ann Carine and Erwin, Justin T. and Daerden, Frank and Wolkenberg, Paulina and Coheur, Pierre-François}, title = {Retrieval and characterization of carbon monoxide (CO) vertical profiles in the Martian atmosphere from observations of PFS/MEX}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2019}, volume = {238}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2019.05.009} }
Clarisse L, Clerbaux C, Franco B, Hadji-Lazaro J, Whitburn S, Kopp A, Hurtmans D and Coheur P-F (2019), "A Decadal Data Set of Global Atmospheric Dust Retrieved From IASI Satellite Measurements", Journal of Geophysical Research: Atmospheres. Vol. 124(3), pp. 1618 – 1647. [Abstract] [BibTeX] [DOI]
Abstract: Aerosol is an important component of the Earth's atmosphere, affecting weather, climate, and diverse elements of the biosphere. Satellite sounders are an essential tool for measuring the highly variable distributions of atmospheric aerosol. Here we present a new algorithm for estimating atmospheric dust optical depths and associated retrieval uncertainties from spectral radiance measurements of the Infrared Atmospheric Sounding Interferometer (IASI). The retrieval is based on the calculation of a dust index and on a neural network trained with synthetic IASI spectra. It has an inherent high sensitivity to dust and efficiently discriminates dust from other aerosols. In particular, over remote dust-free areas, the retrieved levels of optical depth have a low bias. Over sea, noise levels are markedly lower than over land. Performance over deserts is comparable to that of other land surfaces. We use ground-based coarse mode aerosol measurements from the AErosol RObotic NETwork to validate the new product. The overall assessment is favorable, with standard deviations in line with estimated uncertainties, low biases, and high correlation coefficients. However, a systematic relative bias occurs between sites dominated by African and Asian dust sources respectively, likely linked to differences in mineralogy. The retrieval has been performed on over a decade of IASI data, and the resulting data set is now publicly available. We present a global seasonal dust climatology based on this record and compare it with those obtained from independent satellite measurements (Moderate Resolution Imaging Spectroradiometer and a third-party IASI product) and dust optical depth from the ECMWF model. ©2019. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Clarisse2019b, author = {Clarisse, L. and Clerbaux, C. and Franco, B. and Hadji-Lazaro, J. and Whitburn, S. and Kopp, A.K. and Hurtmans, D. and Coheur, P.-F.}, title = {A Decadal Data Set of Global Atmospheric Dust Retrieved From IASI Satellite Measurements}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2019}, volume = {124}, number = {3}, pages = {1618 – 1647}, note = {All Open Access, Green Open Access}, doi = {10.1029/2018JD029701} }
Clarisse L, Van Damme M, Clerbaux C and Coheur P-F (2019), "Tracking down global NH3 point sources with wind-adjusted superresolution", Atmospheric Measurement Techniques. Vol. 12(10), pp. 5457 – 5473. [Abstract] [BibTeX] [DOI]
Abstract: As a precursor of atmospheric aerosols, ammonia (NH3) is one of the primary gaseous air pollutants. Given its short atmospheric lifetime, ambient NH3 concentrations are dominated by local sources. In a recent study, Van Damme et al. (2018) have highlighted the importance of NH3 point sources, especially those associated with feedlots and industrial ammonia production. Their emissions were shown to be largely underestimated in bottom-up emission inventories. The discovery was made possible thanks to the use of oversampling techniques applied to 9 years of global daily IASI NH3 satellite measurements. Oversampling allows one to increase the spatial resolution of averaged satellite data beyond what the satellites natively offer. Here we apply for the first time superresolution techniques, which are commonplace in many fields that rely on imaging, to measurements of an atmospheric sounder, whose images consist of just single pixels. We demonstrate the principle on synthetic data and on IASI measurements of a surface parameter. Superresolution is a priori less suitable to be applied on measurements of variable atmospheric constituents, in particular those affected by transport. However, by first applying the wind-rotation technique, which was introduced in the study of other primary pollutants, superresolution becomes highly effective in mapping NH3 at a very high spatial resolution. We show that plume transport can be revealed in greater detail than what was previously thought to be possible. Next, using this wind-adjusted superresolution technique, we introduce a new type of NH3 map that allows tracking down point sources more easily than the regular oversampled average. On a subset of known emitters, the source could be located within a median distance of 1.5 km. We subsequently present a new global point-source catalog consisting of more than 500 localized and categorized point sources. Compared to our previous catalog, the number of identified sources more than doubled. In addition, we refined the classification of industries into five categories - fertilizer, coking, soda ash, geothermal and explosives industries - and introduced a new urban category for isolated NH3 hotspots over cities. The latter mainly consists of African megacities, as clear isolation of such urban hotspots is almost never possible elsewhere due to the presence of a diffuse background with higher concentrations. The techniques presented in this paper can most likely be exploited in the study of point sources of other short-lived atmospheric pollutants such as SO2 and NO2. © 2019. This work is distributed under the Creative Commons Attribution 4.0 License.
BibTeX: @article{Clarisse2019a, author = {Clarisse, Lieven and Van Damme, Martin and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Tracking down global NH3 point sources with wind-adjusted superresolution}, journal = {Atmospheric Measurement Techniques}, year = {2019}, volume = {12}, number = {10}, pages = {5457 – 5473}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-12-5457-2019} }
Clarisse L, Van Damme M, Gardner W, Coheur P-F, Clerbaux C, Whitburn S, Hadji-Lazaro J and Hurtmans D (2019), " Atmospheric ammonia (NH 3 ) emanations from Lake Natron’s saline mudflats ", Scientific Reports. Vol. 9(1) [Abstract] [BibTeX] [DOI]
Abstract: In a recent global analysis of satellite-derived atmospheric NH 3 data, a hotspot was observed in the vicinity of Lake Natron, Tanzania. The lake is in the centre of an endorheic (limited drainage) basin and has shallow, saline-alkaline waters. Its remote location and the absence of nearby large anthropogenic sources suggest that the observed NH 3 is mainly of natural origin. Here we explore 10 years of IASI NH 3 satellite data and other publicly available datasets over the area to characterize the natural NH 3 emissions in this unique ecosystem. Temporal analysis reveals that the emissions are episodic and linked with the lake’s surface area. The largest NH 3 column loadings generally occur at the end of the dry season in September–November over Lake Natron’s largest mudflat, that is exposed with receding water levels. The timing is different from the agricultural dominated NH 3 emissions in the wider Natron area, which peak early in the year, after the first wet season. The likely source of NH 3 at Lake Natron is decomposition of organic material, either from rivers and springs or produced in the lake (plankton, bird excreta). High temperatures and alkalinity are known to promote NH 3 losses from soda lakes. We formulate six processes that may explain why the largest losses are observed specifically over concentrated brines and/or exposed sediments. As a by-product, we also show that hyperspectral infrared sounders such as IASI are capable of mapping different types of evaporative minerals such as trona and thermonatrite. © 2019, The Author(s).
BibTeX: @article{Clarisse2019, author = {Clarisse, L. and Van Damme, M. and Gardner, W. and Coheur, P.-F. and Clerbaux, C. and Whitburn, S. and Hadji-Lazaro, J. and Hurtmans, D.}, title = { Atmospheric ammonia (NH 3 ) emanations from Lake Natron’s saline mudflats }, journal = {Scientific Reports}, year = {2019}, volume = {9}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.1038/s41598-019-39935-3} }
Dammers E, McLinden CA, Griffin D, Shephard MW, Van Der Graaf S, Lutsch E, Schaap M, Gainairu-Matz Y, Fioletov V, Van Damme M, Whitburn S, Clarisse L, Cady-Pereira K, Clerbaux C, Francois Coheur P and Erisman JW (2019), "NH3 emissions from large point sources derived from CrIS and IASI satellite observations", Atmospheric Chemistry and Physics. Vol. 19(19), pp. 12261 – 12293. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) is an essential reactive nitrogen species in the biosphere and through its use in agriculture in the form of fertilizer (important for sustaining humankind). The current emission levels, however, are up to 4 times higher than in the previous century and continue to grow with uncertain consequences to human health and the environment. While NH3 at its current levels is a hazard to environmental and human health, the atmospheric budget is still highly uncertain, which is a product of an overall lack of measurements. The capability to measure NH3 with satellites has opened up new ways to study the atmospheric NH3 budget. In this study, we present the first estimates of NH3 emissions, lifetimes and plume widths from large (>∼ 5 kt yr-1) agricultural and industrial point sources from Cross-Track Infrared Sounder (CrIS) satellite observations across the globe with a consistent methodology. The same methodology is also applied to the Infrared Atmospheric Sounding Interferometer (IASI) (A and B) satellite observations, and we show that the satellites typically provide comparable results that are within the uncertainty of the estimates. The computed NH3 lifetime for large point sources is on average 2:35±1:16 h. For the 249 sources with emission levels detectable by the CrIS satellite, there are currently 55 locations missing (or underestimated by more than an order of magnitude) from the current Hemispheric Transport Atmospheric Pollution version 2 (HTAPv2) emission inventory and only 72 locations with emissions within a factor of 2 compared to the inventories. The CrIS emission estimates give a total of 5622 kt yr-1, for the sources analyzed in this study, which is around a factor of ∼ 2:5 higher than the emissions reported in HTAPv2. Furthermore, the study shows that it is possible to accurately detect short-and long-Term changes in emissions, demonstrating the possibility of using satellite-observed NH3 to constrain emission inventories. © 2019 Author(s).
BibTeX: @article{Dammers2019, author = {Dammers, Enrico and McLinden, Chris A. and Griffin, Debora and Shephard, Mark W. and Van Der Graaf, Shelley and Lutsch, Erik and Schaap, Martijn and Gainairu-Matz, Yonatan and Fioletov, Vitali and Van Damme, Martin and Whitburn, Simon and Clarisse, Lieven and Cady-Pereira, Karen and Clerbaux, Cathy and Francois Coheur, Pierre and Erisman, Jan Willem}, title = {NH3 emissions from large point sources derived from CrIS and IASI satellite observations}, journal = {Atmospheric Chemistry and Physics}, year = {2019}, volume = {19}, number = {19}, pages = {12261 – 12293}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-19-12261-2019} }
Ekman J, Jönsson P, Godefroid M, Nazé C, Gaigalas G and Bieroń J (2019), "RIS 4: A program for relativistic isotope shift calculations", Computer Physics Communications. Vol. 235, pp. 433 – 446. [Abstract] [BibTeX] [DOI]
Abstract: Spectral lines from different isotopes display a small separation in energy, commonly referred to as the line isotope shift. The program RIS 4 (Relativistic Isotope Shift) calculates normal and specific mass shift parameters as well as field shift electronic factors from relativistic multiconfiguration Dirac–Hartree–Fock wave functions. These quantities, together with available nuclear data, determine isotope-dependent energy shifts. Using a reformulation of the field shift, it is possible to study, in a model-independent way, the atomic energy shifts arising from changes in nuclear charge distributions, e.g. deformations. Program summary: Program title: RIS 4 Program Files doi: http://dx.doi.org/10.17632/8vjpf69zch.1 Licensing provisions: MIT Programming language: Fortran 77 and Fortran 90 Journal reference of previous version: Comput. Phys. Comm. 184 (2013) 2187 Does the new version supersede the previous version?: Yes Subprograms used: GRASP 2K VERSION 1_1 Nature of problem: Prediction of level and transition isotope shifts in atoms using four-component relativistic wave functions. Solution method: The nuclear mass shifts and field shifts are treated using first order perturbation theory. The electron density and the normal and specific mass shift parameters can be expressed as [Formula presented], where [Formula presented] is the relevant operator and [Formula presented] is the configuration state expansion, where P, J and MJ are the parity and angular quantum numbers, respectively. The matrix elements, in turn, can be decomposed as sums over radial integrals multiplied by angular coefficients. The angular coefficients are calculated using routines from the GRASP2K VERSION 1_1 package [1]. Reasons for new version: This new version calculates field shift electronic factors resulting from non-constant (varying) electron densities inside the nucleus. Summary of revisions: This new version uses an expression of the field shift that through a polynomial expansion of the electron density contains higher order radial moments and thus takes the varying electron density within the nuclear volume into account. Restrictions: The complexity of the cases that can be handled is entirely determined by the GRASP2K package [1] used for the generation of the electronic wave functions. Unusual features: Using a reformulation of the field shift, it is possible to study the atomic energy shifts arising from changes in nuclear charge distributions, e.g. deformations. References: [1] P. Jönsson, G. Gaigalas, J. Bieroń, C. Froese Fischer, I.P. Grant, New version: Grasp2K relativistic atomic structure package, Comput. Phys. Commun. 184 (9) (2013) 2197–2203. © 2018
BibTeX: @article{Ekman2019, author = {Ekman, J. and Jönsson, P. and Godefroid, M. and Nazé, C. and Gaigalas, G. and Bieroń, J.}, title = {RIS 4: A program for relativistic isotope shift calculations}, journal = {Computer Physics Communications}, year = {2019}, volume = {235}, pages = {433 – 446}, doi = {10.1016/j.cpc.2018.08.017} }
Franco B, Clarisse L, Stavrakou T, Müller J-F, Pozzer A, Hadji-Lazaro J, Hurtmans D, Clerbaux C and Coheur P-F (2019), "Acetone Atmospheric Distribution Retrieved From Space", Geophysical Research Letters. Vol. 46(5), pp. 2884 – 2893. [Abstract] [BibTeX] [DOI]
Abstract: As one of the most abundant oxygenated volatile organic compounds in the atmosphere, acetone (CH3C[O]CH3) influences atmospheric oxidants levels and ozone formation. Here we report the first unambiguous identification of acetone from the nadir-viewing satellite sounder Infrared Atmospheric Sounding Interferometer (IASI). Via a neural network-based retrieval approach that was previously applied to the retrieval of other weak absorbers, we obtain daily global acetone retrievals. A first intercomparison with independent measurements is conducted. As the retrieval method is computationally fast, it allowed the full reprocessing of the 2007–2018 IASI time series. Analysis of the retrieved global product and its seasonality suggests that emissions of acetone and precursors from the terrestrial biosphere at Northern Hemisphere middle and high latitudes are the main contributors to the atmospheric acetone abundance, more than year-round oxidation of anthropogenic isoalkanes. Remarkably, biomass burning does not appear to be a strong global source of acetone. ©2019. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Franco2019, author = {Franco, B. and Clarisse, L. and Stavrakou, T. and Müller, J.-F. and Pozzer, A. and Hadji-Lazaro, J. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.}, title = {Acetone Atmospheric Distribution Retrieved From Space}, journal = {Geophysical Research Letters}, year = {2019}, volume = {46}, number = {5}, pages = {2884 – 2893}, note = {All Open Access, Green Open Access}, doi = {10.1029/2019GL082052} }
Froese Fischer C and Godefroid MR (2019), "Electron correlation in the lanthanides: 4f2 spectrum of Ce2+", Physical Review A. Vol. 99(3) [Abstract] [BibTeX] [DOI]
Abstract: Atoms and ions of lanthanides have multiple opens shells along with an open 4fk subshell. This paper studies the effect of electron correlation in such systems and how wave functions can be determined for the accurate prediction of atomic properties in the case of Ce2+ where k=2, using the multireference single- and double-excitation method. An efficient higher-order method is recommended for more reliable results. © 2019 American Physical Society.
BibTeX: @article{FroeseFischer2019, author = {Froese Fischer, Charlotte and Godefroid, Michel R.}, title = {Electron correlation in the lanthanides: 4f2 spectrum of Ce2+}, journal = {Physical Review A}, year = {2019}, volume = {99}, number = {3}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.99.032511} }
Gans B, Boyé-Péronne S and Liévin J (2019), "Vibronic structure of the cyanobutadiyne cation. II. Theoretical exploration of the complex energy landscape of HC5N+", Journal of Chemical Physics. Vol. 150(24) [Abstract] [BibTeX] [DOI]
Abstract: The results of an extensive ab initio study of the cyanobutadiyne cation, initially motivated by threshold-photoelectron spectroscopy experiments [see the study by Gans et al., J. Chem. Phys. 150, 244304 (2019)], are reported in the present paper. Calculations at the internally contracted multireference configuration interaction level of theory have been performed to derive the rovibronic properties of the seven lowest electronic states of HC5N+. Equilibrium geometries, rotational constants, vibrational frequencies, electric dipole moments, and spin-orbit constants have been calculated and compared with experimental data when available. Adiabatic and vertical ionization energies from the neutral ground state as well as transition energies within the cation electronic manifold are predicted, using the convergence to the complete basis set limit. The accurate description of the complex energy landscape up to 32 000 cm-1 above the ionization potential allows us to perform Franck-Condon simulations of the photoionization spectrum to the X+ 2Π, A+ 2Π, B+ 2ς+, and C+ 2Π states and allows us to simulate the A+ 2Π → X+ 2Π emission spectrum. The vibronic perturbations occurring on the excited potential energy surfaces are revealed and discussed, in particular, for the 3 2Π surface, which presents a double-well topography. © 2019 Author(s).
BibTeX: @article{Gans2019a, author = {Gans, Bérenger and Boyé-Péronne, Séverine and Liévin, Jacques}, title = {Vibronic structure of the cyanobutadiyne cation. II. Theoretical exploration of the complex energy landscape of HC5N+}, journal = {Journal of Chemical Physics}, year = {2019}, volume = {150}, number = {24}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.5097691} }
Gans B, Lamarre N, Guillemin J-C, Douin S, Alcaraz C, Romanzin C, Garcia GA, Liévin J and Boyé-Péronne S (2019), "Vibronic structure of the cyanobutadiyne cation. I. VUV photoionization study of HC5N", Journal of Chemical Physics. Vol. 150(24) [Abstract] [BibTeX] [DOI]
Abstract: We report the vacuum-ultraviolet threshold-photoelectron spectrum of HC5N recorded over a wide spectral range, from 84 000 to 120 000 cm-1, with a 120 cm-1 spectral resolution, better than what was achieved in previous photoelectron studies, and with mass selectivity. The adiabatic ionization potential of cyanobutadiyne is measured at 85 366 (±40) cm-1. Assignment of the vibrational bands of the four lowest electronic states X+2Π, A+2Π, B+2ς+, and C+2Π are performed, supported by high level ab initio calculations which are fully detailed in Paper II [B. Gans et al., J. Chem. Phys. 150, 244303 (2019)] and by Franck-Condon simulations. Only vibrational stretching modes are observed in the threshold-photoelectron spectra. The ground state of HC5N+ exhibits a vibrational progression in the ν2 stretching mode involving mainly the elongation of the CC triple bonds, whereas the A+ and C+ excited electronic states show a progression in the stretching mode mainly associated with the elongation of the CN bond, i.e., ν4 and ν3, respectively. The B+ state appears almost as a vibrationless structure in close vicinity to the A+ state. © 2019 Author(s).
BibTeX: @article{Gans2019, author = {Gans, Bérenger and Lamarre, Nicolas and Guillemin, Jean-Claude and Douin, Stéphane and Alcaraz, Christian and Romanzin, Claire and Garcia, Gustavo A. and Liévin, Jacques and Boyé-Péronne, Séverine}, title = {Vibronic structure of the cyanobutadiyne cation. I. VUV photoionization study of HC5N}, journal = {Journal of Chemical Physics}, year = {2019}, volume = {150}, number = {24}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.5097688} }
Georges R, Thiévin J, Benidar A, Carles S, Amyay B, Louviot M, Boudon V and Vander Auwera J (2019), "High enthalpy source dedicated to quantitative infrared emission spectroscopy of gas flows at elevated temperatures", Review of Scientific Instruments. Vol. 90(9) [Abstract] [BibTeX] [DOI]
Abstract: The High Enthalpy Source (HES) is a novel high temperature source developed to measure infrared line-by-line integrated absorption cross sections of flowing gases up to 2000 K. The HES relies on a porous graphite furnace designed to uniformly heat a constant flow of gas. The flow compensates thermal dissociation by renewing continuously the gas sample and eliminating dissociation products. The flowing characteristics have been investigated using computational fluid dynamics simulation confirming good temperature uniformity. The HES has been coupled to a high-resolution Fourier transform spectrometer to record emission spectra of methane at temperatures ranging between 700 and 1400 K. A radiative model has been developed to extract absolute line intensities from the recorded spectra. © 2019 Author(s).
BibTeX: @article{Georges2019, author = {Georges, R. and Thiévin, J. and Benidar, A. and Carles, S. and Amyay, B. and Louviot, M. and Boudon, V. and Vander Auwera, J.}, title = {High enthalpy source dedicated to quantitative infrared emission spectroscopy of gas flows at elevated temperatures}, journal = {Review of Scientific Instruments}, year = {2019}, volume = {90}, number = {9}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.5097696} }
Hedelt P, Efremenko DS, Loyola DG, Spurr R and Clarisse L (2019), "Sulfur dioxide layer height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM", Atmospheric Measurement Techniques. Vol. 12(10), pp. 5503 – 5517. [Abstract] [BibTeX] [DOI]
Abstract: The accurate determination of the location, height, and loading of sulfur dioxide (SO2) plumes emitted by volcanic eruptions is essential for aviation safety. The SO2 layer height is also one of the most critical parameters with respect to determining the impact on the climate. Retrievals of SO2 plume height have been carried out using satellite UV backscatter measurements, but, until now, such algorithms are very time-consuming. We have developed an extremely fast yet accurate SO2 layer height retrieval using the Full-Physics Inverse Learning Machine (FP_ILM) algorithm. This is the first time the algorithm has been applied to measurements from the TROPOMI instrument onboard the Sentinel-5 Precursor platform. In this paper, we demonstrate the ability of the FP_ILM algorithm to retrieve SO2 plume layer heights in near-real-time applications with an accuracy of better than 2 km for SO2 total columns larger than 20 DU. We present SO2 layer height results for the volcanic eruptions of Sinabung in February 2018, Sierra Negra in June 2018, and Raikoke in June 2019, observed by TROPOMI. © 2019 BMJ Publishing Group. All rights reserved.
BibTeX: @article{Hedelt2019, author = {Hedelt, Pascal and Efremenko, Dmitry S. and Loyola, Diego G. and Spurr, Robert and Clarisse, Lieven}, title = {Sulfur dioxide layer height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM}, journal = {Atmospheric Measurement Techniques}, year = {2019}, volume = {12}, number = {10}, pages = {5503 – 5517}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-12-5503-2019} }
Hillenbrand P-M, Bowen K, Liévin J, Urbain X and Savin D (2019), "Experimental and Theoretical Studies of the Isotope Exchange Reaction D + H3 + → H2D+ + H", Astrophysical Journal. Vol. 877(1) [Abstract] [BibTeX] [DOI]
Abstract: Deuterated molecules are important chemical tracers of prestellar and protostellar cores. Up to now, the titular reaction has been assumed to contribute to the generation of these deuterated molecules. We have measured the merged-beams rate coefficient for this reaction as a function of the relative collision energy in the range of about 10meV-10 eV. By varying the internal temperature of the reacting H+ 3 molecules, we found indications for the existence of a reaction barrier. We have performed detailed theoretical calculations for the zero-point-corrected energy profile of the reaction and determined a new value for the barrier height of ≈68 meV. Furthermore, we have calculated the tunneling probability through the barrier. Our experimental and theoretical results show that the reaction is essentially closed at astrochemically relevant temperatures. We derive a thermal rate coefficient of <1 × 10-12 cm3 s-1 for temperatures below 75 K with tunneling effects included and below 155 K without tunneling. © 2019. The American Astronomical Society. All rights reserved.
BibTeX: @article{Hillenbrand2019, author = {Hillenbrand, P.-M. and Bowen, K.P. and Liévin, J. and Urbain, X. and Savin, D.W.}, title = {Experimental and Theoretical Studies of the Isotope Exchange Reaction D + H3 + → H2D+ + H}, journal = {Astrophysical Journal}, year = {2019}, volume = {877}, number = {1}, note = {All Open Access, Bronze Open Access}, doi = {10.3847/1538-4357/ab16dc} }
Kas M, Loreau J, Liévin J and Vaeck N (2019), "Cold reactive and nonreactive collisions of Li and Rb with C2-: Implications for hybrid-trap experiments", Physical Review A. Vol. 99(4) [Abstract] [BibTeX] [DOI]
Abstract: We present a theoretical investigation of cold reactive and nonreactive collisions of Li and Rb atoms with C2-. The potential energy surfaces for the singlet and triplet states of the Li-C2- and Rb-C2- systems have been obtained using the CASSCF followed by ic-MRCI approach with extended basis sets. The potential energy surfaces are then used to investigate the associative detachment reaction and to calculate rotationally inelastic cross sections at low collision energies by means of the close-coupling method. The results are compared to those obtained for other anionic systems such as Rb-OH-, and the implications for hybrid-trap experiments and sympathetic cooling experiments are explored. Furthermore, we discuss the possibility to perform Doppler thermometry on the C2- anion and investigate the collision process involving excited electronic states. © 2019 American Physical Society.
BibTeX: @article{Kas2019, author = {Kas, Milaim and Loreau, Jérôme and Liévin, Jacques and Vaeck, Nathalie}, title = {Cold reactive and nonreactive collisions of Li and Rb with C2-: Implications for hybrid-trap experiments}, journal = {Physical Review A}, year = {2019}, volume = {99}, number = {4}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.99.042702} }
Kas M, Loreau J, Liévin J and Vaeck N (2019), "Reactivity of Hydrated Hydroxide Anion Clusters with H and Rb: An ab Initio Study", Journal of Physical Chemistry A. Vol. 123(41), pp. 8893 – 8906. [Abstract] [BibTeX] [DOI]
Abstract: We present a theoretical investigation of the hydrated hydroxide anion clusters, OH(H2O)n-, and of the collisional complexes, H-OH(H2O)n- and Rb-OH(H2O)n- (with n = 1-4). The MP2 and CCSD(T) methods are used to calculate interaction energies, optimized geometries, and vertical detachment energies. Parts of the potential energy surfaces are explored with a focus on the autodetachment region. We point out the importance of diffuse functions to correctly describe the latter. We use our results to discuss the different water loss and electronic detachment channels, which are the main reaction routes at room temperature and below. In particular, we have considered a direct and an indirect process for the electronic detachment, depending on whether water loss follows or precedes the detachment of the excess electron. We use our results to discuss the implications for astrochemistry and hybrid trap experiments in the context of cold chemistry. © 2019 American Chemical Society.
BibTeX: @article{Kas2019a, author = {Kas, Milaim and Loreau, Jérôme and Liévin, Jacques and Vaeck, Nathalie}, title = {Reactivity of Hydrated Hydroxide Anion Clusters with H and Rb: An ab Initio Study}, journal = {Journal of Physical Chemistry A}, year = {2019}, volume = {123}, number = {41}, pages = {8893 – 8906}, note = {All Open Access, Green Open Access}, doi = {10.1021/acs.jpca.9b05971} }
Korablev O, Vandaele AC, Montmessin F, Fedorova AA, Trokhimovskiy A, Forget F, Lefèvre F, Daerden F, Thomas IR, Trompet L, Erwin JT, Aoki S, Robert S, Neary L, Viscardy S, Grigoriev AV, Ignatiev NI, Shakun A, Patrakeev A, Belyaev DA, Bertaux J-L, Olsen KS, Baggio L, Alday J, Ivanov YS, Ristic B, Mason J, Willame Y, Depiesse C, Hetey L, Berkenbosch S, Clairquin R, Queirolo C, Beeckman B, Neefs E, Patel MR, Bellucci G, López-Moreno J-J, Wilson CF, Etiope G, Zelenyi L, Svedhem H, Vago JL, Alonso-Rodrigo G, Altieri F, Anufreychik K, Arnold G, Bauduin S, Bolsée D, Carrozzo G, Clancy RT, Cloutis E, Crismani M, Da Pieve F, D’Aversa E, Duxbury N, Encrenaz T, Fouchet T, Funke B, Fussen D, Garcia-Comas M, Gérard J-C, Giuranna M, Gkouvelis L, Gonzalez-Galindo F, Grassi D, Guerlet S, Hartogh P, Holmes J, Hubert B, Kaminski J, Karatekin O, Kasaba Y, Kass D, Khatuntsev I, Kleinböhl A, Kokonkov N, Krasnopolsky V, Kuzmin R, Lacombe G, Lanciano O, Lellouch E, Lewis S, Luginin M, Liuzzi G, López-Puertas M, López-Valverde M, Määttänen A, Mahieux A, Marcq E, Martin-Torres J, Maslov I, Medvedev A, Millour E, Moshkin B, Mumma M, Nakagawa H, Novak RE, Oliva F, Patsaev D, Piccialli A, Quantin-Nataf C, Renotte E, Ritter B, Rodin A, Schmidt F, Schneider N, Shematovich V, Smith M, Teanby NA, Thiemann E, Thomas N, Vander Auwera J, Vazquez L, Villanueva G, Vincendon M, Whiteway J, Wilquet V, Wolff MJ, Wolkenberg P, Yelle R, Young R, Zasova L and Zorzano MP (2019), "No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations", Nature. Vol. 568(7753), pp. 517 – 520. [Abstract] [BibTeX] [DOI]
Abstract: The detection of methane on Mars has been interpreted as indicating that geochemical or biotic activities could persist on Mars today1. A number of different measurements of methane show evidence of transient, locally elevated methane concentrations and seasonal variations in background methane concentrations2–5. These measurements, however, are difficult to reconcile with our current understanding of the chemistry and physics of the Martian atmosphere6,7, which—given methane’s lifetime of several centuries—predicts an even, well mixed distribution of methane1,6,8. Here we report highly sensitive measurements of the atmosphere of Mars in an attempt to detect methane, using the ACS and NOMAD instruments onboard the ESA-Roscosmos ExoMars Trace Gas Orbiter from April to August 2018. We did not detect any methane over a range of latitudes in both hemispheres, obtaining an upper limit for methane of about 0.05 parts per billion by volume, which is 10 to 100 times lower than previously reported positive detections2,4. We suggest that reconciliation between the present findings and the background methane concentrations found in the Gale crater4 would require an unknown process that can rapidly remove or sequester methane from the lower atmosphere before it spreads globally. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
BibTeX: @article{Korablev2019a, author = {Korablev, Oleg and Vandaele, Ann Carine and Montmessin, Franck and Fedorova, Anna A. and Trokhimovskiy, Alexander and Forget, François and Lefèvre, Franck and Daerden, Frank and Thomas, Ian R. and Trompet, Loïc and Erwin, Justin T. and Aoki, Shohei and Robert, Séverine and Neary, Lori and Viscardy, Sébastien and Grigoriev, Alexey V. and Ignatiev, Nikolay I. and Shakun, Alexey and Patrakeev, Andrey and Belyaev, Denis A. and Bertaux, Jean-Loup and Olsen, Kevin S. and Baggio, Lucio and Alday, Juan and Ivanov, Yuriy S. and Ristic, Bojan and Mason, Jon and Willame, Yannick and Depiesse, Cédric and Hetey, Laszlo and Berkenbosch, Sophie and Clairquin, Roland and Queirolo, Claudio and Beeckman, Bram and Neefs, Eddy and Patel, Manish R. and Bellucci, Giancarlo and López-Moreno, Jose-Juan and Wilson, Colin F. and Etiope, Giuseppe and Zelenyi, Lev and Svedhem, Håkan and Vago, Jorge L. and Alonso-Rodrigo, Gustavo and Altieri, Francesca and Anufreychik, Konstantin and Arnold, Gabriele and Bauduin, Sophie and Bolsée, David and Carrozzo, Giacomo and Clancy, R. Todd and Cloutis, Edward and Crismani, Matteo and Da Pieve, Fabiana and D’Aversa, Emiliano and Duxbury, Natalia and Encrenaz, Therese and Fouchet, Thierry and Funke, Bernd and Fussen, Didier and Garcia-Comas, Maia and Gérard, Jean-Claude and Giuranna, Marco and Gkouvelis, Leo and Gonzalez-Galindo, Francisco and Grassi, Davide and Guerlet, Sandrine and Hartogh, Paul and Holmes, James and Hubert, Benoît and Kaminski, Jacek and Karatekin, Ozgur and Kasaba, Yasumasa and Kass, David and Khatuntsev, Igor and Kleinböhl, Armin and Kokonkov, Nikita and Krasnopolsky, Vladimir and Kuzmin, Ruslan and Lacombe, Gaétan and Lanciano, Orietta and Lellouch, Emmanuel and Lewis, Stephen and Luginin, Mikhail and Liuzzi, Giuliano and López-Puertas, Manuel and López-Valverde, Miguel and Määttänen, Anni and Mahieux, Arnaud and Marcq, Emmanuel and Martin-Torres, Javier and Maslov, Igor and Medvedev, Alexander and Millour, Ehouarn and Moshkin, Boris and Mumma, Michael J. and Nakagawa, Hiromu and Novak, Robert E. and Oliva, Fabrizio and Patsaev, Dmitry and Piccialli, Arianna and Quantin-Nataf, Cathy and Renotte, Etienne and Ritter, Birgit and Rodin, Alexander and Schmidt, Frédéric and Schneider, Nick and Shematovich, Valery and Smith, Michael D. and Teanby, Nicholas A. and Thiemann, Ed and Thomas, Nicolas and Vander Auwera, Jean and Vazquez, Luis and Villanueva, Geronimo and Vincendon, Matthieu and Whiteway, James and Wilquet, Valérie and Wolff, Michael J. and Wolkenberg, Paulina and Yelle, Roger and Young, Roland and Zasova, Ludmila and Zorzano, Maria Paz}, title = {No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations}, journal = {Nature}, year = {2019}, volume = {568}, number = {7753}, pages = {517 – 520}, doi = {10.1038/s41586-019-1096-4} }
Korablev O, Vandaele AC, Montmessin F, Fedorova AA, Trokhimovskiy A, Forget F, Lefèvre F, Daerden F, Thomas IR, Trompet L, Erwin JT, Aoki S, Robert S, Neary L, Viscardy S, Grigoriev AV, Ignatiev NI, Shakun A, Patrakeev A, Belyaev DA, Bertaux J-L, Olsen KS, Baggio L, Alday J, Ivanov YS, Ristic B, Mason J, Willame Y, Depiesse C, Hetey L, Berkenbosch S, Clairquin R, Queirolo C, Beeckman B, Neefs E, Patel MR, Bellucci G, López-Moreno J-J, Wilson CF, Etiope G, Zelenyi L, Svedhem H, Vago JL, Alonso-Rodrigo G, Altieri F, Anufreychik K, Arnold G, Bauduin S, Bolsée D, Carrozzo G, Clancy RT, Cloutis E, Crismani M, Da Pieve F, D’Aversa E, Duxbury N, Encrenaz T, Fouchet T, Funke B, Fussen D, Garcia-Comas M, Gérard J-C, Giuranna M, Gkouvelis L, Gonzalez-Galindo F, Grassi D, Guerlet S, Hartogh P, Holmes J, Hubert B, Kaminski J, Karatekin O, Kasaba Y, Kass D, Khatuntsev I, Kleinböhl A, Kokonkov N, Krasnopolsky V, Kuzmin R, Lacombe G, Lanciano O, Lellouch E, Lewis S, Luginin M, Liuzzi G, López-Puertas M, López-Valverde M, Määttänen A, Mahieux A, Marcq E, Martin-Torres J, Maslov I, Medvedev A, Millour E, Moshkin B, Mumma MJ, Nakagawa H, Novak RE, Oliva F, Patsaev D, Piccialli A, Quantin-Nataf C, Renotte E, Ritter B, Rodin A, Schmidt F, Schneider N, Shematovich V, Smith MD, Teanby NA, Thiemann E, Thomas N, Vander Auwera J, Vazquez L, Villanueva G, Vincendon M, Whiteway J, Wilquet V, Wolff MJ, Wolkenberg P, Yelle R, Young R, Zasova L and Zorzano MP (2019), "Publisher Correction: No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations (Nature, (2019), 568, 7753, (517-520), 10.1038/s41586-019-1096-4)", Nature. Vol. 569(7754), pp. E2. [Abstract] [BibTeX] [DOI]
Abstract: The surname of author Cathy Quantin-Nataf was misspelled ‘Quantin-Nata’, authors Ehouarn Millour and Roland Young were missing from the ACS and NOMAD Science Teams list, and minor changes have been made to the author and affiliation lists; see accompanying Amendment. These errors have been corrected online. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
BibTeX: @article{Korablev2019, author = {Korablev, Oleg and Vandaele, Ann Carine and Montmessin, Franck and Fedorova, Anna A. and Trokhimovskiy, Alexander and Forget, François and Lefèvre, Franck and Daerden, Frank and Thomas, Ian R. and Trompet, Loïc and Erwin, Justin T. and Aoki, Shohei and Robert, Séverine and Neary, Lori and Viscardy, Sébastien and Grigoriev, Alexey V. and Ignatiev, Nikolay I. and Shakun, Alexey and Patrakeev, Andrey and Belyaev, Denis A. and Bertaux, Jean-Loup and Olsen, Kevin S. and Baggio, Lucio and Alday, Juan and Ivanov, Yuriy S. and Ristic, Bojan and Mason, Jon and Willame, Yannick and Depiesse, Cédric and Hetey, Laszlo and Berkenbosch, Sophie and Clairquin, Roland and Queirolo, Claudio and Beeckman, Bram and Neefs, Eddy and Patel, Manish R. and Bellucci, Giancarlo and López-Moreno, Jose-Juan and Wilson, Colin F. and Etiope, Giuseppe and Zelenyi, Lev and Svedhem, Håkan and Vago, Jorge L. and Alonso-Rodrigo, Gustavo and Altieri, Francesca and Anufreychik, Konstantin and Arnold, Gabriele and Bauduin, Sophie and Bolsée, David and Carrozzo, Giacomo and Clancy, R. Todd and Cloutis, Edward and Crismani, Matteo and Da Pieve, Fabiana and D’Aversa, Emiliano and Duxbury, Natalia and Encrenaz, Therese and Fouchet, Thierry and Funke, Bernd and Fussen, Didier and Garcia-Comas, Maia and Gérard, Jean-Claude and Giuranna, Marco and Gkouvelis, Leo and Gonzalez-Galindo, Francisco and Grassi, Davide and Guerlet, Sandrine and Hartogh, Paul and Holmes, James and Hubert, Benoît and Kaminski, Jacek and Karatekin, Ozgur and Kasaba, Yasumasa and Kass, David and Khatuntsev, Igor and Kleinböhl, Armin and Kokonkov, Nikita and Krasnopolsky, Vladimir and Kuzmin, Ruslan and Lacombe, Gaétan and Lanciano, Orietta and Lellouch, Emmanuel and Lewis, Stephen and Luginin, Mikhail and Liuzzi, Giuliano and López-Puertas, Manuel and López-Valverde, Miguel and Määttänen, Anni and Mahieux, Arnaud and Marcq, Emmanuel and Martin-Torres, Javier and Maslov, Igor and Medvedev, Alexander and Millour, Ehouarn and Moshkin, Boris and Mumma, Michael J. and Nakagawa, Hiromu and Novak, Robert E. and Oliva, Fabrizio and Patsaev, Dmitry and Piccialli, Arianna and Quantin-Nataf, Cathy and Renotte, Etienne and Ritter, Birgit and Rodin, Alexander and Schmidt, Frédéric and Schneider, Nick and Shematovich, Valery and Smith, Michael D. and Teanby, Nicholas A. and Thiemann, Ed and Thomas, Nicolas and Vander Auwera, Jean and Vazquez, Luis and Villanueva, Geronimo and Vincendon, Matthieu and Whiteway, James and Wilquet, Valérie and Wolff, Michael J. and Wolkenberg, Paulina and Yelle, Roger and Young, Roland and Zasova, Ludmila and Zorzano, Maria Paz}, title = {Publisher Correction: No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations (Nature, (2019), 568, 7753, (517-520), 10.1038/s41586-019-1096-4)}, journal = {Nature}, year = {2019}, volume = {569}, number = {7754}, pages = {E2}, note = {All Open Access, Bronze Open Access}, doi = {10.1038/s41586-019-1164-9} }
Kwabia-Tchana F, Attafi Y, Manceron L, Doizi D, Vander Auwera J and Perrin A (2019), "Line intensities for the ν6 and 2ν3 bands of methyl iodide (12CH3I)", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 222-223, pp. 130 – 137. [Abstract] [BibTeX] [DOI]
Abstract: The goal of this study is to measure for the first time absolute line intensities for the ν6 band of methyl iodide (CH3I) centered at 892.918 cm–1. High-resolution Fourier transform spectra were recorded at various pressures for the whole 500–1450 cm–1 spectral range. Using these spectra, a large set of CH3I individual line intensities was measured for the ν6 band. These experimental intensities were least squares fitted to derive the expansion of the ν6 transition moment operator. The theoretical model used to describe the line positions and intensities accounts for the hyperfine structure in the 61 and ground states and for the vibration-rotation resonances that couple the 61 energy levels with those of the 32 and 21 vibrational states [Perrin et al., J. Mol. Spectrosc. 324 (2016) 28–35]. As the 2ν3 band is extremely weak, its associated transition moment operator was estimated from band strength available in the literature. A comprehensive list of line positions and intensities was generated for the ν6 and 2ν3 bands of CH3I at 11 µm, which should be useful for the possible detection of this species by the future IASI-NG satellite instrument (Infrared Atmospheric Sounding Interferometer New Generation), now under preparation (https://iasi-ng.cnes.fr/en/IASI-NG/index.htm). © 2018
BibTeX: @article{KwabiaTchana2019, author = {Kwabia-Tchana, F. and Attafi, Y. and Manceron, L. and Doizi, D. and Vander Auwera, J. and Perrin, A.}, title = {Line intensities for the ν6 and 2ν3 bands of methyl iodide (12CH3I)}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2019}, volume = {222-223}, pages = {130 – 137}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2018.10.001} }
Lachatre M, Fortems-Cheiney A, Foret G, Siour G, Dufour G, Clarisse L, Clerbaux C, Coheur P-F, Van Damme M and Beekmann M (2019), "The unintended consequence of SO2 and NO2 regulations over China: Increase of ammonia levels and impact on PM2.5 concentrations", Atmospheric Chemistry and Physics. Vol. 19(10), pp. 6701 – 6716. [Abstract] [BibTeX] [DOI]
Abstract: Air pollution reaching hazardous levels in many Chinese cities has been a major concern in China over the past decades. New policies have been applied to regulate anthropogenic pollutant emissions, leading to changes in atmospheric composition and in particulate matter (PM) production. Increasing levels of atmospheric ammonia columns have been observed by satellite during recent years. In particular, observations from the Infrared Atmospheric Sounding Interferometer (IASI) reveal an increase of these columns by 15% and 65% from 2011 to 2013 and 2015, respectively, over eastern China. In this paper we performed model simulations for 2011, 2013 and 2015 in order to understand the origin of this increase and to quantify the link between ammonia and the inorganic components of particles: NHC+4(p)/SO2-4(p)/NO-3(p). Interannual change of meteorology can be excluded as a reason: year 2015 meteorology leads to enhanced sulfate production over eastern China, which increases the ammonium and decreases the ammonia content, which is contrary to satellite observations. Reductions in SO2 and NOx emissions from 2011 to 2015 of 37.5% and 21% respectively, as constrained from satellite data, lead to decreased inorganic matter (by 14% for NH+4(p) +SO2-4(p) + NO-3(p)). This in turn leads to increased gaseous NH3(g) tropospheric columns by as much as 24% and 49% (sampled corresponding to IASI data availability) from 2011 to 2013 and 2015 respectively and thus can explain most of the observed increase. © Author(s) 2019.
BibTeX: @article{Lachatre2019, author = {Lachatre, Mathieu and Fortems-Cheiney, Audrey and Foret, Gilles and Siour, Guillaume and Dufour, Gaëlle and Clarisse, Lieven and Clerbaux, Cathy and Coheur, Pierre-François and Van Damme, Martin and Beekmann, Matthias}, title = {The unintended consequence of SO2 and NO2 regulations over China: Increase of ammonia levels and impact on PM2.5 concentrations}, journal = {Atmospheric Chemistry and Physics}, year = {2019}, volume = {19}, number = {10}, pages = {6701 – 6716}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-19-6701-2019} }
Launoy T, Loreau J, Dochain A, Liévin J, Vaeck N and Urbain X (2019), "Mutual Neutralization in Li+-D- Collisions: A Combined Experimental and Theoretical Study", Astrophysical Journal. Vol. 883(1) [Abstract] [BibTeX] [DOI]
Abstract: We present a combined experimental and theoretical study of the mutual neutralization (MN) process in collisions of lithium ions (Li+) with deuterium anions (D-) at collision energies below 1 eV. We employ a merged-beam apparatus to determine total and state-to-state MN cross sections. We perform nuclear dynamics calculations using the multichannel Landau-Zener model based on accurate ab initio molecular data. We obtain an excellent agreement between the experimental and theoretical results over the energy range covered in this work. We show that the basis sets used in the ab initio calculations have a limited influence on the total cross section, but strongly impacts the results obtained for the partial cross sections or the reaction branching ratios. This demonstrates the important role of high-precision measurements to validate the theoretical approaches used to study gas-phase reactive processes. Finally, we compute MN rate coefficients for Li+ + H- and Li+ + D-, and discuss their significance for astrochemistry models. © 2019. The American Astronomical Society. All rights reserved.
BibTeX: @article{Launoy2019, author = {Launoy, Thibaut and Loreau, Jérôme and Dochain, Arnaud and Liévin, Jacques and Vaeck, Nathalie and Urbain, Xavier}, title = {Mutual Neutralization in Li+-D- Collisions: A Combined Experimental and Theoretical Study}, journal = {Astrophysical Journal}, year = {2019}, volume = {883}, number = {1}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.3847/1538-4357/ab3346} }
Liuzzi G, Villanueva GL, Mumma MJ, Smith MD, Daerden F, Ristic B, Thomas I, Vandaele AC, Patel MR, Lopez-Moreno J-J, Bellucci G, Allen M, Alonso-Rodrigo G, Altieri F, Aoki S, Bauduin S, Bolsée D, Clancy T, Cloutis E, D'Aversa E, Depiesse C, Erwin J, Fedorova A, Formisano V, Funke B, Fussen D, Garcia-Comas M, Geminale A, Gérard J-C, Gillotay D, Giuranna M, Gonzalez-Galindo F, Hewson W, Homes J, Ignatiev N, Kaminski J, Karatekin O, Kasaba Y, Lanciano O, Lefèvre F, Lewis S, López-Puertas M, López-Valverde M, Mahieux A, Mason J, Mc Connell J, Hiromu Neary Nakagawa L, Neefs E, Novak R, Oliva F, Piccialli A, Renotte E, Robert S, Sindoni G, Stiepen A, Trokhimovskiy A, Vander Auwera J, Viscardy S, Whiteway J, Willame Y, Wilquet V, Wolff M, Wolkenberg P, Aparicio del Moral B, Barzin P, Beeckman B, BenMoussa A, Berkenbosch S, Biondi D, Bonnewijn S, Candini GP, Clairquin R, Cubas J, Giordanengo B, Gissot S, Gomez A, Hathi B, Jeronimo Zafra J, Leese M, Maes J, Mazy E, Mazzoli A, Meseguer J, Morales R, Orban A, Pastor-Morales M, Perez-grande I, Queirolo C, Rodriguez Gomez J, Saggin B, Samain V, Sanz Andres A, Sanz R, Simar J-F and Thibert T (2019), "Methane on Mars: New insights into the sensitivity of CH4 with the NOMAD/ExoMars spectrometer through its first in-flight calibration", Icarus. Vol. 321, pp. 671 – 690. [Abstract] [BibTeX] [DOI]
Abstract: The Nadir and Occultation for MArs Discovery instrument (NOMAD), onboard the ExoMars Trace Gas Orbiter (TGO) spacecraft was conceived to observe Mars in solar occultation, nadir, and limb geometries, and will be able to produce an outstanding amount of diverse data, mostly focused on properties of the atmosphere. The infrared channels of the instrument operate by combining an echelle grating spectrometer with an Acousto-Optical Tunable Filter (AOTF). Using in-flight data, we characterized the instrument performance and parameterized its calibration. In particular: an accurate frequency calibration was achieved, together with its variability due to thermal effects on the grating. The AOTF properties and transfer function were also quantified, and we developed and tested a realistic method to compute the spectral continuum transmitted through the coupled grating and AOTF system. The calibration results enabled unprecedented insights into the important problem of the sensitivity of NOMAD to methane abundances in the atmosphere. We also deeply characterized its performance under realistic conditions of varying aerosol abundances, diverse albedos and changing illumination conditions as foreseen over the nominal mission. The results show that, in low aerosol conditions, NOMAD single spectrum, 1σ sensitivity to CH4 is around 0.33 ppbv at 20 km of altitude when performing solar occultations, and better than 1 ppbv below 30 km. In dusty conditions, we show that the sensitivity drops to 0 below 10 km. In Nadir geometry, results demonstrate that NOMAD will be able to produce seasonal maps of CH4 with a sensitivity around 5 ppbv over most of planet's surface with spatial integration over 5 × 5° bins. Results show also that such numbers can be improved by a factor of 10 to 30 by data binning. Overall, our results quantify NOMAD's capability to address the variable aspects of Martian climate. © 2018 Elsevier Inc.
BibTeX: @article{Liuzzi2019, author = {Liuzzi, Giuliano and Villanueva, Geronimo L. and Mumma, Michael J. and Smith, Michael D. and Daerden, Frank and Ristic, Bojan and Thomas, Ian and Vandaele, Ann Carine and Patel, Manish R. and Lopez-Moreno, José-Juan and Bellucci, Giancarlo and Allen, Mark and Alonso-Rodrigo, Gustavo and Altieri, Francesca and Aoki, Shohei and Bauduin, Sophie and Bolsée, David and Clancy, Todd and Cloutis, Edward and D'Aversa, Emiliano and Depiesse, Cédric and Erwin, Justin and Fedorova, Anna and Formisano, Vittorio and Funke, Bernd and Fussen, Didier and Garcia-Comas, Maia and Geminale, Anna and Gérard, Jean-Claude and Gillotay, Didier and Giuranna, Marco and Gonzalez-Galindo, Francisco and Hewson, Will and Homes, James and Ignatiev, Nicolai and Kaminski, Jacek and Karatekin, Ozgur and Kasaba, Yasumasa and Lanciano, Orietta and Lefèvre, Franck and Lewis, Stephen and López- Puertas, Manuel and López-Valverde, Miguel and Mahieux, Arnaud and Mason, Jon and Mc Connell, Jack and Hiromu Neary Nakagawa, Lori and Neefs, Eddy and Novak, R. and Oliva, Fabrizio and Piccialli, Arianna and Renotte, Etienne and Robert, Severine and Sindoni, Giuseppe and Stiepen, Arnaud and Trokhimovskiy, Alexander and Vander Auwera, Jean and Viscardy, Sébastien and Whiteway, Jim and Willame, Yannick and Wilquet, Valérie and Wolff, Michael and Wolkenberg, Paulina and Aparicio del Moral, Beatriz and Barzin, Pascal and Beeckman, Bram and BenMoussa, Ali and Berkenbosch, Sophie and Biondi, David and Bonnewijn, Sabrina and Candini, Gian Paolo and Clairquin, Roland and Cubas, Javier and Giordanengo, Boris and Gissot, Samuel and Gomez, Alejandro and Hathi, Brijen and Jeronimo Zafra, Jose and Leese, Mark and Maes, Jeroen and Mazy, Emmanuel and Mazzoli, Alexandra and Meseguer, Jose and Morales, Rafael and Orban, Anne and Pastor-Morales, M. and Perez-grande, Isabel and Queirolo, Claudio and Rodriguez Gomez, Julio and Saggin, Bortolino and Samain, Valérie and Sanz Andres, Angel and Sanz, Rosario and Simar, Juan-Felipe and Thibert, Tanguy}, title = {Methane on Mars: New insights into the sensitivity of CH4 with the NOMAD/ExoMars spectrometer through its first in-flight calibration}, journal = {Icarus}, year = {2019}, volume = {321}, pages = {671 – 690}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.icarus.2018.09.021} }
Lutsch E, Strong K, Jones DBA, Ortega I, Hannigan JW, Dammers E, Shephard MW, Morris E, Murphy K, Evans MJ, Parrington M, Whitburn S, Van Damme M, Clarisse L, Coheur P-F, Clerbaux C, Croft B, Martin RV, Pierce JR and Fisher JA (2019), "Unprecedented Atmospheric Ammonia Concentrations Detected in the High Arctic From the 2017 Canadian Wildfires", Journal of Geophysical Research: Atmospheres. Vol. 124(14), pp. 8178 – 8202. [Abstract] [BibTeX] [DOI]
Abstract: From 17–22 August 2017 simultaneous enhancements of ammonia (NH3), carbon monoxide (CO), hydrogen cyanide (HCN), and ethane (C2H6) were detected from ground-based solar absorption Fourier transform infrared (FTIR) spectroscopic measurements at two high-Arctic sites: Eureka (80.05°N, 86.42°W) Nunavut, Canada, and Thule (76.53°N, 68.74°W), Greenland. These enhancements were attributed to wildfires in British Columbia and the Northwest Territories of Canada using FLEXPART back-trajectories and fire locations from Moderate Resolution Imaging Spectroradiometer (MODIS) and found to be the greatest observed enhancements in more than a decade of measurements at Eureka (2006–2017) and Thule (1999–2017). Observations of gas-phase NH3 from these wildfires illustrate that boreal wildfires may be a considerable episodic source of NH3 in the summertime high Arctic. Comparisons of GEOS-Chem model simulations using the Global Fire Assimilation System (GFASv1.2) biomass burning emissions to FTIR measurements and Infrared Atmospheric Sounding Interferometer (IASI) measurements showed that the transport of wildfire emissions to the Arctic was underestimated in GEOS-Chem. However, GEOS-Chem simulations showed that these wildfires contributed to surface layer NH3 and NH4 + enhancements of 0.01–0.11 ppbv and 0.05–1.07 ppbv, respectively, over the Canadian Archipelago from 15–23 August 2017. ©2019. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Lutsch2019, author = {Lutsch, Erik and Strong, Kimberly and Jones, Dylan B. A. and Ortega, Ivan and Hannigan, James W. and Dammers, Enrico and Shephard, Mark W. and Morris, Eleanor and Murphy, Killian and Evans, Mathew J. and Parrington, Mark and Whitburn, Simon and Van Damme, Martin and Clarisse, Lieven and Coheur, Pierre-Francois and Clerbaux, Cathy and Croft, Betty and Martin, Randall V. and Pierce, Jeffrey R. and Fisher, Jenny A.}, title = {Unprecedented Atmospheric Ammonia Concentrations Detected in the High Arctic From the 2017 Canadian Wildfires}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2019}, volume = {124}, number = {14}, pages = {8178 – 8202}, note = {All Open Access, Green Open Access}, doi = {10.1029/2019JD030419} }
Maggiolo R, Gibbons A, Cessateur G, Keyser JD, Dhooghe F, Gunell H, Loreau J, Mousis O and Vaeck N (2019), "Effect of the Surface Roughness of Icy Grains on Molecular Oxygen Chemistry in Molecular Clouds", Astrophysical Journal. Vol. 882(2) [Abstract] [BibTeX] [DOI]
Abstract: Molecular cloud and protosolar nebula chemistry involves a strong interaction between the gas phase and the surface of icy grains. The exchanges between the gas phase and the solid phase depend not only on the adsorption and desorption rates but also on the geometry of the surface of the grains. Indeed, for sufficient levels of surface roughness, atoms and molecules have a significant probability to collide with the grain icy mantle several times before being potentially captured. In consequence, their net sticking probability may differ from their sticking probability for a single collision with the grain surface. We estimate the effectiveness of the recapture on uneven surfaces for the various desorption processes at play in astrophysical environments. We show that surface roughness has a significant effect on the desorption rates. We focus in particular on the production of O2 since unexpectedly large amounts of it, probably incorporated in the comet when it formed, have been detected in the coma of comet 67P by the Rosetta probe. Our results suggest that the higher escape probability of hydrogen compared to heavier species on rough surfaces can contribute to enhancing the production of O2 in the icy mantles of grains while keeping its abundance low in the gas phase and may significantly decrease the desorption probability of molecules involved in the O2 chemical network. © 2019. The American Astronomical Society. All rights reserved..
BibTeX: @article{Maggiolo2019, author = {Maggiolo, R. and Gibbons, A. and Cessateur, G. and Keyser, J. De and Dhooghe, F. and Gunell, H. and Loreau, J. and Mousis, O. and Vaeck, N.}, title = {Effect of the Surface Roughness of Icy Grains on Molecular Oxygen Chemistry in Molecular Clouds}, journal = {Astrophysical Journal}, year = {2019}, volume = {882}, number = {2}, note = {All Open Access, Bronze Open Access}, doi = {10.3847/1538-4357/ab3400} }
Papoulia A, Ekman J, Gaigalas G, Godefroid M, Gustafsson S, Hartman H, Li W, Radžiute L, Rynku P, Schiffmann S, Wang K and Jönsson P (2019), "Coulomb (Velocity) Gauge Recommended in Multiconfiguration Calculations of Transition Data Involving Rydberg Series", Atoms. Vol. 7(4) [Abstract] [BibTeX] [DOI]
Abstract: Astronomical spectroscopy has recently expanded into the near-infrared (nIR) wavelength region, raising the demands on atomic transition data. The interpretation of the observed spectra largely relies on theoretical results, and progress towards the production of accurate theoretical data must continuously be made. Spectrum calculations that target multiple atomic states at the same time are by nomeans trivial. Further, numerous atomic systems involve Rydberg series,which are associated with additional difficulties. In this work, we demonstrate how the challenges in the computations of Rydberg series can be handled in large-scale multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction (RCI) calculations. By paying special attention to the construction of the radial orbital basis that builds the atomic state functions, transition data that are weakly sensitive to the choice of gauge can be obtained. Additionally, we show that the Babushkin gauge should not always be considered as the preferred gauge, and that, in the computations of transition data involving Rydberg series, the Coulomb gauge could be more appropriate for the analysis of astrophysical spectra. To illustrate the above, results from computations of transitions involving Rydberg series in the astrophysically important C IV and C III ions are presented and analyzed. © 2019 by the authors.
BibTeX: @article{Papoulia2019, author = {Papoulia, Asimina and Ekman, Jörgen and Gaigalas, Gediminas and Godefroid, Michel and Gustafsson, Stefan and Hartman, Henrik and Li, Wenxian and Radžiute, Laima and Rynku, Pavel and Schiffmann, Sacha and Wang, Kai and Jönsson, Per}, title = {Coulomb (Velocity) Gauge Recommended in Multiconfiguration Calculations of Transition Data Involving Rydberg Series}, journal = {Atoms}, year = {2019}, volume = {7}, number = {4}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atoms7040106} }
Pardini F, Queißer M, Naismith A, Watson I, Clarisse L and Burton M (2019), "Initial constraints on triggering mechanisms of the eruption of Fuego volcano (Guatemala) from 3 June 2018 using IASI satellite data", Journal of Volcanology and Geothermal Research. Vol. 376, pp. 54 – 61. [Abstract] [BibTeX] [DOI]
Abstract: On 3 June 2018 Volcán de Fuego (Guatemala) erupted explosively with unusual intensity, producing wide-spread ash dispersal and pyroclastic flows of >11 km length, which destroyed a community on Fuego's flanks, causing hundreds of fatalities. Here, we analyze satellite measurements of the SO 2 plume emitted during the most intense eruptive phase. Key eruption parameters including the injection height and SO 2 flux time-series indicate a degassing intensity at least three orders of magnitude above baseline levels. Our results suggest a steady 2.5 hour climactic paroxysmal phase of the eruption with a mass eruption rate of 1.4kg s −1 based on the combination of plume height estimates and an eruption column model, producing 0.03 ± 0.004 km 3 of tephra. We detect at least 130 kt of emitted SO 2 from satellite images, producing a minimum dissolved magmatic sulfur concentration of 500 ppm. Possible source mechanisms are discussed, which may be useful in assessing the risks posed by future large-magnitude eruptions to the large populations that live on Fuego's flanks. This study shows that even under challenging conditions of a tropical atmosphere during the rainy season, vital eruption parameters to constrain source mechanisms of eruptions can be retrieved from satellite remote sensing data. © 2019 The Authors
BibTeX: @article{Pardini2019, author = {Pardini, F. and Queißer, M. and Naismith, A. and Watson, I.M. and Clarisse, L. and Burton, M.R.}, title = {Initial constraints on triggering mechanisms of the eruption of Fuego volcano (Guatemala) from 3 June 2018 using IASI satellite data}, journal = {Journal of Volcanology and Geothermal Research}, year = {2019}, volume = {376}, pages = {54 – 61}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.jvolgeores.2019.03.014} }
Tzompa-Sosa Z, Henderson B, Keller C, Travis K, Mahieu E, Franco B, Estes M, Helmig D, Fried A, Richter D, Weibring P, Walega J, Blake D, Hannigan J, Ortega I, Conway S, Strong K and Fischer E (2019), " Atmospheric Implications of Large C 2 -C 5 Alkane Emissions From the U.S. Oil and Gas Industry ", Journal of Geophysical Research: Atmospheres. Vol. 124(2), pp. 1148 – 1169. [Abstract] [BibTeX] [DOI]
Abstract: Emissions of C 2 -C 5 alkanes from the U.S. oil and gas sector have changed rapidly over the last decade. We use a nested GEOS-Chem simulation driven by updated 2011NEI emissions with aircraft, surface, and column observations to (1) examine spatial patterns in the emissions and observed atmospheric abundances of C 2 -C 5 alkanes over the United States and (2) estimate the contribution of emissions from the U.S. oil and gas industry to these patterns. The oil and gas sector in the updated 2011NEI contributes over 80% of the total U.S. emissions of ethane (C 2 H 6 ) and propane (C 3 H 8 ), and emissions of these species are largest in the central United States. Observed mixing ratios of C 2 -C 5 alkanes show enhancements over the central United States below 2 km. A nested GEOS-Chem simulation underpredicts observed C 3 H 8 mixing ratios in the boundary layer over several U.S. regions, and the relative underprediction is not consistent, suggesting C 3 H 8 emissions should receive more attention moving forward. Our decision to consider only C 4 -C 5 alkane emissions as a single lumped species produces a geographic distribution similar to observations. Due to the increasing importance of oil and gas emissions in the United States, we recommend continued support of existing long-term measurements of C 2 -C 5 alkanes. We suggest additional monitoring of C 2 -C 5 alkanes downwind of northeastern Colorado, Wyoming, and western North Dakota to capture changes in these regions. The atmospheric chemistry modeling community should also evaluate whether chemical mechanisms that lump larger alkanes are sufficient to understand air quality issues in regions with large emissions of these species. ©2018. American Geophysical Union. All Rights Reserved.
BibTeX: @article{TzompaSosa2019, author = {Tzompa-Sosa, Z.A. and Henderson, B.H. and Keller, C.A. and Travis, K. and Mahieu, E. and Franco, B. and Estes, M. and Helmig, D. and Fried, A. and Richter, D. and Weibring, P. and Walega, J. and Blake, D.R. and Hannigan, J.W. and Ortega, I. and Conway, S. and Strong, K. and Fischer, E.V.}, title = { Atmospheric Implications of Large C 2 -C 5 Alkane Emissions From the U.S. Oil and Gas Industry }, journal = {Journal of Geophysical Research: Atmospheres}, year = {2019}, volume = {124}, number = {2}, pages = {1148 – 1169}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1029/2018JD028955} }
Vandaele AC, Korablev O, Daerden F, Aoki S, Thomas IR, Altieri F, López-Valverde M, Villanueva G, Liuzzi G, Smith MD, Erwin JT, Trompet L, Fedorova AA, Montmessin F, Trokhimovskiy A, Belyaev DA, Ignatiev NI, Luginin M, Olsen KS, Baggio L, Alday J, Bertaux J-L, Betsis D, Bolsée D, Clancy RT, Cloutis E, Depiesse C, Funke B, Garcia-Comas M, Gérard J-C, Giuranna M, Gonzalez-Galindo F, Grigoriev AV, Ivanov YS, Kaminski J, Karatekin O, Lefèvre F, Lewis S, López-Puertas M, Mahieux A, Maslov I, Mason J, Mumma MJ, Neary L, Neefs E, Patrakeev A, Patsaev D, Ristic B, Robert S, Schmidt F, Shakun A, Teanby NA, Viscardy S, Willame Y, Whiteway J, Wilquet V, Wolff MJ, Bellucci G, Patel MR, López-Moreno J-J, Forget F, Wilson CF, Svedhem H, Vago JL, Rodionov D, Alonso-Rodrigo G, Bauduin S, Carrozzo G, Crismani M, Da Pieve F, D’Aversa E, Etiope G, Fussen D, Geminale A, Gkouvelis L, Holmes J, Hubert B, Kasaba Y, Kass D, Kleinböhl A, Lanciano O, Nakagawa H, Novak RE, Oliva F, Piccialli A, Renotte E, Ritter B, Schneider N, Sindoni G, Thiemann E, Vander Auwera J, Wolkenberg P, Yelle R, Anufreychik K, Arnold G, Duxbury N, Fouchet T, Grassi D, Guerlet S, Hartogh P, Khatuntsev I, Kokonkov N, Krasnopolsky V, Kuzmin R, Lacombe G, Lellouch E, Määttänen A, Marcq E, Martin-Torres J, Medvedev A, Millour E, Moshkin B, Quantin-Nataf C, Rodin A, Shematovich V, Thomas N, Trokhimovsky A, Vazquez L, Vincendon M, Young R, Zasova L, Zelenyi L and Zorzano MP (2019), "Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter", Nature. Vol. 568(7753), pp. 521 – 525. [Abstract] [BibTeX] [DOI]
Abstract: Global dust storms on Mars are rare1,2 but can affect the Martian atmosphere for several months. They can cause changes in atmospheric dynamics and inflation of the atmosphere3, primarily owing to solar heating of the dust3. In turn, changes in atmospheric dynamics can affect the distribution of atmospheric water vapour, with potential implications for the atmospheric photochemistry and climate on Mars4. Recent observations of the water vapour abundance in the Martian atmosphere during dust storm conditions revealed a high-altitude increase in atmospheric water vapour that was more pronounced at high northern latitudes5,6, as well as a decrease in the water column at low latitudes7,8. Here we present concurrent, high-resolution measurements of dust, water and semiheavy water (HDO) at the onset of a global dust storm, obtained by the NOMAD and ACS instruments onboard the ExoMars Trace Gas Orbiter. We report the vertical distribution of the HDO/H2O ratio (D/H) from the planetary boundary layer up to an altitude of 80 kilometres. Our findings suggest that before the onset of the dust storm, HDO abundances were reduced to levels below detectability at altitudes above 40 kilometres. This decrease in HDO coincided with the presence of water-ice clouds. During the storm, an increase in the abundance of H2O and HDO was observed at altitudes between 40 and 80 kilometres. We propose that these increased abundances may be the result of warmer temperatures during the dust storm causing stronger atmospheric circulation and preventing ice cloud formation, which may confine water vapour to lower altitudes through gravitational fall and subsequent sublimation of ice crystals3. The observed changes in H2O and HDO abundance occurred within a few days during the development of the dust storm, suggesting a fast impact of dust storms on the Martian atmosphere. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
BibTeX: @article{Vandaele2019a, author = {Vandaele, Ann Carine and Korablev, Oleg and Daerden, Frank and Aoki, Shohei and Thomas, Ian R. and Altieri, Francesca and López-Valverde, Miguel and Villanueva, Geronimo and Liuzzi, Giuliano and Smith, Michael D. and Erwin, Justin T. and Trompet, Loïc and Fedorova, Anna A. and Montmessin, Franck and Trokhimovskiy, Alexander and Belyaev, Denis A. and Ignatiev, Nikolay I. and Luginin, Mikhail and Olsen, Kevin S. and Baggio, Lucio and Alday, Juan and Bertaux, Jean-Loup and Betsis, Daria and Bolsée, David and Clancy, R. Todd and Cloutis, Edward and Depiesse, Cédric and Funke, Bernd and Garcia-Comas, Maia and Gérard, Jean-Claude and Giuranna, Marco and Gonzalez-Galindo, Francisco and Grigoriev, Alexey V. and Ivanov, Yuriy S. and Kaminski, Jacek and Karatekin, Ozgur and Lefèvre, Franck and Lewis, Stephen and López-Puertas, Manuel and Mahieux, Arnaud and Maslov, Igor and Mason, Jon and Mumma, Michael J. and Neary, Lori and Neefs, Eddy and Patrakeev, Andrey and Patsaev, Dmitry and Ristic, Bojan and Robert, Séverine and Schmidt, Frédéric and Shakun, Alexey and Teanby, Nicholas A. and Viscardy, Sébastien and Willame, Yannick and Whiteway, James and Wilquet, Valérie and Wolff, Michael J. and Bellucci, Giancarlo and Patel, Manish R. and López-Moreno, Jose-Juan and Forget, François and Wilson, Colin F. and Svedhem, Håkan and Vago, Jorge L. and Rodionov, Daniel and Alonso-Rodrigo, Gustavo and Bauduin, Sophie and Carrozzo, Giacomo and Crismani, Matteo and Da Pieve, Fabiana and D’Aversa, Emiliano and Etiope, Giuseppe and Fussen, Didier and Geminale, Anna and Gkouvelis, Leo and Holmes, James and Hubert, Benoît and Kasaba, Yasumasa and Kass, David and Kleinböhl, Armin and Lanciano, Orietta and Nakagawa, Hiromu and Novak, Robert E. and Oliva, Fabrizio and Piccialli, Arianna and Renotte, Etienne and Ritter, Birgit and Schneider, Nick and Sindoni, Giuseppe and Thiemann, Ed and Vander Auwera, Jean and Wolkenberg, Paulina and Yelle, Roger and Anufreychik, Konstantin and Arnold, Gabriele and Duxbury, Natalia and Fouchet, Thierry and Grassi, Davide and Guerlet, Sandrine and Hartogh, Paul and Khatuntsev, Igor and Kokonkov, Nikita and Krasnopolsky, Vladimir and Kuzmin, Ruslan and Lacombe, Gaétan and Lellouch, Emmanuel and Määttänen, Anni and Marcq, Emmanuel and Martin-Torres, Javier and Medvedev, Alexander and Millour, Ehouarn and Moshkin, Boris and Quantin-Nataf, Cathy and Rodin, Alexander and Shematovich, Valery and Thomas, Nicolas and Trokhimovsky, Alexander and Vazquez, Luis and Vincendon, Matthieu and Young, Roland and Zasova, Ludmila and Zelenyi, Lev and Zorzano, Maria Paz}, title = {Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter}, journal = {Nature}, year = {2019}, volume = {568}, number = {7753}, pages = {521 – 525}, doi = {10.1038/s41586-019-1097-3} }
Vandaele AC, Korablev O, Daerden F, Aoki S, Thomas IR, Altieri F, López-Valverde M, Villanueva G, Liuzzi G, Smith MD, Erwin JT, Trompet L, Fedorova AA, Montmessin F, Trokhimovskiy A, Belyaev DA, Ignatiev NI, Luginin M, Olsen KS, Baggio L, Alday J, Bertaux J-L, Betsis D, Bolsée D, Clancy RT, Cloutis E, Depiesse C, Funke B, Garcia-Comas M, Gérard J-C, Giuranna M, Gonzalez-Galindo F, Grigoriev AV, Ivanov YS, Kaminski J, Karatekin O, Lefèvre F, Lewis S, López-Puertas M, Mahieux A, Maslov I, Mason J, Mumma MJ, Neary L, Neefs E, Patrakeev A, Patsaev D, Ristic B, Robert S, Schmidt F, Shakun A, Teanby NA, Viscardy S, Willame Y, Whiteway J, Wilquet V, Wolff MJ, Bellucci G, Patel MR, López-Moreno J-J, Forget F, Wilson CF, Young R, Svedhem H, Vago JL, Rodionov D, Alonso-Rodrigo G, Bauduin S, Carrozzo G, Crismani M, Da Pieve F, D’Aversa E, Etiope G, Fussen D, Geminale A, Gkouvelis L, Holmes J, Hubert B, Kasaba Y, Kass D, Kleinböhl A, Lanciano O, Nakagawa H, Novak RE, Oliva F, Piccialli A, Renotte E, Ritter B, Schneider N, Sindoni G, Thiemann E, Vander Auwera J, Wolkenberg P, Yelle R, Anufreychik K, Arnold G, Duxbury N, Fouchet T, Grassi D, Guerlet S, Hartogh P, Khatuntsev I, Kokonkov N, Krasnopolsky V, Kuzmin R, Lacombe G, Lellouch E, Määttänen A, Marcq E, Martin-Torres J, Medvedev A, Millour E, Moshkin B, Quantin-Nataf C, Rodin A, Shematovich V, Thomas N, Trokhimovsky A, Vazquez L, Vincendon M, Zasova L, Zelenyi L and Zorzano MP (2019), "Publisher Correction: Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter (Nature, (2019), 568, 7753, (521-525), 10.1038/s41586-019-1097-3)", Nature. Vol. 569(7754), pp. E1. [Abstract] [BibTeX] [DOI]
Abstract: The surname of author Cathy Quantin-Nataf was misspelled ‘Quantin-Nata’ , authors Ehouarn Millour and Roland Young were missing from the ACS Science Team list, and minor changes have been made to the author and affiliation lists; see accompanying Amendment. These errors have been corrected online. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
BibTeX: @article{Vandaele2019, author = {Vandaele, Ann Carine and Korablev, Oleg and Daerden, Frank and Aoki, Shohei and Thomas, Ian R. and Altieri, Francesca and López-Valverde, Miguel and Villanueva, Geronimo and Liuzzi, Giuliano and Smith, Michael D. and Erwin, Justin T. and Trompet, Loïc and Fedorova, Anna A. and Montmessin, Franck and Trokhimovskiy, Alexander and Belyaev, Denis A. and Ignatiev, Nikolay I. and Luginin, Mikhail and Olsen, Kevin S. and Baggio, Lucio and Alday, Juan and Bertaux, Jean-Loup and Betsis, Daria and Bolsée, David and Clancy, R. Todd and Cloutis, Edward and Depiesse, Cédric and Funke, Bernd and Garcia-Comas, Maia and Gérard, Jean-Claude and Giuranna, Marco and Gonzalez-Galindo, Francisco and Grigoriev, Alexey V. and Ivanov, Yuriy S. and Kaminski, Jacek and Karatekin, Ozgur and Lefèvre, Franck and Lewis, Stephen and López-Puertas, Manuel and Mahieux, Arnaud and Maslov, Igor and Mason, Jon and Mumma, Michael J. and Neary, Lori and Neefs, Eddy and Patrakeev, Andrey and Patsaev, Dmitry and Ristic, Bojan and Robert, Séverine and Schmidt, Frédéric and Shakun, Alexey and Teanby, Nicholas A. and Viscardy, Sébastien and Willame, Yannick and Whiteway, James and Wilquet, Valérie and Wolff, Michael J. and Bellucci, Giancarlo and Patel, Manish R. and López-Moreno, Jose-Juan and Forget, François and Wilson, Colin F. and Young, Roland and Svedhem, Håkan and Vago, Jorge L. and Rodionov, Daniel and Alonso-Rodrigo, Gustavo and Bauduin, Sophie and Carrozzo, Giacomo and Crismani, Matteo and Da Pieve, Fabiana and D’Aversa, Emiliano and Etiope, Giuseppe and Fussen, Didier and Geminale, Anna and Gkouvelis, Leo and Holmes, James and Hubert, Benoît and Kasaba, Yasumasa and Kass, David and Kleinböhl, Armin and Lanciano, Orietta and Nakagawa, Hiromu and Novak, Robert E. and Oliva, Fabrizio and Piccialli, Arianna and Renotte, Etienne and Ritter, Birgit and Schneider, Nick and Sindoni, Giuseppe and Thiemann, Ed and Vander Auwera, Jean and Wolkenberg, Paulina and Yelle, Roger and Anufreychik, Konstantin and Arnold, Gabriele and Duxbury, Natalia and Fouchet, Thierry and Grassi, Davide and Guerlet, Sandrine and Hartogh, Paul and Khatuntsev, Igor and Kokonkov, Nikita and Krasnopolsky, Vladimir and Kuzmin, Ruslan and Lacombe, Gaétan and Lellouch, Emmanuel and Määttänen, Anni and Marcq, Emmanuel and Martin-Torres, Javier and Medvedev, Alexander and Millour, Ehouarn and Moshkin, Boris and Quantin-Nataf, Cathy and Rodin, Alexander and Shematovich, Valery and Thomas, Nicolas and Trokhimovsky, Alexander and Vazquez, Luis and Vincendon, Matthieu and Zasova, Ludmila and Zelenyi, Lev and Zorzano, Maria Paz}, title = {Publisher Correction: Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter (Nature, (2019), 568, 7753, (521-525), 10.1038/s41586-019-1097-3)}, journal = {Nature}, year = {2019}, volume = {569}, number = {7754}, pages = {E1}, note = {All Open Access, Bronze Open Access}, doi = {10.1038/s41586-019-1163-x} }
Wespes C, Hurtmans D, Chabrillat S, Ronsmans G, Clerbaux C and Coheur P-F (2019), "Is the recovery of stratospheric O3 speeding up in the Southern Hemisphere? An evaluation from the first IASI decadal record (2008-2017)", Atmospheric Chemistry and Physics. Vol. 19(22), pp. 14031 – 14056. [Abstract] [BibTeX] [DOI]
Abstract: In this paper, we present the global fingerprint of recent changes in middle-upper stratosphere (MUSt; 25 hPa) ozone (O3) in comparison with lower stratosphere (LSt; 150-25 hPa) O3 derived from the first 10 years of the IASI/Metop-A satellite measurements (January 2008-December 2017). The IASI instrument provides vertically resolved O3 profiles with very high spatial and temporal (twice daily) samplings, allowing O3 changes to be monitored in these two regions of the stratosphere. By applying multivariate regression models with adapted geophysical proxies on daily mean O3 time series, we discriminate anthropogenic trends from various modes of natural variability, such as the El Niño-Southern Oscillation (ENSO). The representativeness of the O3 response to its natural drivers is first examined. One important finding relies on a pronounced contrast between a positive LSt O3 response to ENSO in the extratropics and a negative one in the tropics, with a delay of 3 months, which supports a stratospheric pathway for the ENSO influence on lower stratospheric and tropospheric O3. In terms of trends, we find an unequivocal O3 recovery from the available period of measurements in winter-spring at middle to high latitudes for the two stratospheric layers sounded by IASI ( 35 N-S in the MUSt and 45 S in the LSt) as well as in the total columns at southern latitudes (45 S) where the increase reaches its maximum. These results confirm the effectiveness of the Montreal Protocol and its amendments and represent the first detection of a significant recovery of O3 concurrently in the lower, in the middle-upper stratosphere and in the total column from one single satellite dataset. A significant decline in O3 at northern mid-latitudes in the LSt is also detected, especially in winter-spring of the Northern Hemisphere. Given counteracting trends in the LSt and MUSt at these latitudes, the decline is not categorical in total O3. When freezing the regression coefficients determined for each natural driver over the whole IASI period but adjusting a trend, we calculate a significant speeding up in the O3 response to the decline of O3-depleting substances (ODSs) in the total column, in the LSt and, to a lesser extent, in the MUSt, at high southern latitudes over the year. Results also show a small significant acceleration of the O3 decline at northern mid-latitudes in the LSt and in the total column over the last few years. That, specifically, needs urgent investigation to identify its exact origin and apprehend its impact on climate change. Additional years of IASI measurements would, however, be required to confirm the O3 change rates observed in the stratospheric layers over the last few years. © Author(s) 2019.
BibTeX: @article{Wespes2019, author = {Wespes, Catherine and Hurtmans, Daniel and Chabrillat, Simon and Ronsmans, Gaetane and Clerbaux, Cathy and Coheur, Pierre-Francois}, title = {Is the recovery of stratospheric O3 speeding up in the Southern Hemisphere? An evaluation from the first IASI decadal record (2008-2017)}, journal = {Atmospheric Chemistry and Physics}, year = {2019}, volume = {19}, number = {22}, pages = {14031 – 14056}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-19-14031-2019} }
Xie L, Yang X, Wraith C, Babcock C, Bieroń J, Billowes J, Bissell M, Blaum K, Cheal B, Filippin L, Flanagan K, Garcia Ruiz R, Gins W, Gaigalas G, Godefroid M, Gorges C, Grob L, Heylen H, Jönsson P, Kaufmann S, Kowalska M, Krämer J, Malbrunot-Ettenauer S, Neugart R, Neyens G, Nörtershäuser W, Otsuka T, Papuga J, Sánchez R, Tsunoda Y and Yordanov D (2019), "Nuclear charge radii of 62−80Zn and their dependence on cross-shell proton excitations", Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. Vol. 797 [Abstract] [BibTeX] [DOI]
Abstract: Nuclear charge radii of 62−80Zn have been determined using collinear laser spectroscopy of bunched ion beams at CERN-ISOLDE. The subtle variations of observed charge radii, both within one isotope and along the full range of neutron numbers, are found to be well described in terms of the proton excitations across the Z=28 shell gap, as predicted by large-scale shell model calculations. It comprehensively explains the changes in isomer-to-ground state mean square charge radii of 69−79Zn, the inversion of the odd-even staggering around N=40 and the odd-even staggering systematics of the Zn charge radii. With two protons above Z=28, the observed charge radii of the Zn isotopic chain show a cumulative effect of different aspects of nuclear structure including single particle structure, shell closure, correlations and deformations near the proposed doubly magic nuclei, 68Ni and 78Ni. © 2019 The Author(s)
BibTeX: @article{Xie2019, author = {Xie, L. and Yang, X.F. and Wraith, C. and Babcock, C. and Bieroń, J. and Billowes, J. and Bissell, M.L. and Blaum, K. and Cheal, B. and Filippin, L. and Flanagan, K.T. and Garcia Ruiz, R.F. and Gins, W. and Gaigalas, G. and Godefroid, M. and Gorges, C. and Grob, L.K. and Heylen, H. and Jönsson, P. and Kaufmann, S. and Kowalska, M. and Krämer, J. and Malbrunot-Ettenauer, S. and Neugart, R. and Neyens, G. and Nörtershäuser, W. and Otsuka, T. and Papuga, J. and Sánchez, R. and Tsunoda, Y. and Yordanov, D.T.}, title = {Nuclear charge radii of 62−80Zn and their dependence on cross-shell proton excitations}, journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, year = {2019}, volume = {797}, note = {All Open Access, Gold Open Access}, doi = {10.1016/j.physletb.2019.134805} }
Amyay B, Gardez A, Georges R, Biennier L, Vander Auwera J, Richard C and Boudon V (2018), " Erratum: "New investigation of the ν 3 C-H stretching region of 12 CH 4 through the analysis of high temperature infrared emission spectra" [J. Chem. Phys. 148, 134306 (2018) ", The Journal of chemical physics. Vol. 148(16), pp. 169902. [BibTeX] [DOI]
BibTeX: @article{Amyay2018a, author = {Amyay, Badr and Gardez, Aline and Georges, Robert and Biennier, Ludovic and Vander Auwera, Jean and Richard, Cyril and Boudon, Vincent}, title = { Erratum: "New investigation of the ν 3 C-H stretching region of 12 CH 4 through the analysis of high temperature infrared emission spectra" [J. Chem. Phys. 148, 134306 (2018) }, journal = {The Journal of chemical physics}, year = {2018}, volume = {148}, number = {16}, pages = {169902}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.5034108} }
Amyay B, Gardez A, Georges R, Biennier L, Vander Auwera J, Richard C and Boudon V (2018), "New investigation of the ν 3 C-H stretching region of 12CH4 through the analysis of high temperature infrared emission spectra", Journal of Chemical Physics. Vol. 148(13) [Abstract] [BibTeX] [DOI]
Abstract: The ν3 C-H stretching region of methane was reinvestigated in this work using high temperature (620-1715 K) emission spectra recorded in Rennes at Doppler limited resolution. This work follows our recent global analysis of the Dyad system Δn = ±1 (1000-1500 cm-1), with n being the polyad number [B. Amyay et al., J. Chem. Phys. 144, 24312 (2016)]. Thanks to the high temperature, new assignments of vibration-rotation methane line positions have been achieved successfully in the Pentad system and some associated hot bands (Δn = ±2) observed in the spectral region 2600-3300 cm-1. In particular, rotational assignments in the cold band [Pentad-ground state (GS)] and in the first related hot band (Octad-Dyad) were extended up to J = 30 and 27, respectively. In addition, 1525 new transitions belonging to the Tetradecad-Pentad hot band system were assigned for the first time, up to J = 20. The effective global model used to deal with the new assignments was developed to the 6th order for the first three polyads (Monad, Dyad, and Pentad), and to the 5th order for both the Octad and the Tetradecad. 1306 effective parameters were fitted with a dimensionless standard deviation σ = 2.64. The root mean square deviations dRMS obtained are 4.18 × 10-3 cm-1 for the Pentad-GS cold band, 2.48 × 10-3 cm-1 for the Octad-Dyad, and 1.43 × 10-3 cm-1 for the Tetradecad-Pentad hot bands. © 2018 Author(s).
BibTeX: @article{Amyay2018, author = {Amyay, Badr and Gardez, Aline and Georges, Robert and Biennier, Ludovic and Vander Auwera, Jean and Richard, Cyril and Boudon, Vincent}, title = {New investigation of the ν 3 C-H stretching region of 12CH4 through the analysis of high temperature infrared emission spectra}, journal = {Journal of Chemical Physics}, year = {2018}, volume = {148}, number = {13}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.5023331} }
Aourir N, Nemouchi M, Godefroid M and Jönsson P (2018), "Theoretical hyperfine structures of F 19 i and O 17 i", Physical Review A. Vol. 97(3) [Abstract] [BibTeX] [DOI]
Abstract: Multiconfiguration Hartree-Fock (MCHF) and multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations are performed for the 2p5Po2, 2p4(3P)3s4P, 2p4(3P)3s2P, and 2p4(3P)3p4So states of F19 i to determine their hyperfine constants. Several computing strategies are considered to investigate electron correlation and relativistic effects. High-order correlation contributions are included in MCHF calculations based on single and double multireference expansions. The largest components of the single reference MCHF wave functions are selected to define the multireference (MR) sets. In this scheme, relativistic corrections are evaluated in the Breit-Pauli approximation. A similar strategy is used for the calculation of MCDHF relativistic wave functions and hyperfine parameters. While correlation and relativistic corrections are found to be rather small for the ground state, we highlight large relativistic effects on the hyperfine constant A3/2 of 2p4(3P)3p4So and, to a lesser extent, on A1/2 of 2p4(3P)3s4P. As expected for such a light system, electron correlation effects dominate over relativity in the calculation of the hyperfine interaction of all other levels considered. We also revisit the hyperfine constants of 2p3(4S)3sSo5 and 2p3(4S)3p5P in O17 using similar strategies. The results are found to be in excellent agreement with experiment. © 2018 American Physical Society.
BibTeX: @article{Aourir2018, author = {Aourir, Nouria and Nemouchi, Messaoud and Godefroid, Michel and Jönsson, Per}, title = {Theoretical hyperfine structures of F 19 i and O 17 i}, journal = {Physical Review A}, year = {2018}, volume = {97}, number = {3}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.97.032506} }
Bauduin S, Irwin P, Lellouch E, Cottini V, Moreno R, Nixon C, Teanby N, Ansty T and Flasar F (2018), "Retrieval of H2O abundance in Titan's stratosphere: A (re)analysis of CIRS/Cassini and PACS/Herschel observations", Icarus. Vol. 311, pp. 288 – 305. [Abstract] [BibTeX] [DOI]
Abstract: Since its first measurement 20 years ago by the Infrared Space Observatory (ISO), the water (H2O) mole fraction in Titan's stratosphere remains uncertain due to large differences between the determinations from available measurements. More particularly, the recent measurements made from the Herschel observatory (PACS and HIFI) estimated the H2O mole fraction to be 0.023 ppb at 12.1 mbar. A mixing ratio of 0.14 ppb at 10.7 mbar was, however, retrieved from nadir spatially-resolved observations of Cassini/CIRS. At the same pressure level (10.7 mbar), this makes a difference of a factor of 5.5 between PACS and CIRS measurements, and this has notably prevented current models from fully constraining the oxygen flux flowing into Titan's atmosphere. In this work, we try to understand the differences between the H2O mole fractions estimated from Herschel/PACS and Cassini/CIRS observations. The strategy for this is to 1) analyse recent disc-averaged observations of CIRS to investigate if the observation geometry could explain the previous observed differences, and 2) (re)analyse the three types of observation with the same retrieval scheme to assess if previous differences in retrieval codes/methodology could be responsible for the previous discrepancies. With this analysis, we show that using the same retrieval method better reconcile the previous measurements of these instruments. However, the addition of the disc-averaged CIRS observations, instead of confirming the consistency between the different datasets, reveals discrepancies between one of the CIRS disc-averaged set of observations and PACS measurements. This raises new questions regarding the possibility of latitudinal variations of H2O, which could be triggered by seasonal changes of the meridional circulation. As it has already been shown for nitriles and hydrocarbons, this circulation could potentially impact the latitudinal distribution of H2O through the subsidence or upwelling of air rich in H2O. The possible influence of spatial/time variations of the OH/H2O input flux in Titan's atmosphere is also discussed. The analysis of more observations will be needed in future work to address the questions arising from this work and to improve the understanding of the sources of H2O in Titan's atmosphere. © 2018 Elsevier Inc.
BibTeX: @article{Bauduin2018, author = {Bauduin, S. and Irwin, P.G.J. and Lellouch, E. and Cottini, V. and Moreno, R. and Nixon, C.A. and Teanby, N.A. and Ansty, T. and Flasar, F.M.}, title = {Retrieval of H2O abundance in Titan's stratosphere: A (re)analysis of CIRS/Cassini and PACS/Herschel observations}, journal = {Icarus}, year = {2018}, volume = {311}, pages = {288 – 305}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.icarus.2018.04.003} }
Bieroń J, Filippin L, Gaigalas G, Godefroid M, Jönsson P and Pyykkö P (2018), "Ab initio calculations of the hyperfine structure of zinc and evaluation of the nuclear quadrupole moment Q(Zn 67)", Physical Review A. Vol. 97(6) [Abstract] [BibTeX] [DOI]
Abstract: The relativistic multiconfiguration Dirac-Hartree-Fock and the nonrelativistic multiconfiguration Hartree-Fock methods have been employed to calculate the magnetic dipole and electric quadrupole hyperfine structure constants of zinc. The calculated electric field gradients for the 4s4pP1o3 and 4s4pP2o3 states, together with experimental values of the electric quadrupole hyperfine structure constants, made it possible to extract a nuclear electric quadrupole moment Q(Zn67)=0.122(10) b. The error bar was evaluated in a quasistatistical approach - the calculations were carried out with 11 different methods, and then the error bar was estimated from the differences between the results obtained with those methods. © 2018 American Physical Society.
BibTeX: @article{Bieron2018, author = {Bieroń, Jacek and Filippin, Livio and Gaigalas, Gediminas and Godefroid, Michel and Jönsson, Per and Pyykkö, Pekka}, title = {Ab initio calculations of the hyperfine structure of zinc and evaluation of the nuclear quadrupole moment Q(Zn 67)}, journal = {Physical Review A}, year = {2018}, volume = {97}, number = {6}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.97.062505} }
Boudon V, Grigoryan T, Philipot F, Richard C, Tchana FK, Manceron L, Rizopoulos A, Auwera JV and Encrenaz T (2018), "Line positions and intensities for the ν3 band of 5 isotopologues of germane for planetary applications", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 205, pp. 174 – 183. [Abstract] [BibTeX] [DOI]
Abstract: The germane molecule, GeH4, is present in the atmospheres of giant planets Jupiter and Saturn. The ongoing NASA mission Juno has renewed interest in its spectroscopy, whose accurate modeling is essential for the retrieval of other tropospheric species. We present here the first complete analysis and modeling of line positions and intensities in the strongly absorbing ν1/ν3 stretching dyad region near 2100 cm−1, for all five germane isotopologues in natural abundance. New infrared spectra were recorded, absolute intensities were extracted through a careful procedure and modeled thanks to the formalism and programs developed in the Dijon group. A database of calculated germane lines, GeCaSDa, has been build and is available online through the Virtual Atomic and Molecular Data Centre (VAMDC) portal and at http://vamdc.icb.cnrs.fr/PHP/gecasda.php. © 2017 Elsevier Ltd
BibTeX: @article{Boudon2018a, author = {Boudon, V. and Grigoryan, T. and Philipot, F. and Richard, C. and Tchana, F. Kwabia and Manceron, L. and Rizopoulos, A. and Auwera, J. Vander and Encrenaz, Th.}, title = {Line positions and intensities for the ν3 band of 5 isotopologues of germane for planetary applications}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2018}, volume = {205}, pages = {174 – 183}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2017.10.017} }
Boudon V, Sears T and Coheur P-F (2018), "Introduction to the special issue on molecular spectroscopy, atmospheric composition and climate change", Journal of Molecular Spectroscopy. Vol. 348, pp. 1. [BibTeX] [DOI]
BibTeX: @article{Boudon2018, author = {Boudon, Vincent and Sears, Trevor and Coheur, Pierre-François}, title = {Introduction to the special issue on molecular spectroscopy, atmospheric composition and climate change}, journal = {Journal of Molecular Spectroscopy}, year = {2018}, volume = {348}, pages = {1}, doi = {10.1016/j.jms.2018.04.005} }
Boynard A, Hurtmans D, Garane K, Goutail F, Hadji-Lazaro J, Elissavet Koukouli M, Wespes C, Vigouroux C, Keppens A, Pazmino A, Balis D, Loyola D, Valks P, Sussmann R, Smale D, Coheur P-F and Clerbaux C (2018), "Validation of the IASI FORLI/EUMETSAT ozone products using satellite (GOME-2), ground-based (Brewer-Dobson, SAOZ, FTIR) and ozonesonde measurements", Atmospheric Measurement Techniques. Vol. 11(9), pp. 5125 – 5152. [Abstract] [BibTeX] [DOI]
Abstract: This paper assesses the quality of IASI (Infrared Atmospheric Sounding Interferometer)/Metop-A (IASI-A) and IASI/Metop-B (IASI-B) ozone (O3) products (total and partial O3 columns) retrieved with the Fast Optimal Retrievals on Layers for IASI Ozone (FORLI-O3; v20151001) software for 9 years (2008-July 2017) through an extensive intercomparison and validation exercise using independent observations (satellite, ground-based and ozonesonde). Compared with the previous version of FORLI-O3 (v20140922), several improvements have been introduced in FORLI-O3 v20151001, including absorbance look-up tables recalculated to cover a larger spectral range, with additional numerical corrections. This leads to a change of ĝ1/4 4 % in the total ozone column (TOC) product, which is mainly associated with a decrease in the retrieved O3 concentration in the middle stratosphere (above 30 hPa/25 km). IASI-A and IASI-B TOCs are consistent, with a global mean difference of less than 0.3 % for both daytime and nighttime measurements; IASI-A is slightly higher than IASI-B. A global difference of less than 2.4 % is found for the tropospheric (TROPO) O3 column product (IASI-A is lower than IASI-B), which is partly due to a temporary issue related to the IASI-A viewing angle in 2015. Our validation shows that IASI-A and IASI-B TOCs are consistent with GOME-2 (Global Ozone Monitoring Experiment-2), Dobson, Brewer, SAOZ (Système d'Analyse par Observation Zénithale) and FTIR (Fourier transform infrared) TOCs, with global mean differences in the range of 0.1 %-2 % depending on the instruments compared. The worst agreement with UV-vis retrieved TOC (satellite and ground) is found at the southern high latitudes. The IASI-A and ground-based TOC comparison for the period from 2008 to July 2017 shows the long-Term stability of IASI-A, with insignificant or small negative drifts of 1 %-3 % decadeĝ'1. The comparison results of IASI-A and IASI-B against smoothed FTIR and ozonesonde partial O3 columns vary with altitude and latitude, with the maximum standard deviation being seen for the 300-150 hPa column (20 %-40 %) due to strong ozone variability and large total retrievals errors. Compared with ozonesonde data, the IASI-A and IASI-B O3 TROPO column (defined as the column between the surface and 300 hPa) is positively biased in the high latitudes (4 %-5 %) and negatively biased in the midlatitudes and tropics (11 %-13 % and 16 %-19 %, respectively). The IASI-A-To-ozonesonde TROPO comparison for the period from 2008 to 2016 shows a significant negative drift in the Northern Hemisphere of ĝ'8.6±3.4 % decadeĝ'1, which is also found in the IASI-A-To-FTIR TROPO comparison. When considering the period from 2011 to 2016, the drift value for the TROPO column decreases and becomes statistically insignificant. The observed negative drifts of the IASI-A TROPO O3 product (8 %-16 % decadeĝ'1) over the 2008-2017 period might be taken into consideration when deriving trends from this product and this time period. . © Author(s) 2018.
BibTeX: @article{Boynard2018, author = {Boynard, Anne and Hurtmans, Daniel and Garane, Katerina and Goutail, Florence and Hadji-Lazaro, Juliette and Elissavet Koukouli, Maria and Wespes, Catherine and Vigouroux, Corinne and Keppens, Arno and Pazmino, Andrea and Balis, Dimitris and Loyola, Diego and Valks, Pieter and Sussmann, Ralf and Smale, Dan and Coheur, Pierre-François and Clerbaux, Cathy}, title = {Validation of the IASI FORLI/EUMETSAT ozone products using satellite (GOME-2), ground-based (Brewer-Dobson, SAOZ, FTIR) and ozonesonde measurements}, journal = {Atmospheric Measurement Techniques}, year = {2018}, volume = {11}, number = {9}, pages = {5125 – 5152}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-11-5125-2018} }
Brühl C, Schallock J, Klingmüller K, Robert C, Bingen C, Clarisse L, Heckel A, North P and Rieger L (2018), "Stratospheric aerosol radiative forcing simulated by the chemistry climate model EMAC using Aerosol CCI satellite data", Atmospheric Chemistry and Physics. Vol. 18(17), pp. 12845 – 12857. [Abstract] [BibTeX] [DOI]
Abstract: This paper presents decadal simulations of stratospheric and tropospheric aerosol and its radiative effects by the chemistry general circulation model EMAC constrained with satellite observations in the framework of the ESA Aerosol CCI project such as GOMOS (Global Ozone Monitoring by Occultation of Stars) and (A)ATSR ((Advanced) Along Track Scanning Radiometer) on the ENVISAT (European Environmental Satellite), IASI (Infrared Atmospheric Sounding Interferometer) on MetOp (Meteorological Operational Satellite), and, additionally, OSIRIS (Optical Spectrograph and InfraRed Imaging System). In contrast to most other studies, the extinctions and optical depths from the model are compared to the observations at the original wavelengths of the satellite instruments covering the range from the UV (ultraviolet) to terrestrial IR (infrared). This avoids conversion artifacts and provides additional constraints for model aerosol and interpretation of the observations. MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) SO2 limb measurements are used to identify plumes of more than 200 volcanic eruptions. These three-dimensional SO2 plumes are added to the model SO2 at the eruption times. The interannual variability in aerosol extinction in the lower stratosphere, and of stratospheric aerosol radiative forcing at the tropopause, is dominated by the volcanoes. To explain the seasonal cycle of the GOMOS and OSIRIS observations, desert dust simulated by a new approach and transported to the lowermost stratosphere by the Asian summer monsoon and tropical convection turns out to be essential. This also applies to the radiative heating by aerosol in the lowermost stratosphere. The existence of wet dust aerosol in the lowermost stratosphere is indicated by the patterns of the wavelength dependence of extinction in observations and simulations. Additional comparison with (A)ATSR total aerosol optical depth at different wavelengths and IASI dust optical depth demonstrates that the model is able to represent stratospheric as well as tropospheric aerosol consistently. © Author(s) 2018.
BibTeX: @article{Bruehl2018, author = {Brühl, Christoph and Schallock, Jennifer and Klingmüller, Klaus and Robert, Charles and Bingen, Christine and Clarisse, Lieven and Heckel, Andreas and North, Peter and Rieger, Landon}, title = {Stratospheric aerosol radiative forcing simulated by the chemistry climate model EMAC using Aerosol CCI satellite data}, journal = {Atmospheric Chemistry and Physics}, year = {2018}, volume = {18}, number = {17}, pages = {12845 – 12857}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-18-12845-2018} }
De Ruette N, Dochain A, Launoy T, Nascimento R, Kaminska M, Stockett M, Vaeck N, Schmidt H, Cederquist H and Urbain X (2018), "Mutual Neutralization of O- with O+ and N+ at Subthermal Collision Energies", Physical Review Letters. Vol. 121(8) [Abstract] [BibTeX] [DOI]
Abstract: We have measured total absolute cross sections for the mutual neutralization (MN) of O- with O+ and N+. A fine resolution (of about 50 meV) in the kinetic energy spectra of the product neutral atoms allows unique identification of the atomic states participating in the mutual neutralization process. Cross sections and branching ratios have also been calculated down to 1 meV center-of-mass collision energy for these two systems, with a multichannel Landau-Zener model and an asymptotic method for the ionic-covalent coupling matrix elements. The importance of two-electron processes in one-electron transfer is demonstrated by the dominant contribution of a core-excited configuration of the nitrogen atom in N++O- collisions. This effect is partially accounted for by introducing configuration mixing in the evaluation of coupling matrix elements. © 2018 American Physical Society.
BibTeX: @article{DeRuette2018, author = {De Ruette, N. and Dochain, A. and Launoy, T. and Nascimento, R.F. and Kaminska, M. and Stockett, M.H. and Vaeck, N. and Schmidt, H.T. and Cederquist, H. and Urbain, X.}, title = {Mutual Neutralization of O- with O+ and N+ at Subthermal Collision Energies}, journal = {Physical Review Letters}, year = {2018}, volume = {121}, number = {8}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevLett.121.083401} }
Filippin L, Schiffmann S, Dohet-Eraly J, Baye D and Godefroid M (2018), "Relativistic semiempirical-core-potential calculations in Ca+, Sr+, and Ba+ ions on Lagrange meshes", Physical Review A. Vol. 97(1) [Abstract] [BibTeX] [DOI]
Abstract: Relativistic atomic structure calculations are carried out in alkaline-earth-metal ions using a semiempirical-core-potential approach. The systems are partitioned into frozen-core electrons and an active valence electron. The core orbitals are defined by a Dirac-Hartree-Fock calculation using the grasp2k package. The valence electron is described by a Dirac-like Hamiltonian involving a core-polarization potential to simulate the core-valence electron correlation. The associated equation is solved with the Lagrange-mesh method, which is an approximate variational approach having the form of a mesh calculation because of the use of a Gauss quadrature to calculate matrix elements. Properties involving the low-lying metastable D3/2,5/22 states of Ca+, Sr+, and Ba+ are studied, such as polarizabilities, one- and two-photon decay rates, and lifetimes. Good agreement is found with other theory and observation, which is promising for further applications in alkalilike systems. © 2018 American Physical Society.
BibTeX: @article{Filippin2018, author = {Filippin, Livio and Schiffmann, Sacha and Dohet-Eraly, Jérémy and Baye, Daniel and Godefroid, Michel}, title = {Relativistic semiempirical-core-potential calculations in Ca+, Sr+, and Ba+ ions on Lagrange meshes}, journal = {Physical Review A}, year = {2018}, volume = {97}, number = {1}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.97.012506} }
Gamrath S, Palmeri P, Quinet P, Bouazza S and Godefroid M (2018), "MCDHF calculations of isotope shifts in neutral antimony", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 218, pp. 38 – 45. [Abstract] [BibTeX] [DOI]
Abstract: Ab initio multiconfiguration Dirac–Hartree–Fock (MCDHF) calculations have been carried out in order to determine the isotope shift (IS) electronic parameters of transitions belonging to electric dipole (E1) transition arrays 5s25p3−5s25p26s, 5s25p26s−5s25p26p and 5s25p26s−5s25p27p in neutral antimony, Sb I. In a correlation model limited to single and double excitations from the valence shells, these parameters, combined with the changes in mean-square nuclear charge radius δ⟨r2⟩123,121 compiled by Angeli and Marinova [3] produce isotope shifts values in good agreement with the most recent measurements by high-resolution emission and optogalvanic absorption spectroscopy of Sobolewski et al. [5] but not with the old measurements of Buchholz et al. [4] for 5p3−5p26s. However, our analysis does not allow to reject the latter due to the large uncertainty affecting δ⟨r2⟩123,121, i.e. 0.072 ± 0.048 fm2 [3]. This shows the need of a more accurate determination of this nuclear parameter. Although improving excitation energies, the inclusion of core-valence correlation limited to one hole in the 4d core subshell destroyed the theory-experiment agreement on the IS parameters. © 2018 Elsevier Ltd
BibTeX: @article{Gamrath2018, author = {Gamrath, S. and Palmeri, P. and Quinet, P. and Bouazza, S. and Godefroid, M.}, title = {MCDHF calculations of isotope shifts in neutral antimony}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2018}, volume = {218}, pages = {38 – 45}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2018.07.004} }
Gaudel A, Cooper O, Ancellet G, Barret B, Boynard A, Burrows J, Clerbaux C, Coheur P-F, Cuesta J, Cuevas E, Doniki S, Dufour G, Ebojie F, Foret G, Garcia O, Granados-Muñoz M, Hannigan J, Hase F, Hassler B, Huang G, Hurtmans D, Jaffe D, Jones N, Kalabokas P, Kerridge B, Kulawik S, Latter B, Leblanc T, Le Flochmoën E, Lin W, Liu J, Liu X, Mahieu E, McClure-Begley A, Neu J, Osman M, Palm M, Petetin H, Petropavlovskikh I, Querel R, Rahpoe N, Rozanov A, Schultz M, Schwab J, Siddans R, Smale D, Steinbacher M, Tanimoto H, Tarasick D, Thouret V, Thompson A, Trickl T, Weatherhead E, Wespes C, Worden H, Vigouroux C, Xu X, Zeng G and Ziemke J (2018), "Tropospheric Ozone Assessment Report: Present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation", Elementa. Vol. 6 [Abstract] [BibTeX] [DOI]
Abstract: The Tropospheric Ozone Assessment Report (TOAR) is an activity of the International Global Atmospheric Chemistry Project. This paper is a component of the report, focusing on the present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation. Utilizing the TOAR surface ozone database, several figures present the global distribution and trends of daytime average ozone at 2702 non-urban monitoring sites, highlighting the regions and seasons of the world with the greatest ozone levels. Similarly, ozonesonde and commercial aircraft observations reveal ozone's distribution throughout the depth of the free troposphere. Long-term surface observations are limited in their global spatial coverage, but data from remote locations indicate that ozone in the 21st century is greater than during the 1970s and 1980s. While some remote sites and many sites in the heavily polluted regions of East Asia show ozone increases since 2000, many others show decreases and there is no clear global pattern for surface ozone changes since 2000. Two new satellite products provide detailed views of ozone in the lower troposphere across East Asia and Europe, revealing the full spatial extent of the spring and summer ozone enhancements across eastern China that cannot be assessed from limited surface observations. Sufficient data are now available (ozonesondes, satellite, aircraft) across the tropics from South America eastwards to the western Pacific Ocean, to indicate a likely tropospheric column ozone increase since the 1990s. The 2014-2016 mean tropospheric ozone burden (TOB) between 60°N-60°S from five satellite products is 300 Tg ± 4%. While this agreement is excellent, the products differ in their quantification of TOB trends and further work is required to reconcile the differences. Satellites can now estimate ozone's global long-wave radiative effect, but evaluation is difficult due to limited in situ observations where the radiative effect is greatest. © 2018 The Author(s).
BibTeX: @article{Gaudel2018, author = {Gaudel, A. and Cooper, O.R. and Ancellet, G. and Barret, B. and Boynard, A. and Burrows, J.P. and Clerbaux, C. and Coheur, P.-F. and Cuesta, J. and Cuevas, E. and Doniki, S. and Dufour, G. and Ebojie, F. and Foret, G. and Garcia, O. and Granados-Muñoz, M.J. and Hannigan, J.W. and Hase, F. and Hassler, B. and Huang, G. and Hurtmans, D. and Jaffe, D. and Jones, N. and Kalabokas, P. and Kerridge, B. and Kulawik, S. and Latter, B. and Leblanc, T. and Le Flochmoën, E. and Lin, W. and Liu, J. and Liu, X. and Mahieu, E. and McClure-Begley, A. and Neu, J.L. and Osman, M. and Palm, M. and Petetin, H. and Petropavlovskikh, I. and Querel, R. and Rahpoe, N. and Rozanov, A. and Schultz, M.G. and Schwab, J. and Siddans, R. and Smale, D. and Steinbacher, M. and Tanimoto, H. and Tarasick, D.W. and Thouret, V. and Thompson, A.M. and Trickl, T. and Weatherhead, E. and Wespes, C. and Worden, H.M. and Vigouroux, C. and Xu, X. and Zeng, G. and Ziemke, J.}, title = {Tropospheric Ozone Assessment Report: Present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation}, journal = {Elementa}, year = {2018}, volume = {6}, note = {All Open Access, Gold Open Access}, doi = {10.1525/elementa.291} }
Keppens A, Lambert J-C, Granville J, Hubert D, Verhoelst T, Compernolle S, Latter B, Kerridge B, Siddans R, Boynard A, Hadji-Lazaro J, Clerbaux C, Wespes C, Hurtmans DR, Coheur P-F, Van Peet JC, Vander RJ, Garane K, Elissavet Koukouli M, Balis D, Delcloo A, Kivi R, Stübi R, Godin-Beekmann S, Van Roozendael M and Zehner C (2018), "Quality assessment of the Ozone-cci Climate Research Data Package (release 2017) - Part 2: Ground-based validation of nadir ozone profile data products", Atmospheric Measurement Techniques. Vol. 11(6), pp. 3769 – 3800. [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric ozone plays a key role in air quality and the radiation budget of the Earth, both directly and through its chemical influence on other trace gases. Assessments of the atmospheric ozone distribution and associated climate change therefore demand accurate vertically resolved ozone observations with both stratospheric and tropospheric sensitivity, on both global and regional scales, and both in the long term and at shorter timescales. Such observations have been acquired by two series of European nadir-viewing ozone profilers, namely the scattered-light UV-visible spectrometers of the GOME family, launched regularly since 1995 (GOME, SCIAMACHY, OMI, GOME-2A/B, TROPOMI, and the upcoming Sentinel-5 series), and the thermal infrared emission sounders of the IASI type, launched regularly since 2006 (IASI on Metop platforms and the upcoming IASI-NG on Metop-SG). In particular, several Level-2 retrieved, Level-3 monthly gridded, and Level-4 assimilated nadir ozone profile data products have been improved and harmonized in the context of the ozone project of the European Space Agency's Climate Change Initiative (ESA Ozone-cci). To verify their fitness for purpose, these ozone datasets must undergo a comprehensive quality assessment (QA), including (a) detailed identification of their geographical, vertical, and temporal domains of validity; (b) quantification of their potential bias, noise, and drift and their dependences on major influence quantities; and (c) assessment of the mutual consistency of data from different sounders. For this purpose we have applied to the Ozone-cci Climate Research Data Package (CRDP) released in 2017 the versatile QA and validation system Multi-TASTE, which has been developed in the context of several heritage projects (ESA's Multi-TASTE, EUMETSAT's O3M-SAF, and the European Commission's FP6 GEOmon and FP7 QA4ECV). This work, as the second in a series of four Ozone-cci validation papers, reports for the first time on data content studies, information content studies and ground-based validation for both the GOME- and IASI-type climate data records combined. The ground-based reference measurements have been provided by the Network for the Detection of Atmospheric Composition Change (NDACC), NASA's Southern Hemisphere Additional Ozonesonde programme (SHADOZ), and other ozonesonde and lidar stations contributing to the World Meteorological Organisation's Global Atmosphere Watch (WMO GAW). The nadir ozone profile CRDP quality assessment reveals that all nadir ozone profile products under study fulfil the GCOS user requirements in terms of observation frequency and horizontal and vertical resolution. Yet all L2 observations also show sensitivity outliers in the UTLS and are strongly correlated vertically due to substantial averaging kernel fluctuations that extend far beyond the kernel's 15km FWHM. The CRDP typically does not comply with the GCOS user requirements in terms of total uncertainty and decadal drift, except for the UV-visible L4 dataset. The drift values of the L2 GOME and OMI, the L3 IASI, and the L4 assimilated products are found to be overall insignificant, however, and applying appropriate altitude-dependent bias and drift corrections make the data fit for climate and atmospheric composition monitoring and modelling purposes. Dependence of the Ozone-cci data quality on major influence quantities - resulting in data screening suggestions to users - and perspectives for the Copernicus Sentinel missions are additionally discussed. © 2018 Copernicus GmbH. All rights reserved.
BibTeX: @article{Keppens2018, author = {Keppens, Arno and Lambert, Jean-Christopher and Granville, José and Hubert, Daan and Verhoelst, Tijl and Compernolle, Steven and Latter, Barry and Kerridge, Brian and Siddans, Richard and Boynard, Anne and Hadji-Lazaro, Juliette and Clerbaux, Cathy and Wespes, Catherine and Hurtmans, Daniel R. and Coheur, Pierre-François and Van Peet, Jacob C.A. and Vander, Ronald J.A. and Garane, Katerina and Elissavet Koukouli, Maria and Balis, Dimitris and Delcloo, Andy and Kivi, Rigel and Stübi, Réné and Godin-Beekmann, Sophie and Van Roozendael, Michel and Zehner, Claus}, title = {Quality assessment of the Ozone-cci Climate Research Data Package (release 2017) - Part 2: Ground-based validation of nadir ozone profile data products}, journal = {Atmospheric Measurement Techniques}, year = {2018}, volume = {11}, number = {6}, pages = {3769 – 3800}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-11-3769-2018} }
Lacour J-L, Risi C, Worden J, Clerbaux C and Coheur P-F (2018), "Importance of depth and intensity of convection on the isotopic composition of water vapor as seen from IASI and TES δD observations", Earth and Planetary Science Letters. Vol. 481, pp. 387 – 394. [Abstract] [BibTeX] [DOI]
Abstract: We use tropical observations of the water vapor isotopic composition, derived from IASI and TES spaceborne measurements, to show that the isotopic composition of water vapor in the free troposphere is sensitive to both the depth and the intensity of convection. We find that for any given precipitation intensity, vapor associated with deep convection is isotopically depleted relative to vapor associated with shallow convection. The intensity of precipitation also plays a role as for any given depth of convection, the relative enrichment of water vapor decreases as the intensity of precipitation increases. Shallow convection, via the uplifting of enriched boundary layer air into the free troposphere and the convective detrainment, enriches the free troposphere. In contrast, deep convection is associated with processes that deplete the water vapor in the free troposphere, such as rain re-evaporation. The results of this study allow for a better identification of the parameters controlling the isotopic composition of the free troposphere and indicate that the isotopic composition of water vapor can be used to evaluate the relative contributions of shallow and deep convection in global models. © 2017 Elsevier B.V.
BibTeX: @article{Lacour2018, author = {Lacour, Jean-Lionel and Risi, Camille and Worden, John and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Importance of depth and intensity of convection on the isotopic composition of water vapor as seen from IASI and TES δD observations}, journal = {Earth and Planetary Science Letters}, year = {2018}, volume = {481}, pages = {387 – 394}, doi = {10.1016/j.epsl.2017.10.048} }
Leifer I, Melton C, Tratt DM, Buckland KN, Chang CS, Frash J, Hall JL, Kuze A, Leen B, Clarisse L, Lundquist T, Van Damme M, Vigil S, Whitburn S and Yurganov L (2018), "Validation of mobile in situ measurements of dairy husbandry emissions by fusion of airborne/surface remote sensing with seasonal context from the Chino Dairy Complex", Environmental Pollution. , pp. 2111 – 2134. [Abstract] [BibTeX] [DOI]
Abstract: Mobile in situ concentration and meteorology data were collected for the Chino Dairy Complex in the Los Angeles Basin by AMOG (AutoMObile trace Gas) Surveyor on 25 June 2015 to characterize husbandry emissions in the near and far field in convoy mode with MISTIR (Mobile Infrared Sensor for Tactical Incident Response), a mobile upwards-looking, column remote sensing spectrometer. MISTIR reference flux validated AMOG plume inversions at different information levels including multiple gases, GoogleEarth imagery, and airborne trace gas remote sensing data. Long-term (9-yr.) Infrared Atmospheric Sounding Interferometer satellite data provided spatial and trace gas temporal context. For the Chino dairies, MISTIR-AMOG ammonia (NH3) agreement was within 5% (15.7 versus 14.9 Gg yr−1, respectively) using all information. Methane (CH4) emissions were 30 Gg yr−1 for a 45,200 herd size, indicating that Chino emission factors are greater than previously reported. Single dairy inversions were much less successful. AMOG-MISTIR agreement was 57% due to wind heterogeneity from downwind structures in these near-field measurements and emissions unsteadiness. AMOG CH4, NH3, and CO2 emissions were 91, 209, and 8200 Mg yr−1, implying 2480, 1870, and 1720 head using published emission factors. Plumes fingerprinting identified likely sources including manure storage, cowsheds, and a structure with likely natural gas combustion. NH3 downwind of Chino showed a seasonal variation of a factor of ten, three times larger than literature suggests. Chino husbandry practices and trends in herd size and production were reviewed and unlikely to add seasonality. Higher emission seasonality was proposed as legacy soil emissions, the results of a century of husbandry, supported by airborne remote sensing data showing widespread emissions from neighborhoods that were dairies 15 years prior, and AMOG and MISTIR observations. Seasonal variations provide insights into the implications of global climate change and must be considered when comparing surveys from different seasons. Where sufficient information from multiple gases and number of likely sources, high emissions accuracy can be achieved for in situ data plume inversion. © 2018
BibTeX: @article{Leifer2018, author = {Leifer, Ira and Melton, Christopher and Tratt, David M. and Buckland, Kerry N. and Chang, Clement S. and Frash, Jason and Hall, Jeffrey L. and Kuze, Akihiko and Leen, Brian and Clarisse, Lieven and Lundquist, Tryg and Van Damme, Martin and Vigil, Sam and Whitburn, Simon and Yurganov, Leonid}, title = {Validation of mobile in situ measurements of dairy husbandry emissions by fusion of airborne/surface remote sensing with seasonal context from the Chino Dairy Complex}, journal = {Environmental Pollution}, year = {2018}, pages = {2111 – 2134}, doi = {10.1016/j.envpol.2018.03.078} }
Loreau J, Ryabchenko S, Burgos JMM and Vaeck N (2018), "Charge transfer in low-energy collisions of H with He+ and H+ with He in excited states", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 51(8) [Abstract] [BibTeX] [DOI]
Abstract: The charge transfer process in collisions of excited (n = 2, 3) hydrogen atoms with He+ and in collisions of excited helium atoms with H+ is studied theoretically. A combination of a fully quantum-mechanical method and a semi-classical approach is employed to calculate the charge-exchange cross sections at collision energies from 0.1 eV u-1 up to 1 keV u-1. These methods are based on accurate ab initio potential energy curves and non-adiabatic couplings for the molecular ion HeH+. Charge transfer can occur either in singlet or in triplet states, and the differences between the singlet and triplet spin manifolds are discussed. The dependence of the cross section on the quantum numbers n and l of the initial state is demonstrated. The isotope effect on the charge transfer cross sections, arising at low collision energy when H is substituted by D or T, is investigated. Rate coefficients are calculated for all isotopes up to 106 K. Finally, the impact of the present calculations on models of laboratory plasmas is discussed. © 2018 IOP Publishing Ltd.
BibTeX: @article{Loreau2018, author = {Loreau, J. and Ryabchenko, S. and Burgos, J M Munoz and Vaeck, N.}, title = {Charge transfer in low-energy collisions of H with He+ and H+ with He in excited states}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2018}, volume = {51}, number = {8}, note = {All Open Access, Green Open Access}, doi = {10.1088/1361-6455/aab425} }
Luo J, Pan LL, Honomichl SB, Bergman JW, Randel WJ, Francis G, Clerbaux C, George M, Liu X and Tian W (2018), "Space-time variability in UTLS chemical distribution in the Asian summer monsoon viewed by limb and nadir satellite sensors", Atmospheric Chemistry and Physics. Vol. 18(16), pp. 12511 – 12530. [Abstract] [BibTeX] [DOI]
Abstract: The Asian summer monsoon (ASM) creates a hemispheric-scale signature in trace-gas distributions in the upper troposphere and lower stratosphere (UTLS). Data from satellite retrievals are the best source of information for characterizing these large-scale signatures. Measurements from the Microwave Limb Sounder (MLS), a limb-viewing satellite sensor, have been the most widely used retrieval products for these types of studies. This work explores the information for the ASM influence on UTLS chemical distribution from two nadir-viewing sensors, the Infrared Atmospheric Sounding Interferometer (IASI) and the Ozone Monitoring Instrument (OMI), together with the MLS. Day-to-day changes in carbon monoxide (CO) and ozone (O3) tracer distributions in response to dynamical variability are examined to assess how well the data from different sensors provide useful information for studying the impact of sub-seasonal-scale dynamics on chemical fields. Our results, using June-August 2008 data, show that although the MLS provides relatively sparse horizontal sampling on daily timescales, interpolated daily CO distributions show a high degree of dynamical consistency with the synoptic-scale structure of and variability in the anticyclone. Our analysis also shows that the IASI CO retrieval has sufficient sensitivity to produce upper tropospheric (UT) CO with variabilities independent from the lower to middle tropospheric CO. The consistency of IASI CO field with the synoptic-scale anticyclone dynamical variability demonstrates that the IASI UT CO product is a physically meaningful dataset. Furthermore, IASI CO vertical cross sections combined with the daily maps provide the first observational evidence for a model analyses-based hypothesis on the preferred ASM vertical transport location and the subsequent horizontal redistribution via east-west eddy shedding. Similarly, the OMI O3 profile product is shown to be capable of distinguishing the tropospheric-dominated air mass in the anticyclone from the stratospheric-dominated background on a daily timescale, providing consistent and complementary information to the MLS. These results not only highlight the complementary information between nadir and limb sensors but also demonstrate the value of process-based retrieval evaluation for characterizing satellite data information content. © 2018 Copernicus GmbH. All rights reserved.
BibTeX: @article{Luo2018, author = {Luo, Jiali and Pan, Laura L. and Honomichl, Shawn B. and Bergman, John W. and Randel, William J. and Francis, Gene and Clerbaux, Cathy and George, Maya and Liu, Xiong and Tian, Wenshou}, title = {Space-time variability in UTLS chemical distribution in the Asian summer monsoon viewed by limb and nadir satellite sensors}, journal = {Atmospheric Chemistry and Physics}, year = {2018}, volume = {18}, number = {16}, pages = {12511 – 12530}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-18-12511-2018} }
Lurton T, Jégou F, Berthet G, Renard J-B, Clarisse L, Schmidt A, Brogniez C and Roberts TJ (2018), "Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in situ and satellite observations", Atmospheric Chemistry and Physics. Vol. 18(5), pp. 3223 – 3247. [Abstract] [BibTeX] [DOI]
Abstract: Volcanic eruptions impact climate through the injection of sulfur dioxide (SO2), which is oxidized to form sulfuric acid aerosol particles that can enhance the stratospheric aerosol optical depth (SAOD). Besides large-magnitude eruptions, moderate-magnitude eruptions such as Kasatochi in 2008 and Sarychev Peak in 2009 can have a significant impact on stratospheric aerosol and hence climate. However, uncertainties remain in quantifying the atmospheric and climatic impacts of the 2009 Sarychev Peak eruption due to limitations in previous model representations of volcanic aerosol microphysics and particle size, whilst biases have been identified in satellite estimates of post-eruption SAOD. In addition, the 2009 Sarychev Peak eruption co-injected hydrogen chloride (HCl) alongside SO2, whose potential stratospheric chemistry impacts have not been investigated to date. We present a study of the stratospheric SO2-particle-HCl processing and impacts following Sarychev Peak eruption, using the Community Earth System Model version 1.0 (CESM1) Whole Atmosphere Community Climate Model (WACCM)-Community Aerosol and Radiation Model for Atmospheres (CARMA) sectional aerosol microphysics model (with no a priori assumption on particle size). The Sarychev Peak 2009 eruption injected 0.9ĝ€Tg of SO2 into the upper troposphere and lower stratosphere (UTLS), enhancing the aerosol load in the Northern Hemisphere. The post-eruption evolution of the volcanic SO2 in space and time are well reproduced by the model when compared to Infrared Atmospheric Sounding Interferometer (IASI) satellite data. Co-injection of 27ĝ€Ggĝ€†HCl causes a lengthening of the SO2 lifetime and a slight delay in the formation of aerosols, and acts to enhance the destruction of stratospheric ozone and mono-nitrogen oxides (NOx) compared to the simulation with volcanic SO2 only. We therefore highlight the need to account for volcanic halogen chemistry when simulating the impact of eruptions such as Sarychev on stratospheric chemistry. The model-simulated evolution of effective radius (reff) reflects new particle formation followed by particle growth that enhances reff to reach up to 0.2ĝ€μm on zonal average. Comparisons of the model-simulated particle number and size distributions to balloon-borne in situ stratospheric observations over Kiruna, Sweden, in August and September 2009, and over Laramie, USA, in June and November 2009 show good agreement and quantitatively confirm the post-eruption particle enhancement. We show that the model-simulated SAOD is consistent with that derived from the Optical Spectrograph and InfraRed Imager System (OSIRIS) when both the saturation bias of OSIRIS and the fact that extinction profiles may terminate well above the tropopause are taken into account. Previous modelling studies (involving assumptions on particle size) that reported agreement with (biased) post-eruption estimates of SAOD derived from OSIRIS likely underestimated the climate impact of the 2009 Sarychev Peak eruption. © Author(s) 2018.
BibTeX: @article{Lurton2018, author = {Lurton, Thibaut and Jégou, Fabrice and Berthet, Gwenaël and Renard, Jean-Baptiste and Clarisse, Lieven and Schmidt, Anja and Brogniez, Colette and Roberts, Tjarda J}, title = {Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in situ and satellite observations}, journal = {Atmospheric Chemistry and Physics}, year = {2018}, volume = {18}, number = {5}, pages = {3223 – 3247}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-18-3223-2018} }
Lyoussi A, Doizi D, Reymond La Ruinaz S, Haykal I, Manceron L, Perrin A, Boudon V, Vander Auwera J, Tchana FK and Faye M (2018), "Analytical measurements of fission products during a severe nuclear accident", EPJ Web of Conferences. Vol. 170 [Abstract] [BibTeX] [DOI]
Abstract: The Fukushima accident emphasized the fact that ways to monitor in real time the evolution of a nuclear reactor during a severe accident remain to be developed. No fission products were monitored during twelve days; only dose rates were measured, which is not sufficient to carry out an online diagnosis of the event. The first measurements were announced with little reliability for low volatile fission products. In order to improve the safety of nuclear plants and minimize the industrial, ecological and health consequences of a severe accident, it is necessary to develop new reliable measurement systems, operating at the earliest and closest to the emission source of fission products. Through the French program ANR « Projet d'Investissement d'Avenir , the aim of the DECA-PF project (diagnosis of core degradation from fission products measurements) is to monitor in real time the release of the major fission products (krypton, xenon, gaseous forms of iodine and ruthenium) outside the nuclear reactor containment. These products are released at different times during a nuclear accident and at different states of the nuclear core degradation. Thus, monitoring these fission products gives information on the situation inside the containment and helps to apply the Severe Accident Management procedures. Analytical techniques have been proposed and evaluated. The results are discussed here. © The Authors, published by EDP Sciences, 2018.
BibTeX: @conference{Lyoussi2018, author = {Lyoussi, A. and Doizi, D. and Reymond La Ruinaz, S. and Haykal, I. and Manceron, L. and Perrin, A. and Boudon, V. and Vander Auwera, J. and Tchana, F. Kwabia and Faye, M.}, title = {Analytical measurements of fission products during a severe nuclear accident}, journal = {EPJ Web of Conferences}, year = {2018}, volume = {170}, note = {All Open Access, Gold Open Access}, doi = {10.1051/epjconf/201817008005} }
Müller J-F, Stavrakou T, Bauwens M, George M, Hurtmans D, Coheur P-F, Clerbaux C and Sweeney C (2018), "Top-Down CO Emissions Based On IASI Observations and Hemispheric Constraints on OH Levels", Geophysical Research Letters. Vol. 45(3), pp. 1621 – 1629. [Abstract] [BibTeX] [DOI]
Abstract: Assessments of carbon monoxide emissions through inverse modeling are dependent on the modeled abundance of the hydroxyl radical (OH) which controls both the primary sink of CO and its photochemical source through hydrocarbon oxidation. However, most chemistry transport models (CTMs) fall short of reproducing constraints on hemispherically averaged OH levels derived from methylchloroform (MCF) observations. Here we construct five different OH fields compatible with MCF-based analyses, and we prescribe those fields in a global CTM to infer CO fluxes based on Infrared Atmospheric Sounding Interferometer (IASI) CO columns. Each OH field leads to a different set of optimized emissions. Comparisons with independent data (surface, ground-based remotely sensed, aircraft) indicate that the inversion adopting the lowest average OH level in the Northern Hemisphere (7.8 × 105 molec cm−3, ∼18% lower than the best estimate based on MCF measurements) provides the best overall agreement with all tested observation data sets. ©2018. The Authors.
BibTeX: @article{Mueller2018, author = {Müller, J.-F. and Stavrakou, T. and Bauwens, M. and George, M. and Hurtmans, D. and Coheur, P.-F. and Clerbaux, C. and Sweeney, C.}, title = {Top-Down CO Emissions Based On IASI Observations and Hemispheric Constraints on OH Levels}, journal = {Geophysical Research Letters}, year = {2018}, volume = {45}, number = {3}, pages = {1621 – 1629}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1002/2017GL076697} }
Nechita-Banda N, Krol M, Van Der Werf GR, Kaiser JW, Pandey S, Huijnen V, Clerbaux C, Coheur P, Deeter MN and Röckmann T (2018), "Monitoring emissions from the 2015 Indonesian fires using CO satellite data", Philosophical Transactions of the Royal Society B: Biological Sciences. Vol. 373(1760) [Abstract] [BibTeX] [DOI]
Abstract: Southeast Asia, in particular Indonesia, has periodically struggled with intense fire events. These events convert substantial amounts of carbon stored as peat to atmospheric carbon dioxide (CO2) and significantly affect atmospheric composition on a regional to global scale. During the recent 2015 El Niño event, peat fires led to strong enhancements of carbon monoxide (CO), an air pollutant and well-known tracer for biomass burning. These enhancements were clearly observed from space by the Infrared Atmospheric Sounding Interferometer (IASI) and the Measurements of Pollution in the Troposphere (MOPITT) instruments. We use these satellite observations to estimate CO fire emissions within an inverse modelling framework. We find that the derived CO emissions for each sub-region of Indonesia and Papua are substantially different from emission inventories, highlighting uncertainties in bottom-up estimates. CO fire emissions based on either MOPITT or IASI have a similar spatial pattern and evolution in time, and a 10% uncertainty based on a set of sensitivity tests we performed. Thus, CO satellite data have a high potential to complement existing operational fire emission estimates based on satellite observations of fire counts, fire radiative power and burned area, in better constraining fire occurrence and the associated conversion of peat carbon to atmospheric CO2. A total carbon release to the atmosphere of 0.35–0.60 Pg C can be estimated based on our results. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications’. © 2018 The Authors.
BibTeX: @article{NechitaBanda2018, author = {Nechita-Banda, Narcisa and Krol, Maarten and Van Der Werf, Guido R. and Kaiser, Johannes W. and Pandey, Sudhanshu and Huijnen, Vincent and Clerbaux, Cathy and Coheur, Pierre and Deeter, Merritt N. and Röckmann, Thomas}, title = {Monitoring emissions from the 2015 Indonesian fires using CO satellite data}, journal = {Philosophical Transactions of the Royal Society B: Biological Sciences}, year = {2018}, volume = {373}, number = {1760}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1098/rstb.2017.0307} }
Nightingale J, Boersma KF, Muller J-P, Compernolle S, Lambert J-C, Blessing S, Giering R, Gobron N, Smedt ID, Coheur P, George M, Schulz J and Wood A (2018), "Quality assurance framework development based on six new ECV data products to enhance user confidence for climate applications", Remote Sensing. Vol. 10(8) [Abstract] [BibTeX] [DOI]
Abstract: Data from Earth observation (EO) satellites are increasingly used to monitor the environment, understand variability and change, inform evaluations of climate model forecasts, and manage natural resources. Policymakers are progressively relying on the information derived from these datasets to make decisions on mitigating and adapting to climate change. These decisions should be evidence based, which requires confidence in derived products, as well as the reference measurements used to calibrate, validate, or inform product development. In support of the European Union's Earth Observation Programmes Copernicus Climate Change Service (C3S), the Quality Assurance for Essential Climate Variables (QA4ECV) project fulfilled a gap in the delivery of climate quality satellite-derived datasets, by prototyping a generic system for the implementation and evaluation of quality assurance (QA) measures for satellite-derived ECV climate data record products. The project demonstrated the QA system on six new long-term, climate quality ECV data records for surface albedo, leaf area index (LAI), fraction of absorbed photosynthetically active radiation (FAPAR), nitrogen dioxide (NO2), formaldehyde (HCHO), and carbon monoxide (CO). The provision of standardised QA information provides data users with evidence-based confidence in the products and enables judgement on the fitness-for-purpose of various ECV data products and their specific applications. © 2018 by the authors.
BibTeX: @article{Nightingale2018, author = {Nightingale, Joanne and Boersma, Klaas Folkert and Muller, Jan-Peter and Compernolle, Steven and Lambert, Jean-Christopher and Blessing, Simon and Giering, Ralf and Gobron, Nadine and Smedt, Isabelle De and Coheur, Pierre and George, Maya and Schulz, Jörg and Wood, Alexander}, title = {Quality assurance framework development based on six new ECV data products to enhance user confidence for climate applications}, journal = {Remote Sensing}, year = {2018}, volume = {10}, number = {8}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.3390/rs10081254} }
Ronsmans G, Wespes C, Hurtmans D, Clerbaux C and Coheur P-F (2018), "Spatio-temporal variations of nitric acid total columns from 9 years of IASI measurements-A driver study", Atmospheric Chemistry and Physics. Vol. 18(7), pp. 4403 – 4423. [Abstract] [BibTeX] [DOI]
Abstract: This study aims to understand the spatial and temporal variability of HNO3 total columns in terms of explanatory variables. To achieve this, multiple linear regressions are used to fit satellite-derived time series of HNO3 daily averaged total columns. First, an analysis of the IASI 9-year time series (2008-2016) is conducted based on various equivalent latitude bands. The strong and systematic denitrification of the southern polar stratosphere is observed very clearly. It is also possible to distinguish, within the polar vortex, three regions which are differently affected by the denitrification. Three exceptional denitrification episodes in 2011, 2014 and 2016 are also observed in the Northern Hemisphere, due to unusually low arctic temperatures. The time series are then fitted by multivariate regressions to identify what variables are responsible for HNO3 variability in global distributions and time series, and to quantify their respective influence. Out of an ensemble of proxies (annual cycle, solar flux, quasi-biennial oscillation, multivariate ENSO index, Arctic and Antarctic oscillations and volume of polar stratospheric clouds), only the those defined as significant (p value<0.05) by a selection algorithm are retained for each equivalent latitude band. Overall, the regression gives a good representation of HNO3 variability, with especially good results at high latitudes (60-80% of the observed variability explained by the model). The regressions show the dominance of annual variability in all latitudinal bands, which is related to specific chemistry and dynamics depending on the latitudes. We find that the polar stratospheric clouds (PSCs) also have a major influence in the polar regions, and that their inclusion in the model improves the correlation coefficients and the residuals. However, there is still a relatively large portion of HNO3 variability that remains unexplained by the model, especially in the intertropical regions, where factors not included in the regression model (such as vegetation fires or lightning) may be at play. © 2018 Author(s).
BibTeX: @article{Ronsmans2018, author = {Ronsmans, Gaétane and Wespes, Catherine and Hurtmans, Daniel and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Spatio-temporal variations of nitric acid total columns from 9 years of IASI measurements-A driver study}, journal = {Atmospheric Chemistry and Physics}, year = {2018}, volume = {18}, number = {7}, pages = {4403 – 4423}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-18-4403-2018} }
Santos L, Herman M, Desouter-Lecomte M and Vaeck N (2018), "Rovibrational laser control targeting a dark state in acetylene. Simulation in the Ns = 1, Nr = 5 polyad", Molecular Physics. Vol. 116(17), pp. 2213 – 2225. [Abstract] [BibTeX] [DOI]
Abstract: Optimal control theory in the Liouville space is used to perform rovibrational control by means of a laser pulse in a polyad of acetylene in order to populate a dark vibrational state. The initial mixed state is a truncated Boltzmann distribution of rotational levels from J=27 to J=31 of the ground vibrational state. The target state is a rotational equidistribution of levels ranging from J=28 to J=32 of the first excited vibrational dark state including quanta of energy in each bending modes, with positive vibrational angular momenta. The simulation is performed by using a manifold of eigenstates of a full-dimensional Hamiltonian calibrated by high precision spectroscopy known as the global acetylene Hamiltonian [B. Amyay et al., J. Chem. Phys. 131, 114301 (2009)]. The control is successful as an Uhlmann's fidelity of 0.98 is reached. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX: @article{Santos2018, author = {Santos, L. and Herman, M. and Desouter-Lecomte, M. and Vaeck, N.}, title = {Rovibrational laser control targeting a dark state in acetylene. Simulation in the Ns = 1, Nr = 5 polyad}, journal = {Molecular Physics}, year = {2018}, volume = {116}, number = {17}, pages = {2213 – 2225}, doi = {10.1080/00268976.2018.1469797} }
Schultz MG, Stadtler S, Schröder S, Taraborrelli D, Franco B, Krefting J, Henrot A, Ferrachat S, Lohmann U, Neubauer D, Siegenthaler-Le Drian C, Wahl S, Kokkola H, Kühn T, Rast S, Schmidt H, Stier P, Kinnison D, Tyndall GS, Orlando JJ and Wespes C (2018), "The chemistry-climate model ECHAM6.3-HAM2.3-MOZ1.0", Geoscientific Model Development. Vol. 11(5), pp. 1695 – 1723. [Abstract] [BibTeX] [DOI]
Abstract: The chemistry-climate model ECHAM-HAMMOZ contains a detailed representation of tropospheric and stratospheric reactive chemistry and state-of-the-art parameterizations of aerosols using either a modal scheme (M7) or a bin scheme (SALSA). This article describes and evaluates the model version ECHAM6.3-HAM2.3-MOZ1.0 with a focus on the tropospheric gas-phase chemistry. A 10-year model simulation was performed to test the stability of the model and provide data for its evaluation. The comparison to observations concentrates on the year 2008 and includes total column observations of ozone and CO from IASI and OMI, Aura MLS observations of temperature, HNO3, ClO, and O3 for the evaluation of polar stratospheric processes, an ozonesonde climatology, surface ozone observations from the TOAR database, and surface CO data from the Global Atmosphere Watch network. Global budgets of ozone, OH, NOx, aerosols, clouds, and radiation are analyzed and compared to the literature. ECHAM-HAMMOZ performs well in many aspects. However, in the base simulation, lightning NOx emissions are very low, and the impact of the heterogeneous reaction of HNO3 on dust and sea salt aerosol is too strong. Sensitivity simulations with increased lightning NOx or modified heterogeneous chemistry deteriorate the comparison with observations and yield excessively large ozone budget terms and too much OH. We hypothesize that this is an impact of potential issues with tropical convection in the ECHAM model. © 2018 Author(s).
BibTeX: @article{Schultz2018, author = {Schultz, Martin G. and Stadtler, Scarlet and Schröder, Sabine and Taraborrelli, Domenico and Franco, Bruno and Krefting, Jonathan and Henrot, Alexandra and Ferrachat, Sylvaine and Lohmann, Ulrike and Neubauer, David and Siegenthaler-Le Drian, Colombe and Wahl, Sebastian and Kokkola, Harri and Kühn, Thomas and Rast, Sebastian and Schmidt, Hauke and Stier, Philip and Kinnison, Doug and Tyndall, Geoffrey S. and Orlando, John J. and Wespes, Catherine}, title = {The chemistry-climate model ECHAM6.3-HAM2.3-MOZ1.0}, journal = {Geoscientific Model Development}, year = {2018}, volume = {11}, number = {5}, pages = {1695 – 1723}, note = {All Open Access, Gold Open Access}, doi = {10.5194/gmd-11-1695-2018} }
Sun K, Zhu L, Cady-Pereira K, Chan Miller C, Chance K, Clarisse L, Coheur P-F, González Abad G, Huang G, Liu X, Van Damme M, Yang K and Zondlo M (2018), "A physics-based approach to oversample multi-satellite, multispecies observations to a common grid", Atmospheric Measurement Techniques. Vol. 11(12), pp. 6679 – 6701. [Abstract] [BibTeX] [DOI]
Abstract: Satellite remote sensing of the Earth's atmospheric composition usually samples irregularly in space and time, and many applications require spatially and temporally averaging the satellite observations (level 2) to a regular grid (level 3). When averaging level 2 data over a long period to a target level 3 grid that is significantly finer than the sizes of level 2 pixels, this process is referred to as. An agile, physics-based oversampling approach is developed to represent each satellite observation as a sensitivity distribution on the ground, instead of a point or a polygon as assumed in previous methods. This sensitivity distribution can be determined by the spatial response function of each satellite sensor. A generalized 2-D super Gaussian function is proposed to characterize the spatial response functions of both imaging grating spectrometers (e.g., OMI, OMPS, and TROPOMI) and scanning Fourier transform spectrometers (e.g., GOSAT, IASI, and CrIS). Synthetic OMI and IASI observations were generated to compare the errors due to simplifying satellite fields of view (FOVs) as polygons (tessellation error) and the errors due to discretizing the smooth spatial response function on a finite grid (discretization error). The balance between these two error sources depends on the target grid size, the ground size of the FOV, and the smoothness of spatial response functions. Explicit consideration of the spatial response function is favorable for fine-grid oversampling and smoother spatial response. For OMI, it is beneficial to oversample using the spatial response functions for grids finer than ∼ 16 km. The generalized 2-D super Gaussian function also enables smoothing of the level 3 results by decreasing the shape-determining exponents, which is useful for a high noise level or sparse satellite datasets. This physical oversampling approach is especially advantageous during smaller temporal windows and shows substantially improved visualization of trace gas distribution and local gradients when applied to OMI NO2 products and IASI NH3 products. There is no appreciable difference in the computational time when using the physical oversampling versus other oversampling methods. © 2018 Author(s).
BibTeX: @article{Sun2018, author = {Sun, Kang and Zhu, Lei and Cady-Pereira, Karen and Chan Miller, Christopher and Chance, Kelly and Clarisse, Lieven and Coheur, Pierre-François and González Abad, Gonzalo and Huang, Guanyu and Liu, Xiong and Van Damme, Martin and Yang, Kai and Zondlo, Mark}, title = {A physics-based approach to oversample multi-satellite, multispecies observations to a common grid}, journal = {Atmospheric Measurement Techniques}, year = {2018}, volume = {11}, number = {12}, pages = {6679 – 6701}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-11-6679-2018} }
Van Damme M, Clarisse L, Whitburn S, Hadji-Lazaro J, Hurtmans D, Clerbaux C and Coheur P-F (2018), "Industrial and agricultural ammonia point sources exposed", Nature. Vol. 564(7734), pp. 99 – 103. [Abstract] [BibTeX] [DOI]
Abstract: Through its important role in the formation of particulate matter, atmospheric ammonia affects air quality and has implications for human health and life expectancy1,2. Excess ammonia in the environment also contributes to the acidification and eutrophication of ecosystems3–5 and to climate change6. Anthropogenic emissions dominate natural ones and mostly originate from agricultural, domestic and industrial activities7. However, the total ammonia budget and the attribution of emissions to specific sources remain highly uncertain across different spatial scales7–9. Here we identify, categorize and quantify the world’s ammonia emission hotspots using a high-resolution map of atmospheric ammonia obtained from almost a decade of daily IASI satellite observations. We report 248 hotspots with diameters smaller than 50 kilometres, which we associate with either a single point source or a cluster of agricultural and industrial point sources—with the exception of one hotspot, which can be traced back to a natural source. The state-of-the-art EDGAR emission inventory10 mostly agrees with satellite-derived emission fluxes within a factor of three for larger regions. However, it does not adequately represent the majority of point sources that we identified and underestimates the emissions of two-thirds of them by at least one order of magnitude. Industrial emitters in particular are often found to be displaced or missing. Our results suggest that it is necessary to completely revisit the emission inventories of anthropogenic ammonia sources and to account for the rapid evolution of such sources over time. This will lead to better health and environmental impact assessments of atmospheric ammonia and the implementation of suitable nitrogen management strategies. © 2018, Springer Nature Limited.
BibTeX: @article{VanDamme2018, author = {Van Damme, Martin and Clarisse, Lieven and Whitburn, Simon and Hadji-Lazaro, Juliette and Hurtmans, Daniel and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Industrial and agricultural ammonia point sources exposed}, journal = {Nature}, year = {2018}, volume = {564}, number = {7734}, pages = {99 – 103}, doi = {10.1038/s41586-018-0747-1} }
Vandaele AC, Lopez-Moreno J-J, Patel M, Bellucci G, Daerden F, Ristic B, Robert S, Thomas IR, Wilquet V, Allen M, Alonso-Rodrigo G, Altieri F, Aoki S, Bolsée D, Clancy T, Cloutis E, Depiesse C, Drummond R, Fedorova A, Formisano V, Funke B, González-Galindo F, Geminale A, Gérard J-C, Giuranna M, Hetey L, Ignatiev N, Kaminski J, Karatekin O, Kasaba Y, Leese M, Lefèvre F, Lewis SR, López-Puertas M, López-Valverde M, Mahieux A, Mason J, McConnell J, Mumma M, Neary L, Neefs E, Renotte E, Rodriguez-Gomez J, Sindoni G, Smith M, Stiepen A, Trokhimovsky A, Vander Auwera J, Villanueva G, Viscardy S, Whiteway J, Willame Y, Wolff M, Patel M, D’aversa E, Fussen D, Garcia-Comas M, Hewson W, McConnel J, Novak R, Oliva F, Piccialli A, Aparicio Del Moral B, Barzin P, Benmoussa A, Berkenbosch S, Biondi D, Bonnewijn S, Candini GP, Clairquin R, Cubas J, De-Lanoye S, Giordanengo B, Gissot S, Gomez A, Maes J, Mazy E, Mazzoli A, Meseguer J, Morales R, Orban A, Pastor-Morales MDC, Perez-Grande I, Queirolo C, Saggin B, Samain V, Sanz Andres A, Sanz R, Simar J-F, Thibert T and Zafra JJ (2018), "NOMAD, an Integrated Suite of Three Spectrometers for the ExoMars Trace Gas Mission: Technical Description, Science Objectives and Expected Performance", Space Science Reviews. Vol. 214(5) [Abstract] [BibTeX] [DOI]
Abstract: The NOMAD (“Nadir and Occultation for MArs Discovery”) spectrometer suite on board the ExoMars Trace Gas Orbiter (TGO) has been designed to investigate the composition of Mars’ atmosphere, with a particular focus on trace gases, clouds and dust. The detection sensitivity for trace gases is considerably improved compared to previous Mars missions, compliant with the science objectives of the TGO mission. This will allow for a major leap in our knowledge and understanding of the Martian atmospheric composition and the related physical and chemical processes. The instrument is a combination of three spectrometers, covering a spectral range from the UV to the mid-IR, and can perform solar occultation, nadir and limb observations. In this paper, we present the science objectives of the instrument and explain the technical principles of the three spectrometers. We also discuss the expected performance of the instrument in terms of spatial and temporal coverage and detection sensitivity. © 2018, The Author(s).
BibTeX: @article{Vandaele2018, author = {Vandaele, Ann Carine and Lopez-Moreno, J.-J. and Patel, M.R. and Bellucci, Giancarlo and Daerden, Frank and Ristic, Bojan and Robert, Séverine and Thomas, Ian R. and Wilquet, Valerie and Allen, Mark and Alonso-Rodrigo, Gustavo and Altieri, Francesca and Aoki, Shohei and Bolsée, David and Clancy, Todd and Cloutis, Edward and Depiesse, Cédric and Drummond, Rachel and Fedorova, Anna and Formisano, Vittorio and Funke, Bernd and González-Galindo, F. and Geminale, Anna and Gérard, Jean-Claude and Giuranna, Marco and Hetey, Laszlo and Ignatiev, Nicolai and Kaminski, Jacek and Karatekin, Ozgur and Kasaba, Yasumasa and Leese, Mark and Lefèvre, Franck and Lewis, Stephen R. and López-Puertas, Manuel and López-Valverde, Miguel and Mahieux, Arnaud and Mason, Jon and McConnell, J. and Mumma, Mike and Neary, Lori and Neefs, Eddy and Renotte, Etienne and Rodriguez-Gomez, Julio and Sindoni, Giuseppe and Smith, Mike and Stiepen, Arnaud and Trokhimovsky, Alexander and Vander Auwera, Jean and Villanueva, Geronimo and Viscardy, Sébastien and Whiteway, Jim and Willame, Yannick and Wolff, Mike and Patel, Manish and D’aversa, Emiliano and Fussen, Didier and Garcia-Comas, Maya and Hewson, Will and McConnel, Jack and Novak, Robert and Oliva, Fabrizio and Piccialli, Arianna and Aparicio Del Moral, Beatriz and Barzin, Pascal and Benmoussa, Ali and Berkenbosch, Sophie and Biondi, David and Bonnewijn, Sabrina and Candini, Gian Paolo and Clairquin, Roland and Cubas, Javier and De-Lanoye, Sofie and Giordanengo, Boris and Gissot, Samuel and Gomez, Alejandro and Maes, Jeroen and Mazy, Emmanuel and Mazzoli, Alexandra and Meseguer, Jose and Morales, Rafael and Orban, Anne and Pastor-Morales, Maria Del Carmen and Perez-Grande, Isabel and Queirolo, Claudio and Saggin, Bortolino and Samain, Valérie and Sanz Andres, Angel and Sanz, Rosario and Simar, Juan-Felipe and Thibert, Tanguy and Zafra, Jose Jeronimo}, title = {NOMAD, an Integrated Suite of Three Spectrometers for the ExoMars Trace Gas Mission: Technical Description, Science Objectives and Expected Performance}, journal = {Space Science Reviews}, year = {2018}, volume = {214}, number = {5}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1007/s11214-018-0517-2} }
Vander Auwera J, Reymond-Laruinaz S, Boudon V, Doizi D and Manceron L (2018), "Line intensity measurements and analysis in the ν3 band of ruthenium tetroxide", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 204, pp. 103 – 111. [Abstract] [BibTeX] [DOI]
Abstract: Ruthenium tetroxide (RuO4) is a heavy tetrahedral molecule characterized by an unusual volatility near ambient temperature. Because of its chemical toxicity and the radiological impact of its 103Ru and 106Ru isotopologues, the possible remote sensing of this compound in the atmosphere has renewed interest in its spectroscopic properties. The present contribution is the first investigation dealing with high-resolution line-by-line intensity measurements for the strong fundamental band observed near 10 μm, associated with the excitation of the infrared active stretching mode ν3. It relies on new, high resolution FTIR spectra recorded at room temperature, using a specially constructed cell and an isotopically pure sample of 102Ru16O4. Relying on an effective Hamiltonian and associated effective dipole moment [S Reymond–Laruinaz et al, J Mol Spectrosc 2015;315:46–54], the measured line intensities were assigned and dipole moment parameters determined. A HITRAN-formatted frequency and intensity line list was generated. © 2017 Elsevier Ltd
BibTeX: @article{VanderAuwera2018a, author = {Vander Auwera, J. and Reymond-Laruinaz, S. and Boudon, V. and Doizi, D. and Manceron, L.}, title = {Line intensity measurements and analysis in the ν3 band of ruthenium tetroxide}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2018}, volume = {204}, pages = {103 – 111}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2017.09.016} }
Vander Auwera J and Vanfleteren T (2018), "Line positions and intensities in the 7400–8600 cm−1 region of the ammonia spectrum "*, Molecular Physics. Vol. 116(23-24), pp. 3621 – 3630. [Abstract] [BibTeX] [DOI]
Abstract: The positions and intensities of 1936 lines observed in the range 7400–8600 cm−1 of two absorption spectra of ammonia recorded at high resolution using Fourier transform spectroscopy are reported. The accuracy of these line positions is estimated to range from 0.001 to 0.002 cm−1 from the lower to the upper limits of the spectral range considered, while the accuracy of the line intensities is estimated to be around 10% or better. Also reported are less-accurately measured positions and intensities of 1985 lines retrieved from these two spectra or from only one of them. These results are compared with the data measured recently in a spectrum recorded in 1980 at the Kitt Peak National Solar Observatory [Barton et al., J. Mol. Spectrosc. 325, 7 (2016)] and provided in HITRAN 2016, as well as line positions and intensities measured in this work in the same Kitt Peak spectrum. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX: @article{VanderAuwera2018, author = {Vander Auwera, J. and Vanfleteren, T.}, title = {Line positions and intensities in the 7400–8600 cm−1 region of the ammonia spectrum* }, journal = {Molecular Physics}, year = {2018}, volume = {116}, number = {23-24}, pages = {3621 – 3630}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268976.2018.1467054} }
Wang K, Song C, Jönsson P, Zanna GD, Schiffmann S, Godefroid M, Gaigalas G, Zhao X, Si R, Chen C and Yan J (2018), "Benchmarking Atomic Data from Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: S-like Ions from Crix to Cuxiv", Astrophysical Journal, Supplement Series. Vol. 239(2) [Abstract] [BibTeX] [DOI]
Abstract: We present a consistent set of calculated energies and E1, M1, E2, M2 radiative transition data for the main n = 3 levels from the 3s 23p 4, 3p 6, 3p6, 3s3p43d, 3s23p23d2, 3s3p5, 3s23p33d, and 3s3p33d2 configurations for S-like ions from Cr ix to Cu xiv. The fully relativistic multiconfiguration Dirac-Hartree-Fock method implemented in the GRASP2K code is used to perform the present calculations. The excitation energies of the lowest 47 levels from the , , and configurations, producing the strongest lines, are found to be in good agreement, reaching spectroscopic accuracy, with the latest experimental values for Fe xi evaluated by Del Zanna. Our energies can reliably be used to identify in astrophysical and laboratory spectra the levels in other S-like ions, which are mostly unknown. On the contrary, significant discrepancies with the 3s3p 43d levels were found, emphasizing the need for more detailed experimental studies. A few new tentative identifications are suggested. The benchmarks we present indicate that our consistent set of radiative data is accurate and can be used for spectral line modeling. © 2018. The American Astronomical Society. All rights reserved..
BibTeX: @article{Wang2018a, author = {Wang, K. and Song, C.X. and Jönsson, P. and Zanna, G. Del and Schiffmann, S. and Godefroid, M. and Gaigalas, G. and Zhao, X.H. and Si, R. and Chen, C.Y. and Yan, J.}, title = {Benchmarking Atomic Data from Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: S-like Ions from Crix to Cuxiv}, journal = {Astrophysical Journal, Supplement Series}, year = {2018}, volume = {239}, number = {2}, note = {All Open Access, Bronze Open Access}, doi = {10.3847/1538-4365/aaedba} }
Wang K, Song CX, Jönsson P, Ekman J, Godefroid M, Zhang CY, Si R, Zhao XH, Chen CY and Yan J (2018), "Large-scale Multiconfiguration Dirac-Hartree-Fock and Relativistic Configuration Interaction Calculations of Transition Data for B-like S xii", Astrophysical Journal. Vol. 864(2) [Abstract] [BibTeX] [DOI]
Abstract: Excitation energies and lifetimes for the 213 lowest states of the n ≤ 5 configurations in B-like S xii are calculated using highly correlated wave functions, optimized with the fully relativistic multiconfiguration Dirac-Hartree-Fock method. Multipole transition rates and associated radiative data (line strengths and oscillator strengths) for transitions connecting these levels are also reported. The theoretical excitation energies are systematically compared with the NIST Atomic Spectra Database in which misidentifications are pointed out. After eliminating the latter, a mean energy difference with the standard deviation between computed and observed energies of 12 ±341 cm-1 is obtained for the n ≥ 3 high-lying states. This level of accuracy confirms that elaborate ab initio calculations can assist in the identification of new emission lines in the solar and other astrophysical spectra. The present work provides atomic data of high accuracy for an ion of astrophysical interest, B-like S xii, for which experimental data are scarce. © 2018. The American Astronomical Society. All rights reserved.
BibTeX: @article{Wang2018, author = {Wang, Kai and Song, Chang Xian and Jönsson, Per and Ekman, Jörgen and Godefroid, Michel and Zhang, Chun Yu and Si, Ran and Zhao, Xiao Hui and Chen, Chong Yang and Yan, Jun}, title = {Large-scale Multiconfiguration Dirac-Hartree-Fock and Relativistic Configuration Interaction Calculations of Transition Data for B-like S xii}, journal = {Astrophysical Journal}, year = {2018}, volume = {864}, number = {2}, note = {All Open Access, Bronze Open Access}, doi = {10.3847/1538-4357/aad5dc} }
Wespes C, Hurtmans D, Clerbaux C, Boynard A and Coheur P-F (2018), "Decrease in tropospheric O3 levels in the Northern Hemisphere observed by IASI", Atmospheric Chemistry and Physics. Vol. 18(9), pp. 6867 – 6885. [Abstract] [BibTeX] [DOI]
Abstract: In this study, we describe the recent changes in the tropospheric ozone (O3) columns measured by the Infrared Atmospheric Sounding Interferometer (IASI), onboard the Metop satellite, during the first 9 years of operation (January 2008 to May 2017). Using appropriate multivariate regression methods, we differentiate significant linear trends from other sources of O3 variations captured by IASI. The geographical patterns of the adjusted O3 trends are provided and discussed on the global scale. Given the large contribution of the natural variability in comparison with that of the trend (25-85% vs. 15-50%, respectively) to the total O3 variations, we estimate that additional years of IASI measurements are generally required to detect the estimated O3 trends with high precision. Globally, additional 6 months to 6 years of measurements, depending on the regions and the seasons, are needed to detect a trend of \|5\|DUdecadeg-1. An exception is interestingly found during summer at mid-and high latitudes of the Northern Hemisphere (NH; ∼ 40 to ∼75°N), where the large absolute fitted trend values (∼ \|0.5\|DUyrg-1 on average) combined with the small model residuals (∼ 10%) allow for detection of a band-like pattern of significant negative trends. Despite no consensus in terms of tropospheric O3 trends having been reached from the available independent datasets (UV or IR satellites, O3 sondes, aircrafts, ground-based measurements, etc.) for the reasons that are discussed in the text, this finding is consistent with the reported decrease in O3 precursor emissions in recent years, especially in Europe and USA. The influence of continental pollution on that latitudinal band is further investigated and supported by the analysis of the O3-CO relationship (in terms of correlation coefficient, regression slope and covariance) that we found to be the strongest at northern midlatitudes in summer. © 2018 Author(s).
BibTeX: @article{Wespes2018, author = {Wespes, Catherine and Hurtmans, Daniel and Clerbaux, Cathy and Boynard, Anne and Coheur, Pierre-François}, title = {Decrease in tropospheric O3 levels in the Northern Hemisphere observed by IASI}, journal = {Atmospheric Chemistry and Physics}, year = {2018}, volume = {18}, number = {9}, pages = {6867 – 6885}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-18-6867-2018} }
Alkadrou A, Bourgeois M-T, Rotger M, Boudon V and Vander Auwera J (2017), "Corrigendum to “Global frequency and intensity analysis of the ν10/ν7/ν4/ν12 band system of 12C2H4 at 10 μm using the D2 h top data system” (Journal of Quantitative Spectroscopy and Radiative Transfer (2017) 190 (88) (S0022407315303162) (10.1016/j.jqsrt.2016.05.024))", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 190, pp. 88. [Abstract] [BibTeX] [DOI]
Abstract: This corrigendum provides a new version of one of the 3 supplementary data files associated with the article A. Alkadrou et al., J. Quant. Spectrosc. Radiat. Transf. 182 (2016) 158–171, namely the HITRAN-formatted linelist generated as described in section 5 of the article. Indeed, the Ka and Kc labels of the upper levels of a number of transitions belonging to the ν10, ν7 and ν4 bands listed in this supplementary data file were found to be incorrect. The linelist provided with this corrigendum corrects these erroneous assignments, and provides Ka and Kc labels for all the upper levels. © 2017 Elsevier Ltd
BibTeX: @article{Alkadrou2017, author = {Alkadrou, A. and Bourgeois, M.-T. and Rotger, M. and Boudon, V. and Vander Auwera, J.}, title = {Corrigendum to “Global frequency and intensity analysis of the ν10/ν7/ν4/ν12 band system of 12C2H4 at 10 μm using the D2 h top data system” (Journal of Quantitative Spectroscopy and Radiative Transfer (2017) 190 (88) (S0022407315303162) (10.1016/j.jqsrt.2016.05.024))}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2017}, volume = {190}, pages = {88}, doi = {10.1016/j.jqsrt.2017.01.007} }
Bauduin S, Clarisse L, Theunissen M, George M, Hurtmans D, Clerbaux C and Coheur P-F (2017), "IASI's sensitivity to near-surface carbon monoxide (CO): Theoretical analyses and retrievals on test cases", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 189, pp. 428 – 440. [Abstract] [BibTeX] [DOI]
Abstract: Separating concentrations of carbon monoxide (CO) in the boundary layer from the rest of the atmosphere with nadir satellite measurements is of particular importance to differentiate emission from transport. Although thermal infrared (TIR) satellite sounders are considered to have limited sensitivity to the composition of the near-surface atmosphere, previous studies show that they can provide information on CO close to the ground in case of high thermal contrast. In this work we investigate the capability of IASI (Infrared Atmospheric Sounding Interferometer) to retrieve near-surface CO concentrations, and we quantitatively assess the influence of thermal contrast on such retrievals. We present a 3-part analysis, which relies on both theoretical forward simulations and retrievals on real data, performed for a large range of negative and positive thermal contrast situations. First, we derive theoretically the IASI detection threshold of CO enhancement in the boundary layer, and we assess its dependence on thermal contrast. Then, using the optimal estimation formalism, we quantify the role of thermal contrast on the error budget and information content of near-surface CO retrievals. We demonstrate that, contrary to what is usually accepted, large negative thermal contrast values (ground cooler than air) lead to a better decorrelation between CO concentrations in the low and the high troposphere than large positive thermal contrast (ground warmer than the air). In the last part of the paper we use Mexico City and Barrow as test cases to contrast our theoretical predictions with real retrievals, and to assess the accuracy of IASI surface CO retrievals through comparisons to ground-based in-situ measurements. © 2017 Elsevier Ltd
BibTeX: @article{Bauduin2017, author = {Bauduin, Sophie and Clarisse, Lieven and Theunissen, Michael and George, Maya and Hurtmans, Daniel and Clerbaux, Cathy and Coheur, Pierre-François}, title = {IASI's sensitivity to near-surface carbon monoxide (CO): Theoretical analyses and retrievals on test cases}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2017}, volume = {189}, pages = {428 – 440}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.jqsrt.2016.12.022} }
Bègue N, Vignelles D, Berthet G, Portafaix T, Payen G, Jégou F, Benchérif H, Jumelet J, Lurton T, Renard J-B, Clarisse L, Duverger V, Posny F, Metzger J-M and Godin-Beekmann S (2017), "Long-range transport of stratospheric aerosols in the Southern Hemisphere following the 2015 Calbuco eruption", Atmospheric Chemistry and Physics. Vol. 17(24), pp. 15019 – 15036. [Abstract] [BibTeX] [DOI]
Abstract: After 43 years of inactivity, the Calbuco volcano, which is located in the southern part of Chile, erupted on 22 April 2015. The space-time evolutions (distribution and transport) of its aerosol plume are investigated by combining satellite (CALIOP, IASI, OMPS), in situ aerosol counting (LOAC OPC) and lidar observations, and the MIMOSA advection model. The Calbuco aerosol plume reached the Indian Ocean 1 week after the eruption. Over the Reunion Island site (21 S, 55.5 E), the aerosol signal was unambiguously enhanced in comparison with "background" conditions, with a volcanic aerosol layer extending from 18 to 21 km during the May-July period. All the data reveal an increase by a factor of 2 in the SAOD (stratospheric aerosol optical depth) with respect to values observed before the eruption. The aerosol mass e-folding time is approximately 90 days, which is rather close to the value (80 days) reported for the Sarychev eruption. Microphysical measurements obtained before, during, and after the eruption reflecting the impact of the Calbuco eruption on the lower stratospheric aerosol content have been analyzed over the Reunion Island site. During the passage of the plume, the volcanic aerosol was characterized by an effective radius of 0.160.02 μm with a unimodal size distribution for particles above 0.2 μm in diameter. Particle concentrations for sizes larger than 1 μm are too low to be properly detected by the LOAC OPC. The aerosol number concentration was 20 times higher that observed before and 1 year after the eruption. According to OMPS and lidar observations, a tendency toward conditions before the eruption was observed by April 2016. The volcanic aerosol plume is advected eastward in the Southern Hemisphere and its latitudinal extent is clearly bounded by the subtropical barrier and the polar vortex. The transient behavior of the aerosol layers observed above Reunion Island between May and July 2015 reflects an inhomogeneous spatio-temporal distribution of the plume, which is controlled by the localization of these dynamical barriers. © Author(s) 2017.
BibTeX: @article{Begue2017, author = {Bègue, Nelson and Vignelles, Damien and Berthet, Gwenaël and Portafaix, Thierry and Payen, Guillaume and Jégou, Fabrice and Benchérif, Hassan and Jumelet, Julien and Lurton, Thibaut and Renard, Jean-Baptiste and Clarisse, Lieven and Duverger, Vincent and Posny, Françoise and Metzger, Jean-Marc and Godin-Beekmann, Sophie}, title = {Long-range transport of stratospheric aerosols in the Southern Hemisphere following the 2015 Calbuco eruption}, journal = {Atmospheric Chemistry and Physics}, year = {2017}, volume = {17}, number = {24}, pages = {15019 – 15036}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-17-15019-2017} }
Doppelbauer MJ, Schullian O, Loreau J, Vaeck N, Van Der Avoird A, Rennick CJ, Softley TP and Heazlewood BR (2017), "Using a direct simulation Monte Carlo approach to model collisions in a buffer gas cell", Journal of Chemical Physics. Vol. 146(4) [Abstract] [BibTeX] [DOI]
Abstract: A direct simulation Monte Carlo (DSMC) method is applied to model collisions between He buffer gas atoms and ammonia molecules within a buffer gas cell. State-to-state cross sections, calculated as a function of the collision energy, enable the inelastic collisions between He and NH3 to be considered explicitly. The inclusion of rotational-state-changing collisions affects the translational temperature of the beam, indicating that elastic and inelastic processes should not be considered in isolation. The properties of the cold molecular beam exiting the cell are examined as a function of the cell parameters and operating conditions; the rotational and translational energy distributions are in accord with experimental measurements. The DSMC calculations show that thermalisation occurs well within the typical 10-20 mm length of many buffer gas cells, suggesting that shorter cells could be employed in many instances - yielding a higher flux of cold molecules. © 2017 Author(s).
BibTeX: @article{Doppelbauer2017, author = {Doppelbauer, Maximilian J. and Schullian, Otto and Loreau, Jerome and Vaeck, Nathalie and Van Der Avoird, Ad and Rennick, Christopher J. and Softley, Timothy P. and Heazlewood, Brianna R.}, title = {Using a direct simulation Monte Carlo approach to model collisions in a buffer gas cell}, journal = {Journal of Chemical Physics}, year = {2017}, volume = {146}, number = {4}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1063/1.4974253} }
Duflot V, Baray J-L, Payen G, Marquestaut N, Posny F, Metzger J-M, Langerock B, Vigouroux C, Hadji-Lazaro J, Portafaix T, De Mazière M, Coheur P-F, Clerbaux C and Cammas J-P (2017), "Tropospheric ozone profiles by DIAL at Maïdo Observatory (Reunion Island): System description, instrumental performance and result comparison with ozone external data set", Atmospheric Measurement Techniques. Vol. 10(9), pp. 3359 – 3373. [Abstract] [BibTeX] [DOI]
Abstract: In order to recognize the importance of ozone (O3) in the troposphere and lower stratosphere in the tropics, a DIAL (differential absorption lidar) tropospheric O3 lidar system (LIO3TUR) was developed and installed at the Université de la Réunion campus site (close to the sea) on Reunion Island (southern tropics) in 1998. From 1998 to 2010, it acquired 427 O3 profiles from the low to the upper troposphere and has been central to several studies. In 2012, the system was moved up to the new Maïdo Observatory facility (2160-l. - metres above mean sea level) where it started operation in February 2013. The current system (LIO3T) configuration generates a 266 beam obtained with the fourth harmonic of a Nd:YAG laser sent into a Raman cell filled up with deuterium (using helium as buffer gas), generating the 289 and 316 beams to enable the use of the DIAL method for O3 profile measurements. The optimal range for the actual system is 6-19ga.m.s.l., depending on the instrumental and atmospheric conditions. For a 1gh integration time, vertical resolution varies from 0.7gkm at 6ga.m.s.l. to 1.3gkm at 19ga.m.s.l., and mean uncertainty within the 6-19gkm range is between 6 and 13g%. Comparisons with eight electrochemical concentration cell (ECC) sondes simultaneously launched from the Maïdo Observatory show good agreement between data sets with a 6.8g% mean absolute relative difference (D) between 6 and 17ga.m.s.l. (LIO3T lower than ECC). Comparisons with 37 ECC sondes launched from the nearby Gillot site during the daytime in a ±24gh window around lidar shooting result in a 9.4g% D between 6 and 19ga.m.s.l. (LIO3T lower than ECC). Comparisons with 11 ground-based Network for Detection of Atmospheric Composition Change (NDACC) Fourier transform infrared (FTIR) spectrometer measurements acquired during the daytime in a ±24gh window around lidar shooting show good agreement between data sets with a D of 11.8g% for the 8.5-16gkm partial column (LIO3T higher than FTIR), and comparisons with 39 simultaneous Infrared Atmospheric Sounding Interferometer (IASI) observations over Reunion Island show good agreement between data sets with a D of 11.3g% for the 6-16gkm partial column (LIO3T higher than IASI). ECC, LIO3TUR and LIO3T O3 monthly climatologies all exhibit the same range of values and patterns. In particular, the Southern Hemisphere biomass burning seasonal enhancement and the ozonopause altitude decrease in late austral winter-spring, as well as the sign of deep convection bringing boundary layer O3-poor air masses up to the middle-upper troposphere in late austral summer, are clearly visible in all data sets. © Author(s) 2017.
BibTeX: @article{Duflot2017, author = {Duflot, Valentin and Baray, Jean-Luc and Payen, Guillaume and Marquestaut, Nicolas and Posny, Francoise and Metzger, Jean-Marc and Langerock, Bavo and Vigouroux, Corinne and Hadji-Lazaro, Juliette and Portafaix, Thierry and De Mazière, Martine and Coheur, Pierre-Francois and Clerbaux, Cathy and Cammas, Jean-Pierre}, title = {Tropospheric ozone profiles by DIAL at Maïdo Observatory (Reunion Island): System description, instrumental performance and result comparison with ozone external data set}, journal = {Atmospheric Measurement Techniques}, year = {2017}, volume = {10}, number = {9}, pages = {3359 – 3373}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-10-3359-2017} }
Filippin L, Bieroń J, Gaigalas G, Godefroid M and Jönsson P (2017), "Multiconfiguration calculations of electronic isotope-shift factors in Zn i", Physical Review A. Vol. 96(4) [Abstract] [BibTeX] [DOI]
Abstract: The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of electronic isotope-shift factors for a set of transitions between low-lying states in neutral zinc. These electronic quantities, together with observed isotope shifts between different pairs of isotopes, provide the changes in mean-square charge radii of the atomic nuclei. Within this computational approach, different models for electron correlation are explored in a systematic way to determine a reliable computational strategy and to estimate theoretical error bars of the isotope-shift factors. © 2017 American Physical Society.
BibTeX: @article{Filippin2017, author = {Filippin, Livio and Bieroń, Jacek and Gaigalas, Gediminas and Godefroid, Michel and Jönsson, Per}, title = {Multiconfiguration calculations of electronic isotope-shift factors in Zn i}, journal = {Physical Review A}, year = {2017}, volume = {96}, number = {4}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.96.042502} }
Fusina L, Di Lonardo G, Canè E, Predoi-Cross A, Rozario H and Herman M (2017), "The high resolution spectrum of 15NH3 in the far-infrared: Rotation-inversion transitions in the ground, v2=1, 2 and v4=1 states", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 203, pp. 417 – 424. [Abstract] [BibTeX] [DOI]
Abstract: The high resolution spectrum of 15NH3 has been recorded at unapodized resolution of 0.00096 cm−1 in the region 60–600 cm−1 using the Bruker IFS 125 Fourier transform spectrometer located at the far-infrared beam-line, Canadian Light Source. We report on the observation and analysis of the rotation-inversion spectrum in the ground, v2=1, 2 and v4=1 states. All the rotation-inversion transitions in the ground state together with the pure inversion transitions present in the literature were fitted simultaneously on the basis of a rotation-inversion Hamiltonian which includes distortion constants up to the 12th power in the angular momentum and the Δk=±3 and Δk=±6 interaction terms. A set of effective parameters was also obtained for the v2=1 state adopting the same theoretical model. For the v2=2 and v4=1 states only a list of observed transitions is reported. The wavenumbers of all the assigned transitions were compared with their theoretically predicted values [S.N. Yurchenko, J. Quant. Spectrosc. Radiat. Transf., 2015, 152, 28]. The present results noticeably improve the wavenumber line list in the HITRAN data base [L. S. Rothman et al. J. Quant. Spectrosc. Radiat. Transf.,2013, 130, 4]. © 2017 Elsevier Ltd
BibTeX: @article{Fusina2017, author = {Fusina, Luciano and Di Lonardo, Gianfranco and Canè, Elisabetta and Predoi-Cross, Adriana and Rozario, Hoimonti and Herman, Michel}, title = {The high resolution spectrum of 15NH3 in the far-infrared: Rotation-inversion transitions in the ground, v2=1, 2 and v4=1 states}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2017}, volume = {203}, pages = {417 – 424}, doi = {10.1016/j.jqsrt.2017.01.021} }
Gordon I, Rothman L, Hill C, Kochanov R, Tan Y, Bernath P, Birk M, Boudon V, Campargue A, Chance K, Drouin B, Flaud J-M, Gamache R, Hodges J, Jacquemart D, Perevalov V, Perrin A, Shine K, Smith M-A, Tennyson J, Toon G, Tran H, Tyuterev V, Barbe A, Császár A, Devi V, Furtenbacher T, Harrison J, Hartmann J-M, Jolly A, Johnson T, Karman T, Kleiner I, Kyuberis A, Loos J, Lyulin O, Massie S, Mikhailenko S, Moazzen-Ahmadi N, Müller H, Naumenko O, Nikitin A, Polyansky O, Rey M, Rotger M, Sharpe S, Sung K, Starikova E, Tashkun S, Auwera JV, Wagner G, Wilzewski J, Wcisło P, Yu S and Zak E (2017), "The HITRAN2016 molecular spectroscopic database", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 203, pp. 3 – 69. [Abstract] [BibTeX] [DOI]
Abstract: This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 300 additional molecules important in different areas of atmospheric science have been added to the database. The compilation can be accessed through www.hitran.org. Most of the HITRAN data have now been cast into an underlying relational database structure that offers many advantages over the long-standing sequential text-based structure. The new structure empowers the user in many ways. It enables the incorporation of an extended set of fundamental parameters per transition, sophisticated line-shape formalisms, easy user-defined output formats, and very convenient searching, filtering, and plotting of data. A powerful application programming interface making use of structured query language (SQL) features for higher-level applications of HITRAN is also provided. © 2017
BibTeX: @article{Gordon2017, author = {Gordon, I.E. and Rothman, L.S. and Hill, C. and Kochanov, R.V. and Tan, Y. and Bernath, P.F. and Birk, M. and Boudon, V. and Campargue, A. and Chance, K.V. and Drouin, B.J. and Flaud, J.-M. and Gamache, R.R. and Hodges, J.T. and Jacquemart, D. and Perevalov, V.I. and Perrin, A. and Shine, K.P. and Smith, M.-A.H. and Tennyson, J. and Toon, G.C. and Tran, H. and Tyuterev, V.G. and Barbe, A. and Császár, A.G. and Devi, V.M. and Furtenbacher, T. and Harrison, J.J. and Hartmann, J.-M. and Jolly, A. and Johnson, T.J. and Karman, T. and Kleiner, I. and Kyuberis, A.A. and Loos, J. and Lyulin, O.M. and Massie, S.T. and Mikhailenko, S.N. and Moazzen-Ahmadi, N. and Müller, H.S.P. and Naumenko, O.V. and Nikitin, A.V. and Polyansky, O.L. and Rey, M. and Rotger, M. and Sharpe, S.W. and Sung, K. and Starikova, E. and Tashkun, S.A. and Auwera, J. Vander and Wagner, G. and Wilzewski, J. and Wcisło, P. and Yu, S. and Zak, E.J.}, title = {The HITRAN2016 molecular spectroscopic database}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2017}, volume = {203}, pages = {3 – 69}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.jqsrt.2017.06.038} }
Hartmann J-M, Vander Auwera J, Boulet C, Birot M, Dourges M-A, Toupance T, El Hamzaoui H, Ausset P, Carré Y, Kocon L, Capoen B and Bouazaoui M (2017), "Infrared absorption by molecular gases to probe porous materials and comparisons with other techniques", Microporous and Mesoporous Materials. Vol. 237, pp. 31 – 37. [Abstract] [BibTeX] [DOI]
Abstract: Infrared transmission spectra of several molecular gases inside three porous silica samples with pore sizes ranging from 7 nm to several tens of nm have been recorded with a Fourier transform spectrometer. Their analysis shows that consistent values of the percentage of open porosity and average pore size can be retrieved from these non intrusive nor destructive optical measurements. The samples have also been characterized using mercury intrusion/extrusion and the nitrogen sorption method. The results of these different probing techniques are in good agreement when the methods used are adapted to the involved pore size. This consistency demonstrates that light absorption by confined gases is a valuable porosimetry tool. © 2016 Elsevier Inc.
BibTeX: @article{Hartmann2017, author = {Hartmann, J.-M. and Vander Auwera, J. and Boulet, C. and Birot, M. and Dourges, M.-A. and Toupance, T. and El Hamzaoui, H. and Ausset, P. and Carré, Y. and Kocon, L. and Capoen, B. and Bouazaoui, M.}, title = {Infrared absorption by molecular gases to probe porous materials and comparisons with other techniques}, journal = {Microporous and Mesoporous Materials}, year = {2017}, volume = {237}, pages = {31 – 37}, doi = {10.1016/j.micromeso.2016.09.014} }
Hashemi R, Dudaryonok A, Lavrentieva N, Vandaele A, Vander Auwera J, Nikitin A, Tyuterev V, Sung K, Smith M, Devi V and Predoi-Cross A (2017), "Fourier Transform Spectroscopy of two trace gases namely Methane and Carbon monoxide for planetary and atmospheric research application", Journal of Physics: Conference Series. Vol. 810(1) [Abstract] [BibTeX] [DOI]
Abstract: Two atmospheric trace gases, namely methane and carbon monoxide have been considered in this study. Fourier transform absorption spectra of the 2-0 band of 12C16O mixed with CO2 have been recorded at total pressures from 156 to 1212 hPa and at 4 different temperatures between 240 K and 283 K. CO2 pressure-induced line broadening and line shift coefficients, and the associated temperature dependence have been measured in an multi-spectrum non-linear least squares analysis using Voigt profiles with an asymmetric profile due to line mixing. The measured CO2-broadening and CO2-shift parameters were compared with theoretical values, calculated by collaborators. In addition, the CO2-broadening and shift coefficients have been calculated for individual temperatures using the Exponential Power Gap (EPG) semi-empirical method. We also discuss the retrieved line shape parameters for Methane transitions in the spectral range known as the Methane Octad. We used high resolution spectra of pure methane and of dilute mixtures of methane in dry air, recorded with high signal to noise ratio at temperatures between 148 K and room temperature using the Bruker IFS 125 HR Fourier transform spectrometer (FTS) at the Jet Propulsion Laboratory, Pasadena, California. Theoretical calculations for line parameters have been performed and the results are compared with the previously published values and with the line parameters available in the GEISA2015 [1] and HITRAN2012 [2] databases. © Published under licence by IOP Publishing Ltd.
BibTeX: @conference{Hashemi2017, author = {Hashemi, R. and Dudaryonok, A.S. and Lavrentieva, N.N. and Vandaele, A.C. and Vander Auwera, J. and Nikitin, A.V. and Tyuterev, V.I.G. and Sung, K. and Smith, M.A.H. and Devi, V.M. and Predoi-Cross, A.}, title = {Fourier Transform Spectroscopy of two trace gases namely Methane and Carbon monoxide for planetary and atmospheric research application}, journal = {Journal of Physics: Conference Series}, year = {2017}, volume = {810}, number = {1}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/810/1/012008} }
Jönsson P, Gaigalas G, Rynkun P, Radžiute L, Ekman J, Gustafsson S, Hartman H, Wang K, Godefroid M, Fischer CF, Grant I, Brage T and Del Zanna G (2017), "Multiconfiguration dirac-hartree-fock calculations with spectroscopic accuracy: Applications to astrophysics", Atoms. Vol. 5(2) [Abstract] [BibTeX] [DOI]
Abstract: Atomic data, such as wavelengths, spectroscopic labels, broadening parameters and transition rates, are necessary for many applications, especially in plasma diagnostics, and for interpreting the spectra of distant astrophysical objects. The experiment with its limited resources is unlikely to ever be able to provide a complete dataset on any atomic system. Instead, the bulk of the data must be calculated. Based on fundamental principles and well-justified approximations, theoretical atomic physics derives and implements algorithms and computational procedures that yield the desired data. We review progress and recent developments in fully-relativistic multiconfiguration Dirac-Hartree-Fock methods and show how large-scale calculations can give transition energies of spectroscopic accuracy, i.e., with an accuracy comparable to the one obtained from observations, as well as transition rates with estimated uncertainties of a few percent for a broad range of ions. Finally, we discuss further developments and challenges. © 2017 by the authors.
BibTeX: @article{Joensson2017, author = {Jönsson, Per and Gaigalas, Gediminas and Rynkun, Pavel and Radžiute, Laima and Ekman, Jörgen and Gustafsson, Stefan and Hartman, Henrik and Wang, Kai and Godefroid, Michel and Fischer, Charlotte Froese and Grant, Ian and Brage, Tomas and Del Zanna, Giulio}, title = {Multiconfiguration dirac-hartree-fock calculations with spectroscopic accuracy: Applications to astrophysics}, journal = {Atoms}, year = {2017}, volume = {5}, number = {2}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atoms5020016} }
Kas M, Loreau J, Liévin J and Vaeck N (2017), "Ab initio study of the neutral and anionic alkali and alkaline earth hydroxides: Electronic structure and prospects for sympathetic cooling of OH-", Journal of Chemical Physics. Vol. 146(19) [Abstract] [BibTeX] [DOI]
Abstract: We have performed a systematic ab initio study on alkali and alkaline earth hydroxide neutral (MOH) and anionic (MOH-) species where M = Li, Na, K, Rb, Cs or Be, Mg, Ca, Sr, Ba. The CCSD(T) method with extended basis sets and Dirac-Fock relativistic effective core potentials for the heavier atoms has been used to study their equilibrium geometries, interaction energies, electron affinities, electric dipole moment, and potential energy surfaces. All neutral and anionic species exhibit a linear shape with the exception of BeOH, BeOH-, and MgOH-, for which the equilibrium structure is found to be bent. Our analysis shows that the alkaline earth hydroxide anions are valence-bound whereas the alkali hydroxide anions are dipole bound. In the context of sympathetic cooling of OH- by collision with ultracold alkali and alkaline earth atoms, we investigate the 2D MOH- potential energy surfaces and the associative detachment reaction M + OH→- MOH + e-, which is the only energetically allowed reactive channel in the cold regime. We discuss the implication for the sympathetic cooling of OH- and conclude that Li and K are the best candidates for an ultracold buffer gas. © 2017 Author(s).
BibTeX: @article{Kas2017, author = {Kas, Milaim and Loreau, Jérôme and Liévin, Jacques and Vaeck, Nathalie}, title = {Ab initio study of the neutral and anionic alkali and alkaline earth hydroxides: Electronic structure and prospects for sympathetic cooling of OH-}, journal = {Journal of Chemical Physics}, year = {2017}, volume = {146}, number = {19}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.4983627} }
Lacour J-L, Flamant C, Risi C, Clerbaux C and Coheur P-F (2017), "Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δd observations", Atmospheric Chemistry and Physics. Vol. 17(15), pp. 9645 – 9663. [Abstract] [BibTeX] [DOI]
Abstract: The isotopic composition of water vapour in the North Atlantic free troposphere is investigated with Infrared Atmospheric Sounding Interferometer (IASI) measurements of the D/H ratio (δD) above the ocean. We show that in the vicinity of West Africa, the seasonality of δD is particularly strong (130 ‰), which is related with the influence of the Saharan heat low (SHL) during summertime. The SHL indeed largely influences the dynamic in that region by producing deep turbulent mixing layers, yielding a specific water vapour isotopic footprint. The influence of the SHL on the isotopic budget is analysed on various time and space scales and is shown to be large, highlighting the importance of the SHL dynamics on the moistening and the HDO enrichment of the free troposphere over the North Atlantic. The potential influence of the SHL is also investigated on the inter-annual scale as we also report important variations in δD above the Canary archipelago region. We interpret the variability in the enrichment, using backward trajectory analyses, in terms of the ratio of air masses coming from the North Atlantic and air masses coming from the African continent. Finally, the interest of IASI high sampling capabilities is further illustrated by presenting spatial distributions of δD and humidity above the North Atlantic from which we show that the different sources and dehydration pathways controlling the humidity can be disentangled thanks to the added value of δD observations. More generally, our results demonstrate the utility of δD observations obtained from the IASI sounder to gain insight into the hydrological cycle processes in the West African region. © Author(s) 2017.
BibTeX: @article{Lacour2017, author = {Lacour, Jean-Lionel and Flamant, Cyrille and Risi, Camille and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δd observations}, journal = {Atmospheric Chemistry and Physics}, year = {2017}, volume = {17}, number = {15}, pages = {9645 – 9663}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-17-9645-2017} }
Launoy T, Béroff K, Chabot M, Martinet G, Le Padellec A, Pino T, Bouneau S, Vaeck N, Liévin J, Féraud G, Loreau J and Mahajan T (2017), "Ion-pair dissociation of highly excited carbon clusters: Size and charge effects", Physical Review A. Vol. 95(2) [Abstract] [BibTeX] [DOI]
Abstract: We present measurements of ion-pair dissociation (IPD) of highly excited neutral and ionized carbon clusters Cn=2-5(q=0-3)+. The tool for producing these species was a high-velocity collision between Cn+ projectiles (v=2.25 a.u.) and helium atoms. The setup allowed us to detect in coincidence anionic and cationic fragments, event by event, leading to a direct and unambiguous identification of the IPD process. Compared with dissociation without anion emission, we found typical 10-4 IPD rates, not depending much on the size and charge of the (n,q) species. Exceptions were observed for C2+ and, to a lesser extent, C43+ whose IPDs were notably lower. We tentatively interpret IPDs of C2+ and C3+ by using a statistical approach based on the counting of final states allowed by energetic criteria. The model is able to furnish the right order of magnitude for the experimental IPD rates and to provide a qualitative explanation of the lower IPD rate observed in C2+. © 2017 American Physical Society.
BibTeX: @article{Launoy2017, author = {Launoy, Thibaut and Béroff, Karine and Chabot, Marin and Martinet, Guillaume and Le Padellec, Arnaud and Pino, Thomas and Bouneau, Sandra and Vaeck, Nathalie and Liévin, Jacques and Féraud, Géraldine and Loreau, Jérôme and Mahajan, Thejus}, title = {Ion-pair dissociation of highly excited carbon clusters: Size and charge effects}, journal = {Physical Review A}, year = {2017}, volume = {95}, number = {2}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.95.022711} }
Leifer I, Melton C, Tratt DM, Buckland KN, Clarisse L, Coheur P, Frash J, Gupta M, Johnson PD, Leen JB, Van Damme M, Whitburn S and Yurganov L (2017), "Remote sensing and in situ measurements of methane and ammonia emissions from a megacity dairy complex: Chino, CA", Environmental Pollution. Vol. 221, pp. 37 – 51. [Abstract] [BibTeX] [DOI]
Abstract: Methane (CH4) and ammonia (NH3) directly and indirectly affect the atmospheric radiative balance with the latter leading to aerosol generation. Both have important spectral features in the Thermal InfraRed (TIR) that can be studied by remote sensing, with NH3allowing discrimination of husbandry from other CH4sources. Airborne hyperspectral imagery was collected for the Chino Dairy Complex in the Los Angeles Basin as well as in situ CH4, carbon dioxide (CO2) and NH3data. TIR data showed good spatial agreement with in situ measurements and showed significant emissions heterogeneity between dairies. Airborne remote sensing mapped plume transport for ∼20 km downwind, documenting topographic effects on plume advection. Repeated multiple gas in situ measurements showed that emissions were persistent on half-year timescales. Inversion of one dairy plume found annual emissions of 4.1 × 105 kg CH4, 2.2 × 105 kg NH3, and 2.3 × 107 kg CO2, suggesting 2300, 4000, and 2100 head of cattle, respectively, and Chino Dairy Complex emissions of 42 Gg CH4and 8.4 Gg NH3implying ∼200k cows, ∼30% more than Peischl et al. (2013) estimated for June 2010. Far-field data showed chemical conversion and/or deposition of Chino NH3occurs within the confines of the Los Angeles Basin on a four to six h timescale, faster than most published rates, and likely from higher Los Angeles oxidant loads. Satellite observations from 2011 to 2014 confirmed that observed in situ transport patterns were representative and suggests much of the Chino Dairy Complex emissions are driven towards eastern Orange County, with a lesser amount transported to Palm Springs, CA. Given interest in mitigating husbandry health impacts from air pollution emissions, this study highlights how satellite observations can be leveraged to understand exposure and how multiple gas in situ emissions studies can inform on best practices given that emissions reduction of one gas could increase those of others. © 2016 Elsevier Ltd
BibTeX: @article{Leifer2017, author = {Leifer, Ira and Melton, Christopher and Tratt, David M. and Buckland, Kerry N. and Clarisse, Lieven and Coheur, Pierre and Frash, Jason and Gupta, Manish and Johnson, Patrick D. and Leen, J. Brian and Van Damme, Martin and Whitburn, Simon and Yurganov, Leonid}, title = {Remote sensing and in situ measurements of methane and ammonia emissions from a megacity dairy complex: Chino, CA}, journal = {Environmental Pollution}, year = {2017}, volume = {221}, pages = {37 – 51}, doi = {10.1016/j.envpol.2016.09.083} }
Li Y, Thompson TM, Van Damme M, Chen X, Benedict KB, Shao Y, Day D, Boris A, Sullivan AP, Ham J, Whitburn S, Clarisse L, Coheur P-F and Collett JL (2017), "Temporal and spatial variability of ammonia in urban and agricultural regions of northern Colorado, United States", Atmospheric Chemistry and Physics. Vol. 17(10), pp. 6197 – 6213. [Abstract] [BibTeX] [DOI]
Abstract: Concentrated agricultural activities and animal feeding operations in the northeastern plains of Colorado represent an important source of atmospheric ammonia (NH3). The NH3 from these sources contributes to regional fine particle formation and to nitrogen deposition to sensitive ecosystems in Rocky Mountain National Park (RMNP), located ∼80 km to the west. In order to better understand temporal and spatial differences in NH3 concentrations in this source region, weekly concentrations of NH3 were measured at 14 locations during the summers of 2010 to 2015 using Radiello passive NH3 samplers. Weekly (biweekly in 2015) average NH3 concentrations ranged from 2.66 to 42.7μ-3, with the highest concentrations near large concentrated animal feeding operations (CAFOs). The annual summertime mean NH3 concentrations were stable in this region from 2010 to 2015, providing a baseline against which concentration changes associated with future changes in regional NH3 emissions can be assessed. Vertical profiles of NH3 were also measured on the 300 m Boulder Atmospheric Observatory (BAO) tower throughout 2012. The highest NH3 concentration along the vertical profile was always observed at the 10 m height (annual average concentration of 4.63 μgm-3), decreasing toward the surface (4.35g μg-3) and toward higher altitudes (1.93g μg-3). The NH3 spatial distributions measured using the passive samplers are compared with NH3 columns retrieved by the Infrared Atmospheric Sounding Interferometer (IASI) satellite and concentrations simulated by the Comprehensive Air Quality Model with Extensions (CAMx). The satellite comparison adds to a growing body of evidence that IASI column retrievals of NH3 provide very useful insight into regional variability in atmospheric NH3, in this case even in a region with strong local sources and sharp spatial gradients. The CAMx comparison indicates that the model does a reasonable job simulating NH3 concentrations near sources but tends to underpredict concentrations at locations farther downwind. Excess NH3 deposition by the model is hypothesized as a possible explanation for this trend. © 2017 Author(s).
BibTeX: @article{Li2017, author = {Li, Yi and Thompson, Tammy M. and Van Damme, Martin and Chen, Xi and Benedict, Katherine B. and Shao, Yixing and Day, Derek and Boris, Alexandra and Sullivan, Amy P. and Ham, Jay and Whitburn, Simon and Clarisse, Lieven and Coheur, Pierre-François and Collett, Jeffrey L.}, title = {Temporal and spatial variability of ammonia in urban and agricultural regions of northern Colorado, United States}, journal = {Atmospheric Chemistry and Physics}, year = {2017}, volume = {17}, number = {10}, pages = {6197 – 6213}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-17-6197-2017} }
Luo J, Pan LL, Honomichl SB, Bergman JW, Randel WJ, Francis G, Clerbaux C, George M, Liu X and Tian W (2017), "Space-Time Variability of UTLS Chemical Distribution in the Asian Summer Monsoon Viewed by Limb and Nadir Satellite Sensors", Atmospheric Chemistry and Physics. Vol. 18(16), pp. 12511 – 12530. [Abstract] [BibTeX] [DOI]
Abstract: The Asian Summer Monsoon (ASM) creates a hemispheric scale signature in trace gas distributions in the upper troposphere and lower stratosphere (UTLS). Data from satellite retrievals are the best source of information for characterizing these large-scale signatures. Measurements from the Microwave Limb Sounder (MLS), a limb viewing satellite sensor, have been the most widely used retrieval products for these type of studies. This work explores the information content for the ASM upper troposphere from two nadir-viewing sensors, IASI and OMI. Day-to-day behaviour of carbon monoxide (CO) and ozone (O3) in the UTLS from these two nadir-viewing sensors are analysed in comparison to MLS to examine the information content for the ASM UTLS trace gas analyses. Day-to-day changes in tracer distributions in response to dynamical variability is explored, to assess whether these nadir viewing sensors provide useful information for investigating sub-seasonal variability. Our result shows that both nadir-viewing instruments capture the impact of ASM dynamics on spatial distribution of tracers in the UTLS. Despite the limited vertical resolution, tropospheric profiles from IASI are able to represent the upper tropospheric enhancement of CO in the region of ASM anticyclone. Similarly, the OMI O3 profile product is capable of distinguishing the tropospheric dominated air mass in the anticyclone from the stratospheric dominated background on a daily time scale. The high horizontal sampling density of IASI data show finer structures in the horizontal distribution of CO compared to the limb viewing MLS, including CO enhancement in the upper troposphere over the western Pacific resulting from the eastward eddy shedding of the ASM anticyclone. Sub-seasonal variability of tracers is correlated with the dynamical structure of the anticyclone as represented by the geopotential height (GPH) field, and systematic differences between the nadir and limb sounder results are discussed. © Author(s) 2017.
BibTeX: @article{Luo2017, author = {Luo, Jiali and Pan, Laura L. and Honomichl, Shawn B. and Bergman, John W. and Randel, William J. and Francis, Gene and Clerbaux, Cathy and George, Maya and Liu, Xiong and Tian, Wenshou}, title = {Space-Time Variability of UTLS Chemical Distribution in the Asian Summer Monsoon Viewed by Limb and Nadir Satellite Sensors}, journal = {Atmospheric Chemistry and Physics}, year = {2017}, volume = {18}, number = {16}, pages = {12511 – 12530}, note = {All Open Access, Green Open Access}, doi = {10.5194/acp-2017-252} }
Mahieu E, Bader W, Bovy B, Demoulin P, Flock O, Franco B, Lejeune B, Prignon M, Roland G and Servais C (2017), "Monitoring of the earth's atmosphere from the Jungfraujoch station: A journey started by the Liège team is more than 65 years!; [Surveillance De L'atmosphère Terrestre Depuis La Station Du Jungfraujoch : Une Épopée Liégeoise Entamée Voici Plus De 65 Ans !]", BSGLg. Vol. 68(1), pp. 119 – 130. [Abstract] [BibTeX]
Abstract: It is in the early 1950s that researchers from the University of Liège started to investigate the Earth's atmosphere from the Jungfraujoch scientific station, in the Swiss Alps, at a time when concerns related to atmospheric composition changes were nonexistent. Since then, a worldwide unique infrared observational data base has been carefully collected. The exploitation of these observations has allowed constituting multi-decadal time series crucial for the characterization of the changes that affected our atmosphere and for the identification of their causes. In this paper, we first remind about the successive steps which led to establishing the observational program of the Liège team at the Jungfraujoch and we evoke important findings which justified its continuation. Then we present some recent results relevant to the Montreal and Kyoto Protocols, or related to the monitoring of air quality. © 2017 Societe Geographique de Liege. All rights reserved.
BibTeX: @article{Mahieu2017, author = {Mahieu, Emmanuel and Bader, Whitney and Bovy, Benoît and Demoulin, Philippe and Flock, Olivier and Franco, Bruno and Lejeune, Bernard and Prignon, Maxime and Roland, Ginette and Servais, Christian}, title = {Monitoring of the earth's atmosphere from the Jungfraujoch station: A journey started by the Liège team is more than 65 years!; [Surveillance De L'atmosphère Terrestre Depuis La Station Du Jungfraujoch : Une Épopée Liégeoise Entamée Voici Plus De 65 Ans !]}, journal = {BSGLg}, year = {2017}, volume = {68}, number = {1}, pages = {119 – 130} }
Malavelle FF, Haywood JM, Jones A, Gettelman A, Clarisse L, Bauduin S, Allan RP, Karset IHH, Kristjánsson JE, Oreopoulos L, Cho N, Lee D, Bellouin N, Boucher O, Grosvenor DP, Carslaw KS, Dhomse S, Mann GW, Schmidt A, Coe H, Hartley ME, Dalvi M, Hill AA, Johnson BT, Johnson CE, Knight JR, O'Connor FM, Stier P, Myhre G, Platnick S, Stephens GL, Takahashi H and Thordarson T (2017), "Strong constraints on aerosol-cloud interactions from volcanic eruptions", Nature. Vol. 546(7659), pp. 485 – 491. [Abstract] [BibTeX] [DOI]
Abstract: Aerosols have a potentially large effect on climate, particularly through their interactions with clouds, but the magnitude of this effect is highly uncertain. Large volcanic eruptions produce sulfur dioxide, which in turn produces aerosols; these eruptions thus represent a natural experiment through which to quantify aerosol-cloud interactions. Here we show that the massive 2014-2015 fissure eruption in Holuhraun, Iceland, reduced the size of liquid cloud droplets - consistent with expectations - but had no discernible effect on other cloud properties. The reduction in droplet size led to cloud brightening and global-mean radiative forcing of around -0.2 watts per square metre for September to October 2014. Changes in cloud amount or cloud liquid water path, however, were undetectable, indicating that these indirect effects, and cloud systems in general, are well buffered against aerosol changes. This result will reduce uncertainties in future climate projections, because we are now able to reject results from climate models with an excessive liquid-water-path response. © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
BibTeX: @article{Malavelle2017, author = {Malavelle, Florent F. and Haywood, Jim M. and Jones, Andy and Gettelman, Andrew and Clarisse, Lieven and Bauduin, Sophie and Allan, Richard P. and Karset, Inger Helene H. and Kristjánsson, Jón Egill and Oreopoulos, Lazaros and Cho, Nayeong and Lee, Dongmin and Bellouin, Nicolas and Boucher, Olivier and Grosvenor, Daniel P. and Carslaw, Ken S. and Dhomse, Sandip and Mann, Graham W. and Schmidt, Anja and Coe, Hugh and Hartley, Margaret E. and Dalvi, Mohit and Hill, Adrian A. and Johnson, Ben T. and Johnson, Colin E. and Knight, Jeff R. and O'Connor, Fiona M. and Stier, Philip and Myhre, Gunnar and Platnick, Steven and Stephens, Graeme L. and Takahashi, Hanii and Thordarson, Thorvaldur}, title = {Strong constraints on aerosol-cloud interactions from volcanic eruptions}, journal = {Nature}, year = {2017}, volume = {546}, number = {7659}, pages = {485 – 491}, doi = {10.1038/nature22974} }
Moussallam Y, Tamburello G, Peters N, Apaza F, Schipper CI, Curtis A, Aiuppa A, Masias P, Boichu M, Bauduin S, Barnie T, Bani P, Giudice G and Moussallam M (2017), "Volcanic gas emissions and degassing dynamics at Ubinas and Sabancaya volcanoes; implications for the volatile budget of the central volcanic zone", Journal of Volcanology and Geothermal Research. Vol. 343, pp. 181 – 191. [Abstract] [BibTeX] [DOI]
Abstract: Emission of volcanic gas is thought to be the dominant process by which volatiles transit from the deep earth to the atmosphere. Volcanic gas emissions, remain poorly constrained, and volcanoes of Peru are entirely absent from the current global dataset. In Peru, Sabancaya and Ubinas volcanoes are by far the largest sources of volcanic gas. Here, we report the first measurements of the compositions and fluxes of volcanic gases emitted from these volcanoes. The measurements were acquired in November 2015. We determined an average SO2 flux of 15.3 ± 2.3 kg s− 1 (1325-ton day− 1) at Sabancaya and of 11.4 ± 3.9 kg s− 1 (988-ton day− 1) at Ubinas using scanning ultraviolet spectroscopy and dual UV camera systems. In-situ Multi-GAS analyses yield molar proportions of H2O, CO2, SO2, H2S and H2 gases of 73, 15, 10 1.15 and 0.15 mol% at Sabancaya and of 96, 2.2, 1.2 and 0.05 mol% for H2O, CO2, SO2 and H2S at Ubinas. Together, these data imply cumulative fluxes for both volcanoes of 282, 30, 27, 1.2 and 0.01 kg s− 1 of H2O, CO2, SO2, H2S and H2 respectively. Sabancaya and Ubinas volcanoes together contribute about 60% of the total CO2 emissions from the Central Volcanic zone, and dominate by far the total revised volatile budget of the entire Central Volcanic Zone of the Andes. © 2017 Elsevier B.V.
BibTeX: @article{Moussallam2017, author = {Moussallam, Yves and Tamburello, Giancarlo and Peters, Nial and Apaza, Fredy and Schipper, C. Ian and Curtis, Aaron and Aiuppa, Alessandro and Masias, Pablo and Boichu, Marie and Bauduin, Sophie and Barnie, Talfan and Bani, Philipson and Giudice, Gaetano and Moussallam, Manuel}, title = {Volcanic gas emissions and degassing dynamics at Ubinas and Sabancaya volcanoes; implications for the volatile budget of the central volcanic zone}, journal = {Journal of Volcanology and Geothermal Research}, year = {2017}, volume = {343}, pages = {181 – 191}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jvolgeores.2017.06.027} }
Paulot F, Paynter D, Ginoux P, Naik V, Whitburn S, Van Damme M, Clarisse L, Coheur P-F and Horowitz L (2017), "Gas-aerosol partitioning of ammonia in biomass burning plumes: Implications for the interpretation of spaceborne observations of ammonia and the radiative forcing of ammonium nitrate", Geophysical Research Letters. Vol. 44(15), pp. 8084 – 8093. [Abstract] [BibTeX] [DOI]
Abstract: Satellite-derived enhancement ratios of NH3 relative to CO column burden (ERNH3/CO) in fires over Alaska, the Amazon, and South Equatorial Africa are 35, 45, and 70% lower than the corresponding ratio of their emissions factors (ERNH3/CO) from biomass burning derived from in situ observations. Simulations performed using the Geophysical Fluid Dynamics Laboratory AM3 global chemistry-climate model show that these regional differences may not entirely stem from an overestimate of NH3 emissions but rather from changes in the gas-aerosol partitioning of NH3 to NH4+. Differences between (ERNH3/CO) and (EFNH3/CO) are largest in regions where is high, consistent with the production of NH4NO3. Biomass burning is estimated to contribute 11–23% of the global burden and direct radiative effect (DRE) of NH4NO3 (−15 to −28 mW m−2), despite accounting for less than 6% of the global source of NH3. Production of NH4NO3 is largely concentrated over the Amazon and South Equatorial Africa, where its DRE can reach −1.9 W m−2 during the biomass burning season. ©2017. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Paulot2017, author = {Paulot, F. and Paynter, D. and Ginoux, P. and Naik, V. and Whitburn, S. and Van Damme, M. and Clarisse, L. and Coheur, P.-F. and Horowitz, L.W.}, title = {Gas-aerosol partitioning of ammonia in biomass burning plumes: Implications for the interpretation of spaceborne observations of ammonia and the radiative forcing of ammonium nitrate}, journal = {Geophysical Research Letters}, year = {2017}, volume = {44}, number = {15}, pages = {8084 – 8093}, doi = {10.1002/2017GL074215} }
Pommier M, Clerbaux C and Coheur P-F (2017), "Determination of enhancement ratios of HCOOH relative to CO in biomass burning plumes by the Infrared Atmospheric Sounding Interferometer (IASI)", Atmospheric Chemistry and Physics. Vol. 17(18), pp. 11089 – 11105. [Abstract] [BibTeX] [DOI]
Abstract: Formic acid (HCOOH) concentrations are often underestimated by models, and its chemistry is highly uncertain. HCOOH is, however, among the most abundant atmospheric volatile organic compounds, and it is potentially responsible for rain acidity in remote areas. HCOOH data from the Infrared Atmospheric Sounding Interferometer (IASI) are analyzed from 2008 to 2014 to estimate enhancement ratios from biomass burning emissions over seven regions. Fire-affected HCOOH and CO total columns are defined by combining total columns from IASI, geographic location of the fires from Moderate Resolution Imaging Spectroradiometer (MODIS), and the surface wind speed field from the European Centre for Medium-Range Weather Forecasts (ECMWF). Robust correlations are found between these fire-affected HCOOH and CO total columns over the selected biomass burning regions, allowing the calculation of enhancement ratios equal to 7.30g × g 10g'3g ±g 0.08g × g 10g'3g molg molg'1 over Amazonia (AMA), 11.10g × g 10g'3g ±g 1.37g × g 10g'3g molg molg'1 over Australia (AUS), 6.80g × g 10g'3g ±g 0.44g × g 10g'3g molg molg'1 over India (IND), 5.80g × g 10g'3g ±g 0.15g × g 10g'3g molg molg'1 over Southeast Asia (SEA), 4.00g × g 10g'3g ±g 0.19g × g 10g'3g molg molg'1 over northern Africa (NAF), 5.00g × g 10g'3g ±g 0.13g × g 10g'3g molg molg'1 over southern Africa (SAF), and 4.40g × g 10g'3g ±g 0.09g × g 10g'3g molg molg'1 over Siberia (SIB), in a fair agreement with previous studies. In comparison with referenced emission ratios, it is also shown that the selected agricultural burning plumes captured by IASI over India and Southeast Asia correspond to recent plumes where the chemistry or the sink does not occur. An additional classification of the enhancement ratios by type of fuel burned is also provided, showing a diverse origin of the plumes sampled by IASI, especially over Amazonia and Siberia. The variability in the enhancement ratios by biome over the different regions show that the levels of HCOOH and CO do not only depend on the fuel types. © Author(s) 2017.
BibTeX: @article{Pommier2017, author = {Pommier, Matthieu and Clerbaux, Cathy and Coheur, Pierre-Francois}, title = {Determination of enhancement ratios of HCOOH relative to CO in biomass burning plumes by the Infrared Atmospheric Sounding Interferometer (IASI)}, journal = {Atmospheric Chemistry and Physics}, year = {2017}, volume = {17}, number = {18}, pages = {11089 – 11105}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-17-11089-2017} }
Sutcliffe B and Woolley RG (2017), "The position of the clamped nuclei electronic hamiltonian in quantum mechanics", Handbook of Computational Chemistry. , pp. 69 – 121. [Abstract] [BibTeX] [DOI]
Abstract: Arguments are advanced to support the view that at present it is not possible to derive molecular structure from the full quantum mechanical Coulomb Hamiltonian associated with a given molecular formula that is customarily regarded as representing the molecule in terms of its constituent electrons and nuclei. However molecular structure may be identified provided that some additional chemically motivated assumptions that lead to the clamped nuclei Hamiltonian are added to the quantum mechanical account. © Springer International Publishing Switzerland 2017.
BibTeX: @book{Sutcliffe2017, author = {Sutcliffe, Brian and Woolley, R. Guy}, title = {The position of the clamped nuclei electronic hamiltonian in quantum mechanics}, journal = {Handbook of Computational Chemistry}, year = {2017}, pages = {69 – 121}, doi = {10.1007/978-3-319-27282-5_2} }
Troian-Gautier L, Mugeniwabagara E, Fusaro L, Cauët E, Kirsch-De Mesmaeker A and Luhmer M (2017), "Photo-CIDNP Reveals Different Protonation Sites Depending on the Primary Step of the Photoinduced Electron-/Proton-Transfer Process with Ru(II) Polyazaaromatic Complexes", Journal of the American Chemical Society. Vol. 139(42), pp. 14909 – 14912. [Abstract] [BibTeX] [DOI]
Abstract: The excited-state quenching of [Ru(TAP)2(HAT)]2+ (TAP = 1,4,5,8-tetraazaphenanthrene, HAT= 1,4,5,8,9,12-hexaazatriphenylene) by hydroquinone (H2Q), N-acetyl-tyrosine (N-Ac-Tyr) or guanosine-5′-monophosphate (GMP) was investigated at various pH values. The quenching occurs via electron/proton transfer, as evidenced by transient absorption spectroscopy and confirmed by 1H photochemically induced dynamic nuclear polarization (photo-CIDNP). Reductive quenching also occurs in strongly acidic solution despite a much shorter lifetime of the protonated excited-state complex. Photo-CIDNP revealed a different mechanism at low pH, involving protonation before electron transfer and yielding a distinct protonated monoreduced complex. The experimental photo-CIDNP patterns are consistent with density functional theory calculations. This work highlights the power of 1H photo-CIDNP for characterizing, at the atomic level, transient species involved in electron-transfer processes. © 2017 American Chemical Society.
BibTeX: @article{TroianGautier2017, author = {Troian-Gautier, Ludovic and Mugeniwabagara, Epiphanie and Fusaro, Luca and Cauët, Emilie and Kirsch-De Mesmaeker, Andrée and Luhmer, Michel}, title = {Photo-CIDNP Reveals Different Protonation Sites Depending on the Primary Step of the Photoinduced Electron-/Proton-Transfer Process with Ru(II) Polyazaaromatic Complexes}, journal = {Journal of the American Chemical Society}, year = {2017}, volume = {139}, number = {42}, pages = {14909 – 14912}, doi = {10.1021/jacs.7b09513} }
Tzompa-Sosa Z, Mahieu E, Franco B, Keller C, Turner A, Helmig D, Fried A, Richter D, Weibring P, Walega J, Yacovitch T, Herndon S, Blake D, Hase F, Hannigan J, Conway S, Strong K, Schneider M and Fischer E (2017), "Revisiting global fossil fuel and biofuel emissions of ethane", Journal of Geophysical Research. Vol. 122(4), pp. 2493 – 2512. [Abstract] [BibTeX] [DOI]
Abstract: Recent measurements over the Northern Hemisphere indicate that the long-term decline in the atmospheric burden of ethane (C2H6) has ended and the abundance increased dramatically between 2010 and 2014. The rise in C2H6 atmospheric abundances has been attributed to oil and natural gas extraction in North America. Existing global C2H6 emission inventories are based on outdated activity maps that do not account for current oil and natural gas exploitation regions. We present an updated global C2H6 emission inventory based on 2010 satellite-derived CH4 fluxes with adjusted C2H6 emissions over the U.S. from the National Emission Inventory (NEI 2011). We contrast our global 2010 C2H6 emission inventory with one developed for 2001. The C2H6 difference between global anthropogenic emissions is subtle (7.9 versus 7.2 Tg yr-1), but the spatial distribution of the emissions is distinct. In the 2010 C2H6 inventory, fossil fuel sources in the Northern Hemisphere represent half of global C2H6 emissions and 95% of global fossil fuel emissions. Over the U.S., unadjusted NEI 2011 C2H6 emissions produce mixing ratios that are 14-50% of those observed by aircraft observations (2008-2014). When the NEI 2011 C2H6 emission totals are scaled by a factor of 1.4, the Goddard Earth Observing System Chem model largely reproduces a regional suite of observations, with the exception of the central U.S., where it continues to underpredict observed mixing ratios in the lower troposphere. We estimate monthly mean contributions of fossil fuel C2H6 emissions to ozone and peroxyacetyl nitrate surface mixing ratios over North America of 1% and 8%, respectively. © 2017. American Geophysical Union. All Rights Reserved.
BibTeX: @article{TzompaSosa2017, author = {Tzompa-Sosa, Z.A. and Mahieu, E. and Franco, B. and Keller, C.A. and Turner, A.J. and Helmig, D. and Fried, A. and Richter, D. and Weibring, P. and Walega, J. and Yacovitch, T.I. and Herndon, S.C. and Blake, D.R. and Hase, F. and Hannigan, J.W. and Conway, S. and Strong, K. and Schneider, M. and Fischer, E.V.}, title = {Revisiting global fossil fuel and biofuel emissions of ethane}, journal = {Journal of Geophysical Research}, year = {2017}, volume = {122}, number = {4}, pages = {2493 – 2512}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2016JD025767} }
Van Damme M, Whitburn S, Clarisse L, Clerbaux C, Hurtmans D and Coheur P-F (2017), "Version 2 of the IASI NH3 neural network retrieval algorithm: Near-real-time and reanalysed datasets", Atmospheric Measurement Techniques. Vol. 10(12), pp. 4905 – 4914. [Abstract] [BibTeX] [DOI]
Abstract: Recently, Whitburn et al.(2016) presented a neural-network-based algorithm for retrieving atmospheric ammonia (NH3) columns from Infrared Atmospheric Sounding Interferometer (IASI) satellite observations. In the past year, several improvements have been introduced, and the resulting new baseline version, Artificial Neural Network for IASI (ANNI)-NH3-v2.1, is documented here. One of the main changes to the algorithm is that separate neural networks were trained for land and sea observations, resulting in a better training performance for both groups. By reducing and transforming the input parameter space, performance is now also better for observations associated with favourable sounding conditions (i.e. enhanced thermal contrasts). Other changes relate to the introduction of a bias correction over land and sea and the treatment of the satellite zenith angle. In addition to these algorithmic changes, new recommendations for post-filtering the data and for averaging data in time or space are formulated. We also introduce a second dataset (ANNI-NH3-v2.1R-I) which relies on ERA-Interim ECMWF meteorological input data, along with surface temperature retrieved from a dedicated network, rather than the operationally provided Eumetsat IASI Level 2 (L2) data used for the standard near-real-time version. The need for such a dataset emerged after a series of sharp discontinuities were identified in the NH3 time series, which could be traced back to incremental changes in the IASI L2 algorithms for temperature and clouds. The reanalysed dataset is coherent in time and can therefore be used to study trends. Furthermore, both datasets agree reasonably well in the mean on recent data, after the date when the IASI meteorological L2 version 6 became operational (30 September 2014). © Author(s) 2017. This work is distributed under the Creative Commons Attribution 4.0 License.
BibTeX: @article{VanDamme2017, author = {Van Damme, Martin and Whitburn, Simon and Clarisse, Lieven and Clerbaux, Cathy and Hurtmans, Daniel and Coheur, Pierre-François}, title = {Version 2 of the IASI NH3 neural network retrieval algorithm: Near-real-time and reanalysed datasets}, journal = {Atmospheric Measurement Techniques}, year = {2017}, volume = {10}, number = {12}, pages = {4905 – 4914}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-10-4905-2017} }
Vanfleteren T, Földes T, Herman M, Liévin J, Loreau J and Coudert LH (2017), "Experimental and theoretical investigations of H2O-Ar", Journal of Chemical Physics. Vol. 147(1) [Abstract] [BibTeX] [DOI]
Abstract: We have used continuous-wave cavity ring-down spectroscopy to record the spectrum of H2O-Ar in the 2OH excitation range of H2O. 24 sub-bands have been observed. Their rotational structure (Trot = 12 K) is analyzed and the lines are fitted separately for ortho and para species together with microwave and far infrared data from the literature, with a unitless standard deviation σ=0.98 and 1.31, respectively. Their vibrational analysis is supported by a theoretical input based on an intramolecular potential energy surface obtained through ab initio calculations and computation of the rotational energy of sub-states of the complex with the water monomer in excited vibrational states up to the first hexad. For the ground and (010) vibrational states, the theoretical results agree well with experimental energies and rotational constants in the literature. For the excited vibrational states of the first hexad, they guided the assignment of the observed sub-bands. The upper state vibrational predissociation lifetime is estimated to be 3 ns from observed spectral linewidths. © 2017 Author(s).
BibTeX: @article{Vanfleteren2017, author = {Vanfleteren, Thomas and Földes, Tomas and Herman, Michel and Liévin, Jacques and Loreau, Jérôme and Coudert, Laurent H.}, title = {Experimental and theoretical investigations of H2O-Ar}, journal = {Journal of Chemical Physics}, year = {2017}, volume = {147}, number = {1}, doi = {10.1063/1.4990738} }
Vanfleteren T, Földes T, Rizopoulos A and Herman M (2017), "Overtone, 2OH spectroscopy of H2O[sbnd]Kr", Journal of Molecular Spectroscopy. Vol. 342, pp. 92 – 99. [Abstract] [BibTeX] [DOI]
Abstract: We have used continuous-wave cavity ring-down spectroscopy to record the spectrum of H2O[sbnd]Kr in the 2OH excitation range of H2O. 11 sub-bands have been observed for the main krypton isotope, 84 Kr. Their rotational structure (Trot=18 K) is analyzed and the lines fitted together with literature microwave data, with a unitless standard deviation σ=0.86 and 1.32 for ortho and para species, respectively. 4 more sub-bands are observed for the three other isotopes and are also analyzed. The upper state vibrational predissociation lifetime is estimated to 4 ns from observed spectral linewidths. © 2017 Elsevier Inc.
BibTeX: @article{Vanfleteren2017a, author = {Vanfleteren, Thomas and Földes, Tomas and Rizopoulos, Athéna and Herman, Michel}, title = {Overtone, 2OH spectroscopy of H2O[sbnd]Kr}, journal = {Journal of Molecular Spectroscopy}, year = {2017}, volume = {342}, pages = {92 – 99}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jms.2017.06.010} }
Wang K, Jönsson P, Ekman J, Brage T, Chen CY, Fischer CF, Gaigalas G and Godefroid M (2017), "Comment on "theoretical Confirmation of the Low Experimental 3C/3D f -Value Ratio in Fe xvii "", Physical Review Letters. Vol. 119(18) [Abstract] [BibTeX] [DOI]
Abstract: A Comment on the Letter by Mendoza and Bautista [Phys. Rev. Lett. 118, 163002 (2017)PRLTAO0031-900710.1103/PhysRevLett.118.163002]. © 2017 American Physical Society.
BibTeX: @article{Wang2017a, author = {Wang, Kai and Jönsson, Per and Ekman, Jörgen and Brage, Tomas and Chen, Chong Yang and Fischer, Charlotte Froese and Gaigalas, Gediminas and Godefroid, Michel}, title = {Comment on "theoretical Confirmation of the Low Experimental 3C/3D f -Value Ratio in Fe xvii "}, journal = {Physical Review Letters}, year = {2017}, volume = {119}, number = {18}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevLett.119.189301} }
Wang K, Jönsson P, Ekman J, Gaigalas G, Godefroid M, Si R, Chen Z, Li S, Chen C and Yan J (2017), "Extended Calculations of Spectroscopic Data: Energy Levels, Lifetimes, and Transition Rates for O-like Ions from Cr xxiii", Astrophysical Journal, Supplement Series. Vol. 229(2) [Abstract] [BibTeX] [DOI]
Abstract: Employing two state-of-the-art methods, multiconfiguration Dirac-Hartree-Fock and second-order many-body perturbation theory, the excitation energies and lifetimes for the lowest 200 states of the 2s22p4, 2s2p5, 2p6, 2s22p33s, 2s22p33p, 2s22p33d, 2s2p43s, 2s2p43p, and 2s2p43d configurations, and multipole (electric dipole (E1), magnetic dipole (M1), and electric quadrupole (E2)) transition rates, line strengths, and oscillator strengths among these states are calculated for each O-like ion, from Cr XVII to Zn XXIII. Our two data sets are compared with the National Institute of Standards and Technology and CHIANTI compiled values, and previous calculations. The data are accurate enough for identification and deblending of new emission lines from the Sun and other astrophysical sources. The amount of high-accuracy data is significantly increased for the n = 3 states of several O-like ions of astrophysical interest, where experimental data are very scarce. © 2017. The American Astronomical Society. All rights reserved.
BibTeX: @article{Wang2017, author = {Wang, K. and Jönsson, P. and Ekman, J. and Gaigalas, G. and Godefroid, M.R. and Si, R. and Chen, Z.B. and Li, S. and Chen, C.Y. and Yan, J.}, title = {Extended Calculations of Spectroscopic Data: Energy Levels, Lifetimes, and Transition Rates for O-like Ions from Cr xxiii}, journal = {Astrophysical Journal, Supplement Series}, year = {2017}, volume = {229}, number = {2}, note = {All Open Access, Bronze Open Access}, doi = {10.3847/1538-4365/aa6847} }
Wespes C, Hurtmans D, Clerbaux C and Coheur P-F (2017), "O3 variability in the troposphere as observed by IASI over 2008-2016: Contribution of atmospheric chemistry and dynamics", Journal of Geophysical Research. Vol. 122(4), pp. 2429 – 2451. [Abstract] [BibTeX] [DOI]
Abstract: We analyze the ozone (O3) variability in the troposphere (from ground to 300 hPa) using 8 years (January 2008 to March 2016) of O3 profile measurements provided by the Infrared Atmospheric Sounding Interferometer (IASI) on board the MetOp satellite. The capability of IASI to monitor the year-to-year variability in that layer is examined first in terms of vertical sensitivity, a priori contribution, and correlations in the deseasonalized anomalies with the upper layers. We present global patterns of the main geophysical drivers (e.g., solar flux, Quasi-biennal Oscillation-QBO, North Atlantic Oscillation-NAO, and El Niño-Southern Oscillation-ENSO) of IASI O3 variations, obtained by applying appropriate annual and seasonal multivariate regression models on time series of spatially gridded averaged O3. The results show that the models are able to explain most of the O3 variability captured by IASI. Large O3 changes in the North Arctic/Euro-Atlantic sector and over the equatorial band are attributed to the NAO and the QBO effects, respectively. ENSO is modeled as the main contributor to the O3 variations in the tropical band where direct effects of warm and cool ENSO phases are highlighted with a clear tropical-extratropical gradient. A strong west-east gradient in the tropics is also found and likely reflects an indirect effect related to ENSO dry conditions. Finally, we also show that the ENSO perturbs the O3 variability far from the tropics into middle and high latitudes where a significant 4-month time-lag in the response of O3 to ENSO is identified for the first time. © 2017. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Wespes2017, author = {Wespes, C. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.}, title = {O3 variability in the troposphere as observed by IASI over 2008-2016: Contribution of atmospheric chemistry and dynamics}, journal = {Journal of Geophysical Research}, year = {2017}, volume = {122}, number = {4}, pages = {2429 – 2451}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2016JD025875} }
Whitburn S, Van Damme M, Clarisse L, Hurtmans D, Clerbaux C and Coheur P-F (2017), "IASI-derived NH3 enhancement ratios relative to CO for the tropical biomass burning regions", Atmospheric Chemistry and Physics. Vol. 17(19), pp. 12239 – 12252. [Abstract] [BibTeX] [DOI]
Abstract: Vegetation fires are a major source of ammonia (NH3) in the atmosphere. Their emissions are mainly estimated using bottom-up approaches that rely on uncertain emission factors. In this study, we derive new biome-specific NH3 enhancement ratios relative to carbon monoxide (CO), ERNH3 / CO (directly related to the emission factors), from the measurements of the IASI sounder onboard the Metop-A satellite. This is achieved for large tropical regions and for an 8-year period (2008-2015). We find substantial differences in the ERNH3 / CO ratios between the biomes studied, with calculated values ranging from 7 × 10-3 to 23 × 10-3. For evergreen broadleaf forest these are typically 50-75% higher than for woody savanna and savanna biomes. This variability is attributed to differences in fuel types and size and is in line with previous studies. The analysis of the spatial and temporal distribution of the ERNH3 / CO ratio also reveals a (sometimes large) within-biome variability. On a regional level, woody savanna shows, for example, a mean ERNH3 / CO ratio for the region of Africa south of the Equator that is 40-75% lower than in the other five regions studied, probably reflecting regional differences in fuel type and burning conditions. The same variability is also observed on a yearly basis, with a peak in the ERNH3 / CO ratio observed for the year 2010 for all biomes. These results highlight the need for the development of dynamic emission factors that take into better account local variations in fuel type and fire conditions. We also compare the IASI-derived ERNH3 / CO ratio with values reported in the literature, usually calculated from ground-based or airborne measurements. We find general good agreement in the referenced ERNH3 / CO ratio except for cropland, for which the ERNH3 / CO ratio shows an underestimation of about 2-2.5 times. © 2017 Author(s).
BibTeX: @article{Whitburn2017, author = {Whitburn, Simon and Van Damme, Martin and Clarisse, Lieven and Hurtmans, Daniel and Clerbaux, Cathy and Coheur, Pierre-François}, title = {IASI-derived NH3 enhancement ratios relative to CO for the tropical biomass burning regions}, journal = {Atmospheric Chemistry and Physics}, year = {2017}, volume = {17}, number = {19}, pages = {12239 – 12252}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-17-12239-2017} }
Wraith C, Yang X, Xie L, Babcock C, Bieroń J, Billowes J, Bissell M, Blaum K, Cheal B, Filippin L, Garcia Ruiz R, Gins W, Grob L, Gaigalas G, Godefroid M, Gorges C, Heylen H, Honma M, Jönsson P, Kaufmann S, Kowalska M, Krämer J, Malbrunot-Ettenauer S, Neugart R, Neyens G, Nörtershäuser W, Nowacki F, Otsuka T, Papuga J, Sánchez R, Tsunoda Y and Yordanov D (2017), "Evolution of nuclear structure in neutron-rich odd-Zn isotopes and isomers", Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. Vol. 771, pp. 385 – 391. [Abstract] [BibTeX] [DOI]
Abstract: Collinear laser spectroscopy was performed on Zn (Z=30) isotopes at ISOLDE, CERN. The study of hyperfine spectra of nuclei across the Zn isotopic chain, N=33–49, allowed the measurement of nuclear spins for the ground and isomeric states in odd-A neutron-rich nuclei up to N=50. Exactly one long-lived (>10 ms) isomeric state has been established in each 69–79Zn isotope. The nuclear magnetic dipole moments and spectroscopic quadrupole moments are well reproduced by large-scale shell–model calculations in the f5pg9 and fpg9d5 model spaces, thus establishing the dominant term in their wave function. The magnetic moment of the intruder Iπ=1/2+ isomer in 79Zn is reproduced only if the νs1/2 orbital is added to the valence space, as realized in the recently developed PFSDG-U interaction. The spin and moments of the low-lying isomeric state in 73Zn suggest a strong onset of deformation at N=43, while the progression towards 79Zn points to the stability of the Z=28 and N=50 shell gaps, supporting the magicity of 78Ni. © 2017 The Author(s)
BibTeX: @article{Wraith2017, author = {Wraith, C. and Yang, X.F. and Xie, L. and Babcock, C. and Bieroń, J. and Billowes, J. and Bissell, M.L. and Blaum, K. and Cheal, B. and Filippin, L. and Garcia Ruiz, R.F. and Gins, W. and Grob, L.K. and Gaigalas, G. and Godefroid, M. and Gorges, C. and Heylen, H. and Honma, M. and Jönsson, P. and Kaufmann, S. and Kowalska, M. and Krämer, J. and Malbrunot-Ettenauer, S. and Neugart, R. and Neyens, G. and Nörtershäuser, W. and Nowacki, F. and Otsuka, T. and Papuga, J. and Sánchez, R. and Tsunoda, Y. and Yordanov, D.T.}, title = {Evolution of nuclear structure in neutron-rich odd-Zn isotopes and isomers}, journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, year = {2017}, volume = {771}, pages = {385 – 391}, note = {All Open Access, Gold Open Access}, doi = {10.1016/j.physletb.2017.05.085} }
Zhang X, Wu Y, Liu X, Reis S, Jin J, Dragosits U, Van Damme M, Clarisse L, Whitburn S, Coheur P-F and Gu B (2017), "Ammonia emissions may be substantially underestimated in China", Environmental Science and Technology. Vol. 51(21), pp. 12089 – 12096. [Abstract] [BibTeX] [DOI]
Abstract: China is a global hotspot of atmospheric ammonia (NH3) emissions and, as a consequence, very high nitrogen (N) deposition levels are documented. However, previous estimates of total NH3 emissions in China were much lower than inference from observed deposition values would suggest, highlighting the need for further investigation. Here, we reevaluated NH3 emissions based on a mass balance approach, validated by N deposition monitoring and satellite observations, for China for the period of 2000 to 2015. Total NH3 emissions in China increased from 12.1 ± 0.8 Tg N yr-1 in 2000 to 15.6 ± 0.9 Tg N yr-1 in 2015 at an annual rate of 1.9%, which is approximately 40% higher than existing studies suggested. This difference is mainly due to more emission sources now having been included and NH3 emission rates from mineral fertilizer application and livestock having been underestimated previously. Our estimated NH3 emission levels are consistent with the measured deposition of NHx (including NH4 + and NH3) on land (11-14 Tg N yr-1) and the substantial increases in NH3 concentrations observed by satellite measurements over China. These findings substantially improve our understanding on NH3 emissions, implying that future air pollution control strategies have to consider the potentials of reducing NH3 emission in China. © 2017 American Chemical Society.
BibTeX: @article{Zhang2017, author = {Zhang, Xiuming and Wu, Yiyun and Liu, Xuejun and Reis, Stefan and Jin, Jiaxin and Dragosits, Ulrike and Van Damme, Martin and Clarisse, Lieven and Whitburn, Simon and Coheur, Pierre-François and Gu, Baojing}, title = {Ammonia emissions may be substantially underestimated in China}, journal = {Environmental Science and Technology}, year = {2017}, volume = {51}, number = {21}, pages = {12089 – 12096}, note = {All Open Access, Green Open Access}, doi = {10.1021/acs.est.7b02171} }
Alkadrou A, Bourgeois M-T, Rotger M, Boudon V and Vander Auwera J (2016), "Global frequency and intensity analysis of the ν10/ν7/ν4/ν12 band system of 12C2H4 at 10 μm using the D2h Top Data System", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 182, pp. 158 – 171. [Abstract] [BibTeX] [DOI]
Abstract: A global frequency and intensity analysis of the infrared tetrad of 12C2H4 located in the 600-1500cm-1 region was carried out using the tensorial formalism developed in Dijon for X2Y4 asymmetric-top molecules. It relied on spectroscopic information available in the literature and retrieved from high-resolution Fourier transform infrared spectra recorded in Brussels in the frame of either the present or previous work. In particular, 645 and 131 line intensities have been respectively measured for the weak ν10 and ν4 bands. Including the Coriolis interactions affecting the upper vibrational levels 101, 71, 41 and 121, a total of 10 757 line positions and 1645 line intensities have been assigned and fitted with global root mean square deviations of 2.6×10-4cm-1 and 2.5%, respectively. Relying on the results of the present work and available in the literature, a list of parameters for 65 776 lines in the ν10, ν7, ν4 and ν12 bands of 12C2H4 was generated. To the best of our knowledge, this is the first time that a global intensity analysis is carried out in this range of the ethylene spectrum. © 2016 Elsevier Ltd.
BibTeX: @article{Alkadrou2016, author = {Alkadrou, A. and Bourgeois, M.-T. and Rotger, M. and Boudon, V. and Vander Auwera, J.}, title = {Global frequency and intensity analysis of the ν10/ν7/ν4/ν12 band system of 12C2H4 at 10 μm using the D2h Top Data System}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2016}, volume = {182}, pages = {158 – 171}, doi = {10.1016/j.jqsrt.2016.05.024} }
Amyay B, Fayt A, Herman M and Vander Auwera J (2016), "Vibration-rotation spectroscopic database on acetylene, X1Σg+ (12C2H2)", Journal of Physical and Chemical Reference Data. Vol. 45(2) [Abstract] [BibTeX] [DOI]
Abstract: A complete set of calculated vibration-rotation energies of 12C2H2 (X1Σg+) is provided for all vibrational states up to 13 000 cm-1 and some at higher energies, with rotational (J) and vibrational angular momentum (l) quantum numbers such that 0 ≤ J ≤ 100 and 0 ≤ \|l\| ≤ 20, respectively. The calculation is performed using a global effective Hamiltonian and related spectroscopic constants from the literature [B. Amyay et al., J. Mol. Spectrosc. 267, 80 (2011)], based on the polyad model. The numerical values of all related polyad matrix elements are also provided. The model and equations for the Hamiltonian matrix elements are gathered. The experimental acetylene database used for determining the parameters is listed. © 2016 AIP Publishing LLC for the National Institute of Standards and Technology.
BibTeX: @article{Amyay2016a, author = {Amyay, B. and Fayt, A. and Herman, M. and Vander Auwera, J.}, title = {Vibration-rotation spectroscopic database on acetylene, X1Σg+ (12C2H2)}, journal = {Journal of Physical and Chemical Reference Data}, year = {2016}, volume = {45}, number = {2}, doi = {10.1063/1.4947297} }
Amyay B, Louviot M, Pirali O, Georges R, Vander Auwera J and Boudon V (2016), "Global analysis of the high temperature infrared emission spectrum of 12CH4 in the dyad (ν 2/ ν 4) region", Journal of Chemical Physics. Vol. 144(2) [Abstract] [BibTeX] [DOI]
Abstract: We report new assignments of vibration-rotation line positions of methane (12CH4) in the so-called dyad (ν2/ν4) region (1100-1500 cm-1), and the resulting update of the vibration-rotation effective model of methane, previously reported by Nikitin et al. [Phys. Chem. Chem. Phys. 15, 10071 (2013)], up to and including the tetradecad. High resolution (0.01 cm-1) emission spectra of methane have been recorded up to about 1400 K using the high-enthalpy source developed at Institut de Physique de Rennes associated with the Fourier transform spectrometer of the SOLEIL synchrotron facility (AILES beamline). Analysis of these spectra allowed extending rotational assignments in the well-known cold band (dyad-ground state (GS)) and related hot bands in the pentad-dyad system (3000 cm-1) up to Jmax = 30 and 29, respectively. In addition, 8512 new transitions belonging to the octad-pentad (up to J = 28) and tetradecad-octad (up to J = 21) hot band systems were successfully identified. As a result, the MeCaSDa database of methane was significantly improved. The line positions assigned in this work, together with the information available in the literature, were fitted using 1096 effective parameters with a dimensionless standard deviation σ = 2.09. The root mean square deviations dRMS are 3.60 × 10-3 cm-1 for dyad-GS cold band, 4.47 ×10-3 cm-1 for the pentad-dyad, 5.43 × 10-3 cm-1 for the octad-pentad, and 4.70 × 10-3 cm-1 for the tetradecad-octad hot bands. The resulting new line list will contribute to improve opacity and radiative transfer models for hot atmospheres, such as those of hot-Jupiter type exoplanets. © 2016 AIP Publishing LLC.
BibTeX: @article{Amyay2016, author = {Amyay, Badr and Louviot, Maud and Pirali, Olivier and Georges, Robert and Vander Auwera, Jean and Boudon, Vincent}, title = {Global analysis of the high temperature infrared emission spectrum of 12CH4 in the dyad (ν 2/ ν 4) region}, journal = {Journal of Chemical Physics}, year = {2016}, volume = {144}, number = {2}, doi = {10.1063/1.4939521} }
Balis D, Koukouli M-E, Siomos N, Dimopoulos S, Mona L, Pappalardo G, Marenco F, Clarisse L, J Ventress L, Carboni E, G Grainger R, Wang P, Tilstra G, Van Der A R, Theys N and Zehner C (2016), "Validation of ash optical depth and layer height retrieved from passive satellite sensors using EARLINET and airborne lidar data: the case of the Eyjafjallajökull eruption", Atmospheric Chemistry and Physics. Vol. 16(9), pp. 5705 – 5720. [Abstract] [BibTeX] [DOI]
Abstract: The vulnerability of the European airspace to volcanic eruptions was brought to the attention of the public and the scientific community by the 2010 eruptions of the Icelandic volcano Eyjafjallajökull. As a consequence of this event, ash concentration thresholds replaced the ĝ zero tolerance to ashĝ€ rule, drastically changing the requirements on satellite ash retrievals. In response to that, the ESA funded several projects aiming at creating an optimal end-to-end system for volcanic ash plume monitoring and prediction. Two of them, namely the SACS-2 and SMASH projects, developed and improved dedicated satellite-derived ash plume and sulfur dioxide level assessments. The validation of volcanic ash levels and height extracted from the GOME-2 and IASI instruments on board the MetOp-A satellite is presented in this work. EARLINET lidar measurements are compared to different satellite retrievals for two eruptive episodes in April and May 2010. Comparisons were also made between satellite retrievals and aircraft lidar data obtained with the UK's BAe-146-301 Atmospheric Research Aircraft (managed by the Facility for Airborne Atmospheric Measurements, FAAM) over the United Kingdom and the surrounding regions. The validation results are promising for most satellite products and are within the estimated uncertainties of each of the comparative data sets, but more collocation scenes would be desirable to perform a comprehensive statistical analysis. The satellite estimates and the validation data sets are better correlated for high ash optical depth values, with correlation coefficients greater than 0.8. The IASI retrievals show a better agreement concerning the ash optical depth and ash layer height when compared with the ground-based and airborne lidar data. © Author(s) 2016. CC Attribution 3.0 License.
BibTeX: @article{Balis2016a, author = {Balis, Dimitris and Koukouli, Maria-Elissavet and Siomos, Nikolaos and Dimopoulos, Spyridon and Mona, Lucia and Pappalardo, Gelsomina and Marenco, Franco and Clarisse, Lieven and J Ventress, Lucy and Carboni, Elisa and G Grainger, Roy and Wang, Ping and Tilstra, Gijsbert and Van Der A, Ronald and Theys, Nicolas and Zehner, Claus}, title = {Validation of ash optical depth and layer height retrieved from passive satellite sensors using EARLINET and airborne lidar data: the case of the Eyjafjallajökull eruption}, journal = {Atmospheric Chemistry and Physics}, year = {2016}, volume = {16}, number = {9}, pages = {5705 – 5720}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-16-5705-2016} }
Balis D, Siomos N, Koukouli M, Clarisse L, Carboni E, Ventress L, Grainger R, Mona L and Pappalardo G (2016), "Validation of ASH Optical Depth and Layer Height from IASI using Earlinet Lidar Data", EPJ Web of Conferences. Vol. 119 [Abstract] [BibTeX] [DOI]
Abstract: The 2010 eruptions of the Icelandic volcano Eyjafjallajokull attracted the attention of the public and the scientific community to the vulnerability of the European airspace to volcanic eruptions. The European Space Agency project "Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards", called for the creation of an optimal End-to-End System for Volcanic Ash Plume Monitoring and Prediction. This system is based on improved and dedicated satellite-derived ash plume and sulphur dioxide level assessments, as well as an extensive validation, using among others ground-based measurements (Koukouli et al., 2014). The validation of volcanic ash levels and height extracted from IASI/MetopA is presented in this work with emphasis on the ash plume height and ash optical depth levels. European Aerosol Research Lidar Network [EARLINET] lidar measurements are compared to different satellite estimates for two eruptive episodes. The validation results are extremely promising within the estimated uncertainties of each of the comparative datasets. © 2016 Owned by the authors, published by EDP Sciences.
BibTeX: @conference{Balis2016, author = {Balis, D. and Siomos, N. and Koukouli, M. and Clarisse, L. and Carboni, E. and Ventress, L. and Grainger, R. and Mona, L. and Pappalardo, G.}, title = {Validation of ASH Optical Depth and Layer Height from IASI using Earlinet Lidar Data}, journal = {EPJ Web of Conferences}, year = {2016}, volume = {119}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.1051/epjconf/201611907006} }
Bauduin S, Clarisse L, Hadji-Lazaro J, Theys N, Clerbaux C and Coheur P-F (2016), "Retrieval of near-surface sulfur dioxide (SO2) concentrations at a global scale using IASI satellite observations", Atmospheric Measurement Techniques. Vol. 9(2), pp. 721 – 740. [Abstract] [BibTeX] [DOI]
Abstract: SO2 from volcanic eruptions is now operationally monitored from space in both the ultraviolet (UV) and thermal infrared (TIR) spectral range, but anthropogenic SO2 has almost solely been measured from UV sounders. Indeed, TIR instruments are well known to have a poor sensitivity to the planetary boundary layer (PBL), due to generally low thermal contrast (TC) between the ground and the air above it. Recent studies have demonstrated the capability of the Infrared Atmospheric Sounding Interferometer (IASI) to measure near-surface SO2 locally, for specific atmospheric conditions. In this work, we develop a retrieval method allowing the inference of SO2 near-surface concentrations from IASI measurements at a global scale. This method consists of two steps. Both are based on the computation of radiance indexes representing the strength of the SO2 ν3 band in IASI spectra. The first step allows the peak altitude of SO2 to be retrieved and near-surface SO2 to be selected. In the second step, 0-4 km columns of SO2 are inferred using a look-up table (LUT) approach. Using this new retrieval method, we obtain the first global distribution of near-surface SO2 from IASI-A, and identify the dominant anthropogenic hotspot sources and volcanic degassing. The 7-year daily time evolution of SO2 columns above two industrial source areas (Beijing in China and Sar Cheshmeh in Iran) is investigated and correlated to the seasonal variations of the parameters that drive the IASI sensitivity to the PBL composition. Apart from TC, we show that humidity is the most important parameter which determines IR sensitivity to nearsurface SO2 in the ν3 band. As IASI provides global measurements twice daily, the differences between the retrieved columns for the morning and evening orbits are investigated. This paper finally presents a first intercomparison of the measured 0-4 km columns with an independent iterative retrieval method and with observations of the Ozone Monitoring Instrument (OMI). © Author(s) 2016.
BibTeX: @article{Bauduin2016, author = {Bauduin, Sophie and Clarisse, Lieven and Hadji-Lazaro, Juliette and Theys, Nicolas and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Retrieval of near-surface sulfur dioxide (SO2) concentrations at a global scale using IASI satellite observations}, journal = {Atmospheric Measurement Techniques}, year = {2016}, volume = {9}, number = {2}, pages = {721 – 740}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-9-721-2016} }
Bissell M, Carette T, Flanagan K, Vingerhoets P, Billowes J, Blaum K, Cheal B, Fritzsche S, Godefroid M, Kowalska M, Krämer J, Neugart R, Neyens G, Nörtershäuser W and Yordanov D (2016), "Cu charge radii reveal a weak sub-shell effect at N=40", Physical Review C. Vol. 93(6) [Abstract] [BibTeX] [DOI]
Abstract: Collinear laser spectroscopy on Cu58-75 isotopes was performed at the CERN-ISOLDE radioactive ion beam facility. In this paper we report on the isotope shifts obtained from these measurements. State-of-the-art atomic physics calculations have been undertaken in order to determine the changes in mean-square charge radii δ(r2)A,A′ from the observed isotope shifts. A local minimum is observed in these radii differences at N=40, providing evidence for a weak N=40 sub-shell effect. However, comparison of δ(r2)A,A′ with a droplet model prediction including static deformation deduced from the spectroscopic quadrupole moments, points to the persistence of correlations at N=40. © 2016 authors. Published by the American Physical Society.
BibTeX: @article{Bissell2016, author = {Bissell, M.L. and Carette, T. and Flanagan, K.T. and Vingerhoets, P. and Billowes, J. and Blaum, K. and Cheal, B. and Fritzsche, S. and Godefroid, M. and Kowalska, M. and Krämer, J. and Neugart, R. and Neyens, G. and Nörtershäuser, W. and Yordanov, D.T.}, title = {Cu charge radii reveal a weak sub-shell effect at N=40}, journal = {Physical Review C}, year = {2016}, volume = {93}, number = {6}, note = {All Open Access, Green Open Access, Hybrid Gold Open Access}, doi = {10.1103/PhysRevC.93.064318} }
Boichu M, Chiapello I, Brogniez C, Péré J-C, Thieuleux F, Torres B, Blarel L, Mortier A, Podvin T, Goloub P, Söhne N, Clarisse L, Bauduin S, Hendrick F, Theys N, Van Roozendael M and Tanré D (2016), "Current challenges in modelling far-range air pollution induced by the 2014-2015 Bároarbunga fissure eruption (Iceland)", Atmospheric Chemistry and Physics. Vol. 16(17), pp. 10831 – 10845. [Abstract] [BibTeX] [DOI]
Abstract: The 2014-2015 Holuhraun lava-flood eruption of Bároarbunga volcano (Iceland) emitted prodigious amounts of sulfur dioxide into the atmosphere. This eruption caused a large-scale episode of air pollution throughout Western Europe in September 2014, the first event of this magnitude recorded in the modern era. We gathered chemistry-transport simulations and a wealth of complementary observations from satellite sensors (OMI, IASI), ground-based remote sensing (lidar, sunphotometry, differential optical absorption spectroscopy) and ground-level air quality monitoring networks to characterize both the spatial-temporal distributions of volcanic SO2 and sulfate aerosols as well as the dynamics of the planetary boundary layer. Time variations of dynamical and microphysical properties of sulfate aerosols in the aged low-tropospheric volcanic cloud, including loading, vertical distribution, size distribution and single scattering albedo, are provided. Retrospective chemistry-transport simulations at low horizontal resolution (25 km × 25 km) capture the correct temporal dynamics of this far-range air pollution event but fail to reproduce the correct magnitude of SO2 concentration at ground-level. Simulations at higher spatial resolution, relying on two nested domains with finest resolution of 7.3 km × 7.3 km, improve substantially the far-range vertical distribution of the volcanic cloud and subsequently the description of ground-level SO2 concentrations. However, remaining discrepancies between model and observations are shown to result from an inaccurate representation of the planetary boundary layer (PBL) dynamics. Comparison with lidar observations points out a systematic under-estimation of the PBL height by the model, whichever the PBL parameterization scheme. Such a shortcoming impedes the capture of the overlying Bároarbunga cloud into the PBL at the right time and in sufficient quantities. This study therefore demonstrates the key role played by the PBL dynamics in accurately modelling large-scale volcanogenic air pollution. © 2016 Author(s).
BibTeX: @article{Boichu2016, author = {Boichu, Marie and Chiapello, Isabelle and Brogniez, Colette and Péré, Jean-Christophe and Thieuleux, Francois and Torres, Benjamin and Blarel, Luc and Mortier, Augustin and Podvin, Thierry and Goloub, Philippe and Söhne, Nathalie and Clarisse, Lieven and Bauduin, Sophie and Hendrick, François and Theys, Nicolas and Van Roozendael, Michel and Tanré, Didier}, title = {Current challenges in modelling far-range air pollution induced by the 2014-2015 Bároarbunga fissure eruption (Iceland)}, journal = {Atmospheric Chemistry and Physics}, year = {2016}, volume = {16}, number = {17}, pages = {10831 – 10845}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-16-10831-2016} }
Boynard A, Hurtmans D, Koukouli ME, Goutail F, Bureau J, Safieddine S, Lerot C, Hadji-Lazaro J, Wespes C, Pommereau J-P, Pazmino A, Zyrichidou I, Balis D, Barbe A, Mikhailenko SN, Loyola D, Valks P, Van Roozendael M, Coheur P-F and Clerbaux C (2016), "Seven years of IASI ozone retrievals from FORLI: Validation with independent total column and vertical profile measurements", Atmospheric Measurement Techniques. Vol. 9(9), pp. 4327 – 4353. [Abstract] [BibTeX] [DOI]
Abstract: This paper presents an extensive intercomparison and validation for the ozone (O3) product measured by the two Infrared Atmospheric Sounding Interferometers (IASIs) launched on board the MetOp-A and MetOp-B satellites in 2006 and in 2012 respectively. IASI O3 total columns and vertical profiles obtained from Fast Optimal Retrievals on Layers for IASI (FORLI) v20140922 software (running up until recently) are validated against independent observations during the period 2008-2014 on a global scale. On average for the period 2013-2014, IASI-A and IASI-B total ozone columns (TOCs) retrieved using FORLI are consistent, with IASI-B providing slightly lower values with a global difference of only 0.2±0.8%. The comparison between IASI-A and IASI-B O3 vertical profiles shows differences within ±2% over the entire altitude range. Global validation results for 7 years of IASI TOCs from FORLI against the Global Ozone Monitoring Experiment-2 (GOME-2) launched on board MetOp-A and Brewer-Dobson data show that, on average, IASI overestimates the ultraviolet (UV) data by 5-6% with the largest differences found in the southern high latitudes. The comparison with UV-visible SAOZ (Système d'Analyse par Observation Zénithale) measurements shows a mean bias between IASI and SAOZ TOCs of 2-4% in the midlatitudes and tropics and 7% at the polar circle. Part of the discrepancies found at high latitudes can be attributed to the limited information content in the observations due to low brightness temperatures. The comparison with ozonesonde vertical profiles (limited to 30km) shows that on average IASI with FORLI processing underestimates O3 by ∼ 5-15% in the troposphere while it overestimates O3 by ∼ 10-40% in the stratosphere, depending on the latitude. The largest relative differences are found in the tropical tropopause region; this can be explained by the low O3 amounts leading to large relative errors. In this study, we also evaluate an updated version of FORLI-O3 retrieval software (v20151001), using look-up tables recalculated to cover a larger spectral range using the latest HITRAN spectroscopic database (HITRAN 2012) and implementing numerical corrections. The assessment of the new O3 product with the same set of observations as that used for the validation exercise shows a correction of ∼ 4% for the TOC positive bias when compared to the UV ground-based and satellite observations, bringing the overall global comparison to ∼ 1-2% on average. This improvement is mainly associated with a decrease in the retrieved O3 concentration in the middle stratosphere (above 30hPa/25km) as shown by the comparison with ozonesonde data. © Author(s) 2016.
BibTeX: @article{Boynard2016, author = {Boynard, Anne and Hurtmans, Daniel and Koukouli, Mariliza E. and Goutail, Florence and Bureau, Jérôme and Safieddine, Sarah and Lerot, Christophe and Hadji-Lazaro, Juliette and Wespes, Catherine and Pommereau, Jean-Pierre and Pazmino, Andrea and Zyrichidou, Irene and Balis, Dimitris and Barbe, Alain and Mikhailenko, Semen N. and Loyola, Diego and Valks, Pieter and Van Roozendael, Michel and Coheur, Pierre-François and Clerbaux, Cathy}, title = {Seven years of IASI ozone retrievals from FORLI: Validation with independent total column and vertical profile measurements}, journal = {Atmospheric Measurement Techniques}, year = {2016}, volume = {9}, number = {9}, pages = {4327 – 4353}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-9-4327-2016} }
Carn S, Clarisse L and Prata A (2016), "Multi-decadal satellite measurements of global volcanic degassing", Journal of Volcanology and Geothermal Research. Vol. 311, pp. 99 – 134. [Abstract] [BibTeX] [DOI]
Abstract: Satellite instruments have been providing measurements of global volcanic emissions of sulfur dioxide (SO2) since 1978, based on observations in the ultraviolet (UV), infrared (IR) and microwave spectral bands. We review recent advances in satellite remote sensing of volcanic gases, focusing on increased instrument sensitivity to tropospheric SO2 emissions and techniques to determine volcanic plume altitude. A synthesis of 36 years of global UV, IR and microwave satellite measurements yields an updated assessment of the volcanic SO2 flux to the upper troposphere and lower stratosphere (UTLS) between 1978 and 2014 ( 1-Tg/yr). The present availability of multiple UV and IR satellite SO2 products provides increased confidence in calculated SO2 loadings for many eruptions. We examine the temporal and latitudinal distribution of volcanic SO2 emissions and reassess the relationship between eruptive SO2 discharge and eruption magnitude, finding a first-order correlation between SO2 emission and volcanic explosivity index (VEI), but with significant scatter. Based on the observed SO2-VEI relation, we estimate the fraction of eruptive SO2 emissions released by the smallest eruptions ( 0.48 Tg/yr), which is not recorded by satellite observations. A detailed breakdown of the sources of measured SO2 emissions reveals intuitively expected correlations between eruption frequency, SO2 loading and volcanic degassing style. We discuss new constraints on e-folding times for SO2 removal in volcanic plumes, and highlight recent measurements of volcanic hydrogen chloride (HCl) injections into the UTLS. An analysis of passive volcanic emissions of SO2 detected in Ozone Monitoring Instrument (OMI) SO2 data since 2004 provides new insight into the location and stability of the dominant sources of volcanic SO2 over the past decade. Since volcanic SO2 emissions constitute a random, highly variable perturbation to the atmosphere-climate system, continued monitoring of volcanic SO2 emissions from space by multiple UV and IR instruments to extend the current multi-decadal record is essential, and near-global, geostationary measurements of SO2 may be available by the end of the current decade. © 2016 The Authors.
BibTeX: @article{Carn2016, author = {Carn, S.A. and Clarisse, L. and Prata, A.J.}, title = {Multi-decadal satellite measurements of global volcanic degassing}, journal = {Journal of Volcanology and Geothermal Research}, year = {2016}, volume = {311}, pages = {99 – 134}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.jvolgeores.2016.01.002} }
Cessateur G, De Keyser J, Maggiolo R, Rubin M, Gronoff G, Gibbons A, Jehin E, Dhooghe F, Gunell H, Vaeck N and Loreau J (2016), "2D photochemical model for forbidden oxygen line emission for comet 1P/Halley", Monthly Notices of the Royal Astronomical Society. Vol. 462, pp. S116 – S123. [Abstract] [BibTeX] [DOI]
Abstract: We present here a 2D model of photochemistry for computing the production and loss mechanisms of the O(1S) and O(1D) states, which are responsible for the emission lines at 577.7, 630, and 636.4 nm, in case of the comet 1P/Halley. The presence of O2 within cometary atmospheres, measured by the in situ Rosetta and Giotto missions, necessitates a revision of the usual photochemical models. Indeed, the photodissociation of molecular oxygen also leads to a significant production of oxygen in excited electronic states. In order to correctly model the solar ultraviolet (UV) flux absorption, we consider here a 2D configuration. While the green to red-doublet ratio is not affected by the solar UV flux absorption, estimates of the red-doublet and green lines emissions are, however, overestimated by a factor of 2 in the 1D model compared to the 2D model. Considering a spherical symmetry, emission maps can be deduced from the 2D model in order to be directly compared to ground and/or in situ observations. © 2017 The Authors.
BibTeX: @article{Cessateur2016, author = {Cessateur, G. and De Keyser, J. and Maggiolo, R. and Rubin, M. and Gronoff, G. and Gibbons, A. and Jehin, E. and Dhooghe, F. and Gunell, H. and Vaeck, N. and Loreau, J.}, title = {2D photochemical model for forbidden oxygen line emission for comet 1P/Halley}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {2016}, volume = {462}, pages = {S116 – S123}, note = {All Open Access, Bronze Open Access}, doi = {10.1093/mnras/stw2150} }
Cessateur G, Keyser JD, Maggiolo R, Gibbons A, Gronoff G, Gunell H, Dhooghe F, Loreau J, Vaeck N, Altwegg K, Bieler A, Briois C, Calmonte U, Combi M, Fiethe B, Fuselier S, Gombosi T, Hässig M, Le Roy L, Neefs E, Rubin M and Sémon T (2016), "Photochemistry of forbidden oxygen lines in the inner coma of 67P/Churyumov-Gerasimenko", Journal of Geophysical Research: Space Physics. Vol. 121(1), pp. 804 – 816. [Abstract] [BibTeX] [DOI]
Abstract: Observations of the green and red-doublet emission lines have previously been realized for several comets. We present here a chemistry-emission coupled model to study the production and loss mechanisms of the O(1S) and O(1D) states, which are responsible for the emission lines of interest for comet 67P/Churyumov-Gerasimenko. The recent discovery of O2 in significant abundance relative to water 3.80 ± 0.85 within the coma of 67P has been taken into consideration for the first time in such models. We evaluate the effect of the presence of O2 on the green to red-doublet emission intensity ratio, which is traditionally used to assess the CO2 abundance within cometary atmospheres. Model simulations, solving the continuity equation with transport, show that not taking O2 into account leads to an underestimation of the CO2 abundance within 67P, with a relative error of about 25%. This strongly suggests that the green to red-doublet emission intensity ratio alone is not a proper tool for determining the CO2 abundance, as previously suggested. Indeed, there is no compelling reason why O2 would not be a common cometary volatile, making revision of earlier assessments regarding the CO2 abundance in cometary atmospheres necessary. The large uncertainties of the CO2 photodissociation cross section imply that more studies are required in order to better constrain the O(1S) and O(1D) production through this mechanism. Space weather phenomena, such as powerful solar flares, could be used as tools for doing so, providing additional information on a good estimation of the O2 abundance within cometary atmospheres. ©2016. The Authors.
BibTeX: @article{Cessateur2016a, author = {Cessateur, G. and Keyser, J. De and Maggiolo, R. and Gibbons, A. and Gronoff, G. and Gunell, H. and Dhooghe, F. and Loreau, J. and Vaeck, N. and Altwegg, K. and Bieler, A. and Briois, C. and Calmonte, U. and Combi, M.R. and Fiethe, B. and Fuselier, S.A. and Gombosi, T.I. and Hässig, M. and Le Roy, L. and Neefs, E. and Rubin, M. and Sémon, T.}, title = {Photochemistry of forbidden oxygen lines in the inner coma of 67P/Churyumov-Gerasimenko}, journal = {Journal of Geophysical Research: Space Physics}, year = {2016}, volume = {121}, number = {1}, pages = {804 – 816}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1002/2015JA022013} }
Clarisse L and Prata F (2016), "Infrared Sounding of Volcanic Ash", Volcanic Ash: Hazard Observation. , pp. 189 – 215. [Abstract] [BibTeX] [DOI]
Abstract: In the first part of this chapter, the spectral content of the thermal infrared spectral region for the sounding of volcanic eruptions is explored through analysis of simulated and real observed spectra. Next, we review the literature on algorithms for the identification and retrieval of volcanic ash, both from broadband and hyperspectral infrared measurements. The final part of this chapter treats the topic of validation of satellite-based ash retrievals. © 2016 Elsevier Ltd. All rights reserved.
BibTeX: @book{Clarisse2016, author = {Clarisse, L. and Prata, F.}, title = {Infrared Sounding of Volcanic Ash}, journal = {Volcanic Ash: Hazard Observation}, year = {2016}, pages = {189 – 215}, doi = {10.1016/B978-0-08-100405-0.00017-3} }
Dammers E, Palm M, Van Damme M, Vigouroux C, Smale D, Conway S, Toon GC, Jones N, Nussbaumer E, Warneke T, Petri C, Clarisse L, Clerbaux C, Hermans C, Lutsch E, Strong K, Hannigan JW, Nakajima H, Morino I, Herrera B, Stremme W, Grutter M, Schaap M, Kruit RJW, Notholt J, Coheur P-F and Erisman JW (2016), "An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements", Atmospheric Chemistry and Physics. Vol. 16(16), pp. 10351 – 10368. [Abstract] [BibTeX] [DOI]
Abstract: Global distributions of atmospheric ammonia (NH3) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-)daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier transform infrared spectroscopy (FTIR) observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC) stations around the world between 2008 and 2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (Nobs Combining double low line 547) give a mean relative difference of ĝ'32.4ĝ€±ĝ€(56.3)ĝ€%, a correlation r of 0.8 with a slope of 0.73. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (-50 to +100%). © Author(s) 2016.
BibTeX: @article{Dammers2016, author = {Dammers, Enrico and Palm, Mathias and Van Damme, Martin and Vigouroux, Corinne and Smale, Dan and Conway, Stephanie and Toon, Geoffrey C. and Jones, Nicholas and Nussbaumer, Eric and Warneke, Thorsten and Petri, Christof and Clarisse, Lieven and Clerbaux, Cathy and Hermans, Christian and Lutsch, Erik and Strong, Kim and Hannigan, James W. and Nakajima, Hideaki and Morino, Isamu and Herrera, Beatriz and Stremme, Wolfgang and Grutter, Michel and Schaap, Martijn and Kruit, Roy J. Wichink and Notholt, Justus and Coheur, Pierre-F. and Erisman, Jan Willem}, title = {An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements}, journal = {Atmospheric Chemistry and Physics}, year = {2016}, volume = {16}, number = {16}, pages = {10351 – 10368}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-16-10351-2016} }
Desrier A, Romanzin C, Lamarre N, Alcaraz C, Gans B, Gauyacq D, Liévin J and Boyé-Péronne S (2016), "Experimental and ab initio characterization of HC3N+ vibronic structure. I. Synchrotron-based threshold photo-electron spectroscopy", Journal of Chemical Physics. Vol. 145(23) [Abstract] [BibTeX] [DOI]
Abstract: Threshold-photoionization spectroscopy of cyanoacetylene (HC3N) and its 15N isotopologue has been investigated in the vacuum-ultraviolet range with a synchrotron-based experiment allowing to record threshold-photoelectron spectrum and photoion yield over a large energy range (from 88 500 to 177 500 cm-1, i.e., from 11 to 22 eV). Adiabatic ionization energies towards the three lowest electronic states X+ 2Π, A+ Σ+2, and B+ Π2 are derived from the threshold-photoelectron spectrum. A detailed description of the vibrational structure of these states is proposed leading to the determination of the vibrational frequencies for most modes. The vibrational assignments and the discussion about the electronic structure are supported by multireference ab initio calculations (CASPT2, MRCI). Unprecedented structures are resolved and tentatively assigned in the region of the B+ X transition. Exploratory calculations highlight the complexity of the electronic landscape of the cation up to approximately 10 eV above its ground state. © 2016 Author(s).
BibTeX: @article{Desrier2016, author = {Desrier, Antoine and Romanzin, Claire and Lamarre, Nicolas and Alcaraz, Christian and Gans, Bérenger and Gauyacq, Dolores and Liévin, Jacques and Boyé-Péronne, Séverine}, title = {Experimental and ab initio characterization of HC3N+ vibronic structure. I. Synchrotron-based threshold photo-electron spectroscopy}, journal = {Journal of Chemical Physics}, year = {2016}, volume = {145}, number = {23}, doi = {10.1063/1.4972019} }
Filippin L, Beerwerth R, Ekman J, Fritzsche S, Godefroid M and Jönsson P (2016), "Multiconfiguration calculations of electronic isotope shift factors in Al i", Physical Review A. Vol. 94(6) [Abstract] [BibTeX] [DOI]
Abstract: The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of electronic isotope shift factors for a set of transitions between low-lying levels of neutral aluminium. These electronic quantities together with observed isotope shifts between different pairs of isotopes provide the changes in mean-square charge radii of the atomic nuclei. Two computational approaches are adopted for the estimation of the mass- and field-shift factors. Within these approaches, different models for electron correlation are explored in a systematic way to determine a reliable computational strategy and to estimate theoretical error bars of the isotope shift factors. © 2016 American Physical Society.
BibTeX: @article{Filippin2016b, author = {Filippin, Livio and Beerwerth, Randolf and Ekman, Jörgen and Fritzsche, Stephan and Godefroid, Michel and Jönsson, Per}, title = {Multiconfiguration calculations of electronic isotope shift factors in Al i}, journal = {Physical Review A}, year = {2016}, volume = {94}, number = {6}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.94.062508} }
Filippin L, Godefroid M and Baye D (2016), "Relativistic two-photon decay rates with the Lagrange-mesh method", Physical Review A. Vol. 93(1) [Abstract] [BibTeX] [DOI]
Abstract: Relativistic two-photon decay rates of the 2s1/2 and 2p1/2 states towards the 1s1/2 ground state of hydrogenic atoms are calculated by using numerically exact energies and wave functions obtained from the Dirac equation with the Lagrange-mesh method. This approach is an approximate variational method taking the form of equations on a grid because of the use of a Gauss quadrature approximation. Highly accurate values are obtained by a simple calculation involving different meshes for the initial, final, and intermediate wave functions and for the calculation of matrix elements. The accuracy of the results with a Coulomb potential is improved by several orders of magnitude in comparison with benchmark values from the literature. The general requirement of gauge invariance is also successfully tested, down to rounding errors. The method provides high accuracies for two-photon decay rates of a particle in other potentials and is applied to a hydrogen atom embedded in a Debye plasma simulated by a Yukawa potential. © 2016 American Physical Society.
BibTeX: @article{Filippin2016a, author = {Filippin, Livio and Godefroid, Michel and Baye, Daniel}, title = {Relativistic two-photon decay rates with the Lagrange-mesh method}, journal = {Physical Review A}, year = {2016}, volume = {93}, number = {1}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.93.012517} }
Filippin L, Godefroid M, Ekman J and Jönsson P (2016), "Core correlation effects in multiconfiguration calculations of isotope shifts in Mg I", Physical Review A. Vol. 93(6) [Abstract] [BibTeX] [DOI]
Abstract: The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of isotope shifts for several well-known transitions in neutral magnesium. Relativistic normal and specific mass shift factors as well as the electronic probability density at the origin are calculated. Combining these electronic quantities with available nuclear data, energy and transition level shifts are determined for the Mg26-Mg24 pair of isotopes. Different models for electron correlation are adopted. It is shown that, although valence and core-valence models provide accurate values for the isotope shifts, the inclusion of core-core excitations in the computational strategy significantly improves the accuracy of the transition energies and normal mass shift factors. © 2016 American Physical Society.
BibTeX: @article{Filippin2016, author = {Filippin, Livio and Godefroid, Michel and Ekman, Jörgen and Jönsson, Per}, title = {Core correlation effects in multiconfiguration calculations of isotope shifts in Mg I}, journal = {Physical Review A}, year = {2016}, volume = {93}, number = {6}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.93.062512} }
Fischer CF, Godefroid M, Brage T, Jönsson P and Gaigalas G (2016), "Advanced multiconfiguration methods for complex atoms: I. Energies and wave functions", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 49(18) [Abstract] [BibTeX] [DOI]
Abstract: Multiconfiguration wave function expansions combined with configuration interaction methods are a method of choice for complex atoms where atomic state functions are expanded in a basis of configuration state functions. Combined with a variational method such as the multiconfiguration Hartree-Fock (MCHF) or multiconfiguration Dirac-Hartree-Fock (MCDHF), the associated set of radial functions can be optimized for the levels of interest. The present review updates the variational MCHF theory to include MCDHF, describes the multireference single and double process for generating expansions and the systematic procedure of a computational scheme for monitoring convergence. It focuses on the calculations of energies and wave functions from which other atomic properties can be predicted such as transition rates, hyperfine structures and isotope shifts, for example. © 2016 IOP Publishing Ltd.
BibTeX: @article{Fischer2016, author = {Fischer, Charlotte Froese and Godefroid, Michel and Brage, Tomas and Jönsson, Per and Gaigalas, Gediminas}, title = {Advanced multiconfiguration methods for complex atoms: I. Energies and wave functions}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2016}, volume = {49}, number = {18}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/49/18/182004} }
Földes T, Vanfleteren T, Rizopoulos A, Herman M, Vander Auwera J, Softley T, Di Lonardo G and Fusina L (2016), "High-resolution room temperature and jet-cooled spectroscopic investigation of 15NH3 in the ν1+ν3 band region (1.51 μm)", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 179, pp. 112 – 125. [Abstract] [BibTeX] [DOI]
Abstract: Spectra of 99% isotopically pure 15NH3 were recorded using cavity ring-down (CRD, 6567-6639 cm-1) and Fourier transform (FT, 6350-6985 cm-1) spectroscopy under jet cooled and room temperature conditions, respectively. Measured line positions on both data sets improve on literature values, in particular by one order of magnitude for the ν1+ν3 band. A room temperature list of line positions, with approximate line intensities, is provided, much more complete and precise than presently available. Line broadening effects in the CRD spectrum allowed lines with J'''- values between 0 and 3 to be identified. Ground state combination differences were used to refine the assignments, further assisted by intensity ratios between the two data sets. Reliable values for J, K and inversion symmetry of the ground state vibrational levels, as well as further information on a/s doublets could be obtained, updating and extending literature assignments. © 2016 Elsevier Ltd.
BibTeX: @article{Foeldes2016, author = {Földes, T. and Vanfleteren, T. and Rizopoulos, A. and Herman, M. and Vander Auwera, J. and Softley, T.P. and Di Lonardo, G. and Fusina, L.}, title = {High-resolution room temperature and jet-cooled spectroscopic investigation of 15NH3 in the ν1+ν3 band region (1.51 μm)}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2016}, volume = {179}, pages = {112 – 125}, doi = {10.1016/j.jqsrt.2016.03.018} }
Fortems-Cheiney A, Dufour G, Hamaoui-Laguel L, Foret G, Siour G, Van Damme M, Meleux F, Coheur P-F, Clerbaux C, Clarisse L, Favez O, Wallasch M and Beekmann M (2016), "Unaccounted variability in NH3 agricultural sources detected by IASI contributing to European spring haze episode", Geophysical Research Letters. Vol. 43(10), pp. 5475 – 5482. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3), whose main source in the troposphere is agriculture, is an important gaseous precursor of atmospheric particulate matter (PM). We derived daily ammonia emissions using NH3 total columns measured from the Infrared Atmospheric Sounding Interferometer (IASI) on board Metop-A, at a relatively high spatial resolution (grid cell of 0.5° × 0.5°). During the European spring haze episodes of 24–31 March 2012 and 8–15 March 2014, IASI reveals NH3 total column magnitudes highlighting higher NH3 emissions over central Europe (especially over Germany, Czech Republic, and eastern France) from the ones provided by the European reference European Monitoring and Evaluation Programme inventory. These ammonia emissions exhibit in addition a large day-to-day variability, certainly due to spreading practices. The increase of NH3 emissions in the model, that reaches +300% locally, leads to an increase of both NH3 and PM2.5 surface concentrations and allows for a better comparison with independent measurements (in terms of bias, root-mean-square error, and correlation). This study suggests that there are good prospects for better quantifying NH3 emissions by atmospheric inversions. ©2016. American Geophysical Union. All Rights Reserved.
BibTeX: @article{FortemsCheiney2016, author = {Fortems-Cheiney, A. and Dufour, G. and Hamaoui-Laguel, L. and Foret, G. and Siour, G. and Van Damme, M. and Meleux, F. and Coheur, P.-F. and Clerbaux, C. and Clarisse, L. and Favez, O. and Wallasch, M. and Beekmann, M.}, title = {Unaccounted variability in NH3 agricultural sources detected by IASI contributing to European spring haze episode}, journal = {Geophysical Research Letters}, year = {2016}, volume = {43}, number = {10}, pages = {5475 – 5482}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2016GL069361} }
Franco B, A Marais E, Bovy B, Bader W, Lejeune B, Roland G, Servais C and Mahieu E (2016), "Diurnal cycle and multi-decadal trend of formaldehyde in the remote atmosphere near 46°N", Atmospheric Chemistry and Physics. Vol. 16(6), pp. 4171 – 4189. [Abstract] [BibTeX] [DOI]
Abstract: Only very few long-term records of formaldehyde (HCHO) exist that are suitable for trend analysis. Furthermore, many uncertainties remain as to its diurnal cycle, representing a large short-term variability superimposed on seasonal and inter-annual variations that should be accounted for when comparing ground-based observations to, e.g., model results. In this study, we derive a multi-decadal time series (January 1988-June 2015) of HCHO total columns from ground-based high-resolution Fourier transform infrared (FTIR) solar spectra recorded at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5°N, 8.0°E, 3580ma. s. l. ), allowing for the characterization of the mid-latitudinal atmosphere for background conditions. First we investigate the HCHO diurnal variation, peaking around noontime and mainly driven by the intra-day insolation modulation and methane (CH4) oxidation. We also characterize quantitatively the diurnal cycles by adjusting a parametric model to the observations, which links the daytime to the HCHO columns according to the monthly intra-day regimes. It is then employed to scale all the individual FTIR measurements on a given daytime in order to remove the effect of the intra-day modulation for improving the trend determination and the comparison with HCHO columns simulated by the state-of-the-art GEOS-Chem v9-02 chemical transport model. Such a parametric model will be useful to scale the Jungfraujoch HCHO columns on satellite overpass times in the framework of future calibration/validation efforts of space-borne sensors. GEOS-Chem sensitivity tests suggest then that the seasonal and inter-annual HCHO column variations above Jungfraujoch are predominantly led by the atmospheric CH4 oxidation, with a maximum contribution of 25% from the anthropogenic non-methane volatile organic compound precursors during wintertime. Finally, trend analysis of the so-scaled 27-year FTIR time series reveals a long-term evolution of the HCHO columns in the remote troposphere to be related to the atmospheric CH4 fluctuations and the short-term OH variability: +2.9%year-1 between 1988 and 1995, -3.7%year-1 over 1996-2002 and +0.8%year-1 from 2003 onwards. © Author(s) 2016.
BibTeX: @article{Franco2016a, author = {Franco, Bruno and A Marais, Eloise and Bovy, Benoît and Bader, Whitney and Lejeune, Bernard and Roland, Ginette and Servais, Christian and Mahieu, Emmanuel}, title = {Diurnal cycle and multi-decadal trend of formaldehyde in the remote atmosphere near 46°N}, journal = {Atmospheric Chemistry and Physics}, year = {2016}, volume = {16}, number = {6}, pages = {4171 – 4189}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-16-4171-2016} }
Franco B, Mahieu E, Emmons L, Tzompa-Sosa Z, Fischer E, Sudo K, Bovy B, Conway S, Griffin D, Hannigan J, Strong K and Walker K (2016), "Evaluating ethane and methane emissions associated with the development of oil and natural gas extraction in North America", Environmental Research Letters. Vol. 11(4) [Abstract] [BibTeX] [DOI]
Abstract: Sharp rises in the atmospheric abundance of ethane (C2H6) have been detected from 2009 onwards in the Northern Hemisphere as a result of the unprecedented growth in the exploitation of shale gas and tight oil reservoirs in North America. Using time series of C2H6 total columns derived from ground-based Fourier transform infrared (FTIR) observations made at five selected Network for the Detection of Atmospheric Composition Change sites, we characterize the recent C2H6 evolution and determine growth rates of ∼5% yr-1 at mid-latitudes and of ∼3% yr-1 at remote sites. Results from CAM-chem simulations with the Hemispheric Transport of Air Pollutants, Phase II bottom-up inventory for anthropogenic emissions are found to greatly underestimate the current C2H6 abundances. Doubling global emissions is required to reconcile the simulations and the observations prior to 2009. We further estimate that North American anthropogenic C2H6 emissions have increased from 1.6 Tg yr-1 in 2008 to 2.8 Tg yr-1 in 2014, i.e. by 75% over these six years. We also completed a second simulation with new top-down emissions of C2H6 from North American oil and gas activities, biofuel consumption and biomass burning, inferred from space-borne observations of methane (CH4) from Greenhouse Gases Observing SATellite. In this simulation, GEOS-Chem is able to reproduce FTIR measurements at the mid-latitudinal sites, underscoring the impact of the North American oil and gas development on the current C2H6 abundance. Finally we estimate that the North American oil and gas emissions of CH4, a major greenhouse gas, grew from 20 to 35 Tg yr-1 over the period 2008-2014, in association with the recent C2H6 rise. © 2016 IOP Publishing Ltd.
BibTeX: @article{Franco2016, author = {Franco, B. and Mahieu, E. and Emmons, L.K. and Tzompa-Sosa, Z.A. and Fischer, E.V. and Sudo, K. and Bovy, B. and Conway, S. and Griffin, D. and Hannigan, J.W. and Strong, K. and Walker, K.A.}, title = {Evaluating ethane and methane emissions associated with the development of oil and natural gas extraction in North America}, journal = {Environmental Research Letters}, year = {2016}, volume = {11}, number = {4}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.1088/1748-9326/11/4/044010} }
Gans B, Lamarre N, Broquier M, Liévin J and Boyé-Péronne S (2016), "Experimental and ab initio characterization of HC3N+ vibronic structure. II. High-resolution VUV PFI-ZEKE spectroscopy", Journal of Chemical Physics. Vol. 145(23) [Abstract] [BibTeX] [DOI]
Abstract: Vacuum-ultraviolet pulsed-field-ionization zero-kinetic-energy photoelectron spectra of X+Π2←XΣ+1 and B+Π2←XΣ+1 transitions of the HC314N and HC315N isotopologues of cyanoacetylene have been recorded. The resolution of the photoelectron spectra allowed us to resolve the vibrational structures and the spin-orbit splittings in the cation. Accurate values of the adiabatic ionization potentials of the two isotopologues (EI/hc(HC314N)=93 909(2) cm-1 and EI/hc(HC315N)=93 912(2) cm-1), the vibrational frequencies of the ν2, ν6, and ν7 vibrational modes, and the spin-orbit coupling constant (ASO = -44(2) cm-1) of the X+Π2 cationic ground state have been derived from the measurements. Using ab initio calculations, the unexpected structure of the B+Π2←XΣ+1 transition is tentatively attributed to a conical intersection between the A+ and B+ electronic states of the cation. © 2016 Author(s).
BibTeX: @article{Gans2016, author = {Gans, Bérenger and Lamarre, Nicolas and Broquier, Michel and Liévin, Jacques and Boyé-Péronne, Séverine}, title = {Experimental and ab initio characterization of HC3N+ vibronic structure. II. High-resolution VUV PFI-ZEKE spectroscopy}, journal = {Journal of Chemical Physics}, year = {2016}, volume = {145}, number = {23}, doi = {10.1063/1.4972018} }
Hadjichrysanthou C, Cauët E, Lawrence E, Vegvari C, De Wolf F and Anderson RM (2016), "Understanding the within-host dynamics of influenza A virus: From theory to clinical implications", Journal of the Royal Society Interface. Vol. 13(119) [Abstract] [BibTeX] [DOI]
Abstract: Mathematical models have provided important insights into acute viral dynamics within individual patients. In this paper, we study the simplest target cell-limited models to investigate the within-host dynamics of influenza A virus infection in humans. Despite the biological simplicity of the models, we show how these can be used to understand the severity of the infection and the key attributes of possible immunotherapy and antiviral drugs for the treatment of infection at different times post infection. Through an analytic approach, we derive and estimate simple summary biological quantities that can provide novel insights into the infection dynamics and the definition of clinical endpoints. We focus on nine quantities, including the area under the viral load curve, peak viral load, the time to peak viral load and the level of cell death due to infection. Using Markov chain Monte Carlo methods, we fitted the models to data collected from 12 untreated volunteers who participated in two clinical studies that tested the antiviral drugs oseltamivir and zanamivir. Based on the results, we also discuss various difficulties in deriving precise estimates of the parameters, even in the very simple models considered, when experimental data are limited to viral load measures and/or there is a limited number of viral load measurements post infection. © 2016 The Authors.
BibTeX: @article{Hadjichrysanthou2016, author = {Hadjichrysanthou, Christoforos and Cauët, Emilie and Lawrence, Emma and Vegvari, Carolin and De Wolf, Frank and Anderson, Roy M.}, title = {Understanding the within-host dynamics of influenza A virus: From theory to clinical implications}, journal = {Journal of the Royal Society Interface}, year = {2016}, volume = {13}, number = {119}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1098/rsif.2016.0289} }
Hashemi R, Predoi-Cross A, Dudaryonok A, Lavrentieva N, Vandaele A and Vander Auwera J (2016), "CO2 pressure broadening and shift coefficients for the 2–0 band of 12C16O", Journal of Molecular Spectroscopy. Vol. 326, pp. 60 – 72. [Abstract] [BibTeX] [DOI]
Abstract: Fourier transform absorption spectra of the 2–0 band of 12C16O mixed with CO2 have been recorded at total pressures from 156 to 1212 hPa and at 4 different temperatures between 240 K and 283 K. CO2 pressure-induced line broadening and line shift coefficients, and the temperature dependence of the former have been measured including line mixing using a multi-spectrum non-linear least squares fitting technique. Different line shape models have been considered to take into account the Dicke narrowing or speed dependence effects. Measured line-shape parameters were compared with theoretical values, calculated for individual temperatures using a semi-empirical method and the Exponential Power Gap (EPG) law. © 2016 Elsevier Inc.
BibTeX: @article{Hashemi2016, author = {Hashemi, R. and Predoi-Cross, A. and Dudaryonok, A.S. and Lavrentieva, N.N. and Vandaele, A.C. and Vander Auwera, J.}, title = {CO2 pressure broadening and shift coefficients for the 2–0 band of 12C16O}, journal = {Journal of Molecular Spectroscopy}, year = {2016}, volume = {326}, pages = {60 – 72}, doi = {10.1016/j.jms.2016.02.014} }
Helmig D, Rossabi S, Hueber J, Tans P, Montzka SA, Masarie K, Thoning K, Plass-Duelmer C, Claude A, Carpenter LJ, Lewis AC, Punjabi S, Reimann S, Vollmer MK, Steinbrecher R, Hannigan JW, Emmons LK, Mahieu E, Franco B, Smale D and Pozzer A (2016), "Reversal of global atmospheric ethane and propane trends largely due to US oil and natural gas production", Nature Geoscience. Vol. 9(7), pp. 490 – 495. [Abstract] [BibTeX] [DOI]
Abstract: Non-methane hydrocarbons such as ethane are important precursors to tropospheric ozone and aerosols. Using data from a global surface network and atmospheric column observations we show that the steady decline in the ethane mole fraction that began in the 1970s halted between 2005 and 2010 in most of the Northern Hemisphere and has since reversed. We calculate a yearly increase in ethane emissions in the Northern Hemisphere of 0.42 (±0.19) Tg yr-1 between mid-2009 and mid-2014. The largest increases in ethane and the shorter-lived propane are seen over the central and eastern USA, with a spatial distribution that suggests North American oil and natural gas development as the primary source of increasing emissions. By including other co-emitted oil and natural gas non-methane hydrocarbons, we estimate a Northern Hemisphere total non-methane hydrocarbon yearly emission increase of 1.2 (±0.8) Tg yr-1. Atmospheric chemical transport modelling suggests that these emissions could augment summertime mean surface ozone by several nanomoles per mole near oil and natural gas production regions. Methane/ethane oil and natural gas emission ratios could suggest a significant increase in associated methane emissions; however, this increase is inconsistent with observed leak rates in production regions and changes in methane's global isotopic ratio. © 2016 Macmillan Publishers Limited.
BibTeX: @article{Helmig2016, author = {Helmig, Detlev and Rossabi, Samuel and Hueber, Jacques and Tans, Pieter and Montzka, Stephen A. and Masarie, Ken and Thoning, Kirk and Plass-Duelmer, Christian and Claude, Anja and Carpenter, Lucy J. and Lewis, Alastair C. and Punjabi, Shalini and Reimann, Stefan and Vollmer, Martin K. and Steinbrecher, Rainer and Hannigan, James W. and Emmons, Louisa K. and Mahieu, Emmanuel and Franco, Bruno and Smale, Dan and Pozzer, Andrea}, title = {Reversal of global atmospheric ethane and propane trends largely due to US oil and natural gas production}, journal = {Nature Geoscience}, year = {2016}, volume = {9}, number = {7}, pages = {490 – 495}, doi = {10.1038/ngeo2721} }
Herman M, Földes T, Didriche K, Lauzin C and Vanfleteren T (2016), "Overtone spectroscopy of molecular complexes containing small polyatomic molecules", International Reviews in Physical Chemistry. Vol. 35(2), pp. 243 – 295. [Abstract] [BibTeX] [DOI]
Abstract: The literature on the high-resolution spectroscopic investigation of molecular complexes containing small polyatomic species excited in their vibrational overtones is reviewed. They turn out to be complexes containing acetylene, ammonia and water, mainly excited in their 2CH, 2NH and 2OH vibrations, respectively. The majority of results published on these systems was obtained using an instrumental set-up based on cw-cavity ring-down spectroscopy, built in the ‘Laboratoire de Chimie quantique et Photophysique’ at the ‘Université libre de Bruxelles’ (CQP/ULB) and named FANTASIO+, which is described. It allowed retrieving upper state vibrational predissociation lifetimes, which are highlighted together with more results. The sequence of experiments at CQP/ULB prior and along the line of those supporting the investigation of molecular complexes is briefly illustrated. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX: @article{Herman2016, author = {Herman, M. and Földes, T. and Didriche, K. and Lauzin, C. and Vanfleteren, T.}, title = {Overtone spectroscopy of molecular complexes containing small polyatomic molecules}, journal = {International Reviews in Physical Chemistry}, year = {2016}, volume = {35}, number = {2}, pages = {243 – 295}, doi = {10.1080/0144235X.2016.1171039} }
Jacquinet-Husson N, Armante R, Scott N, Chédin A, Crépeau L, Boutammine C, Bouhdaoui A, Crevoisier C, Capelle V, Boonne C, Poulet-Crovisier N, Barbe A, Chris Benner D, Boudon V, Brown L, Buldyreva J, Campargue A, Coudert L, Devi V, Down M, Drouin B, Fayt A, Fittschen C, Flaud J-M, Gamache R, Harrison J, Hill C, Hodnebrog Ø, Hu S-M, Jacquemart D, Jolly A, Jiménez E, Lavrentieva N, Liu A-W, Lodi L, Lyulin O, Massie S, Mikhailenko S, Müller H, Naumenko O, Nikitin A, Nielsen C, Orphal J, Perevalov V, Perrin A, Polovtseva E, Predoi-Cross A, Rotger M, Ruth A, Yu S, Sung K, Tashkun S, Tennyson J, Tyuterev V, Vander Auwera J, Voronin B and Makie A (2016), "The 2015 edition of the GEISA spectroscopic database", Journal of Molecular Spectroscopy. Vol. 327, pp. 31 – 72. [Abstract] [BibTeX] [DOI]
Abstract: The GEISA database (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information) has been developed and maintained by the ARA/ABC(t) group at LMD since 1974. GEISA is constantly evolving, taking into account the best available spectroscopic data. This paper presents the 2015 release of GEISA (GEISA-2015), which updates the last edition of 2011 and celebrates the 40th anniversary of the database. Significant updates and additions have been implemented in the three following independent databases of GEISA. The “line parameters database” contains 52 molecular species (118 isotopologues) and transitions in the spectral range from 10−6 to 35,877.031 cm−1, representing 5,067,351 entries, against 3,794,297 in GEISA-2011. Among the previously existing molecules, 20 molecular species have been updated. A new molecule (SO3) has been added. HDO, isotopologue of H2O, is now identified as an independent molecular species. Seven new isotopologues have been added to the GEISA-2015 database. The “cross section sub-database” has been enriched by the addition of 43 new molecular species in its infrared part, 4 molecules (ethane, propane, acetone, acetonitrile) are also updated; they represent 3% of the update. A new section is added, in the near-infrared spectral region, involving 7 molecular species: CH3CN, CH3I, CH3O2, H2CO, HO2, HONO, NH3. The “microphysical and optical properties of atmospheric aerosols sub-database” has been updated for the first time since 2003. It contains more than 40 species originating from NCAR and 20 from the ARIA archive of Oxford University. As for the previous versions, this new release of GEISA and associated management software facilities are implemented and freely accessible on the AERIS/ESPRI atmospheric chemistry data center website. © 2016 Elsevier Inc.
BibTeX: @article{JacquinetHusson2016, author = {Jacquinet-Husson, N. and Armante, R. and Scott, N.A. and Chédin, A. and Crépeau, L. and Boutammine, C. and Bouhdaoui, A. and Crevoisier, C. and Capelle, V. and Boonne, C. and Poulet-Crovisier, N. and Barbe, A. and Chris Benner, D. and Boudon, V. and Brown, L.R. and Buldyreva, J. and Campargue, A. and Coudert, L.H. and Devi, V.M. and Down, M.J. and Drouin, B.J. and Fayt, A. and Fittschen, C. and Flaud, J.-M. and Gamache, R.R. and Harrison, J.J. and Hill, C. and Hodnebrog, Ø. and Hu, S.-M. and Jacquemart, D. and Jolly, A. and Jiménez, E. and Lavrentieva, N.N. and Liu, A.-W. and Lodi, L. and Lyulin, O.M. and Massie, S.T. and Mikhailenko, S. and Müller, H.S.P. and Naumenko, O.V. and Nikitin, A. and Nielsen, C.J. and Orphal, J. and Perevalov, V.I. and Perrin, A. and Polovtseva, E. and Predoi-Cross, A. and Rotger, M. and Ruth, A.A. and Yu, S.S. and Sung, K. and Tashkun, S.A. and Tennyson, J. and Tyuterev, Vl.G. and Vander Auwera, J. and Voronin, B.A. and Makie, A.}, title = {The 2015 edition of the GEISA spectroscopic database}, journal = {Journal of Molecular Spectroscopy}, year = {2016}, volume = {327}, pages = {31 – 72}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jms.2016.06.007} }
Jacquinet-Husson N, Flaud J-M, Gamache RR, Predoi-Cross A and Vander Auwera J (2016), "New visions of spectroscopic databases: An introduction to the special issue", Journal of Molecular Spectroscopy. Vol. 326, pp. 1 – 4. [BibTeX] [DOI]
BibTeX: @article{JacquinetHusson2016a, author = {Jacquinet-Husson, Nicole and Flaud, Jean-Marie and Gamache, Robert R. and Predoi-Cross, Adriana and Vander Auwera, J.}, title = {New visions of spectroscopic databases: An introduction to the special issue}, journal = {Journal of Molecular Spectroscopy}, year = {2016}, volume = {326}, pages = {1 – 4}, doi = {10.1016/j.jms.2016.07.006} }
Jönsson P, Radžiute L, Gaigalas G, Godefroid M, Marques J, Brage T, Froese Fischer C and Grant I (2016), "Accurate multiconfiguration calculations of energy levels, lifetimes, and transition rates for the silicon isoelectronic sequence: Ti IX - Ge XIX, Sr XXV, Zr XXVII, Mo XXIX", Astronomy and Astrophysics. Vol. 585 [Abstract] [BibTeX] [DOI]
Abstract: Multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and relativistic configuration interaction (RCI) calculations are performed for states of the 3s23p2, 3s3p3 and 3s23p3d configurations in the Si-like ions Ti IX - Ge XIX, Sr XXV, Zr XXVII and Mo XXIX. Valence and core-valence electron correlation effects are accounted for through large configuration state function expansions. Calculated energy levels are compared with data from other calculations and with experimental data from the reference databases. Lifetime and transition rates along with uncertainty estimations are given for all ions. Energies from the calculations are in excellent agreement with observations and computed wavelength are almost of spectroscopic accuracy, aiding line identification in spectra. © 2015 ESO.
BibTeX: @article{Joensson2016, author = {Jönsson, P. and Radžiute, L. and Gaigalas, G. and Godefroid, M.R. and Marques, J.P. and Brage, T. and Froese Fischer, C. and Grant, I.P.}, title = {Accurate multiconfiguration calculations of energy levels, lifetimes, and transition rates for the silicon isoelectronic sequence: Ti IX - Ge XIX, Sr XXV, Zr XXVII, Mo XXIX}, journal = {Astronomy and Astrophysics}, year = {2016}, volume = {585}, note = {All Open Access, Bronze Open Access}, doi = {10.1051/0004-6361/201527106} }
Kas M, Loreau J, Liévin J and Vaeck N (2016), "Ab initio study of reactive collisions between Rb(2 S) or Rb(2 P) and OH-(1Σ+)", Journal of Chemical Physics. Vol. 144(20) [Abstract] [BibTeX] [DOI]
Abstract: A theoretical rate constant for the associative detachment reaction Rb(2S) + OH-(1Σ+) → RbOH(1Σ+) + e- of 4 × 10-10 cm3 s-1 at 300 K has been calculated. This result agrees with the experimental rate constant of 2 - 1 + 2 × 1 0 - 10 cm 3 s - 1 obtained by Deiglmayr et al. [Phys. Rev. A 86, 043438 (2012)] for a temperature between 200 K and 600 K. A Langevin-based dynamics which depends on the crossing point between the anion (RbOH-) and neutral (RbOH) potential energy surfaces has been used. The calculations were performed using the ECP28MDF effective core potential to describe the rubidium atom at the CCSD(T) level of theory and extended basis sets. The effect of ECPs and basis set on the height of the crossing point, and hence the rate constant, has been investigated. The temperature dependence of the latter is also discussed. Preliminary work on the potential energy surface for the excited reaction channel Rb(2P) + OH-(1Σ+) calculated at the CASSCF-icMRCI level of theory is presented. We qualitatively discuss the charge transfer and associative detachment reactions arising from this excited entrance channel. © 2016 Author(s).
BibTeX: @article{Kas2016, author = {Kas, Milaim and Loreau, Jérôme and Liévin, Jacques and Vaeck, Nathalie}, title = {Ab initio study of reactive collisions between Rb(2 S) or Rb(2 P) and OH-(1Σ+)}, journal = {Journal of Chemical Physics}, year = {2016}, volume = {144}, number = {20}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.4950784} }
Kremser S, Thomason LW, von Hobe M, Hermann M, Deshler T, Timmreck C, Toohey M, Stenke A, Schwarz JP, Weigel R, Fueglistaler S, Prata FJ, Vernier J-P, Schlager H, Barnes JE, Antuña-Marrero J-C, Fairlie D, Palm M, Mahieu E, Notholt J, Rex M, Bingen C, Vanhellemont F, Bourassa A, Plane JMC, Klocke D, Carn SA, Clarisse L, Trickl T, Neely R, James AD, Rieger L, Wilson JC and Meland B (2016), "Stratospheric aerosol—Observations, processes, and impact on climate", Reviews of Geophysics. Vol. 54(2), pp. 278 – 335. [Abstract] [BibTeX] [DOI]
Abstract: Interest in stratospheric aerosol and its role in climate have increased over the last decade due to the observed increase in stratospheric aerosol since 2000 and the potential for changes in the sulfur cycle induced by climate change. This review provides an overview about the advances in stratospheric aerosol research since the last comprehensive assessment of stratospheric aerosol was published in 2006. A crucial development since 2006 is the substantial improvement in the agreement between in situ and space-based inferences of stratospheric aerosol properties during volcanically quiescent periods. Furthermore, new measurement systems and techniques, both in situ and space based, have been developed for measuring physical aerosol properties with greater accuracy and for characterizing aerosol composition. However, these changes induce challenges to constructing a long-term stratospheric aerosol climatology. Currently, changes in stratospheric aerosol levels less than 20% cannot be confidently quantified. The volcanic signals tend to mask any nonvolcanically driven change, making them difficult to understand. While the role of carbonyl sulfide as a substantial and relatively constant source of stratospheric sulfur has been confirmed by new observations and model simulations, large uncertainties remain with respect to the contribution from anthropogenic sulfur dioxide emissions. New evidence has been provided that stratospheric aerosol can also contain small amounts of nonsulfate matter such as black carbon and organics. Chemistry-climate models have substantially increased in quantity and sophistication. In many models the implementation of stratospheric aerosol processes is coupled to radiation and/or stratospheric chemistry modules to account for relevant feedback processes. ©2016. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Kremser2016, author = {Kremser, Stefanie and Thomason, Larry W. and von Hobe, Marc and Hermann, Markus and Deshler, Terry and Timmreck, Claudia and Toohey, Matthew and Stenke, Andrea and Schwarz, Joshua P. and Weigel, Ralf and Fueglistaler, Stephan and Prata, Fred J. and Vernier, Jean-Paul and Schlager, Hans and Barnes, John E. and Antuña-Marrero, Juan-Carlos and Fairlie, Duncan and Palm, Mathias and Mahieu, Emmanuel and Notholt, Justus and Rex, Markus and Bingen, Christine and Vanhellemont, Filip and Bourassa, Adam and Plane, John M. C. and Klocke, Daniel and Carn, Simon A. and Clarisse, Lieven and Trickl, Thomas and Neely, Ryan and James, Alexander D. and Rieger, Landon and Wilson, James C. and Meland, Brian}, title = {Stratospheric aerosol—Observations, processes, and impact on climate}, journal = {Reviews of Geophysics}, year = {2016}, volume = {54}, number = {2}, pages = {278 – 335}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2015RG000511} }
Li J, Godefroid M and Wang J (2016), "Atomic parameters for the 2p^53p;^2[3/2]-2-2p^53s;^2[3/2]-2^otransition of Ne i relevant in nuclear physics", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 49(11) [Abstract] [BibTeX] [DOI]
Abstract: We calculated the magnetic dipole hyperfine interaction constants and the electric field gradients of and levels of Ne I by using the multiconfiguration Dirac-Hartree-Fock method. The electronic factors contributing to the isotope shifts were also estimated for the transition connecting these two states. Electron correlation and relativistic effects including the Breit interaction were investigated in detail. Combining with recent measurements, we extracted the nuclear quadrupole moment values for 20Ne and 23Ne with a smaller uncertainty than the current available data. Isotope shifts in the transition based on the present calculated field- and mass-shift parameters are in good agreement with the experimental values. However, the field shifts in this transition are two or three orders of magnitude smaller than the mass shifts, making rather difficult to deduce changes in nuclear-charge mean-square radii. According to our theoretical predictions, we suggest using instead transitions connecting levels arising from the 2p53s configuration to the ground state, for which the normal mass shift and specific mass shift contributions counteract each other, producing relatively small mass shifts that are only one order of magnitude larger than relatively large field shifts, especially for the transition. © 2016 IOP Publishing Ltd.
BibTeX: @article{Li2016, author = {Li, Jiguang and Godefroid, Michel and Wang, Jianguo}, title = {Atomic parameters for the 2p^53p;^2[3/2]-2-2p^53s;^2[3/2]-2^otransition of Ne i relevant in nuclear physics}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2016}, volume = {49}, number = {11}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/49/11/115002} }
Lyulin O, Vander Auwera J and Campargue A (2016), "The Fourier transform absorption spectrum of acetylene between 8280 and 8700 cm-1", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 177, pp. 234 – 240. [Abstract] [BibTeX] [DOI]
Abstract: High resolution (0.011 cm-1) room temperature (295 K) Fourier transform absorption spectra (FTS) of acetylene have been analyzed in the 8280-8700 cm-1 range dominated by the ν1+ν2+ν3 band at 8512 cm-1. Line positions and intensities were retrieved from FTS spectra recorded at 3.84 and 56.6 hPa. As a result, a list of 1001 lines was constructed with intensities ranging between about 2×10-26 and 10-22 cm/molecule. Comparison with accurate predictions provided by a global effective operator model led to the assignment of 629 12C2H2 lines. In addition, 114 lines of the 13C12CH2 isotopologue were assigned using information available in the literature. The 12C2H2 lines belong to thirteen bands, nine of which being newly reported. The 13C12CH2 lines belong to three bands, the intensities of which being reported for the first time. Spectroscopic parameters of the 12C2H2 upper vibrational levels were derived from band-by-band analyses of the line positions (typical rms are on the order of 0.002 cm-1). Three of the analyzed bands were found to be affected by rovibrational perturbations, which are discussed in the frame of a global effective Hamiltonian. The obtained line parameters are compared with those of the two bands included in the HITRAN 2012 database. © 2015 Elsevier Ltd.
BibTeX: @article{Lyulin2016, author = {Lyulin, O.M. and Vander Auwera, J. and Campargue, A.}, title = {The Fourier transform absorption spectrum of acetylene between 8280 and 8700 cm-1}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2016}, volume = {177}, pages = {234 – 240}, doi = {10.1016/j.jqsrt.2015.11.026} }
Perrin A, Flaud J-M, Ridolfi M, Vander Auwera J and Carlotti M (2016), "MIPAS database: New HNO3 line parameters at 7.6 μm validated with MIPAS satellite measurements", Atmospheric Measurement Techniques. Vol. 9(5), pp. 2067 – 2076. [Abstract] [BibTeX] [DOI]
Abstract: Improved line positions and intensities have been generated for the 7.6 m spectral region of nitric acid. They were obtained relying on a recent reinvestigation of the nitric acid band system at 7.6 m and comparisons of HNO3 volume mixing ratio profiles retrieved from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) limb emission radiances in the 11 and 7.6 m domains. This has led to an improved database called MIPAS-2015. Comparisons with available laboratory information (individual line intensities, integrated absorption cross sections, and absorption cross sections) show that MIPAS-2015 provides an improved description of the 7.6 m region of nitric acid. This study should help to improve HNO3 satellite retrievals by allowing measurements to be performed simultaneously in the 11 and 7.6 m micro-windows. In particular, it should be useful to analyze existing MIPAS and IASI spectra as well as spectra to be recorded by the forthcoming Infrared Atmospheric Sounding Interferometer-New Generation (IASI-NG) instrument. © 2016 Author(s).
BibTeX: @article{Perrin2016, author = {Perrin, Agnès and Flaud, Jean-Marie and Ridolfi, Marco and Vander Auwera, Jean and Carlotti, Massimo}, title = {MIPAS database: New HNO3 line parameters at 7.6 μm validated with MIPAS satellite measurements}, journal = {Atmospheric Measurement Techniques}, year = {2016}, volume = {9}, number = {5}, pages = {2067 – 2076}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-9-2067-2016} }
Pommier M, Clerbaux C, Coheur P-F, Mahieu E, Müller J-F, Paton-Walsh C, Stavrakou T and Vigouroux C (2016), "HCOOH distributions from IASI for 2008-2014: Comparison with ground-based FTIR measurements and a global chemistry-transport model", Atmospheric Chemistry and Physics. Vol. 16(14), pp. 8963 – 8981. [Abstract] [BibTeX] [DOI]
Abstract: Formic acid (HCOOH) is one of the most abundant volatile organic compounds in the atmosphere. It is a major contributor to rain acidity in remote areas. There are, however, large uncertainties on the sources and sinks of HCOOH and therefore HCOOH is misrepresented by global chemistry-transport models. This work presents global distributions from 2008 to 2014 as derived from the measurements of the Infrared Atmospheric Sounding Interferometer (IASI), based on conversion factors between brightness temperature differences and representative retrieved total columns over seven regions: Northern Africa, southern Africa, Amazonia, Atlantic, Australia, Pacific, and Russia. The dependence of the measured HCOOH signal on the thermal contrast is taken into account in the conversion method. This conversion presents errors lower than 20% for total columns ranging between 0.5 and 1×1016 molec cm-2 but reaches higher values, up to 78 %, for columns that are lower than 0:3×1016 molec cm-2. Signatures from biomass burning events are highlighted, such as in the Southern Hemisphere and in Russia, as well as biogenic emission sources, e.g., over the eastern USA. A comparison between 2008 and 2014 with ground-based Fourier transform infrared spectroscopy (FTIR) measurements obtained at four locations (Maido and Saint-Denis at La Réunion, Jungfraujoch, and Wollongong) is shown. Although IASI columns are found to correlate well with FTIR data, a large bias (> 100 %) is found over the two sites at La Réunion. A better agreement is found at Wollongong with a negligible bias. The comparison also highlights the difficulty of retrieving total columns from IASI measurements over mountainous regions such as Jungfraujoch. A comparison of the retrieved columns with the global chemistry-transport model IMAGESv2 is also presented, showing good representation of the seasonal and interannual cycles over America, Australia, Asia, and Siberia. A global model underestimation of the distribution and a misrepresentation of the seasonal cycle over India are also found. A small positive trend in the IASI columns is observed over Australia, Amazonia, and India over the 2008-2014 period (from 0.7 to 1.5%year-1), while a decrease of ∼0.8% year-1 is measured over Siberia. © Author(s) 2016.
BibTeX: @article{Pommier2016, author = {Pommier, Matthieu and Clerbaux, Cathy and Coheur, Pierre-François and Mahieu, Emmanuel and Müller, Jean-François and Paton-Walsh, Clare and Stavrakou, Trissevgeni and Vigouroux, Corinne}, title = {HCOOH distributions from IASI for 2008-2014: Comparison with ground-based FTIR measurements and a global chemistry-transport model}, journal = {Atmospheric Chemistry and Physics}, year = {2016}, volume = {16}, number = {14}, pages = {8963 – 8981}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-16-8963-2016} }
Popp T, De Leeuw G, Bingen C, Brühl C, Capelle V, Chedin A, Clarisse L, Dubovik O, Grainger R, Griesfeller J, Heckel A, Kinne S, Klüser L, Kosmale M, Kolmonen P, Lelli L, Litvinov P, Mei L, North P, Pinnock S, Povey A, Robert C, Schulz M, Sogacheva L, Stebel K, Zweers DS, Thomas G, Tilstra LG, Vandenbussche S, Veefkind P, Vountas M and Xue Y (2016), "Development, production and evaluation of aerosol climate data records from European satellite observations (Aerosol_cci)", Remote Sensing. Vol. 8(5) [Abstract] [BibTeX] [DOI]
Abstract: Producing a global and comprehensive description of atmospheric aerosols requires integration of ground-based, airborne, satellite and model datasets. Due to its complexity, aerosol monitoring requires the use of several data records with complementary information content. This paper describes the lessons learned while developing and qualifying algorithms to generate aerosol Climate Data Records (CDR) within the European Space Agency (ESA) Aerosol_cci project. An iterative algorithm development and evaluation cycle involving core users is applied. It begins with the application-specific refinement of user requirements, leading to algorithm development, dataset processing and independent validation followed by user evaluation. This cycle is demonstrated for a CDR of total Aerosol Optical Depth (AOD) from two subsequent dual-view radiometers. Specific aspects of its applicability to other aerosol algorithms are illustrated with four complementary aerosol datasets. An important element in the development of aerosol CDRs is the inclusion of several algorithms evaluating the same data to benefit from various solutions to the ill-determined retrieval problem. The iterative approach has produced a 17-year AOD CDR, a 10-year stratospheric extinction profile CDR and a 35-year Absorbing Aerosol Index record. Further evolution cycles have been initiated for complementary datasets to provide insight into aerosol properties (i.e., dust aerosol, aerosol absorption). © 2016 by the authors.
BibTeX: @article{Popp2016, author = {Popp, Thomas and De Leeuw, Gerrit and Bingen, Christine and Brühl, Christoph and Capelle, Virginie and Chedin, Alain and Clarisse, Lieven and Dubovik, Oleg and Grainger, Roy and Griesfeller, Jan and Heckel, Andreas and Kinne, Stefan and Klüser, Lars and Kosmale, Miriam and Kolmonen, Pekka and Lelli, Luca and Litvinov, Pavel and Mei, Linlu and North, Peter and Pinnock, Simon and Povey, Adam and Robert, Charles and Schulz, Michael and Sogacheva, Larisa and Stebel, Kerstin and Zweers, Deborah Stein and Thomas, Gareth and Tilstra, Lieuwe Gijsbert and Vandenbussche, Sophie and Veefkind, Pepijn and Vountas, Marco and Xue, Yong}, title = {Development, production and evaluation of aerosol climate data records from European satellite observations (Aerosol_cci)}, journal = {Remote Sensing}, year = {2016}, volume = {8}, number = {5}, note = {All Open Access, Gold Open Access}, doi = {10.3390/rs8050421} }
Predoi-Cross A, Unni A, Liu W, Schofield I, Holladay C, McKellar A and Hurtmans D (2016), "Corrigendum to "Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing, and speed dependence" [J. Mol. Spectrosc. 245 (2007) 34-51]", Journal of Molecular Spectroscopy. Vol. 322, pp. 55. [BibTeX] [DOI]
BibTeX: @article{PredoiCross2016, author = {Predoi-Cross, A. and Unni, A.V. and Liu, W. and Schofield, I. and Holladay, C. and McKellar, A.R.W. and Hurtmans, D.}, title = {Corrigendum to "Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing, and speed dependence" [J. Mol. Spectrosc. 245 (2007) 34-51]}, journal = {Journal of Molecular Spectroscopy}, year = {2016}, volume = {322}, pages = {55}, doi = {10.1016/j.jms.2015.11.005} }
Quennehen B, Raut J-C, Law K, Daskalakis N, Ancellet G, Clerbaux C, Kim S-W, Lund M, Myhre G, Olivié D, Safieddine S, Skeie R, Thomas J, Tsyro S, Bazureau A, Bellouin N, Hu M, Kanakidou M, Klimont Z, Kupiainen K, Myriokefalitakis S, Quaas J, Rumbold S, Schulz M, Cherian R, Shimizu A, Wang J, Yoon S-C and Zhu T (2016), "Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008", Atmospheric Chemistry and Physics. Vol. 16(17), pp. 10765 – 10792. [Abstract] [BibTeX] [DOI]
Abstract: The ability of seven state-of-the-art chemistry-aerosol models to reproduce distributions of tropospheric ozone and its precursors, as well as aerosols over eastern Asia in summer 2008, is evaluated. The study focuses on the performance of models used to assess impacts of pollutants on climate and air quality as part of the EU ECLIPSE project. Models, run using the same ECLIPSE emissions, are compared over different spatial scales to in situ surface, vertical profiles and satellite data. Several rather clear biases are found between model results and observations, including overestimation of ozone at rural locations downwind of the main emission regions in China, as well as downwind over the Pacific. Several models produce too much ozone over polluted regions, which is then transported downwind. Analysis points to different factors related to the ability of models to simulate VOC-limited regimes over polluted regions and NOx limited regimes downwind. This may also be linked to biases compared to satellite NO2, indicating overestimation of NO2 over and to the north of the northern China Plain emission region. On the other hand, model NO2 is too low to the south and west of this region and over South Korea/Japan. Overestimation of ozone is linked to systematic underestimation of CO particularly at rural sites and downwind of the main Chinese emission regions. This is likely to be due to enhanced destruction of CO by OH. Overestimation of Asian ozone and its transport downwind implies that radiative forcing from this source may be overestimated. Model-observation discrepancies over Beijing do not appear to be due to emission controls linked to the Olympic Games in summer 2008. With regard to aerosols, most models reproduce the satellite-derived AOD patterns over eastern China. Our study nevertheless reveals an overestimation of ECLIPSE model mean surface BC and sulphate aerosols in urban China in summer 2008. The effect of the short-term emission mitigation in Beijing is too weak to explain the differences between the models. Our results rather point to an overestimation of SO2 emissions, in particular, close to the surface in Chinese urban areas. However, we also identify a clear underestimation of aerosol concentrations over northern India, suggesting that the rapid recent growth of emissions in India, as well as their spatial extension, is underestimated in emission inventories. Model deficiencies in the representation of pollution accumulation due to the Indian monsoon may also be playing a role. Comparison with vertical aerosol lidar measurements highlights a general underestimation of scattering aerosols in the boundary layer associated with overestimation in the free troposphere pointing to modelled aerosol lifetimes that are too long. This is likely linked to too strong vertical transport and/or insufficient deposition efficiency during transport or export from the boundary layer, rather than chemical processing (in the case of sulphate aerosols). Underestimation of sulphate in the boundary layer implies potentially large errors in simulated aerosol-cloud interactions, via impacts on boundary-layer clouds. This evaluation has important implications for accurate assessment of air pollutants on regional air quality and global climate based on global model calculations. Ideally, models should be run at higher resolution over source regions to better simulate urban-rural pollutant gradients and/or chemical regimes, and also to better resolve pollutant processing and loss by wet deposition as well as vertical transport. Discrepancies in vertical distributions require further quantification and improvement since these are a key factor in the determination of radiative forcing from short-lived pollutants.
BibTeX: @article{Quennehen2016, author = {Quennehen, B. and Raut, J.-C. and Law, K.S. and Daskalakis, N. and Ancellet, G. and Clerbaux, C. and Kim, S.-W. and Lund, M.T. and Myhre, G. and Olivié, D.J.L. and Safieddine, S. and Skeie, R.B. and Thomas, J.L. and Tsyro, S. and Bazureau, A. and Bellouin, N. and Hu, M. and Kanakidou, M. and Klimont, Z. and Kupiainen, K. and Myriokefalitakis, S. and Quaas, J. and Rumbold, S.T. and Schulz, M. and Cherian, R. and Shimizu, A. and Wang, J. and Yoon, S.-C. and Zhu, T.}, title = {Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008}, journal = {Atmospheric Chemistry and Physics}, year = {2016}, volume = {16}, number = {17}, pages = {10765 – 10792}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-16-10765-2016} }
Robert S, Vandaele A, Thomas I, Willame Y, Daerden F, Delanoye S, Depiesse C, Drummond R, Neefs E, Neary L, Ristic B, Mason J, Lopez-Moreno J-J, Rodriguez-Gomez J, Patel M, Bellucci G, Patel M, Allen M, Altieri F, Aoki S, Bolsée D, Clancy T, Cloutis E, Fedorova A, Formisano V, Funke B, Fussen D, Garcia-Comas M, Geminale A, Gérard J-C, Gillotay D, Giuranna M, Gonzalez-Galindo F, Igna-Tiev N, Kaminski J, Karatekin O, Kasaba Y, Lefèvre F, Lewis S, López-Puertas M, López-Valverde M, Mahieux A, McConnell J, Mumma M, Novak R, Renotte E, Sindoni G, Smith M, Trokhimovskiy A, Vander AJ, Villanueva G, Viscardy S, Whiteway J, Wilquet V, Wolff M, Alonso-Rodrigo G, Aparicio Del Moral B, Barzin P, Benmoussa A, Berkenbosch S, Biondi D, Bonnewijn S, Candini G, Clairquin R, Cubas J, Giordanengo B, Gissot S, Gomez A, Zafra J-J, Leese M, Maes J, Mazy E, Mazzoli A, Meseguer J, Morales R, Orban A, Pastor-Morales M, Perez-Grande I, Saggin B, Samain V, Sanz AA, Sanz R, Simar J-F and Thibert T (2016), "Expected performances of the NOMAD/ExoMars instrument", Planetary and Space Science. Vol. 124, pp. 94 – 104. [Abstract] [BibTeX] [DOI]
Abstract: NOMAD (Nadir and Occultation for MArs Discovery) is one of the four instruments on board the ExoMars Trace Gas Orbiter, scheduled for launch in March 2016. It consists of a suite of three high-resolution spectrometers - SO (Solar Occultation), LNO (Limb, Nadir and Occultation) and UVIS (Ultraviolet and Visible Spectrometer). Based upon the characteristics of the channels and the values of Signal-to-Noise Ratio obtained from radiometric models discussed in (Vandaele et al., 2015a, 2015b; Thomas et al., 2016), the expected performances of the instrument in terms of sensitivity to detection have been investigated. The analysis led to the determination of detection limits for 18 molecules, namely CO, H 2 O, HDO, C 2 H 2 , C 2 H 4 , C 2 H 6 , H 2 CO, CH 4 , SO 2 , H 2 S, HCl, HCN, HO 2 , NH 3 , N 2 O, NO 2 , OCS, O 3 . NOMAD should have the ability to measure methane concentrations < 25 parts per trillion (ppt) in solar occultation mode, and 11 parts per billion in nadir mode. Occultation detections as low as 10 ppt could be made if spectra are averaged (Drummond et al., 2011). Results have been obtained for all three channels in nadir and in solar occultation. © 2016 The Authors. Published by Elsevier Ltd.
BibTeX: @article{Robert2016, author = {Robert, S. and Vandaele, A.C. and Thomas, I. and Willame, Y. and Daerden, F. and Delanoye, S. and Depiesse, C. and Drummond, R. and Neefs, E. and Neary, L. and Ristic, B. and Mason, J. and Lopez-Moreno, J.-J. and Rodriguez-Gomez, J. and Patel, M.R. and Bellucci, G. and Patel, M. and Allen, M. and Altieri, F. and Aoki, S. and Bolsée, D. and Clancy, T. and Cloutis, E. and Fedorova, A. and Formisano, V. and Funke, B. and Fussen, D. and Garcia-Comas, M. and Geminale, A. and Gérard, J.-C. and Gillotay, D. and Giuranna, M. and Gonzalez-Galindo, F. and Igna-Tiev, N. and Kaminski, J. and Karatekin, O. and Kasaba, Y. and Lefèvre, F. and Lewis, S. and López-Puertas, M. and López-Valverde, M. and Mahieux, A. and McConnell, J. and Mumma, M. and Novak, R. and Renotte, E. and Sindoni, G. and Smith, M. and Trokhimovskiy, A. and Vander, Auwera J. and Villanueva, G. and Viscardy, S. and Whiteway, J. and Wilquet, V. and Wolff, M. and Alonso-Rodrigo, G. and Aparicio Del Moral, B. and Barzin, P. and Benmoussa, A. and Berkenbosch, S. and Biondi, D. and Bonnewijn, S. and Candini, G. and Clairquin, R. and Cubas, J. and Giordanengo, B. and Gissot, S. and Gomez, A. and Zafra, J.-J. and Leese, M. and Maes, J. and Mazy, E. and Mazzoli, A. and Meseguer, J. and Morales, R. and Orban, A. and Pastor-Morales, M. and Perez-Grande, I. and Saggin, B. and Samain, V. and Sanz, Andres A. and Sanz, R. and Simar, J.-F. and Thibert, T.}, title = {Expected performances of the NOMAD/ExoMars instrument}, journal = {Planetary and Space Science}, year = {2016}, volume = {124}, pages = {94 – 104}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1016/j.pss.2016.03.003} }
Ronsmans G, Langerock B, Wespes C, Hannigan JW, Hase F, Kerzenmacher T, Mahieu E, Schneider M, Smale D, Hurtmans D, De Mazière M, Clerbaux C and Coheur P-F (2016), "First characterization and validation of FORLI-HNO3 vertical profiles retrieved from IASI/Metop", Atmospheric Measurement Techniques. Vol. 9(9), pp. 4783 – 4801. [Abstract] [BibTeX] [DOI]
Abstract: Knowing the spatial and seasonal distributions of nitric acid (HNO3/ around the globe is of great interest and allows us to comprehend the processes regulating stratospheric ozone, especially in the polar regions. Due to its unprecedented spatial and temporal sampling, the nadir-viewing Infrared Atmospheric Sounding Interferometer (IASI) is capable of sounding the atmosphere twice a day globally, with good spectral resolution and low noise. With the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, we are retrieving, in near real time, columns as well as vertical profiles of several atmospheric species, among which is HNO3. We present in this paper the first characterization of the FORLI-HNO3 profile products, in terms of vertical sensitivity and error budgets. We show that the sensitivity of IASI to HNO3 is highest in the lower stratosphere (10-20 km), where the largest amounts of HNO3 are found, but that the vertical sensitivity of IASI only allows one level of information on the profile (degrees of freedom for signal, DOFS; ∼1). The sensitivity near the surface is negligible in most cases, and for this reason, a partial column (5-35 km) is used for the analyses. Both vertical profiles and partial columns are compared to FTIR ground-based measurements from the Network for the Detection of Atmospheric Composition Change (NDACC) to characterize the accuracy and precision of the FORLI-HNO3 product. The profile validation is conducted through the smoothing of the raw FTIR profiles by the IASI averaging kernels and gives good results, with a slight overestimation of IASI measurements in the upper troposphere/lower stratosphere (UTLS) at the six chosen stations (Thule, Kiruna, Jungfraujoch, Izaña, Lauder and Arrival Heights). The validation of the partial columns (5-35 km) is also conclusive with a mean correlation of 0.93 between IASI and the FTIR measurements. An initial survey of the HNO3 spatial and seasonal variabilities obtained from IASI measurements for a 1-year (2011) data set shows that the expected latitudinal gradient of concentrations from low to high latitudes and the large seasonal variability in polar regions (cycle amplitude around 30% of the seasonal signal, peak to peak) are well represented by IASI data. © Author(s) 2016.
BibTeX: @article{Ronsmans2016, author = {Ronsmans, Gaétane and Langerock, Bavo and Wespes, Catherine and Hannigan, James W. and Hase, Frank and Kerzenmacher, Tobias and Mahieu, Emmanuel and Schneider, Matthias and Smale, Dan and Hurtmans, Daniel and De Mazière, Martine and Clerbaux, Cathy and Coheur, Pierre-François}, title = {First characterization and validation of FORLI-HNO3 vertical profiles retrieved from IASI/Metop}, journal = {Atmospheric Measurement Techniques}, year = {2016}, volume = {9}, number = {9}, pages = {4783 – 4801}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-9-4783-2016} }
Safieddine S, Boynard A, Hao N, Huang F, Wang L, Ji D, Barret B, Ghude SD, Coheur P-F, Hurtmans D and Clerbaux C (2016), "Tropospheric ozone variability during the East Asian summer monsoon as observed by satellite (IASI), aircraft (MOZAIC) and ground stations", Atmospheric Chemistry and Physics. Vol. 16(16), pp. 10489 – 10500. [Abstract] [BibTeX] [DOI]
Abstract: Satellite measurements from the thermal Infrared Atmospheric Sounding Interferometer (IASI), aircraft data from the MOZAIC/IAGOS project, as well as observations from ground-based stations, are used to assess the tropospheric ozone (O3) variability during the East Asian Summer Monsoon (EASM). Six years 2008-2013 of IASI data analysis reveals the ability of the instrument to detect the onset and the progression of the monsoon seen by a decrease in the tropospheric 0-6km O3 column due to the EASM, and to reproduce this decrease from one year to the other. The year-to-year variability is found to be mainly dependent on meteorology. Focusing on the period of May-August 2011, taken as an example year, IASI data show clear inverse relationship between tropospheric 0-6km O3 on one hand and meteorological parameters such as cloud cover, relative humidity and wind speed, on the other hand. Aircraft data from the MOZAIC/IAGOS project for the EASM of 2008-2013 are used to validate the IASI data and to assess the effect of the monsoon on the vertical distribution of the tropospheric O3 at different locations. Results show good agreement with a correlation coefficient of 0.73 (12%) between the 0-6km O3 column derived from IASI and aircraft data. IASI captures very well the inter-annual variation of tropospheric O3 observed by the aircraft data over the studied domain. Analysis of vertical profiles of the aircraft data shows a decrease in the tropospheric O3 that is more important in the free troposphere than in the boundary layer and at 10-20°N than elsewhere. Ground station data at different locations in India and China show a spatiotemporal dependence on meteorology during the monsoon, with a decrease up to 22ppbv in Hyderabad, and up to 5ppbv in the North China Plain. © Author(s) 2016.
BibTeX: @article{Safieddine2016, author = {Safieddine, Sarah and Boynard, Anne and Hao, Nan and Huang, Fuxiang and Wang, Lili and Ji, Dongsheng and Barret, Brice and Ghude, Sachin D. and Coheur, Pierre-Franois and Hurtmans, Daniel and Clerbaux, Cathy}, title = {Tropospheric ozone variability during the East Asian summer monsoon as observed by satellite (IASI), aircraft (MOZAIC) and ground stations}, journal = {Atmospheric Chemistry and Physics}, year = {2016}, volume = {16}, number = {16}, pages = {10489 – 10500}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-16-10489-2016} }
Schiferl LD, Heald CL, Damme MV, Clarisse L, Clerbaux C, Coheur P-F, Nowak JB, Neuman JA, Herndon SC, Roscioli JR and Eilerman SJ (2016), "Interannual variability of ammonia concentrations over the United States: Sources and implications", Atmospheric Chemistry and Physics. Vol. 16(18), pp. 12305 – 12328. [Abstract] [BibTeX] [DOI]
Abstract: The variability of atmospheric ammonia (NH3), emitted largely from agricultural sources, is an important factor when considering how inorganic fine particulate matter (PM2.5) concentrations and nitrogen cycling are changing over the United States. This study combines new observations of ammonia concentration from the surface, aboard aircraft, and retrieved by satellite to both evaluate the simulation of ammonia in a chemical transport model (GEOS-Chem) and identify which processes control the variability of these concentrations over a 5-year period (2008-2012). We find that the model generally underrepresents the ammonia concentration near large source regions (by 26% at surface sites) and fails to reproduce the extent of interannual variability observed at the surface during the summer (JJA). Variability in the base simulation surface ammonia concentration is dominated by meteorology (64%) as compared to reductions in SO2 and NOx emissions imposed by regulation (32%) over this period. Introduction of year-to-year varying ammonia emissions based on animal population, fertilizer application, and meteorologically driven volatilization does not substantially improve the model comparison with observed ammonia concentrations, and these ammonia emissions changes have little effect on the simulated ammonia concentration variability compared to those caused by the variability of meteorology and acid-precursor emissions. There is also little effect on the PM2.5 concentration due to ammonia emissions variability in the summer when gas-phase changes are favored, but variability in wintertime emissions, as well as in early spring and late fall, will have a larger impact on PM2.5 formation. This work highlights the need for continued improvement in both satellite-based and in situ ammonia measurements to better constrain the magnitude and impacts of spatial and temporal variability in ammonia concentrations. © 2016 The Author(s).
BibTeX: @article{Schiferl2016, author = {Schiferl, Luke D. and Heald, Colette L. and Damme, Martin Van and Clarisse, Lieven and Clerbaux, Cathy and Coheur, Pierre-François and Nowak, John B. and Neuman, J. Andrew and Herndon, Scott C. and Roscioli, Joseph R. and Eilerman, Scott J.}, title = {Interannual variability of ammonia concentrations over the United States: Sources and implications}, journal = {Atmospheric Chemistry and Physics}, year = {2016}, volume = {16}, number = {18}, pages = {12305 – 12328}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-16-12305-2016} }
Stavrakou T, Müller J-F, Bauwens M, De Smedt I, Lerot C, Van Roozendael M, Coheur P-F, Clerbaux C, Boersma K, Van Der A and Song Y (2016), "Substantial Underestimation of Post-Harvest Burning Emissions in the North China Plain Revealed by Multi-Species Space Observations", Scientific Reports. Vol. 6 [Abstract] [BibTeX] [DOI]
Abstract: The large-scale burning of crop residues in the North China Plain (NCP), one of the most densely populated world regions, was recently recognized to cause severe air pollution and harmful health effects. A reliable quantification of the magnitude of these fires is needed to assess regional air quality. Here, we use an eight-year record (2005-2012) of formaldehyde measurements from space to constrain the emissions of volatile organic compounds (VOCs) in this region. Using inverse modelling, we derive that satellite-based post-harvest burning fluxes are, on average, at least a factor of 2 higher than state-of-the-art bottom-up statistical estimates, although with significant interannual variability. Crop burning is calculated to cause important increases in surface ozone (+7%) and fine aerosol concentrations (+18%) in the North China Plain in June. The impact of crop fires is also found in satellite observations of other species, glyoxal, nitrogen dioxide and methanol, and we show that those measurements validate the magnitude of the top-down fluxes. Our study indicates that the top-down crop burning fluxes of VOCs in June exceed by almost a factor of 2 the combined emissions from other anthropogenic activities in this region, underscoring the need for targeted actions towards changes in agricultural management practices. © 2016 The Author(s).
BibTeX: @article{Stavrakou2016, author = {Stavrakou, T. and Müller, J.-F. and Bauwens, M. and De Smedt, I. and Lerot, C. and Van Roozendael, M. and Coheur, P.-F. and Clerbaux, C. and Boersma, K.F. and Van Der, A.R. and Song, Y.}, title = {Substantial Underestimation of Post-Harvest Burning Emissions in the North China Plain Revealed by Multi-Species Space Observations}, journal = {Scientific Reports}, year = {2016}, volume = {6}, note = {All Open Access, Gold Open Access}, doi = {10.1038/srep32307} }
Té Y, Jeseck P, Franco B, Mahieu E, Jones N, Paton-Walsh C, Griffith DWT, Buchholz RR, Hadji-Lazaro J, Hurtmans D and Janssen C (2016), "Seasonal variability of surface and column carbon monoxide over the megacity Paris, high-altitude Jungfraujoch and Southern Hemispheric Wollongong stations", Atmospheric Chemistry and Physics. Vol. 16(17), pp. 10911 – 10925. [Abstract] [BibTeX] [DOI]
Abstract: This paper studies the seasonal variation of surface and column CO at three different sites (Paris, Jungfraujoch and Wollongong), with an emphasis on establishing a link between the CO vertical distribution and the nature of CO emission sources. We find the first evidence of a time lag between surface and free tropospheric CO seasonal variations in the Northern Hemisphere. The CO seasonal variability obtained from the total columns and free tropospheric partial columns shows a maximum around March-April and a minimum around September-October in the Northern Hemisphere (Paris and Jungfraujoch). In the Southern Hemisphere (Wollongong) this seasonal variability is shifted by about 6 months. Satellite observations by the IASI-MetOp (Infrared Atmospheric Sounding Interferometer) and MOPITT (Measurements Of Pollution In The Troposphere) instruments confirm this seasonality. Ground-based FTIR (Fourier transform infrared) measurements provide useful complementary information due to good sensitivity in the boundary layer. In situ surface measurements of CO volume mixing ratios at the Paris and Jungfraujoch sites reveal a time lag of the near-surface seasonal variability of about 2 months with respect to the total column variability at the same sites. The chemical transport model GEOS-Chem (Goddard Earth Observing System chemical transport model) is employed to interpret our observations. GEOS-Chem sensitivity runs identify the emission sources influencing the seasonal variation of CO. At both Paris and Jungfraujoch, the surface seasonality is mainly driven by anthropogenic emissions, while the total column seasonality is also controlled by air masses transported from distant sources. At Wollongong, where the CO seasonality is mainly affected by biomass burning, no time shift is observed between surface measurements and total column data. © Author(s) 2016. CC Attribution 3.0 License.
BibTeX: @article{Te2016, author = {Té, Yao and Jeseck, Pascal and Franco, Bruno and Mahieu, Emmanuel and Jones, Nicholas and Paton-Walsh, Clare and Griffith, David W. T. and Buchholz, Rebecca R. and Hadji-Lazaro, Juliette and Hurtmans, Daniel and Janssen, Christof}, title = {Seasonal variability of surface and column carbon monoxide over the megacity Paris, high-altitude Jungfraujoch and Southern Hemispheric Wollongong stations}, journal = {Atmospheric Chemistry and Physics}, year = {2016}, volume = {16}, number = {17}, pages = {10911 – 10925}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-16-10911-2016} }
Thomas I, Vandaele A, Robert S, Neefs E, Drummond R, Daerden F, Delanoye S, Ristic B, Berkenbosch S, Clairquin R, Maes J, Bonnewijn S, Depiesse C, Mahieux A, Trompet L, Neary L, Willame Y, Wilquet V, Nevejans D, Aballea L, Moelans W, De Vos L, Lesschaeve S, Van Vooren N, Lopez-Moreno J-J, Patel M, Bellucci G, Allen M, Altieri F, Aoki S, Bolsée D, Clancy T, Cloutis E, Fedorova A, Formisano V, Funke B, Fussen D, Garcia-Comas M, Geminale A, Gérard J-C, Gillotay D, Giuranna M, Gonzalez-Galindo F, Ignatiev N, Kaminski J, Karatekin O, Kasaba Y, Lefèvre F, Lewis S, López-Puertas M, López-Valverde M, Mason J, McConnell J, Mumma M, Novak R, Renotte E, Sindoni G, Smith M, Trokhimovsky S, Vander Auwera J, Villanueva G, Whiteway J, Wolff M, Alonso-Rodrigo G, Aparicio Del Moral B, Barzin P, BenMoussa A, Biondi D, Candini GP, Cubas J, Giordanengo B, Gissot S, Gomez A, Zafra J-J, Leese M, Mazy E, Mazzoli A, Meseguer J, Morales R, Orban A, Pastor-Morales MDC, Perez-Grande I, Rodriguez-Gomez J, Saggin B, Samain V, Sanz Andres A, Sanz R, Simar J-F and Thibert T (2016), "Optical and radiometric models of the NOMAD instrument Part II: The infrared channels - SO and LNO", Optics Express. Vol. 24(4), pp. 3790 – 3805. [Abstract] [BibTeX] [DOI]
Abstract: NOMAD is a suite of three spectrometers that will be launched in 2016 as part of the joint ESA-Roscosmos ExoMars Trace Gas Orbiter mission. The instrument contains three channels that cover the IR and UV spectral ranges and can perform solar occultation, nadir and limb observations, to detect and map a wide variety of Martian atmospheric gases and trace species. Part I of this work described the models of the UVIS channel; in this second part, we present the optical models representing the two IR channels, SO (Solar Occultation) and LNO (Limb, Nadir and Occultation), and use them to determine signal to noise ratios (SNRs) for many expected observational cases. In solar occultation mode, both the SO and LNO channel exhibit very high SNRs >5000. SNRs of around 100 were found for the LNO channel in nadir mode, depending on the atmospheric conditions, Martian surface properties, and observation geometry. © 2016 Optical Society of America.
BibTeX: @article{Thomas2016, author = {Thomas, I.R. and Vandaele, A.C. and Robert, S. and Neefs, E. and Drummond, R. and Daerden, F. and Delanoye, S. and Ristic, B. and Berkenbosch, S. and Clairquin, R. and Maes, J. and Bonnewijn, S. and Depiesse, C. and Mahieux, A. and Trompet, L. and Neary, L. and Willame, Y. and Wilquet, V. and Nevejans, D. and Aballea, L. and Moelans, W. and De Vos, L. and Lesschaeve, S. and Van Vooren, N. and Lopez-Moreno, J.-J. and Patel, M.R. and Bellucci, G. and Allen, Mark and Altieri, Francesca and Aoki, Shohei and Bolsée, David and Clancy, Todd and Cloutis, Edward and Fedorova, Anna and Formisano, Vittorio and Funke, Bernd and Fussen, Didier and Garcia-Comas, Maya and Geminale, Anna and Gérard, Jean-Claude and Gillotay, Didier and Giuranna, Marco and Gonzalez-Galindo, Francisco and Ignatiev, Nicolai and Kaminski, Jacek and Karatekin, Ozgur and Kasaba, Yasumasa and Lefèvre, Franck and Lewis, Stephen and López-Puertas, Manuel and López-Valverde, Miguel and Mason, Jon and McConnell, Jack and Mumma, Mike and Novak, Robert and Renotte, Etienne and Sindoni, Giuseppe and Smith, Mike and Trokhimovsky, Sacha and Vander Auwera, Jean and Villanueva, Geronimo and Whiteway, Jim and Wolff, Mike and Alonso-Rodrigo, Gustavo and Aparicio Del Moral, Beatriz and Barzin, Pascal and BenMoussa, Ali and Biondi, David and Candini, Gian Paolo and Cubas, Javier and Giordanengo, Boris and Gissot, Samuel and Gomez, Alejandro and Zafra, Jose-Jeronimo and Leese, Mark and Mazy, Emmanuel and Mazzoli, Alexandra and Meseguer, Jose and Morales, Rafael and Orban, Anne and Pastor-Morales, Maria Del Carmen and Perez-Grande, Isabel and Rodriguez-Gomez, Julio and Saggin, Bortolino and Samain, Valérie and Sanz Andres, Angel and Sanz, Rosario and Simar, Juan-Felipe and Thibert, Tanguy}, title = {Optical and radiometric models of the NOMAD instrument Part II: The infrared channels - SO and LNO}, journal = {Optics Express}, year = {2016}, volume = {24}, number = {4}, pages = {3790 – 3805}, note = {All Open Access, Gold Open Access}, doi = {10.1364/OE.24.003790} }
Vander Auwera J, Boulet C, Carré Y, Kocon L and Hartmann J-M (2016), "Confinement-induced infrared absorption by H2 and N2 gases in a porous silica aerogel", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 182, pp. 193 – 198. [Abstract] [BibTeX] [DOI]
Abstract: Transmission spectra in the fundamental bands of H2 and N2 gas inside the pores of a silica aerogel sample were recorded at room temperature and for several pressures using a Fourier transform spectrometer. They first show that, as the absorption is proportional to the pressure, it is due to the interactions of the molecules with the inner surfaces of the pores and not to the dipole induced during gas-phase molecule-molecule collisions. Furthermore, the analysis of the widths and areas of the observed absorption structures indicate that, for the considered aerogel sample, most of the absorption is likely due to "free" molecules moving within the pores with a weak contribution of adsorbed molecules. © 2016 Elsevier Ltd.
BibTeX: @article{VanderAuwera2016, author = {Vander Auwera, J. and Boulet, C. and Carré, Y. and Kocon, L. and Hartmann, J.-M.}, title = {Confinement-induced infrared absorption by H2 and N2 gases in a porous silica aerogel}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2016}, volume = {182}, pages = {193 – 198}, doi = {10.1016/j.jqsrt.2016.05.032} }
Vegvari C, Cauët E, Hadjichrysanthou C, Lawrence E, Weverling G-J, De Wolf F and Anderson RM (2016), "Using clinical trial simulators to analyse the sources of variance in clinical trials of novel therapies for acute viral infections", PLoS ONE. Vol. 11(6) [Abstract] [BibTeX] [DOI]
Abstract: Background About 90% of drugs fail in clinical development. The question is whether trials fail because of insufficient efficacy of the new treatment, or rather because of poor trial design that is unable to detect the true efficacy. The variance of the measured endpoints is a major, largely underestimated source of uncertainty in clinical trial design, particularly in acute viral infections. We use a clinical trial simulator to demonstrate how a thorough consideration of the variability inherent in clinical trials of novel therapies for acute viral infections can improve trial design. Methods and Findings We developed a clinical trial simulator to analyse the impact of three different types of variation on the outcome of a challenge study of influenza treatments for infected patients, including individual patient variability in the response to the drug, the variance of the measurement procedure, and the variance of the lower limit of quantification of endpoint measurements. In addition, we investigated the impact of protocol variation on clinical trial outcome. We found that the greatest source of variance was inter-individual variability in the natural course of infection. Running a larger phase II study can save up to $38 million, if an unlikely to succeed phase III trial is avoided. In addition, low-sensitivity viral load assays can lead to falsely negative trial outcomes. Conclusions Due to high inter-individual variability in natural infection, the most important variable in clinical trial design for challenge studies of potential novel influenza treatments is the number of participants. 100 participants are preferable over 50. Using more sensitive viral load assays increases the probability of a positive trial outcome, but may in some circumstances lead to false positive outcomes. Clinical trial simulations are powerful tools to identify the most important sources of variance in clinical trials and thereby help improve trial design. © 2016 Vegvari et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
BibTeX: @article{Vegvari2016a, author = {Vegvari, Carolin and Cauët, Emilie and Hadjichrysanthou, Christoforos and Lawrence, Emma and Weverling, Gerrit-Jan and De Wolf, Frank and Anderson, Roy M.}, title = {Using clinical trial simulators to analyse the sources of variance in clinical trials of novel therapies for acute viral infections}, journal = {PLoS ONE}, year = {2016}, volume = {11}, number = {6}, note = {All Open Access, Gold Open Access}, doi = {10.1371/journal.pone.0156622} }
Vegvari C, Hadjichrysanthou C, Cauët E, Lawrence E, Cori A, De Wolf F and Anderson RM (2016), "How can viral dynamics models inform endpoint measures in clinical trials of therapies for acute viral infections?", PLoS ONE. Vol. 11(7) [Abstract] [BibTeX] [DOI]
Abstract: Acute viral infections pose many practical challenges for the accurate assessment of the impact of novel therapies on viral growth and decay. Using the example of influenza A, we illustrate how the measurement of infection-related quantities that determine the dynamics of viral load within the human host, can inform investigators on the course and severity of infection and the efficacy of a novel treatment. We estimated the values of key infection-related quantities that determine the course of natural infection from viral load data, using Markov Chain Monte Carlo methods. The data were placebo group viral load measurements collected during volunteer challenge studies, conducted by Roche, as part of the oseltamivir trials. We calculated the values of the quantities for each patient and the correlations between the quantities, symptom severity and body temperature. The greatest variation among individuals occurred in the viral load peak and area under the viral load curve. Total symptom severity correlated positively with the basic reproductive number. The most sensitive endpoint for therapeutic trials with the goal to cure patients is the duration of infection. We suggest laboratory experiments to obtain more precise estimates of virological quantities that can supplement clinical endpoint measurements. © 2016 Vegvari et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
BibTeX: @article{Vegvari2016, author = {Vegvari, Carolin and Hadjichrysanthou, Christoforos and Cauët, Emilie and Lawrence, Emma and Cori, Anne and De Wolf, Frank and Anderson, Roy M.}, title = {How can viral dynamics models inform endpoint measures in clinical trials of therapies for acute viral infections?}, journal = {PLoS ONE}, year = {2016}, volume = {11}, number = {7}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.1371/journal.pone.0158237} }
Wespes C, Hurtmans D, K Emmons L, Safieddine S, Clerbaux C, Edwards DP and Coheur P-F (2016), "Ozone variability in the troposphere and the stratosphere from the first 6 years of IASI observations (2008-2013)", Atmospheric Chemistry and Physics. Vol. 16(9), pp. 5721 – 5743. [Abstract] [BibTeX] [DOI]
Abstract: In this paper, we assess how daily ozone (O3) measurements from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A platform can contribute to the analyses of the processes driving O3 variability in the troposphere and the stratosphere and, in the future, to the monitoring of long-term trends. The temporal evolution of O3 during the first 6 years of IASI (2008-2013) operation is investigated with multivariate regressions separately in four different layers (ground-300, 300-150, 150-25, 25-3ĝ€hPa), by adjusting to the daily time series averaged in 20° zonal bands, seasonal and linear trend terms along with important geophysical drivers of O3 variation (e.g. solar flux, quasi-biennial oscillation (QBO)). The regression model is shown to perform generally very well with a strong dominance of the annual harmonic terms and significant contributions from O3 drivers, in particular in the equatorial region where the QBO and the solar flux contribution dominate. More particularly, despite the short period of the IASI data set available up to now, two noticeable statistically significant apparent trends are inferred from the daily IASI measurements: a positive trend in the upper stratosphere (e.g. 1.74ĝ€±ĝ€0.77ĝ€DUĝ€yearĝ'1 between 30 and 50°ĝ€S), which is consistent with other studies suggesting a turnaround for stratospheric O3 recovery, and a negative trend in the troposphere at the mid-latitudes and high northern latitudes (e.g. ĝ'0.26ĝ€±ĝ€0.11ĝ€DUĝ€yearĝ'1 between 30 and 50°ĝ€N), especially during summer and probably linked to the impact of decreasing ozone precursor emissions. The impact of the high temporal sampling of IASI on the uncertainty in the determination of O3 trend has been further explored by performing multivariate regressions on IASI monthly averages and on ground-based Fourier transform infrared (FTIR) measurements. © Author(s) 2016. CC Attribution 3.0 License.
BibTeX: @article{Wespes2016, author = {Wespes, Catherine and Hurtmans, Daniel and K Emmons, Louisa and Safieddine, Sarah and Clerbaux, Cathy and Edwards, David P. and Coheur, Pierre-François}, title = {Ozone variability in the troposphere and the stratosphere from the first 6 years of IASI observations (2008-2013)}, journal = {Atmospheric Chemistry and Physics}, year = {2016}, volume = {16}, number = {9}, pages = {5721 – 5743}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-16-5721-2016} }
Whitburn S, Van Damme M, Clarisse L, Bauduin S, Heald C, Hadji-Lazaro J, Hurtmans D, Zondlo M, Clerbaux C and Coheur P-F (2016), "A flexible and robust neural network IASI-NH3 retrieval algorithm", Journal of Geophysical Research. Vol. 121(11), pp. 6581 – 6599. [Abstract] [BibTeX] [DOI]
Abstract: In this paper, we describe a new flexible and robust NH3 retrieval algorithm from measurements of the Infrared Atmospheric Sounding Interferometer (IASI). The method is based on the calculation of a spectral hyperspectral range index (HRI) and subsequent conversion to NH3 columns via a neural network. It is an extension of the method presented in Van Damme et al. (2014a) who used lookup tables (LUT) for the radiance-concentration conversion. The new method inherits the advantages of the LUT-based method while providing several significant improvements. These include the following: (1) Complete temperature and humidity vertical profiles can be accounted for. (2) Third-party NH3 vertical profile information can be used. (3) Reported positive biases of LUT retrieval are reduced, and finally (4) a full measurement uncertainty characterization is provided. A running theme in this study, related to item (2), is the importance of the assumed vertical NH3 profile. We demonstrate the advantages of allowing variable profile shapes in the retrieval. As an example, we analyze how the retrievals change when all NH3 is assumed to be confined to the boundary layer. We analyze different averaging procedures in use for NH3 in the literature, introduced to cope with the variable measurement sensitivity and derive global averaged distributions for the year 2013. A comparison with a GEOS-Chem modeled global distribution is also presented, showing a general good correspondence (within ±3×1015 molecules.cm-2) over most of the Northern Hemisphere. However, IASI finds mean columns about 1-1.5×1016 molecules.cm-2 (∼50-60%) lower than GEOS-Chem for India and the North China plain. © 2016. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Whitburn2016, author = {Whitburn, S. and Van Damme, M. and Clarisse, L. and Bauduin, S. and Heald, C.L. and Hadji-Lazaro, J. and Hurtmans, D. and Zondlo, M.A. and Clerbaux, C. and Coheur, P.-F.}, title = {A flexible and robust neural network IASI-NH3 retrieval algorithm}, journal = {Journal of Geophysical Research}, year = {2016}, volume = {121}, number = {11}, pages = {6581 – 6599}, note = {All Open Access, Green Open Access}, doi = {10.1002/2016JD024828} }
Baldassarre G, Pozzoli L, Schmidt C, Unal A, Kindap T, Menzel W, Whitburn S, Coheur P-F, Kavgaci A and Kaiser J (2015), "Using SEVIRI fire observations to drive smoke plumes in the CMAQ air quality model: A case study over Antalya in 2008", Atmospheric Chemistry and Physics. Vol. 15(14), pp. 8539 – 8558. [Abstract] [BibTeX] [DOI]
Abstract: Among the atmospheric emission sources, wildfires are episodic events characterized by large spatial and temporal variability. Therefore, accurate information on gaseous and aerosol emissions from fires for specific regions and seasons is critical for air quality forecasts. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) in geostationary orbit provides fire observations over Africa and the Mediterranean with a temporal resolution of 15 min. It thus resolves the complete fire life cycle and captures the fires' peak intensities, which is not possible in Moderate Resolution Imaging Spectroradiometer (MODIS) fire emission inventories like the Global Fire Assimilation System (GFAS). We evaluate two different operational fire radiative power (FRP) products derived from SEVIRI, by studying a large forest fire in Antalya, Turkey, in July-August 2008. The EUMETSAT Land Surface Analysis Satellite Applications Facility (LSA SAF) has higher FRP values during the fire episode than the Wildfire Automated Biomass Burning Algorithm (WF-ABBA). It is also in better agreement with the co-located, gridded MODIS FRP. Both products miss small fires that frequently occur in the region and are detected by MODIS. Emissions are derived from the FRP products. They are used along-side GFAS emissions in smoke plume simulations with the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model. In comparisons with MODIS aerosol optical thickness (AOT) and Infrared Atmospheric Sounding Interferometer (IASI), CO and NH3 observations show that including the diurnal variability of fire emissions improves the spatial distribution and peak concentrations of the simulated smoke plumes associated with this large fire. They also show a large discrepancy between the currently available operational FRP products, with the LSA SAF being the most appropriate. © Author(s) 2015.
BibTeX: @article{Baldassarre2015, author = {Baldassarre, G. and Pozzoli, L. and Schmidt, C.C. and Unal, A. and Kindap, T. and Menzel, W.P. and Whitburn, S. and Coheur, P.-F. and Kavgaci, A. and Kaiser, J.W.}, title = {Using SEVIRI fire observations to drive smoke plumes in the CMAQ air quality model: A case study over Antalya in 2008}, journal = {Atmospheric Chemistry and Physics}, year = {2015}, volume = {15}, number = {14}, pages = {8539 – 8558}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-15-8539-2015} }
Barré J, Gaubert B, Arellano AFJ, Worden HM, Edwards DP, Deeter MN, Anderson JL, Raeder K, Collins N, Tilmes S, Francis G, Clerbaux C, Emmons LK, Pfister GG, Coheur P-F and Hurtmans D (2015), "Assessing the impacts of assimilating IASI and MOPITT CO retrievals using CESM-CAM-chem and DART", Journal of Geophysical Research. Vol. 120(19), pp. 10501 – 10529. [Abstract] [BibTeX] [DOI]
Abstract: We show the results and evaluation with independent measurements from assimilating both MOPITT (Measurements Of Pollution In The Troposphere) and IASI (Infrared Atmospheric Sounding Interferometer) retrieved profiles into the Community Earth System Model (CESM). We used the Data Assimilation Research Testbed ensemble Kalman filter technique, with the full atmospheric chemistry CESM component Community Atmospheric Model with Chemistry. We first discuss the methodology and evaluation of the current data assimilation system with coupled meteorology and chemistry data assimilation. The different capabilities of MOPITT and IASI retrievals are highlighted, with particular attention to instrument vertical sensitivity and coverage and how these impact the analyses. MOPITT and IASI CO retrievals mostly constrain the CO fields close to the main anthropogenic, biogenic, and biomass burning CO sources. In the case of IASI CO assimilation, we also observe constraints on CO far from the sources. During the simulation time period (June and July 2008), CO assimilation of both instruments strongly improves the atmospheric CO state as compared to independent observations, with the higher spatial coverage of IASI providing better results on the global scale. However, the enhanced sensitivity of multispectral MOPITT observations to near surface CO over the main source regions provides synergistic effects at regional scales. © 2015. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Barre2015, author = {Barré, Jérôme and Gaubert, Benjamin and Arellano, Avelino F. J. and Worden, Helen M. and Edwards, David P. and Deeter, Merritt N. and Anderson, Jeffrey L. and Raeder, Kevin and Collins, Nancy and Tilmes, Simone and Francis, Gene and Clerbaux, Cathy and Emmons, Louisa K. and Pfister, Gabriele G. and Coheur, Pierre-François and Hurtmans, Daniel}, title = {Assessing the impacts of assimilating IASI and MOPITT CO retrievals using CESM-CAM-chem and DART}, journal = {Journal of Geophysical Research}, year = {2015}, volume = {120}, number = {19}, pages = {10501 – 10529}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2015JD023467} }
Berger G, Gelbcke M, Cauët E, Luhmer M, Nève J and Dufrasne F (2015), "Erratum:Corrigendum to "synthesis of 15N-labeled vicinal diamines through N-activated chiral aziridines: Tools for the NMR study of platinum-based anticancer compounds" (Tetrahedron Letters (2013) 54 (545-548) doi:10.1016/j.tetlet.2014.11.086))", Tetrahedron Letters. Vol. 56(2), pp. 485. [BibTeX] [DOI]
BibTeX: @article{Berger2015, author = {Berger, Gilles and Gelbcke, Michel and Cauët, Emilie and Luhmer, Michel and Nève, Jean and Dufrasne, François}, title = {Erratum:Corrigendum to "synthesis of 15N-labeled vicinal diamines through N-activated chiral aziridines: Tools for the NMR study of platinum-based anticancer compounds" (Tetrahedron Letters (2013) 54 (545-548) doi:10.1016/j.tetlet.2014.11.086))}, journal = {Tetrahedron Letters}, year = {2015}, volume = {56}, number = {2}, pages = {485}, doi = {10.1016/j.tetlet.2014.11.086} }
Boichu M, Clarisse L, Péré J-C, Herbin H, Goloub P, Thieuleux F, Ducos F, Clerbaux C and Tanré D (2015), "Temporal variations of flux and altitude of sulfur dioxide emissions during volcanic eruptions: Implications for long-range dispersal of volcanic clouds", Atmospheric Chemistry and Physics. Vol. 15(14), pp. 8381 – 8400. [Abstract] [BibTeX] [DOI]
Abstract: Sulfur-rich degassing, which is mostly composed of sulfur dioxide (SO2), plays a major role in the overall impact of volcanism on the atmosphere and climate. The accurate assessment of this impact is currently hampered by the poor knowledge of volcanic SO2 emissions. Here, using an inversion procedure, we show how assimilating snapshots of the volcanic SO2 load derived from the Infrared Atmospheric Sounding Interferometer (IASI) allows for reconstructing both the flux and altitude of the SO2 emissions with an hourly resolution. For this purpose, the regional chemistry-transport model CHIMERE is used to describe the dispersion of SO2 when released in the atmosphere. As proof of concept, we study the 10 April 2011 eruption of the Etna volcano (Italy), which represents one of the few volcanoes instrumented on the ground for the continuous monitoring of SO2 degassing. We find that the SO2 flux time-series retrieved from satellite imagery using the inverse scheme is in agreement with ground observations during ash-poor phases of the eruption. However, large discrepancies are observed during the ash-rich paroxysmal phase as a result of enhanced plume opacity affecting ground-based ultraviolet (UV) spectroscopic retrievals. As a consequence, the SO2 emission rate derived from the ground is underestimated by almost one order of magnitude. Altitudes of the SO2 emissions predicted by the inverse scheme are validated against an RGB image of the Moderate Resolution Imaging Spectroradiometer (MODIS) capturing the near-source atmospheric pathways followed by Etna plumes, in combination with forward trajectories from the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. At a large distance from the source, modelled SO2 altitudes are compared with independent information on the volcanic cloud height. We find that the altitude predicted by the inverse scheme is in agreement with snapshots of the SO2 height retrieved from recent algorithms exploiting the high spectral resolution of IASI. The validity of the modelled SO2 altitude is further confirmed by the detection of a layer of particles at the same altitude by the spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Analysis of CALIOP colour and depolarization ratios suggests that these particles consist of sulfate aerosols formed from precursory volcanic SO2. The reconstruction of emission altitude, through inversion procedures which assimilate volcanic SO2 column amounts, requires specific meteorological conditions, especially sufficient wind shear so that gas parcels emitted at different altitudes follow distinct trajectories. We consequently explore the possibility and limits of assimilating in inverse schemes infrared (IR) imagery of the volcanic SO2 cloud altitude which will render the inversion procedure independent of the wind shear prerequisite. © Author(s) 2015.
BibTeX: @article{Boichu2015, author = {Boichu, M. and Clarisse, L. and Péré, J.-C. and Herbin, H. and Goloub, P. and Thieuleux, F. and Ducos, F. and Clerbaux, C. and Tanré, D.}, title = {Temporal variations of flux and altitude of sulfur dioxide emissions during volcanic eruptions: Implications for long-range dispersal of volcanic clouds}, journal = {Atmospheric Chemistry and Physics}, year = {2015}, volume = {15}, number = {14}, pages = {8381 – 8400}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-15-8381-2015} }
Bonne J-L, Steen-Larsen HC, Risi C, Werner M, Sodemann H, Lacour J-L, Fettweis X, Cesana G, Delmotte M, Cattani O, Vallelonga P, Kjær HA, Clerbaux C, Sveinbjörnsdóttir ÁE and Masson-Delmotte V (2015), "The summer 2012 Greenland heat wave: In situ and remote sensing observations of water vapor isotopic composition during an atmospheric river event", Journal of Geophysical Research. Vol. 120(7), pp. 2970 – 2989. [Abstract] [BibTeX] [DOI]
Abstract: During 7-12 July 2012, extreme moist and warm conditions occurred over Greenland, leading to widespread surface melt. To investigate the physical processes during the atmospheric moisture transport of this event, we study the water vapor isotopic composition using surface in situ observations in Bermuda Island, South Greenland coast (Ivittuut), and northwest Greenland ice sheet (NEEM), as well as remote sensing observations (Infrared Atmospheric Sounding Interferometer (IASI) instrument on board MetOp-A), depicting propagation of similar surface and midtropospheric humidity and δD signals. Simulations using Lagrangian moisture source diagnostic and water tagging in a regional model showed that Greenland was affected by an atmospheric river transporting moisture from the western subtropical North Atlantic Ocean, which is coherent with observations of snow pit impurities deposited at NEEM. At Ivittuut, surface air temperature, humidity, and δD increases are observed. At NEEM, similar temperature increase is associated with a large and long-lasting 100‰δD enrichment and 15‰ deuterium excess decrease, thereby reaching Ivittuut level. We assess the simulation of this event in two isotope-enabled atmospheric general circulation models (LMDz-iso and ECHAM5-wiso). LMDz-iso correctly captures the timing of propagation for this event identified in IASI data but depict too gradual variations when compared to surface data. Both models reproduce the surface meteorological and isotopic values during the event but underestimate the background deuterium excess at NEEM. Cloud liquid water content parametrization in LMDz-iso poorly impacts the vapor isotopic composition. Our data demonstrate that during this atmospheric river event the deuterium excess signal is conserved from the moisture source to northwest Greenland. © 2015. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Bonne2015, author = {Bonne, Jean-Louis and Steen-Larsen, Hans Christian and Risi, Camille and Werner, Martin and Sodemann, Harald and Lacour, Jean-Lionel and Fettweis, Xavier and Cesana, Grégory and Delmotte, Marc and Cattani, Olivier and Vallelonga, Paul and Kjær, Helle Astrid and Clerbaux, Cathy and Sveinbjörnsdóttir, Árny Erla and Masson-Delmotte, Valérie}, title = {The summer 2012 Greenland heat wave: In situ and remote sensing observations of water vapor isotopic composition during an atmospheric river event}, journal = {Journal of Geophysical Research}, year = {2015}, volume = {120}, number = {7}, pages = {2970 – 2989}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2014JD022602} }
Clerbaux C, Hadji-Lazaro J, Turquety S, George M, Boynard A, Pommier M, Safieddine S, Coheur P-F, Hurtmans D, Clarisse L and Van Damme M (2015), "Tracking pollutants from space: Eight years of IASI satellite observation", Comptes Rendus - Geoscience. Vol. 347(3), pp. 134 – 144. [Abstract] [BibTeX] [DOI]
Abstract: The IASI mission flying onboard the MetOp satellites has been providing global observations of the air composition twice a day since 2007. From the atmospheric spectra recorded by the instruments in the thermal infrared spectral range, concentrations of a series of trace gases can be monitored, enhanced levels of pollution can be detected, and particle types can be determined to some extent. This paper recalls the historical context for the IASI remote sensor, reviews its capability to observe some key species for global and regional pollution monitoring, and reports on information services that benefit from the mission. © 2015 Academie des sciences
BibTeX: @article{Clerbaux2015, author = {Clerbaux, Cathy and Hadji-Lazaro, Juliette and Turquety, Solène and George, Maya and Boynard, Anne and Pommier, Matthieu and Safieddine, Sarah and Coheur, Pierre-François and Hurtmans, Daniel and Clarisse, Lieven and Van Damme, Martin}, title = {Tracking pollutants from space: Eight years of IASI satellite observation}, journal = {Comptes Rendus - Geoscience}, year = {2015}, volume = {347}, number = {3}, pages = {134 – 144}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.crte.2015.06.001} }
Dammers E, Vigouroux C, Palm M, Mahieu E, Warneke T, Smale D, Langerock B, Franco B, Van Damme M, Schaap M, Notholt J and Erisman J (2015), "Retrieval of ammonia from ground-based FTIR solar spectra", Atmospheric Chemistry and Physics. Vol. 15(22), pp. 12789 – 12803. [Abstract] [BibTeX] [DOI]
Abstract: We present a retrieval method for ammonia (NH3) total columns from ground-based Fourier transform infrared (FTIR) observations. Observations from Bremen (53.10° N, 8.85° E), Lauder (45.04° S, 169.68° E), Reúnion (20.9° S, 55.50° E) and Jungfraujoch (46.55° N, 7.98° E) were used to illustrate the capabilities of the method. NH3 mean total columns ranging 3 orders of magnitude were obtained, with higher values at Bremen (mean of 13.47 × 1015 molecules cm-2) and lower values at Jungfraujoch (mean of 0.18 × 1015 molecules cm-2). In conditions with high surface concentrations of ammonia, as in Bremen, it is possible to retrieve information on the vertical gradient, as two layers can be distinguished. The retrieval there is most sensitive to ammonia in the planetary boundary layer, where the trace gas concentration is highest. For conditions with low concentrations, only the total column can be retrieved. Combining the systematic and random errors we have a mean total error of 26 % for all spectra measured at Bremen (number of spectra (N)= 554), 30 % for all spectra from Lauder (N = 2412), 25 % for spectra from Reúnion (N = 1262) and 34 % for spectra measured at Jungfraujoch (N = 2702). The error is dominated by the systematic uncertainties in the spectroscopy parameters. Station-specific seasonal cycles were found to be consistent with known seasonal cycles of the dominant ammonia sources in the station surroundings. The developed retrieval methodology from FTIR instruments provides a new way of obtaining highly time-resolved measurements of ammonia burdens. FTIR-NH3 observations will be useful for understanding the dynamics of ammonia concentrations in the atmosphere and for satellite and model validation. It will also provide additional information to constrain the global ammonia budget. © 2015 Author(s).
BibTeX: @article{Dammers2015, author = {Dammers, E. and Vigouroux, C. and Palm, M. and Mahieu, E. and Warneke, T. and Smale, D. and Langerock, B. and Franco, B. and Van Damme, M. and Schaap, M. and Notholt, J. and Erisman, J.W.}, title = {Retrieval of ammonia from ground-based FTIR solar spectra}, journal = {Atmospheric Chemistry and Physics}, year = {2015}, volume = {15}, number = {22}, pages = {12789 – 12803}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-15-12789-2015} }
Doniki S, Hurtmans D, Clarisse L, Clerbaux C, Worden H, Bowman K and Coheur P-F (2015), "Instantaneous longwave radiative impact of ozone: An application on IASI/MetOp observations", Atmospheric Chemistry and Physics. Vol. 15(22), pp. 12971 – 12987. [Abstract] [BibTeX] [DOI]
Abstract: Ozone is an important greenhouse gas in terms of anthropogenic radiative forcing (RF). RF calculations for ozone were until recently entirely model based, and significant discrepancies were reported due to different model characteristics. However, new instantaneous radiative kernels (IRKs) calculated from hyperspectral thermal IR satellites have been able to help adjudicate between different climate model RF calculations. IRKs are defined as the sensitivity of the outgoing longwave radiation (OLR) flux with respect to the ozone vertical distribution in the full 9.6 μm band. Previous methods applied to measurements from the Tropospheric Emission Spectrometer (TES) on Aura rely on an anisotropy approximation for the angular integration. In this paper, we present a more accurate but more computationally expensive method to calculate these kernels. The method of direct integration is based on similar principles to the anisotropy approximation, but it deals more precisely with the integration of the Jacobians. We describe both methods and highlight their differences with respect to the IRKs and the ozone longwave radiative effect (LWRE), i.e., the radiative impact in OLR due to absorption by ozone, for both tropospheric and total columns, from measurements of the Infrared Atmospheric Sounding Interferometer (IASI) onboard MetOp-A. Biases between the two methods vary from -25 to +20 % for the LWRE, depending on the viewing angle. These biases point to the inadequacy of the anisotropy method, especially at nadir, suggesting that the TES-derived LWREs are biased low by around 25 % and that chemistry-climate model OLR biases with respect to TES are underestimated. In this paper we also exploit the sampling performance of IASI to obtain first daily global distributions of the LWRE, for 12 days (the 15th of each month) in 2011, calculated with the direct integration method. We show that the temporal variation of global and latitudinal averages of the LWRE shows patterns which are controlled by changes in the surface temperature and ozone variation due to specific processes, such as the ozone hole in the polar regions and stratospheric intrusions into the troposphere. © Author(s) 2015.
BibTeX: @article{Doniki2015, author = {Doniki, S. and Hurtmans, D. and Clarisse, L. and Clerbaux, C. and Worden, H.M. and Bowman, K.W. and Coheur, P.-F.}, title = {Instantaneous longwave radiative impact of ozone: An application on IASI/MetOp observations}, journal = {Atmospheric Chemistry and Physics}, year = {2015}, volume = {15}, number = {22}, pages = {12971 – 12987}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-15-12971-2015} }
Duflot V, Wespes C, Clarisse L, Hurtmans D, Ngadi Y, Jones N, Paton-Walsh C, Hadji-Lazaro J, Vigouroux C, De Mazière M, Metzger J-M, Mahieu E, Servais C, Hase F, Schneider M, Clerbaux C and Coheur P-F (2015), "Acetylene (C2H2) and hydrogen cyanide (HCN) from IASI satellite observations: Global distributions, validation, and comparison with model", Atmospheric Chemistry and Physics. Vol. 15(18), pp. 10509 – 10527. [Abstract] [BibTeX] [DOI]
Abstract: We present global distributions of C2H2 and hydrogen cyanide (HCN) total columns derived from the Infrared Atmospheric Sounding Interferometer (IASI) for the years 2008-2010. These distributions are obtained with a fast method allowing to retrieve C2H2 abundance globally with a 5 % precision and HCN abundance in the tropical (subtropical) belt with a 10 % (25 %) precision. IASI data are compared for validation purposes with ground-based Fourier transform infrared (FTIR) spectrometer measurements at four selected stations. We show that there is an overall agreement between the ground-based and space measurements with correlation coefficients for daily mean measurements ranging from 0.28 to 0.81, depending on the site. Global C2H2 and subtropical HCN abundances retrieved from IASI spectra show the expected seasonality linked to variations in the anthropogenic emissions and seasonal biomass burning activity, as well as exceptional events, and are in good agreement with previous spaceborne studies. Total columns simulated by the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) are compared to the ground-based FTIR measurements at the four selected stations. The model is able to capture the seasonality in the two species in most of the cases, with correlation coefficients for daily mean measurements ranging from 0.50 to 0.86, depending on the site. IASI measurements are also compared to the distributions from MOZART-4. Seasonal cycles observed from satellite data are reasonably well reproduced by the model with correlation coefficients ranging from g'0.31 to 0.93 for C2H2 daily means, and from 0.09 to 0.86 for HCN daily means, depending on the considered region. However, the anthropogenic (biomass burning) emissions used in the model seem to be overestimated (underestimated), and a negative global mean bias of 1 % (16 %) of the model relative to the satellite observations was found for C2H2 (HCN). © Author(s) 2015.
BibTeX: @article{Duflot2015, author = {Duflot, V. and Wespes, C. and Clarisse, L. and Hurtmans, D. and Ngadi, Y. and Jones, N. and Paton-Walsh, C. and Hadji-Lazaro, J. and Vigouroux, C. and De Mazière, M. and Metzger, J.-M. and Mahieu, E. and Servais, C. and Hase, F. and Schneider, M. and Clerbaux, C. and Coheur, P.-F.}, title = {Acetylene (C2H2) and hydrogen cyanide (HCN) from IASI satellite observations: Global distributions, validation, and comparison with model}, journal = {Atmospheric Chemistry and Physics}, year = {2015}, volume = {15}, number = {18}, pages = {10509 – 10527}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-15-10509-2015} }
Erisman JW, Dammers E, Van Damme M, Soudzilovskaia N and Schaap M (2015), "Trends in EU nitrogen deposition and impacts on ecosystems", EM: Air and Waste Management Association's Magazine for Environmental Managers. Vol. 65(September), pp. 31 – 35. [Abstract] [BibTeX]
Abstract: An overview of the achievements and the current state of knowledge on reactive nitrogen in Europe, focusing on deposition, critical load exceedances, and modeled and measured trends.
BibTeX: @article{Erisman2015, author = {Erisman, Jan Willem and Dammers, Enrico and Van Damme, Martin and Soudzilovskaia, Nadejda and Schaap, Martijn}, title = {Trends in EU nitrogen deposition and impacts on ecosystems}, journal = {EM: Air and Waste Management Association's Magazine for Environmental Managers}, year = {2015}, volume = {65}, number = {September}, pages = {31 – 35} }
Földes T, Lauzin C, Vanfleteren T, Herman M, Liévin J and Didriche K (2015), "High-resolution, near-infrared CW-CRDS, and ab initio investigations of N2O-HDO", Molecular Physics. Vol. 113(5), pp. 473 – 482. [Abstract] [BibTeX] [DOI]
Abstract: We have investigated the N2O-HDO molecular complex using ab initio calculations at the CCSD(T)-F12a/aug-cc-pVTZ level of theory and using cavity ring-down spectroscopy to probe an HDO/N2O/Ar supersonic jet around 1.58 m. A single a-type vibrational band was observed, 13 cm-1 redshifted compared to the OH+OD excited band in HDO, and 173 vibration-rotation lines were assigned (Trot ≈ 20 K). A weighted fit of existing microwave and present near infrared (NIR) data was achieved using a standard Watson's Hamiltonian (σ = 1.26), producing ground and excited states rotational constants. The comparison of the former with those calculated ab initio suggests a planar geometry in which the OD rather than the OH bond in water is almost parallel to NNO. The equilibrium geometry and dissociation energy (De = -11.7 kJ/mol) of the water-nitrous oxide complex were calculated. The calculations further demonstrate and allow characterising another minimum, 404 cm-1 (ΔE0) higher in energy. Harmonic vibrational frequencies and dissociation energies, D0, were calculated for various conformers and isotopic forms of the complex, in both minima. The absence of N2O-D2O from dedicated NIR experiments is reported and discussed. © 2014 Taylor & Francis.
BibTeX: @article{Foeldes2015, author = {Földes, T. and Lauzin, C. and Vanfleteren, T. and Herman, M. and Liévin, J. and Didriche, K.}, title = {High-resolution, near-infrared CW-CRDS, and ab initio investigations of N2O-HDO}, journal = {Molecular Physics}, year = {2015}, volume = {113}, number = {5}, pages = {473 – 482}, doi = {10.1080/00268976.2014.953611} }
Franco B, Bader W, Toon G, Bray C, Perrin A, Fischer E, Sudo K, Boone C, Bovy B, Lejeune B, Servais C and Mahieu E (2015), "Retrieval of ethane from ground-based FTIR solar spectra using improved spectroscopy: Recent burden increase above Jungfraujoch", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 160, pp. 36 – 49. [Abstract] [BibTeX] [DOI]
Abstract: An improved spectroscopy is used to implement and optimize the retrieval strategy of ethane (C2H6) from ground-based Fourier Transform Infrared (FTIR) solar spectra recorded at the high-altitude station of Jungfraujoch (Swiss Alps, 46.5°N, 8.0°E, 3580m a.s.l.). The improved spectroscopic parameters include C2H6 pseudo-lines in the 2720-3100cm-1 range and updated line parameters for methyl chloride and ozone. These improved spectroscopic parameters allow for substantial reduction of the fitting residuals as well as enhanced information content. They also contribute to limiting oscillations responsible for ungeophysical negative mixing ratio profiles. This strategy has been successfully applied to the Jungfraujoch solar spectra available from 1994 onwards. The resulting time series is compared with C2H6 total columns simulated by the state-of-the-art chemical transport model GEOS-Chem. Despite very consistent seasonal cycles between both data sets, a negative systematic bias relative to the FTIR observations suggests that C2H6 emissions are underestimated in the current inventories implemented in GEOS-Chem. Finally, C2H6 trends are derived from the FTIR time series, revealing a statistically-significant sharp increase of the C2H6 burden in the remote atmosphere above Jungfraujoch since 2009. Evaluating cause of this change in the C2H6 burden, which may be related to the recent massive growth of shale gas exploitation in North America, is of primary importance for atmospheric composition and air quality in the Northern Hemisphere. © 2015 Elsevier Ltd.
BibTeX: @article{Franco2015, author = {Franco, B. and Bader, W. and Toon, G.C. and Bray, C. and Perrin, A. and Fischer, E.V. and Sudo, K. and Boone, C.D. and Bovy, B. and Lejeune, B. and Servais, C. and Mahieu, E.}, title = {Retrieval of ethane from ground-based FTIR solar spectra using improved spectroscopy: Recent burden increase above Jungfraujoch}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2015}, volume = {160}, pages = {36 – 49}, doi = {10.1016/j.jqsrt.2015.03.017} }
Franco B, Hendrick F, Van Roozendael M, Müller J-F, Stavrakou T, Marais E, Bovy B, Bader W, Fayt C, Hermans C, Lejeune B, Pinardi G, Servais C and Mahieu E (2015), "Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations", Atmospheric Measurement Techniques. Vol. 8(4), pp. 1733 – 1756. [Abstract] [BibTeX] [DOI]
Abstract: As an ubiquitous product of the oxidation of many volatile organic compounds (VOCs), formaldehyde (HCHO) plays a key role as a short-lived and reactive intermediate in the atmospheric photo-oxidation pathways leading to the formation of tropospheric ozone and secondary organic aerosols. In this study, HCHO profiles have been successfully retrieved from ground-based Fourier transform infrared (FTIR) solar spectra and UV-visible Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) scans recorded during the July 2010–December 2012 time period at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.). Analysis of the retrieved products has revealed different vertical sensitivity between both remote sensing techniques. Furthermore, HCHO amounts simulated by two state-of-the-art chemical transport models (CTMs), GEOS-Chem and IMAGES v2, have been compared to FTIR total columns and MAX-DOAS 3.6–8 km partial columns, accounting for the respective vertical resolution of each ground-based instrument. Using the CTM outputs as the intermediate, FTIR and MAX-DOAS retrievals have shown consistent seasonal modulations of HCHO throughout the investigated period, characterized by summertime maximum and wintertime minimum. Such comparisons have also highlighted that FTIR and MAX-DOAS provide complementary products for the HCHO retrieval above the Jungfraujoch station. Finally, tests have revealed that the updated IR parameters from the HITRAN 2012 database have a cumulative effect and significantly decrease the retrieved HCHO columns with respect to the use of the HITRAN 2008 compilation. © Author(s) 2015.
BibTeX: @article{Franco2015a, author = {Franco, B. and Hendrick, F. and Van Roozendael, M. and Müller, J.-F. and Stavrakou, T. and Marais, E.A. and Bovy, B. and Bader, W. and Fayt, C. and Hermans, C. and Lejeune, B. and Pinardi, G. and Servais, C. and Mahieu, E.}, title = {Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations}, journal = {Atmospheric Measurement Techniques}, year = {2015}, volume = {8}, number = {4}, pages = {1733 – 1756}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-8-1733-2015} }
George M, Clerbaux C, Bouarar I, Coheur P-F, Deeter M, Edwards D, Francis G, Gille J, Hadji-Lazaro J, Hurtmans D, Inness A, Mao D and Worden H (2015), "An examination of the long-term CO records from MOPITT and IASI: Comparison of retrieval methodology", Atmospheric Measurement Techniques. Vol. 8(10), pp. 4313 – 4328. [Abstract] [BibTeX] [DOI]
Abstract: Carbon monoxide (CO) is a key atmospheric compound that can be remotely sensed by satellite on the global scale. Fifteen years of continuous observations are now available from the MOPITT/Terra mission (2000 to present). Another 15 and more years of observations will be provided by the IASI/MetOp instrument series (2007-2023 >). In order to study long-term variability and trends, a homogeneous record is required, which is not straightforward as the retrieved quantities are instrument and processing dependent. The present study aims at evaluating the consistency between the CO products derived from the MOPITT and IASI missions, both for total columns and vertical profiles, during a 6-year overlap period (2008-2013). The analysis is performed by first comparing the available 2013 versions of the retrieval algorithms (v5T for MOPITT and v20100815 for IASI), and second using a dedicated reprocessing of MOPITT CO profiles and columns using the same a priori information as the IASI product. MOPITT total columns are generally slightly higher over land (bias ranging from 0 to 13 %) than IASI data. When IASI and MOPITT data are retrieved with the same a priori constraints, correlation coefficients are slightly improved. Large discrepancies (total column bias over 15 %) observed in the Northern Hemisphere during the winter months are reduced by a factor of 2 to 2.5. The detailed analysis of retrieved vertical profiles compared with collocated aircraft data from the MOZAIC-IAGOS network, illustrates the advantages and disadvantages of a constant vs. a variable a priori. On one hand, MOPITT agrees better with the aircraft profiles for observations with persisting high levels of CO throughout the year due to pollution or seasonal fire activity (because the climatology-based a priori is supposed to be closer to the real atmospheric state). On the other hand, IASI performs better when unexpected events leading to high levels of CO occur, due to a larger variability associated with the a priori. © 2015 Author(s).
BibTeX: @article{George2015, author = {George, M. and Clerbaux, C. and Bouarar, I. and Coheur, P.-F. and Deeter, M.N. and Edwards, D.P. and Francis, G. and Gille, J.C. and Hadji-Lazaro, J. and Hurtmans, D. and Inness, A. and Mao, D. and Worden, H.M.}, title = {An examination of the long-term CO records from MOPITT and IASI: Comparison of retrieval methodology}, journal = {Atmospheric Measurement Techniques}, year = {2015}, volume = {8}, number = {10}, pages = {4313 – 4328}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-8-4313-2015} }
Golebiowski D, Földes T, Vanfleteren T, Herman M and Perrin A (2015), "Complementary cavity-enhanced spectrometers to investigate the OH + CH combination band in trans -formic acid", Journal of Chemical Physics. Vol. 143(1) [Abstract] [BibTeX] [DOI]
Abstract: We have used continuous-wave cavity ring-down and femto-Fourier transform-cavity-enhanced absorption spectrometers to record the spectrum of the OH-stretching + CH-stretching (ν1 + ν2) combination band in trans-formic acid, with origin close to 6507 cm-1. They, respectively, allowed resolving and simplifying the rotational structure of the band near its origin under jet-cooled conditions (Trot = 10 K) and highlighting the overview of the band under room temperature conditions. The stronger B-type and weaker A-type subbands close to the band origin could be assigned, as well as the main B-type Q branches. The high-resolution analysis was hindered by numerous, severe perturbations. Rotational constants are reported with, however, limited physical meaning. The ν1 + ν2 transition moment is estimated from relative intensities to be 24°away from the principal b-axis of inertia. © 2015 AIP Publishing LLC.
BibTeX: @article{Golebiowski2015, author = {Golebiowski, D. and Földes, T. and Vanfleteren, T. and Herman, M. and Perrin, A.}, title = {Complementary cavity-enhanced spectrometers to investigate the OH + CH combination band in trans -formic acid}, journal = {Journal of Chemical Physics}, year = {2015}, volume = {143}, number = {1}, doi = {10.1063/1.4923256} }
Jecko T, Sutcliffe BT and Woolley RG (2015), "On factorization of molecular wavefunctions", Journal of Physics A: Mathematical and Theoretical. Vol. 48(44) [Abstract] [BibTeX] [DOI]
Abstract: Recently there has been a renewed interest in the chemical physics literature of factorization of the position representation eigenfunctions φ of the molecular Schrödinger equation as originally proposed by Hunter in the 1970s. The idea is to represent φ in the form φχ where χ is purely a function of the nuclear coordinates, while φ must depend on both electron and nuclear position variables in the problem. This is a generalization of the approximate factorization originally proposed by Born and Oppenheimer, the hope being that an 'exact' representation of φ can be achieved in this form with φ and χ interpretable as 'electronic' and 'nuclear' wavefunctions respectively. We offer a mathematical analysis of these proposals that identifies ambiguities stemming mainly from the singularities in the Coulomb potential energy. © 2015 IOP Publishing Ltd.
BibTeX: @article{Jecko2015, author = {Jecko, Thierry and Sutcliffe, Brian T. and Woolley, R. Guy}, title = {On factorization of molecular wavefunctions}, journal = {Journal of Physics A: Mathematical and Theoretical}, year = {2015}, volume = {48}, number = {44}, note = {All Open Access, Green Open Access}, doi = {10.1088/1751-8113/48/44/445201} }
Lacour J-L, Clarisse L, Worden J, Schneider M, Barthlott S, Hase F, Risi C, Clerbaux C, Hurtmans D and Coheur P-F (2015), "Cross-validation of IASI/MetOp derived tropospheric δd with TES and ground-based FTIR observations", Atmospheric Measurement Techniques. Vol. 8(3), pp. 1447 – 1466. [Abstract] [BibTeX] [DOI]
Abstract: The Infrared Atmospheric Sounding Interferometer (IASI) flying onboard MetOpA and MetOpB is able to capture fine isotopic variations of the HDO to H2O ratio (δD) in the troposphere. Such observations at the high spatio-temporal resolution of the sounder are of great interest to improve our understanding of the mechanisms controlling humidity in the troposphere. In this study we aim to empirically assess the validity of our error estimation previously evaluated theoretically. To achieve this, we compare IASI δD retrieved profiles with other available profiles of δD, from the TES infrared sounder onboard AURA and from three ground-based FTIR stations produced within the MUSICA project: the NDACC (Network for the Detection of Atmospheric Composition Change) sites Kiruna and Izaña, and the TCCON site Karlsruhe, which in addition to near-infrared TCCON spectra also records mid-infrared spectra. We describe the achievable level of agreement between the different retrievals and show that these theoretical errors are in good agreement with empirical differences. The comparisons are made at different locations from tropical to Arctic latitudes, above sea and above land. Generally IASI and TES are similarly sensitive to δD in the free troposphere which allows one to compare their measurements directly. At tropical latitudes where IASI's sensitivity is lower than that of TES, we show that the agreement improves when taking into account the sensitivity of IASI in the TES retrieval. For the comparison IASI-FTIR only direct comparisons are performed because the sensitivity profiles of the two observing systems do not allow to take into account their differences of sensitivity. We identify a quasi negligible bias in the free troposphere (-3 ‰) between IASI retrieved δD with the TES, which are bias corrected, but important with the ground-based FTIR reaching -47 ‰. We also suggest that model-satellite observation comparisons could be optimized with IASI thanks to its high spatial and temporal sampling. © Author(s) 2015.
BibTeX: @article{Lacour2015, author = {Lacour, J.-L. and Clarisse, L. and Worden, J. and Schneider, M. and Barthlott, S. and Hase, F. and Risi, C. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F.}, title = {Cross-validation of IASI/MetOp derived tropospheric δd with TES and ground-based FTIR observations}, journal = {Atmospheric Measurement Techniques}, year = {2015}, volume = {8}, number = {3}, pages = {1447 – 1466}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-8-1447-2015} }
Lamarre N, Gans B, Alcaraz C, De Miranda BC, Guillemin J-C, Broquier M, Liévin J and Boyé-Péronne S (2015), "Vibronic structure of the 2Π u ground electronic state of dicyanoacetylene cation revisited by PFI-ZEKE photoelectron spectroscopy and ab initio calculations", Molecular Physics. Vol. 113(24), pp. 3946 – 3954. [Abstract] [BibTeX] [DOI]
Abstract: The X+ 2Πu ← X1Σ+ g transition of dicyanoacetylene has been recorded for the first time using pulsed-field-ionisation zero-kinetic-energy photoelectron spectroscopy. The analysis of the photoelectron spectrum allowed an accurate determination of the adiabatic ionisation potential of C4N2 (Ei, ad./hc = 95,479 ± 2 cm-1) and a description of the vibrational structure of the electronic ground state of the cation which is affected by the Renner-Teller effect and the spin-orbit interaction. The spin-orbit coupling constant was measured as -52 ± 2 cm-1. These results are supported by ab initio calculations performed at the complete active space self-consistent field and second-order perturbation theory levels of theory, with extrapolation to the complete basis set limit. © 2015 Taylor and Francis.
BibTeX: @article{Lamarre2015, author = {Lamarre, Nicolas and Gans, Bérenger and Alcaraz, Christian and De Miranda, Barbara Cunha and Guillemin, Jean-Claude and Broquier, Michel and Liévin, Jacques and Boyé-Péronne, Séverine}, title = {Vibronic structure of the 2Π u ground electronic state of dicyanoacetylene cation revisited by PFI-ZEKE photoelectron spectroscopy and ab initio calculations}, journal = {Molecular Physics}, year = {2015}, volume = {113}, number = {24}, pages = {3946 – 3954}, doi = {10.1080/00268976.2015.1075074} }
Lamouroux J, Régalia L, Thomas X, Vander Auwera J, Gamache R and Hartmann J-M (2015), "CO2 line-mixing database and software update and its tests in the 2.1μm and 4.3μm regions", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 151, pp. 88 – 96. [Abstract] [BibTeX] [DOI]
Abstract: An update of the former version of the database and software for the calculation of CO2-air absorption coefficients taking line-mixing into account [Lamouroux et al. J Quant Spectrosc Radiat Transf 2010;111:2321] is described. In this new edition, the data sets were constructed using parameters from the 2012 version of the HITRAN database and recent measurements of line-shape parameters. Among other improvements, speed-dependent profiles can now be used if line-mixing is treated within the first order approximation. This new package is tested using laboratory spectra measured in the 2.1μm and 4.3μm spectral regions for various pressures, temperatures and CO2 concentration conditions. Despite improvements at 4.3μm at room temperature, the conclusions on the quality of this update are more ambiguous at low temperature and in the 2.1μm region. Further tests using laboratory and atmospheric spectra are thus required for the evaluation of the performances of this updated package. © 2014 Elsevier Ltd.
BibTeX: @article{Lamouroux2015, author = {Lamouroux, J. and Régalia, L. and Thomas, X. and Vander Auwera, J. and Gamache, R.R. and Hartmann, J.-M.}, title = {CO2 line-mixing database and software update and its tests in the 2.1μm and 4.3μm regions}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2015}, volume = {151}, pages = {88 – 96}, doi = {10.1016/j.jqsrt.2014.09.017} }
Launoy T, Chabot M, Martinet G, Pino T, Le Padellec A, Bouneau S, Féraud G, Do Thi N, Vaeck N, Liévin J, Loreau J and Béroff K (2015), "Ion-pair dissociation of highly excited carbon clusters, size and charge effects", Journal of Physics: Conference Series. Vol. 635(3) [Abstract] [BibTeX] [DOI]
Abstract: Ion-pair dissociation of a highly excited molecule is a relaxation process giving rise to emission of anionic and cationic fragments. We present first measurements of ion-pair dissociation of carbon clusters. We found that ion- pair relaxation is an ubiquitous, although very small, relaxation channel common to all sizes and charges of Cq+n species produced in high velocity C+n-He collisions. Quantitative interpretation of measured branching ratios is conducted on the basis of a statistical approach i.e through listing of all possible final states. © Published under licence by IOP Publishing Ltd.
BibTeX: @conference{Launoy2015, author = {Launoy, T. and Chabot, M. and Martinet, G. and Pino, T. and Le Padellec, A. and Bouneau, S. and Féraud, G. and Do Thi, N. and Vaeck, N. and Liévin, J. and Loreau, J. and Béroff, K.}, title = {Ion-pair dissociation of highly excited carbon clusters, size and charge effects}, journal = {Journal of Physics: Conference Series}, year = {2015}, volume = {635}, number = {3}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/635/3/032085} }
Launoy T, Vaeck N, Urbain X, Liévin J, Loreau J, Béroff K and Chabot M (2015), "On the reactivity of ion pairs into different diatomic systems", Journal of Physics: Conference Series. Vol. 635(2) [Abstract] [BibTeX] [DOI]
Abstract: Ion pair collisions are an important process in many astrophysical environments. We present ab initio calculations of highly excited states of C2+ and identify the ion pair channel C2+/C-. We use these results to interpret recent experiments on carbon cluster dissociation. © Published under licence by IOP Publishing Ltd.
BibTeX: @conference{Launoy2015a, author = {Launoy, T. and Vaeck, N. and Urbain, X. and Liévin, J. and Loreau, J. and Béroff, K. and Chabot, M.}, title = {On the reactivity of ion pairs into different diatomic systems}, journal = {Journal of Physics: Conference Series}, year = {2015}, volume = {635}, number = {2}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/635/2/022018} }
Lyulin O, Vander Auwera J and Campargue A (2015), "The Fourier transform absorption spectrum of acetylene between 7000 and 7500cm-1", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 160, pp. 85 – 93. [Abstract] [BibTeX] [DOI]
Abstract: High resolution (0.011cm-1) room temperature (295K) Fourier transform absorption spectra (FTS) of acetylene have been recorded between 7000 and 7500cm-1. Line parameters (positions, intensities and self broadening coefficients) have been measured using a multispectrum treatment of three FTS spectra, recorded at 3.84, 8.04 and 56.6hPa. As a result, a list of 3788 lines was constructed with intensities ranging between about 10-26 and 10-22cm/molecule. Comparison with accurate predictions provided by a global effective operator model (Lyulin OM, Perevalov VI, Teffo JL, Proc. SPIE 2004;5311:134-43) led to the assignment of 2471 of these lines to 12C2H2. The assigned lines belong to 29 12C2H2 bands, 12 of them being newly reported. Spectroscopic parameters of the upper vibrational levels were derived from band-by-band fits of the line positions (typical rms values are on the order of 0.001cm-1). About half of the analyzed bands were found to be affected by rovibrational perturbations. Line parameters obtained in this work were compared with those available for about 350 transitions in the HITRAN 2012 database. The large set of new data will be valuable to refine the parameters of the global effective Hamiltonian and dipole moments of 12C2H2. © 2015 Elsevier Ltd.
BibTeX: @article{Lyulin2015, author = {Lyulin, O.M. and Vander Auwera, J. and Campargue, A.}, title = {The Fourier transform absorption spectrum of acetylene between 7000 and 7500cm-1}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2015}, volume = {160}, pages = {85 – 93}, doi = {10.1016/j.jqsrt.2015.03.018} }
Nazé C, Li J and Godefroid M (2015), "Theoretical isotope shifts in neutral barium", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 91(3) [Abstract] [BibTeX] [DOI]
Abstract: The present work deals with a set of problems in isotope shifts of neutral barium spectral lines. Some well-known transitions (6s21S0-6s6p1,3P1o and 6s21S0-6p23P0) are investigated. Values of the changes in the nuclear mean-square charge radius are deduced from the available experimental isotope shifts using our ab initio electronic factors. The three sets δ r2A,A′ obtained from these lines are consistent with each other. The combination of the available nuclear mean-square radii with our electronic factors for the 6s5d3D1,2-6s6p1P1o transitions produces isotope shift values in conflict with the laser spectroscopy measurements of U. Dammalapati et al. [Eur. Phys. J. D 53, 1 (2009)EPJDF61434-606010.1140/epjd/e2009-00076-x]. © 2015 American Physical Society.
BibTeX: @article{Naze2015, author = {Nazé, C. and Li, J.G. and Godefroid, M.}, title = {Theoretical isotope shifts in neutral barium}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2015}, volume = {91}, number = {3}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.91.032511} }
Predoi-Cross A, Liu W, Murphy R, Povey C, Gamache R, Laraia A, McKellar A, Hurtmans D and Devi V (2015), "Corrigendum to "Measurement and computations for temperature dependences of self-broadened carbon dioxide transitions in the 30012-00001 and 30013-00001 bands" [J. Quant. Spectrosc. Radiat. Transf., 111 (9) (2010) 1065-1079] doi: 10.1016/j.jqsrt.2010.01.003", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 164, pp. 256. [BibTeX] [DOI]
BibTeX: @article{PredoiCross2015, author = {Predoi-Cross, Adriana and Liu, W. and Murphy, Reba and Povey, Chad and Gamache, R. and Laraia, A. and McKellar, A.R.W. and Hurtmans, Daniel and Devi, V.M.}, title = {Corrigendum to "Measurement and computations for temperature dependences of self-broadened carbon dioxide transitions in the 30012-00001 and 30013-00001 bands" [J. Quant. Spectrosc. Radiat. Transf., 111 (9) (2010) 1065-1079] doi: 10.1016/j.jqsrt.2010.01.003}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2015}, volume = {164}, pages = {256}, doi = {10.1016/j.jqsrt.2015.06.017} }
Santos L, Iacobellis N, Herman M, Perry D, Desouter-Lecomte M and Vaeck N (2015), "A test of optimal laser impulsion for controlling population within the N s = 1, N r = 5 polyad of 12C 2H 2 ", Molecular Physics. Vol. 113(24), pp. 4000 – 4006. [Abstract] [BibTeX] [DOI]
Abstract: Optimal control theory has been employed to populate separately two dark states of the acetylene polyad, Ns = 1 and Nr = 5, by indirect coupling via the ground state. Relevant level energies and transition dipole moments are extracted from the experimental literature. The optimal pulses are rather simple. The evolution of the population is shown for the duration of the control process and also for the field-free evolution that follows the control. One of the dark states appears to be a potential target for realistic experimental investigation because the average population of the Rabi oscillation remains high and decoherence is expected to be weak. © 2015 Taylor and Francis.
BibTeX: @article{Santos2015a, author = {Santos, L. and Iacobellis, N. and Herman, M. and Perry, D.S. and Desouter-Lecomte, M. and Vaeck, N.}, title = {A test of optimal laser impulsion for controlling population within the N s = 1, N r = 5 polyad of 12C 2H 2 }, journal = {Molecular Physics}, year = {2015}, volume = {113}, number = {24}, pages = {4000 – 4006}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268976.2015.1102980} }
Santos L, Justum Y, Vaeck N and Desouter-Lecomte M (2015), "Simulation of the elementary evolution operator with the motional states of an ion in an anharmonic trap", Journal of Chemical Physics. Vol. 142(13) [Abstract] [BibTeX] [DOI]
Abstract: Following a recent proposal of L. Wang and D. Babikov [J. Chem. Phys. 137, 064301 (2012)], we theoretically illustrate the possibility of using the motional states of a Cd+ ion trapped in a slightly anharmonic potential to simulate the single-particle time-dependent Schrödinger equation. The simulated wave packet is discretized on a spatial grid and the grid points are mapped on the ion motional states which define the qubit network. The localization probability at each grid point is obtained from the population in the corresponding motional state. The quantum gate is the elementary evolution operator corresponding to the time-dependent Schrödinger equation of the simulated system. The corresponding matrix can be estimated by any numerical algorithm. The radio-frequency field which is able to drive this unitary transformation among the qubit states of the ion is obtained by multi-target optimal control theory. The ion is assumed to be cooled in the ground motional state, and the preliminary step consists in initializing the qubits with the amplitudes of the initial simulated wave packet. The time evolution of the localization probability at the grids points is then obtained by successive applications of the gate and reading out the motional state population. The gate field is always identical for a given simulated potential, only the field preparing the initial wave packet has to be optimized for different simulations. We check the stability of the simulation against decoherence due to fluctuating electric fields in the trap electrodes by applying dissipative Lindblad dynamics. © 2015 AIP Publishing LLC.
BibTeX: @article{Santos2015, author = {Santos, Ludovic and Justum, Yves and Vaeck, Nathalie and Desouter-Lecomte, M.}, title = {Simulation of the elementary evolution operator with the motional states of an ion in an anharmonic trap}, journal = {Journal of Chemical Physics}, year = {2015}, volume = {142}, number = {13}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.4916355} }
Schullian O, Loreau J, Vaeck N, Avoird AVD, Heazlewood B, Rennick C and Softley T (2015), "Simulating rotationally inelastic collisions using a direct simulation Monte Carlo method", Molecular Physics. Vol. 113(24), pp. 3972 – 3978. [Abstract] [BibTeX] [DOI]
Abstract: A new approach to simulating rotational cooling using a direct simulation Monte Carlo (DSMC) method is described and applied to the rotational cooling of ammonia seeded into a helium supersonic jet. The method makes use of ab initio rotational state changing cross sections calculated as a function of collision energy. Each particle in the DSMC simulations is labelled with a vector of rotational populations that evolves with time. Transfer of energy into translation is calculated from the mean energy transfer for this population at the specified collision energy. The simulations are compared with a continuum model for the on-axis density, temperature and velocity; rotational temperature as a function of distance from the nozzle is in accord with expectations from experimental measurements. The method could be applied to other types of gas mixture dynamics under non-uniform conditions, such as buffer gas cooling of NH3 by He. © 2015 Taylor and Francis.
BibTeX: @article{Schullian2015, author = {Schullian, O. and Loreau, J. and Vaeck, N. and Avoird, A. Van Der and Heazlewood, B.R. and Rennick, C.J. and Softley, T.P.}, title = {Simulating rotationally inelastic collisions using a direct simulation Monte Carlo method}, journal = {Molecular Physics}, year = {2015}, volume = {113}, number = {24}, pages = {3972 – 3978}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268976.2015.1098740} }
Softley T, Herman M and Vaeck N (2015), "Special issue on atomic and molecular collision mechanisms", Molecular Physics. Vol. 113(24), pp. 3917. [BibTeX] [DOI]
BibTeX: @article{Softley2015, author = {Softley, Tim and Herman, Michel and Vaeck, Nathalie}, title = {Special issue on atomic and molecular collision mechanisms}, journal = {Molecular Physics}, year = {2015}, volume = {113}, number = {24}, pages = {3917}, note = {All Open Access, Bronze Open Access}, doi = {10.1080/00268976.2015.1114702} }
Stavrakou T, Müller J-F, Bauwens M, De Smedt I, Van Roozendael M, De Mazière M, Vigouroux C, Hendrick F, George M, Clerbaux C, Coheur P-F and Guenther A (2015), "How consistent are top-down hydrocarbon emissions based on formaldehyde observations from GOME-2 and OMI?", Atmospheric Chemistry and Physics. Vol. 15(20), pp. 11861 – 11884. [Abstract] [BibTeX] [DOI]
Abstract: The vertical columns of formaldehyde (HCHO) retrieved from two satellite instruments, the Global Ozone Monitoring Instrument-2 (GOME-2) on Metop-A and the Ozone Monitoring Instrument (OMI) on Aura, are used to constrain global emissions of HCHO precursors from open fires, vegetation and human activities in the year 2010. To this end, the emissions are varied and optimized using the adjoint model technique in the IMAGESv2 global CTM (chemical transport model) on a monthly basis and at the model resolution. Given the different local overpass times of GOME-2 (09:30 LT) and OMI (13:30 LT), the simulated diurnal cycle of HCHO columns is investigated and evaluated against ground-based optical measurements at seven sites in Europe, China and Africa. The modeled diurnal cycle exhibits large variability, reflecting competition between photochemistry and emission variations, with noon or early afternoon maxima at remote locations (oceans) and in regions dominated by anthropogenic emissions, late afternoon or evening maxima over fire scenes, and midday minima in isoprene-rich regions. The agreement between simulated and ground-based columns is generally better in summer (with a clear afternoon maximum at mid-latitude sites) than in winter, and the annually averaged ratio of afternoon to morning columns is slightly higher in the model (1.126) than in the ground-based measurements (1.043). The anthropogenic VOC (volatile organic compound) sources are found to be weakly constrained by the inversions on the global scale, mainly owing to their generally minor contribution to the HCHO columns, except over strongly polluted regions, like China. The OMI-based inversion yields total flux estimates over China close to the bottom-up inventory (24.6 vs. 25.5 TgVOC yrg-1 in the a priori) with, however, pronounced increases in the northeast of China and reductions in the south. Lower fluxes are estimated based on GOME-2 HCHO columns (20.6 TgVOC yrg-1), in particular over the northeast, likely reflecting mismatches between the observed and the modeled diurnal cycle in this region. The resulting biogenic and pyrogenic flux estimates from both optimizations generally show a good degree of consistency. A reduction of the global annual biogenic emissions of isoprene is derived, of 9 and 13 % according to GOME-2 and OMI, respectively, compared to the a priori estimate of 363 Tg in 2010. The reduction is largest (up to 25-40 %) in the Southeastern US, in accordance with earlier studies. The GOME-2 and OMI satellite columns suggest a global pyrogenic flux decrease by 36 and 33 %, respectively, compared to the GFEDv3 (Global Fire Emissions Database) inventory. This decrease is especially pronounced over tropical forests, such as in Amazonia, Thailand and Myanmar, and is supported by comparisons with CO observations from IASI (Infrared Atmospheric Sounding Interferometer). In contrast to these flux reductions, the emissions due to harvest waste burning are strongly enhanced over the northeastern China plain in June (by ca. 70 % in June according to OMI) as well as over Indochina in March. Sensitivity inversions showed robustness of the inferred estimates, which were found to lie within 7 % of the standard inversion results at the global scale. © Author(s) 2015.
BibTeX: @article{Stavrakou2015, author = {Stavrakou, T. and Müller, J.-F. and Bauwens, M. and De Smedt, I. and Van Roozendael, M. and De Mazière, M. and Vigouroux, C. and Hendrick, F. and George, M. and Clerbaux, C. and Coheur, P.-F. and Guenther, A.}, title = {How consistent are top-down hydrocarbon emissions based on formaldehyde observations from GOME-2 and OMI?}, journal = {Atmospheric Chemistry and Physics}, year = {2015}, volume = {15}, number = {20}, pages = {11861 – 11884}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-15-11861-2015} }
Suas-David N, Vanfleteren T, Földes T, Kassi S, Georges R and Herman M (2015), "The Water Dimer Investigated in the 2OH Spectral Range Using Cavity Ring-Down Spectroscopy", Journal of Physical Chemistry A. Vol. 119(39), pp. 10022 – 10034. [Abstract] [BibTeX] [DOI]
Abstract: Two setups based on CW cavity ring-down spectroscopy were used at Bruxelles and Rennes to record jet-cooled water dimer absorption between 7188 and 7285, and between 7357 and 7386 cm-1. Some 19 absorption features are reported, significantly more than in the literature. Limited high-resolution information is available due to strong overlap between neighboring vibration-rotation-tunneling (VRT) structures and to spectral broadening induced by short upper state vibrational predissociation lifetimes, likely to range between 100 and 20 ps. Rotational band contours analyses are performed to assign the partly resolved VRT structures to the v1v2v3,vfvb = 000,11; 200,00; 000,20; and 101,00 zero-order vibrational states. Their wavenumbers are found to be 7192.34, 7225.86, 7240.57, and 7256.99 cm-1, respectively. Both so-called acceptor-switching tunneling components are involved in the assignments whose tentative character is discussed. © 2015 American Chemical Society.
BibTeX: @article{SuasDavid2015, author = {Suas-David, N. and Vanfleteren, T. and Földes, T. and Kassi, S. and Georges, R. and Herman, M.}, title = {The Water Dimer Investigated in the 2OH Spectral Range Using Cavity Ring-Down Spectroscopy}, journal = {Journal of Physical Chemistry A}, year = {2015}, volume = {119}, number = {39}, pages = {10022 – 10034}, doi = {10.1021/acs.jpca.5b06746} }
Sutcliffe BT (2015), "The quantum form of the reaction path Hamiltonian", Molecular Physics. Vol. 113(13-14), pp. 1600 – 1607. [Abstract] [BibTeX] [DOI]
Abstract: An examination is made of the way in which the kinetic energy operator for internal motion alone is commonly constructed in molecular quantum mechanics. It is shown that some care needs to be taken to specify the precise conditions under which the form of the operator so obtained is a valid form. Particular care is needed in constructing a reaction path Hamiltonian. © 2015 Taylor & Francis.
BibTeX: @article{Sutcliffe2015, author = {Sutcliffe, Brian T.}, title = {The quantum form of the reaction path Hamiltonian}, journal = {Molecular Physics}, year = {2015}, volume = {113}, number = {13-14}, pages = {1600 – 1607}, doi = {10.1080/00268976.2014.999839} }
Theys N, De Smedt I, Van Gent J, Danckaert T, Wang T, Hendrick F, Stavrakou T, Bauduin S, Clarisse L, Li C, Krotkov N, Yu H, Brenot H and Van Roozendael M (2015), "Sulfur dioxide vertical column DOAS retrievals from the Ozone Monitoring Instrument: Global observations and comparison to ground-based and satellite data", Journal of Geophysical Research. Vol. 120(6), pp. 2470 – 2491. [Abstract] [BibTeX] [DOI]
Abstract: We present a new data set of sulfur dioxide (SO2) vertical columns from observations of the Ozone Monitoring Instrument (OMI)/AURA instrument between 2004 and 2013. The retrieval algorithm used is an advanced Differential Optical Absorption Spectroscopy (DOAS) scheme combined with radiative transfer calculation. It is developed in preparation for the operational processing of SO2 data product for the upcoming TROPOspheric Monitoring Instrument/Sentinel 5 Precursor mission. We evaluate the SO2 column results with those inferred from other satellite retrievals such as Infrared Atmospheric Sounding Interferometer and OMI (Linear Fit and Principal Component Analysis algorithms). A general good agreement between the different data sets is found for both volcanic and anthropogenic SO2 emission scenarios. We show that our algorithm produces SO2 columns with low noise and is able to provide accurate estimates of SO2. This conclusion is supported by important validation results over the heavily polluted site of Xianghe (China). Nearly 4 years of OMI and ground-based multiaxis DOAS SO2 columns are compared, and an excellent match is found. We also highlight the improved performance of the algorithm in capturing weak SO2 sources by detecting shipping SO2 emissions in long-term averaged data, an unreported measurement from space. © 2015. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Theys2015, author = {Theys, N. and De Smedt, I. and Van Gent, J. and Danckaert, T. and Wang, T. and Hendrick, F. and Stavrakou, T. and Bauduin, S. and Clarisse, L. and Li, C. and Krotkov, N. and Yu, H. and Brenot, H. and Van Roozendael, M.}, title = {Sulfur dioxide vertical column DOAS retrievals from the Ozone Monitoring Instrument: Global observations and comparison to ground-based and satellite data}, journal = {Journal of Geophysical Research}, year = {2015}, volume = {120}, number = {6}, pages = {2470 – 2491}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2014JD022657} }
Tran H, Vander Auwera J, Landsheere X, Ngo N, Pangui E, Morales S, El Hamzaoui H, Capoen B, Bouazaoui M, Boulet C and Hartmann J-M (2015), "Infrared light on molecule-molecule and molecule-surface collisions", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 92(1) [Abstract] [BibTeX] [DOI]
Abstract: By analyzing measured infrared absorption of pure CH4 gas under both "free" (large sample cell) and "confined" (inside the pores of a silica xerogel sample) conditions we give a demonstration that molecule-molecule and molecule-surface collisions lead to very different propensity rules for rotational-state changes. Whereas the efficiency of collisions to change the rotational state (observed through the broadening of the absorption lines) decreases with increasing rotational quantum number J for CH4-CH4 interactions, CH4-surface collisions lead to J-independent linewidths. In the former case, some (weak) collisions are inefficient whereas, in the latter case, a single collision is sufficient to remove the molecule from its initial rotational level. Furthermore, although some gas-phase collisions leave J unchanged and only modify the angular momentum orientation and/or symmetry of the level (as observed through the spectral effects of line mixing), this is not the case for the molecule-surface collisions since they always change J (in the studied J=0-14 range). © 2015 American Physical Society.
BibTeX: @article{Tran2015, author = {Tran, H. and Vander Auwera, J. and Landsheere, X. and Ngo, N.H. and Pangui, E. and Morales, S.B. and El Hamzaoui, H. and Capoen, B. and Bouazaoui, M. and Boulet, C. and Hartmann, J.-M.}, title = {Infrared light on molecule-molecule and molecule-surface collisions}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2015}, volume = {92}, number = {1}, doi = {10.1103/PhysRevA.92.012707} }
Van Damme M, Clarisse L, Dammers E, Liu X, Nowak J, Clerbaux C, Flechard C, Galy-Lacaux C, Xu W, Neuman J, Tang Y, Sutton M, Erisman J and Coheur P (2015), "Towards validation of ammonia (NH3) measurements from the IASI satellite", Atmospheric Measurement Techniques. Vol. 8(3), pp. 1575 – 1591. [Abstract] [BibTeX] [DOI]
Abstract: Limited availability of ammonia (NH3) observations is currently a barrier for effective monitoring of the nitrogen cycle. It prevents a full understanding of the atmospheric processes in which this trace gas is involved and therefore impedes determining its related budgets. Since the end of 2007, the Infrared Atmospheric Sounding Interferometer (IASI) satellite has been observing NH3 from space at a high spatio-temporal resolution. This valuable data set, already used by models, still needs validation. We present here a first attempt to validate IASI-NH3 measurements using existing independent ground-based and airborne data sets. The yearly distributions reveal similar patterns between ground-based and space-borne observations and highlight the scarcity of local NH3 measurements as well as their spatial heterogeneity and lack of representativity. By comparison with monthly resolved data sets in Europe, China and Africa, we show that IASI-NH3 observations are in fair agreement, but they are characterized by a smaller variation in concentrations. The use of hourly and airborne data sets to compare with IASI individual observations allows investigations of the impact of averaging as well as the representativity of independent observations for the satellite footprint. The importance of considering the latter and the added value of densely located airborne measurements at various altitudes to validate IASI-NH3 columns are discussed. Perspectives and guidelines for future validation work on NH3 satellite observations are presented. © Author(s) 2015.
BibTeX: @article{VanDamme2015a, author = {Van Damme, M. and Clarisse, L. and Dammers, E. and Liu, X. and Nowak, J.B. and Clerbaux, C. and Flechard, C.R. and Galy-Lacaux, C. and Xu, W. and Neuman, J.A. and Tang, Y.S. and Sutton, M.A. and Erisman, J.W. and Coheur, P.F.}, title = {Towards validation of ammonia (NH3) measurements from the IASI satellite}, journal = {Atmospheric Measurement Techniques}, year = {2015}, volume = {8}, number = {3}, pages = {1575 – 1591}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-8-1575-2015} }
Van Damme M, Erisman J, Clarisse L, Dammers E, Whitburn S, Clerbaux C, Dolman A and Coheur P-F (2015), "Worldwide spatiotemporal atmospheric ammonia (NH3) columns variability revealed by satellite", Geophysical Research Letters. Vol. 42(20), pp. 8660 – 8668. [Abstract] [BibTeX] [DOI]
Abstract: We exploit 6 years of measurements from the Infrared Atmospheric Sounding Interferometer (IASI)/MetOp-A instrument to identify seasonal patterns and interannual variability of atmospheric NH3. This is achieved by analyzing the time evolution of the monthly mean NH3 columns in 12 subcontinental areas around the world, simultaneously considering measurements from IASI morning and evening overpasses. For most regions, IASI has a sufficient sensitivity throughout the years to capture the seasonal patterns of NH3 columns, and we show that each region is characterized by a well-marked and distinctive cycle, with maxima mainly related to underlying emission processes. The largest column abundances and seasonal amplitudes throughout the years are found in southwestern Asia, with maxima twice as large as what is observed in southeastern China. The relation between emission sources and retrieved NH3 columns is emphasized at a smaller regional scale by inferring a climatology of the month of maximum columns. Key Points Six years of NH3 morning and evening IASI measurements are analyzed Seasonal cycles of atmospheric NH3 are characterized for subcontinental areas Source processes are attributed from a climatology of the month of NH3 maximum © 2015. American Geophysical Union. All Rights Reserved.
BibTeX: @article{VanDamme2015, author = {Van Damme, M. and Erisman, J.W. and Clarisse, L. and Dammers, E. and Whitburn, S. and Clerbaux, C. and Dolman, A.J. and Coheur, P.-F.}, title = {Worldwide spatiotemporal atmospheric ammonia (NH3) columns variability revealed by satellite}, journal = {Geophysical Research Letters}, year = {2015}, volume = {42}, number = {20}, pages = {8660 – 8668}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2015GL065496} }
Van Der Laan-Luijkx I, Van Der Velde I, Krol M, Gatti L, Domingues L, Correia C, Miller J, Gloor M, Van Leeuwen T, Kaiser J, Wiedinmyer C, Basu S, Clerbaux C and Peters W (2015), "Response of the Amazon carbon balance to the 2010 drought derived with CarbonTracker South America", Global Biogeochemical Cycles. Vol. 29(7), pp. 1092 – 1108. [Abstract] [BibTeX] [DOI]
Abstract: Two major droughts in the past decade had large impacts on carbon exchange in the Amazon. Recent analysis of vertical profile measurements of atmospheric CO2 and CO by Gatti et al. (2014) suggests that the 2010 drought turned the normally close-to-neutral annual Amazon carbon balance into a substantial source of nearly 0.5 PgC/yr, revealing a strong drought response. In this study, we revisit this hypothesis and interpret not only the same CO2/CO vertical profile measurements but also additional constraints on carbon exchange such as satellite observations of CO, burned area, and fire hot spots. The results from our CarbonTracker South America data assimilation system suggest that carbon uptake by vegetation was indeed reduced in 2010 but that the magnitude of the decrease strongly depends on the estimated 2010 and 2011 biomass burning emissions. We have used fire products based on burned area (Global Fire Emissions Database version 4), satellite-observed CO columns (Infrared Atmospheric Sounding Interferometer), fire radiative power (Global Fire Assimilation System version 1), and fire hot spots (Fire Inventory from NCAR version 1), and found an increase in biomass burning emissions in 2010 compared to 2011 of 0.16 to 0.24 PgC/yr. We derived a decrease of biospheric uptake ranging from 0.08 to 0.26 PgC/yr, with the range determined from a set of alternative inversions using different biomass burning estimates. Our numerical analysis of the 2010 Amazon drought results in a total reduction of carbon uptake of 0.24 to 0.50 PgC/yr and turns the balance from carbon sink to source. Our findings support the suggestion that the hydrological cycle will be an important driver of future changes in Amazonian carbon exchange. Key Points Amazon carbon budget estimated by CarbonTracker South America Biospheric uptake decreases by 0.08-0.26 PgC/yr in response to 2010 drought Amazon biomass burning emissions more than doubled during 2010 drought ©2015. American Geophysical Union. All Rights Reserved.
BibTeX: @article{VanDerLaanLuijkx2015, author = {Van Der Laan-Luijkx, I.T. and Van Der Velde, I.R. and Krol, M.C. and Gatti, L.V. and Domingues, L.G. and Correia, C.S.C. and Miller, J.B. and Gloor, M. and Van Leeuwen, T.T. and Kaiser, J.W. and Wiedinmyer, C. and Basu, S. and Clerbaux, C. and Peters, W.}, title = {Response of the Amazon carbon balance to the 2010 drought derived with CarbonTracker South America}, journal = {Global Biogeochemical Cycles}, year = {2015}, volume = {29}, number = {7}, pages = {1092 – 1108}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2014GB005082} }
Vandaele A, Neefs E, Drummond R, Thomas I, Daerden F, Lopez-Moreno J, Rodriguez J, Patel M, Bellucci G, Allen M, Altieri F, Bolsée D, Clancy T, Delanoye S, Depiesse C, Cloutis E, Fedorova A, Formisano V, Funke B, Fussen D, Geminale A, Gérard J-C, Giuranna M, Ignatiev N, Kaminski J, Karatekin O, Lefèvre F, López-Puertas M, López-Valverde M, Mahieux A, McConnell J, Mumma M, Neary L, Renotte E, Ristic B, Robert S, Smith M, Trokhimovsky S, Vanderauwera J, Villanueva G, Whiteway J, Wilquet V, Wolff M, Aoki S, Garcia-Comas M, Gillotay D, Gonzalez-Galindo F, Kasabe Y, Lewis S, Mason J, Sindoni G, Willame Y, Alonso-Rodrigo G, Aparicio Del Moral B, Barzin P, Ben Moussa A, Berkenbosch S, Biondi D, Bonnewijn S, Candini GP, Clairquin R, Cubas J, Giordanengo B, Gissot S, Gomez A, Zafra J-J, Leese M, Maes J, Mazy E, Mazzoli A, Meseguer J, Morales R, Orban A, Pastor-Morales MDC, Perez-Grande I, Rodriguez-Gomez J, Saggin B, Samain V, Sanz Andres A, Sanz R, Simar J-F and Thibert T (2015), "Science objectives and performances of NOMAD, a spectrometer suite for the ExoMars TGO mission", Planetary and Space Science. Vol. 119, pp. 233 – 249. [Abstract] [BibTeX] [DOI]
Abstract: The NOMAD spectrometer suite on the ExoMars Trace Gas Orbiter will map the composition and distribution of Mars’atmospheric trace species in unprecedented detail, fulfilling many of the scientific objectives of the joint ESA-Roscosmos ExoMars Trace Gas Orbiter mission. The instrument is a combination of three channels, covering a spectral range from the UV to the IR, and can perform solar occultation, nadir and limb observations. In this paper, we present the science objectives of the instrument and how these objectives have influenced the design of the channels. We also discuss the expected performance of the instrument in terms of coverage and detection sensitivity. © 2015 Elsevier Ltd. All rights reserved.
BibTeX: @article{Vandaele2015a, author = {Vandaele, A.C. and Neefs, E. and Drummond, R. and Thomas, I.R. and Daerden, F. and Lopez-Moreno, J.J. and Rodriguez, J. and Patel, M.R. and Bellucci, G. and Allen, M. and Altieri, F. and Bolsée, D. and Clancy, T. and Delanoye, S. and Depiesse, C. and Cloutis, E. and Fedorova, A. and Formisano, V. and Funke, B. and Fussen, D. and Geminale, A. and Gérard, J.-C. and Giuranna, M. and Ignatiev, N. and Kaminski, J. and Karatekin, O. and Lefèvre, F. and López-Puertas, M. and López-Valverde, M. and Mahieux, A. and McConnell, J. and Mumma, M. and Neary, L. and Renotte, E. and Ristic, B. and Robert, S. and Smith, M. and Trokhimovsky, S. and Vanderauwera, J. and Villanueva, G. and Whiteway, J. and Wilquet, V. and Wolff, M. and Aoki, Shohei and Garcia-Comas, Maya and Gillotay, Didier and Gonzalez-Galindo, Francisco and Kasabe, Yasumasa and Lewis, Stephen and Mason, Jon and Sindoni, Giuseppe and Willame, Yannick and Alonso-Rodrigo, Gustavo and Aparicio Del Moral, Beatriz and Barzin, Pascal and Ben Moussa, Ali and Berkenbosch, Sophie and Biondi, David and Bonnewijn, Sabrina and Candini, Gian Paolo and Clairquin, Roland and Cubas, Javier and Giordanengo, Boris and Gissot, Samuel and Gomez, Alejandro and Zafra, Jose- Jeronimo and Leese, Mark and Maes, Jeroen and Mazy, Emmanuel and Mazzoli, Alexandra and Meseguer, Jose and Morales, Rafael and Orban, Anne and Pastor-Morales, Maria Del Carmen and Perez-Grande, Isabel and Rodriguez-Gomez, Julio and Saggin, Bortolino and Samain, Valérie and Sanz Andres, Angel and Sanz, Rosario and Simar, Juan-Felipe and Thibert, Tanguy}, title = {Science objectives and performances of NOMAD, a spectrometer suite for the ExoMars TGO mission}, journal = {Planetary and Space Science}, year = {2015}, volume = {119}, pages = {233 – 249}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.pss.2015.10.003} }
Vandaele AC, Willame Y, Depiesse C, Thomas IR, Robert S, Bolsée D, Patel MR, Mason JP, Leese M, Lesschaeve S, Antoine P, Daerden F, Delanoye S, Drummond R, Neefs E, Ristic B, Lopez-Moreno J-J, Bellucci G, Allen M, Altieri F, Aoki S, Clancy T, Cloutis E, Fedorova A, Formisano V, Funke B, Fussen D, Garcia-Comas M, Geminale A, Gérard J-C, Gillotay D, Giuranna M, Gonzalez-Galindo F, Ignatiev N, Kaminski J, Karatekin O, Kasaba Y, Lefèvre F, Lewis S, López-Puertas M, López-Valverde M, Mahieux A, Mumma M, Neary L, Novak R, Renotte E, Sindoni G, Smith M, Trokhimovskiy A, Vander Auwera J, Villanueva G, Viscardy S, Whiteway J, Wilquet V, Wolff M, Alonso-Rodrigo G, Aparicio Del Moral B, Barzin P, BenMoussa A, Berkenbosch S, Biondi D, Bonnewijn S, Candini G, Clairquin R, Cubas J, Giordanengo B, Gissot S, Gomez A, Zafra J-J, Maes J, Mazy E, Mazzoli A, Meseguer J, Morales R, Orban A, Pastor-Morales M, Perez-Grande I, Rodriguez-Gomez J, Saggin B, Samain V, Sanz Andres A, Sanz R, Simar J-F and Thibert T (2015), "Optical and radiometric models of the NOMAD instrument Part I: The UVIS channel", Optics Express. Vol. 23(23), pp. 30028 – 30042. [Abstract] [BibTeX] [DOI]
Abstract: The NOMAD instrument has been designed to best fulfil the science objectives of the ExoMars Trace Gas Orbiter mission that will be launched in 2016. The instrument is a combination of three channels that cover the UV, visible and IR spectral ranges and can perform solar occultation, nadir and limb observations. In this series of two papers, we present the optical models representing the three channels of the instrument and use them to determine signal to noise levels for different observation modes and Martian conditions. In this first part, we focus on the UVIS channel, which will sound the Martian atmosphere using nadir and solar occultation viewing modes, covering the 200-650nm spectral range. High SNR levels (>1000) can easily be reached for wavelengths higher than 300nm both in solar occultation and nadir modes when considering binning. Below 300nm SNR are lower primarily because of the lower signal and the impact of atmospheric absorption. © 2015 Optical Society of America.
BibTeX: @article{Vandaele2015, author = {Vandaele, Ann C. and Willame, Yannick and Depiesse, Cédric and Thomas, Ian R. and Robert, Séverine and Bolsée, David and Patel, Manish R. and Mason, Jon P. and Leese, Mark and Lesschaeve, Stefan and Antoine, Philippe and Daerden, Frank and Delanoye, Sofie and Drummond, Rachel and Neefs, Eddy and Ristic, Bojan and Lopez-Moreno, José-Juan and Bellucci, Giancarlo and Allen, M. and Altieri, F. and Aoki, S. and Clancy, T. and Cloutis, E. and Fedorova, A. and Formisano, V. and Funke, B. and Fussen, D. and Garcia-Comas, M. and Geminale, A. and Gérard, J.-C. and Gillotay, D. and Giuranna, M. and Gonzalez-Galindo, F. and Ignatiev, N. and Kaminski, J. and Karatekin, O. and Kasaba, Y. and Lefèvre, F. and Lewis, S. and López-Puertas, M. and López-Valverde, M. and Mahieux, A. and Mumma, M. and Neary, L. and Novak, R. and Renotte, E. and Sindoni, G. and Smith, M. and Trokhimovskiy, A. and Vander Auwera, J. and Villanueva, G. and Viscardy, S. and Whiteway, J. and Wilquet, V. and Wolff, M. and Alonso-Rodrigo, G. and Aparicio Del Moral, B. and Barzin, P. and BenMoussa, A. and Berkenbosch, S. and Biondi, D. and Bonnewijn, S. and Candini, G. and Clairquin, R. and Cubas, J. and Giordanengo, B. and Gissot, S. and Gomez, A. and Zafra, J.-J. and Maes, J. and Mazy, E. and Mazzoli, A. and Meseguer, J. and Morales, R. and Orban, A. and Pastor-Morales, M. and Perez-Grande, I. and Rodriguez-Gomez, J. and Saggin, B. and Samain, V. and Sanz Andres, A. and Sanz, R. and Simar, J.-F. and Thibert, T.}, title = {Optical and radiometric models of the NOMAD instrument Part I: The UVIS channel}, journal = {Optics Express}, year = {2015}, volume = {23}, number = {23}, pages = {30028 – 30042}, note = {All Open Access, Gold Open Access}, doi = {10.1364/OE.23.030028} }
Vanfleteren, Földes T, Vander Auwera J and Herman M (2015), "Analysis of a remarkable perpendicular band in KrH2O with origin close to the ν1 + ν3 R(0) line in H2O", Chemical Physics Letters. Vol. 618, pp. 119 – 122. [Abstract] [BibTeX] [DOI]
Abstract: We have used continuous-wave cavity ring-down spectroscopy to record a band with origin close to 7273.5 cm-1 in a Kr supersonic expansion seeded with H2O. It is assigned to ν1 + ν3 ← GS, Π(101) ← Σ(000) in KrH2O. Several lines of the four most abundant Kr isotopic forms are resolved. The rotational structure (Trot = 18 K) is analyzed and the lines fitted (σ < 0.0004 cm-1) together with literature microwave data. The mean upper state predissociation lifetime is estimated to 4 ns. © 2014 Elsevier B.V. All rights reserved.
BibTeX: @article{Vanfleteren2015c, author = {Vanfleteren and Földes, T. and Vander Auwera, J. and Herman, M.}, title = {Analysis of a remarkable perpendicular band in KrH2O with origin close to the ν1 + ν3 R(0) line in H2O}, journal = {Chemical Physics Letters}, year = {2015}, volume = {618}, pages = {119 – 122}, doi = {10.1016/j.cplett.2014.11.010} }
Vanfleteren T, Földes T and Herman M (2015), "Analysis of a perpendicular band in Ar-H2O with origin close to the ν1 + ν3, R(0) line in H2O", Chemical Physics Letters. Vol. 627, pp. 36 – 38. [Abstract] [BibTeX] [DOI]
Abstract: We have used continuous-wave cavity ring-down spectroscopy to record a band with origin close to 7275.1 cm-1 in an Ar supersonic expansion seeded with H2O. It is assigned to ν1 + ν3 ← GS, Π(101) ← Σ(000) in Ar-H2O. The rotational structure (Trot = 12 K) is analyzed and the lines fitted (σ = 0.0008 cm-1) together with literature microwave data. The fit includes strongly perturbed Q lines, from interaction with a Π state with origin determined to be close to 7274.5 cm-1. The mean upper state predissociation lifetime is determined to be 3 ns for all reported e and f upper levels. © 2015 Elsevier B.V. All rights reserved.
BibTeX: @article{Vanfleteren2015b, author = {Vanfleteren, T. and Földes, T. and Herman, M.}, title = {Analysis of a perpendicular band in Ar-H2O with origin close to the ν1 + ν3, R(0) line in H2O}, journal = {Chemical Physics Letters}, year = {2015}, volume = {627}, pages = {36 – 38}, doi = {10.1016/j.cplett.2015.03.032} }
Vanfleteren T, Földes T, Herman M, Di Lonardo G and Fusina L (2015), "Overtone, 2NH (ν1 + ν3) spectroscopy of 15NH3-Ar", Journal of Molecular Spectroscopy. Vol. 318, pp. 107 – 109. [Abstract] [BibTeX] [DOI]
Abstract: We report on the observation of the Π (11; 2NH) ← Σ (00; ground state) band in 15NH3-Ar, with origin at 6615.943 cm-1, using jet-cooled cw-cavity ring-down spectroscopy. The rotational temperature is estimated to be 7 K. Nineteen rotational lines were assigned. Perturbations were evidenced from anomalous line positions and line widths, but not unraveled. Upper state rotational constants were obtained from the analysis of the nine unperturbed R/P lines. The e-symmetry upper state predissociation lifetimes appear to decrease with J′, from about 1.2 ns to 250 ps from J′ = 1 to 9. © 2015 Elsevier Inc. All rights reserved.
BibTeX: @article{Vanfleteren2015, author = {Vanfleteren, T. and Földes, T. and Herman, M. and Di Lonardo, G. and Fusina, L.}, title = {Overtone, 2NH (ν1 + ν3) spectroscopy of 15NH3-Ar}, journal = {Journal of Molecular Spectroscopy}, year = {2015}, volume = {318}, pages = {107 – 109}, doi = {10.1016/j.jms.2015.10.011} }
Vanfleteren T, Földes T, Liévin J and Herman M (2015), "Overtone, 2NH ( 1+ 3) spectroscopy of NH 3-Ar and NH 3-Kr", Molecular Physics. Vol. 113(24), pp. 3934 – 3945. [Abstract] [BibTeX] [DOI]
Abstract: We have recorded between 6561 and 6671 cm-1 the spectrum of jet-cooled ammonia seeded in Ne, Ar and Kr, using continuous wave cavity ring-down spectroscopy (CW-CRDS). The equivalent absorption pathlength was around 750 m. Three bands are assigned to Π(11)←Σ(00), Π(11)←Π(10) and Δ(?)←Π(10) in the 2NH, 1+3←GS transition of the ortho NH3-Ar dimer. They are rotationally analysed and a simultaneous fitting procedure, together with one far-infrared ground state band from the literature is successfully achieved. A possible Mj-dependent cooling process is reported. Only the first of these bands is observed in the ortho NH3-Kr dimer, and rotationally analysed. Individual line perturbations and anomalous line broadening effects are reported. A J-dependent vibrational predissociation lifetime with a mean value around 0.6 ns is obtained for the Π(11) sub-state in NH3-Ar and NH3-Kr. Two additional bands are assigned to NH3-Ar involving close Π upper sub-states. A group of close bands from the para dimer is identified in NH3-Ar. The energy of all observed ortho and para sub-states is extracted from the analysis. Finally, more bands are reported but their carriers could not be identified. © 2015 Taylor and Francis.
BibTeX: @article{Vanfleteren2015a, author = {Vanfleteren, T. and Földes, T. and Liévin, J. and Herman, M.}, title = {Overtone, 2NH ( 1+ 3) spectroscopy of NH 3-Ar and NH 3-Kr}, journal = {Molecular Physics}, year = {2015}, volume = {113}, number = {24}, pages = {3934 – 3945}, doi = {10.1080/00268976.2015.1072252} }
Vranckx S, Loreau J, Vaeck N, Meier C and Desouter-Lecomte M (2015), "Photodissociation of the carbon monoxide dication in the 3Σ- manifold: Quantum control simulation towards the C2+ + O channel", Journal of Chemical Physics. Vol. 143(16) [Abstract] [BibTeX] [DOI]
Abstract: The photodissociation and laser assisted dissociation of the carbon monoxide dication X3Π CO2+ into the 3Σ- states are investigated. Ab initio electronic structure calculations of the adiabatic potential energy curves, radial nonadiabatic couplings, and dipole moments for the X 3Π state are performed for 13 excited 3Σ- states of CO2+. The photodissociation cross section, calculated by time-dependent methods, shows that the C+ + O+ channels dominate the process in the studied energy range. The carbon monoxide dication CO2+ is an interesting candidate for control because it can be produced in a single, long lived, v = 0 vibrational state due to the instability of all the other excited vibrational states of the ground 3Π electronic state. In a spectral range of about 25 eV, perpendicular transition dipoles couple this 3Π state to a manifold of 3Σ- excited states leading to numerous C+ + O+ channels and a single C2+ + O channel. This unique channel is used as target for control calculations using local control theory. We illustrate the efficiency of this method in order to find a tailored electric field driving the photodissociation in a manifold of strongly interacting electronic states. The selected local pulses are then concatenated in a sequence inspired by the "laser distillation" strategy. Finally, the local pulse is compared with optimal control theory. © 2015 AIP Publishing LLC.
BibTeX: @article{Vranckx2015, author = {Vranckx, S. and Loreau, J. and Vaeck, N. and Meier, C. and Desouter-Lecomte, M.}, title = {Photodissociation of the carbon monoxide dication in the 3Σ- manifold: Quantum control simulation towards the C2+ + O channel}, journal = {Journal of Chemical Physics}, year = {2015}, volume = {143}, number = {16}, doi = {10.1063/1.4934233} }
Wagner A, Blechschmidt A-M, Bouarar I, Brunke E-G, Clerbaux C, Cupeiro M, Cristofanelli P, Eskes H, Flemming J, Flentje H, George M, Gilge S, Hilboll A, Inness A, Kapsomenakis J, Richter A, Ries L, Spangl W, Stein O, Weller R and Zerefos C (2015), "Evaluation of the MACC operational forecast system - Potential and challenges of global near-real-time modelling with respect to reactive gases in the troposphere", Atmospheric Chemistry and Physics. Vol. 15(24), pp. 14005 – 14030. [Abstract] [BibTeX] [DOI]
Abstract: The Monitoring Atmospheric Composition and Climate (MACC) project represents the European Union's Copernicus Atmosphere Monitoring Service (CAMS) (http://www.copernicus.eu/), which became fully operational during 2015. The global near-real-time MACC model production run for aerosol and reactive gases provides daily analyses and 5-day forecasts of atmospheric composition fields. It is the only assimilation system worldwide that is operational to produce global analyses and forecasts of reactive gases and aerosol fields. We have investigated the ability of the MACC analysis system to simulate tropospheric concentrations of reactive gases covering the period between 2009 and 2012. A validation was performed based on carbon monoxide (CO), nitrogen dioxide (NO2) and ozone (O3) surface observations from the Global Atmosphere Watch (GAW) network, the O3 surface observations from the European Monitoring and Evaluation Programme (EMEP) and, furthermore, NO2 tropospheric columns, as well as CO total columns, derived from satellite sensors. The MACC system proved capable of reproducing reactive gas concentrations with consistent quality; however, with a seasonally dependent bias compared to surface and satellite observations - for northern hemispheric surface O3 mixing ratios, positive biases appear during the warm seasons and negative biases during the cold parts of the year, with monthly modified normalised mean biases (MNMBs) ranging between -30 and 30 % at the surface. Model biases are likely to result from difficulties in the simulation of vertical mixing at night and deficiencies in the model's dry deposition parameterisation. Observed tropospheric columns of NO2 and CO could be reproduced correctly during the warm seasons, but are mostly underestimated by the model during the cold seasons, when anthropogenic emissions are at their highest level, especially over the US, Europe and Asia. Monthly MNMBs of the satellite data evaluation range from values between -110 and 40 % for NO2 and at most -20 % for CO, over the investigated regions. The underestimation is likely to result from a combination of errors concerning the dry deposition parameterisation and certain limitations in the current emission inventories, together with an insufficiently established seasonality in the emissions. © Author(s) 2015.
BibTeX: @article{Wagner2015, author = {Wagner, A. and Blechschmidt, A.-M. and Bouarar, I. and Brunke, E.-G. and Clerbaux, C. and Cupeiro, M. and Cristofanelli, P. and Eskes, H. and Flemming, J. and Flentje, H. and George, M. and Gilge, S. and Hilboll, A. and Inness, A. and Kapsomenakis, J. and Richter, A. and Ries, L. and Spangl, W. and Stein, O. and Weller, R. and Zerefos, C.}, title = {Evaluation of the MACC operational forecast system - Potential and challenges of global near-real-time modelling with respect to reactive gases in the troposphere}, journal = {Atmospheric Chemistry and Physics}, year = {2015}, volume = {15}, number = {24}, pages = {14005 – 14030}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-15-14005-2015} }
Whitburn S, Van Damme M, Kaiser J, Van Der Werf G, Turquety S, Hurtmans D, Clarisse L, Clerbaux C and Coheur P-F (2015), "Ammonia emissions in tropical biomass burning regions: Comparison between satellite-derived emissions and bottom-up fire inventories", Atmospheric Environment. Vol. 121, pp. 42 – 54. [Abstract] [BibTeX] [DOI]
Abstract: Vegetation fires emit large amounts of nitrogen compounds in the atmosphere, including ammonia (NH3). These emissions are still subject to large uncertainties. In this study, we analyze time series of monthly NH3 total columns (molec cm-2) from the IASI sounder on board MetOp-A satellite and their relation with MODIS fire radiative power (MW) measurements. We derive monthly NH3 emissions estimates for four regions accounting for a major part of the total area affected by fires (two in Africa, one in central South America and one in Southeast Asia), using a simplified box model, and we compare them to the emissions from both the GFEDv3.1 and GFASv1.0 biomass burning emission inventories. In order to strengthen the analysis, we perform a similar comparison for carbon monoxide (CO), also measured by IASI and for which the emission factors used in the inventories to convert biomass burned to trace gas emissions are thought to be more reliable. In general, a good correspondence between NH3 and CO columns and the FRP is found, especially for regions in central South America with correlation coefficients of 0.82 and 0.66, respectively. The comparison with the two biomass burning emission inventories GFASv1.0 and GFEDv3.1 shows good agreements, particularly in the time of the maximum of emissions for the central South America region and in the magnitude for the region of Africa south of the equator. We find evidence of significant non-pyrogenic emissions for the regions of Africa north of the equator (for NH3) and Southeast Asia (for NH3 and CO). On a yearly basis, total emissions calculated from IASI measurements for the four regions reproduce fairly well the interannual variability from the GFEDv3.1 and GFASv1.0 emissions inventories for NH3 but show values about 1.5-2 times higher than emissions given by the two biomass burning emission inventories, even when assuming a fairly long lifetime of 36 h for that species. © 2015 Elsevier Ltd.
BibTeX: @article{Whitburn2015, author = {Whitburn, S. and Van Damme, M. and Kaiser, J.W. and Van Der Werf, G.R. and Turquety, S. and Hurtmans, D. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F.}, title = {Ammonia emissions in tropical biomass burning regions: Comparison between satellite-derived emissions and bottom-up fire inventories}, journal = {Atmospheric Environment}, year = {2015}, volume = {121}, pages = {42 – 54}, doi = {10.1016/j.atmosenv.2015.03.015} }
Bader W, Stavrakou T, Muller J-F, Reimann S, Boone C, Harrison J, Flock O, Bovy B, Franco B, Lejeune B, Servais C and Mahieu E (2014), "Long-term evolution and seasonal modulation of methanol above Jungfraujoch (46.5° N, 8.0° E): Optimisation of the retrieval strategy, comparison with model simulations and independent observations", Atmospheric Measurement Techniques. Vol. 7(11), pp. 3861 – 3872. [Abstract] [BibTeX] [DOI]
Abstract: Methanol (CH3OH) is the second most abundant organic compound in the Earth's atmosphere after methane. In this study, we present the first long-term time series of methanol total, lower tropospheric and upper tropospheric-lower stratospheric partial columns derived from the analysis of high resolution Fourier transform infrared solar spectra recorded at the Jungfraujoch station (46.5° N, 3580 m a.s.l.). The retrieval of methanol is very challenging due to strong absorptions of ozone in the region of the selected υ8 band of CH3OH. Two wide spectral intervals have been defined and adjusted in order to maximise the information content. Methanol does not exhibit a significant trend over the 1995-2012 time period, but a strong seasonal modulation characterised by maximum values and variability in June-July, minimum columns in winter and a peak-to-peak amplitude of 130%. Analysis and comparisons with in situ measurements carried out at the Jungfraujoch and ACE-FTS (Atmospheric Chemistry Experiment-Fourier transform spectrometer) occultations have been performed. The total and lower tropospheric columns are also compared with IMAGESv2 model simulations. There is no systematic bias between the observations and IMAGESv2 but the model underestimates the peak-to-peak amplitude of the seasonal modulations.
BibTeX: @article{Bader2014, author = {Bader, W. and Stavrakou, T. and Muller, J.-F. and Reimann, S. and Boone, C.D. and Harrison, J.J. and Flock, O. and Bovy, B. and Franco, B. and Lejeune, B. and Servais, C. and Mahieu, E.}, title = {Long-term evolution and seasonal modulation of methanol above Jungfraujoch (46.5° N, 8.0° E): Optimisation of the retrieval strategy, comparison with model simulations and independent observations}, journal = {Atmospheric Measurement Techniques}, year = {2014}, volume = {7}, number = {11}, pages = {3861 – 3872}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-7-3861-2014} }
Barnes MK, Tilstone GH, Smyth TJ, Suggett DJ, Astoreca R, Lancelot C and Kromkamp JC (2014), "Absorption-based algorithm of primary production for total and size-fractionated phytoplankton in coastal waters", Marine Ecology Progress Series. Vol. 504, pp. 73 – 89. [Abstract] [BibTeX] [DOI]
Abstract: Most satellite models of production have been designed and calibrated for use in the open ocean. Coastal waters are optically more complex, and the use of chlorophyll a (chl a) as a first-order predictor of primary production may lead to substantial errors due to significant quantities of coloured dissolved organic matter (CDOM) and total suspended material (TSM) within the first optical depth. We demonstrate the use of phytoplankton absorption as a proxy to estimate primary production in the coastal waters of the North Sea and Western English Channel for both total, micro- and nano+pico-phytoplankton production. The method is implemented to extrapolate the absorption coefficient of phytoplankton and production at the sea surface to depth to give integrated fields of total and micro- and nano+pico-phytoplankton primary production using the peak in absorption coefficient at red wavelengths. The model is accurate to 8% in the Western English Channel and 22% in this region and the North Sea. By comparison, the accuracy of similar chl a based production models was >250%. The applicability of the method to autonomous optical sensors and remotely sensed aircraft data in both coastal and estuarine environments is discussed. © Inter-Research 2014.
BibTeX: @article{Barnes2014, author = {Barnes, Morvan K. and Tilstone, Gavin H. and Smyth, Timothy J. and Suggett, David J. and Astoreca, Rosa and Lancelot, Christiane and Kromkamp, Jacco C.}, title = {Absorption-based algorithm of primary production for total and size-fractionated phytoplankton in coastal waters}, journal = {Marine Ecology Progress Series}, year = {2014}, volume = {504}, pages = {73 – 89}, note = {All Open Access, Bronze Open Access}, doi = {10.3354/meps10751} }
Basu S, Krol M, Butz A, Clerbaux C, Sawa Y, Machida T, Matsueda H, Frankenberg C, Hasekamp O and Aben I (2014), "The seasonal variation of the CO2 flux over Tropical Asia estimated from GOSAT, CONTRAIL, and IASI", Geophysical Research Letters. Vol. 41(5), pp. 1809 – 1815. [Abstract] [BibTeX] [DOI]
Abstract: We estimate the CO2 flux over Tropical Asia in 2009, 2010, and 2011 using Greenhouse Gases Observing Satellite (GOSAT) total column CO 2(XCO2) and in situ measurements of CO2. Compared to flux estimates from assimilating surface measurements of CO 2, GOSAT XCO2 estimates a more dynamic seasonal cycle and a large source in March-May 2010. The more dynamic seasonal cycle is consistent with earlier work by Patra et al. (2011), and the enhanced 2010 source is supported by independent upper air CO2 measurements from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project. Using Infrared Atmospheric Sounding Interferometer (IASI) measurements of total column CO (XCO), we show that biomass burning CO2 can explain neither the dynamic seasonal cycle nor the 2010 source. We conclude that both features must come from the terrestrial biosphere. In particular, the 2010 source points to biosphere response to above-average temperatures that year. Key Points GOSAT estimates a dynamic seasonal cycle over Tropical Asia The GOSAT-estimated seasonal cycle is confirmed by CONTRAIL data IASI CO shows that the dynamism is not caused by biomass burning ©2014. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Basu2014, author = {Basu, S. and Krol, M. and Butz, A. and Clerbaux, C. and Sawa, Y. and Machida, T. and Matsueda, H. and Frankenberg, C. and Hasekamp, O.P. and Aben, I.}, title = {The seasonal variation of the CO2 flux over Tropical Asia estimated from GOSAT, CONTRAIL, and IASI}, journal = {Geophysical Research Letters}, year = {2014}, volume = {41}, number = {5}, pages = {1809 – 1815}, note = {All Open Access, Green Open Access}, doi = {10.1002/2013GL059105} }
Bauduin S, Clarisse L, Clerbaux C, Hurtmans D and Coheur P-F (2014), "IASI observations of sulfur dioxide (SO2) in the boundary layer of Norilsk", Journal of Geophysical Research. Vol. 119(7), pp. 4253 – 4263. [Abstract] [BibTeX] [DOI]
Abstract: Norilsk is one of the most polluted cities in the world, largely because of intense mining of heavy metals. Here we present satellite observations of SO2 in a large area surrounding the city, derived from 4 years of measurements from the Infrared Atmospheric Sounding Interferometer (IASI), the nadir thermal infrared (TIR) sounder onboard the MetOp platforms. TIR instruments are conventionally considered to be inadequate for monitoring near-surface composition, because their sensitivity to the lowest part of the atmosphere is limited by the thermal contrast between the ground and the air above it. We demonstrate that IASI is capable of measuring SO2 (here as a partial column from 0 to 2 km) in Norilsk, thanks to the large temperature inversions and the low humidity in wintertime. We discuss the influence of thermal contrast and of surface humidity on the SO2 retrieved columns and estimate the retrieval errors. Using a simple box model, we derive the yearly total emissions of SO2 from Norilsk and compare them to previously reported values. More generally, we present in this work the first large-scale demonstration of the capability of space-based TIR sounders to measure near-surface SO2 anthropogenic pollution. © 2014. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Bauduin2014, author = {Bauduin, Sophie and Clarisse, Lieven and Clerbaux, Cathy and Hurtmans, Daniel and Coheur, Pierre-François}, title = {IASI observations of sulfur dioxide (SO2) in the boundary layer of Norilsk}, journal = {Journal of Geophysical Research}, year = {2014}, volume = {119}, number = {7}, pages = {4253 – 4263}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2013JD021405} }
Baye D, Filippin L and Godefroid M (2014), "Accurate solution of the Dirac equation on Lagrange meshes", Physical Review E - Statistical, Nonlinear, and Soft Matter Physics. Vol. 89(4) [Abstract] [BibTeX] [DOI]
Abstract: The Lagrange-mesh method is an approximate variational method taking the form of equations on a grid because of the use of a Gauss quadrature approximation. With a basis of Lagrange functions involving associated Laguerre polynomials related to the Gauss quadrature, the method is applied to the Dirac equation. The potential may possess a 1/r singularity. For hydrogenic atoms, numerically exact energies and wave functions are obtained with small numbers n+1 of mesh points, where n is the principal quantum number. Numerically exact mean values of powers -2 to 3 of the radial coordinate r can also be obtained with n+2 mesh points. For the Yukawa potential, a 15-digit agreement with benchmark energies of the literature is obtained with 50 or fewer mesh points. © 2014 American Physical Society.
BibTeX: @article{Baye2014, author = {Baye, Daniel and Filippin, Livio and Godefroid, Michel}, title = {Accurate solution of the Dirac equation on Lagrange meshes}, journal = {Physical Review E - Statistical, Nonlinear, and Soft Matter Physics}, year = {2014}, volume = {89}, number = {4}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevE.89.043305} }
Bogatko S, Cauët E, Geerlings P and De Proft F (2014), "On the coupling of solvent characteristics to the electronic structure of solute molecules", Physical Chemistry Chemical Physics. Vol. 16(8), pp. 3807 – 3814. [Abstract] [BibTeX] [DOI]
Abstract: We present the results of a theoretical investigation focusing on the solvent structure surrounding the -1, 0 and +1 charged species of F, Cl, Br and I halogen atoms and F2, Cl2, Br2 and I 2 di-halogen molecules in a methanol solvent and its influence on the electronic structure of the solute molecules. Our results show a large stabilizing effect arising from the solute-solvent interactions. Well-formed first solvation shells are observed for all species, the structure of which is strongly influenced by the charge of the solute species. Detailed analysis reveals that coordination number, CN, solvent orientation, and solute-solvent distance, d, are important structural characteristics which are coupled to changes in the electronic structure of the solute. We propose that the fundamental chemistry of any solute species is generally regulated by these solvent degrees of freedom. © 2014 the Owner Societies.
BibTeX: @article{Bogatko2014, author = {Bogatko, Stuart and Cauët, Emilie and Geerlings, Paul and De Proft, Frank}, title = {On the coupling of solvent characteristics to the electronic structure of solute molecules}, journal = {Physical Chemistry Chemical Physics}, year = {2014}, volume = {16}, number = {8}, pages = {3807 – 3814}, doi = {10.1039/c3cp54944e} }
Boichu M, Clarisse L, Khvorostyanov D and Clerbaux C (2014), "Improving volcanic sulfur dioxide cloud dispersal forecasts by progressive assimilation of satellite observations", Geophysical Research Letters. Vol. 41(7), pp. 2637 – 2643. [Abstract] [BibTeX] [DOI]
Abstract: Forecasting the dispersal of volcanic clouds during an eruption is of primary importance, especially for ensuring aviation safety. As volcanic emissions are characterized by rapid variations of emission rate and height, the (generally) high level of uncertainty in the emission parameters represents a critical issue that limits the robustness of volcanic cloud dispersal forecasts. An inverse modeling scheme, combining satellite observations of the volcanic cloud with a regional chemistry-transport model, allows reconstructing this source term at high temporal resolution. We demonstrate here how a progressive assimilation of freshly acquired satellite observations, via such an inverse modeling procedure, allows for delivering robust sulfur dioxide (SO2) cloud dispersal forecasts during the eruption. This approach provides a computationally cheap estimate of the expected location and mass loading of volcanic clouds, including the identification of SO2-rich parts. Key Points Refined SO2 cloud dispersal forecasts by assimilation of satellite observations Refined estimation of source emissions using an inverse modeling approach Compared to standard methods, cloud SO2-rich parts are robustly forecasted © 2014. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Boichu2014, author = {Boichu, Marie and Clarisse, Lieven and Khvorostyanov, Dmitry and Clerbaux, Cathy}, title = {Improving volcanic sulfur dioxide cloud dispersal forecasts by progressive assimilation of satellite observations}, journal = {Geophysical Research Letters}, year = {2014}, volume = {41}, number = {7}, pages = {2637 – 2643}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1002/2014GL059496} }
Boyé-Péronne S, Gauyacq D and Liévin J (2014), "Theoretical description of electronically excited vinylidene up to 10 eV: First high level ab initio study of singlet valence and Rydberg states", Journal of Chemical Physics. Vol. 141(17) [Abstract] [BibTeX] [DOI]
Abstract: The first quantitative description of the Rydberg and valence singlet electronic states of vinylidene lying in the 0-10 eV region is performed by using large scale ab initio calculations. A deep analysis of Rydberg-valence interactions has been achieved thanks to the comprehensive information contained in the accurate Multi-Reference Configuration Interaction wavefunctions and an original population analysis highlighting the respective role played by orbital and state mixing in such interactions. The present theoretical approach is thus adequate for dealing with larger than diatomic Rydberg systems. The nine lowest singlet valence states have been optimized. Among them, some are involved in strong Rydberg-valence interactions in the region of the Rydberg state equilibrium geometry. The Rydberg states of vinylidene present a great similarity with the acetylene isomer, concerning their quantum defects and Rydberg molecular orbital character. As in acetylene, strong s-d mixing is revealed in the n = 3 s-d supercomplex. Nevertheless, unlike in acetylene, the close-energy of the two vinylidene ionic cores 2A1 and 2B1 results into two overlapped Rydberg series. These Rydberg series exhibit local perturbations when an accidental degeneracy occurs between them and results in avoided crossings. In addition, some Δl = 1 (s-p and p-d) mixings arise for some Rydberg states and are rationalized in term of electrostatic interaction from the electric dipole moment of the ionic core. The strongest dipole moment of the 2 B1 cationic state also stabilizes the lowest members of the n = 3 Rydberg series converging to this excited state, as compared to the adjacent series converging toward the 2A1 ionic ground state. The overall energies of vinylidene Rydberg states lie above their acetylene counterpart. Finally, predictions for optical transitions in singlet vinylidene are suggested for further experimental spectroscopic characterization of vinylidene. © 2014 AIP Publishing LLC.
BibTeX: @article{BoyePeronne2014, author = {Boyé-Péronne, Séverine and Gauyacq, Dolores and Liévin, Jacques}, title = {Theoretical description of electronically excited vinylidene up to 10 eV: First high level ab initio study of singlet valence and Rydberg states}, journal = {Journal of Chemical Physics}, year = {2014}, volume = {141}, number = {17}, doi = {10.1063/1.4900875} }
Boynard A, Clerbaux C, Clarisse L, Safieddine S, Pommier M, Van Damme M, Bauduin S, Oudot C, Hadji-Lazaro J, Hurtmans D and Coheur P-F (2014), "First simultaneous space measurements of atmospheric pollutants in the boundary layer from IASI: A case study in the North China Plain", Geophysical Research Letters. Vol. 41(2), pp. 645 – 651. [Abstract] [BibTeX] [DOI]
Abstract: In this paper we investigate a severe pollution episode that occurred in Beijing, Tianjin, and the Hebei province in January 2013. The episode was caused by the combination of anthropogenic emissions and a high-pressure system that trapped pollutants in the boundary layer. Using IASI (Infrared Atmospheric Sounding Interferometer) satellite measurements, high concentrations of key trace gases such as carbon monoxide (CO), sulfur dioxide (SO2), and ammonia (NH3) along with ammonium sulfate aerosol ((NH 4)2SO4) are found. We show that IASI is able to detect boundary layer pollution in case of large negative thermal contrast combined with high levels of pollution. Our findings demonstrate that anthropogenic key pollutants, such as CO and SO2, can be monitored by IASI in the North China Plain during wintertime in support of air quality evaluation and management. ©2013. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Boynard2014, author = {Boynard, Anne and Clerbaux, Cathy and Clarisse, Lieven and Safieddine, Sarah and Pommier, Matthieu and Van Damme, Martin and Bauduin, Sophie and Oudot, Charlotte and Hadji-Lazaro, Juliette and Hurtmans, Daniel and Coheur, Pierre-Francois}, title = {First simultaneous space measurements of atmospheric pollutants in the boundary layer from IASI: A case study in the North China Plain}, journal = {Geophysical Research Letters}, year = {2014}, volume = {41}, number = {2}, pages = {645 – 651}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2013GL058333} }
Brenot H, Theys N, Clarisse L, Van Geffen J, Van Gent J, Van Roozendael M, Van Der A R, Hurtmans D, Coheur P-F, Clerbaux C, Valks P, Hedelt P, Prata F, Rasson O, Sievers K and Zehner C (2014), "Support to aviation control service (SACS): An online service for near-real-time satellite monitoring of volcanic plumes", Natural Hazards and Earth System Sciences. Vol. 14(5), pp. 1099 – 1123. [Abstract] [BibTeX] [DOI]
Abstract: Volcanic eruptions emit plumes of ash and gases into the atmosphere, potentially at very high altitudes. Ash-rich plumes are hazardous for airplanes as ash is very abrasive and easily melts inside their engines. With more than 50 active volcanoes per year and the ever-increasing number of commercial flights, the safety of airplanes is a real concern. Satellite measurements are ideal for monitoring global volcanic activity and, in combination with atmospheric dispersion models, to track and forecast volcanic plumes. Here we present the Support to Aviation Control Service (SACS, http://sacs.aeronomie.be), which is a free online service initiated by the European Space Agency (ESA) for the near-real-time (NRT) satellite monitoring of volcanic plumes of SO2 and ash. It combines data from three ultraviolet (UV)-visible and three infrared (IR) spectrometers. The UV-vis sensors are the Ozone Monitoring Instrument (OMI) and the Global Ozone Monitoring Experiment-2 (GOME-2) on-board the two polar orbiting meteorological satellites (MetOp-A & MetOp-B) operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The IR sensors are the Atmospheric InfraRed Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) on-board MetOp-A & MetOp-B. This new multi-sensor warning system of volcanic emissions is based on the selective detection of SO2 and ash. This system is optimised to avoid false alerts while at the same time limiting the number of notifications in case of large plumes. A successful rate with more than 95% of notifications corresponding to true volcanic activity is obtained by the SACS system. copyright © Author(s) 2014.
BibTeX: @article{Brenot2014, author = {Brenot, H. and Theys, N. and Clarisse, L. and Van Geffen, J. and Van Gent, J. and Van Roozendael, M. and Van Der A, R. and Hurtmans, D. and Coheur, P.-F. and Clerbaux, C. and Valks, P. and Hedelt, P. and Prata, F. and Rasson, O. and Sievers, K. and Zehner, C.}, title = {Support to aviation control service (SACS): An online service for near-real-time satellite monitoring of volcanic plumes}, journal = {Natural Hazards and Earth System Sciences}, year = {2014}, volume = {14}, number = {5}, pages = {1099 – 1123}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/nhess-14-1099-2014} }
Carette T and Godefroid M (2014), "Theoretical study of the isotope effects on the detachment thresholds of Si-", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 89(5) [Abstract] [BibTeX] [DOI]
Abstract: The isotope effects in Si- bound levels are studied using the multiconfiguration Hartree-Fock ab initio approach. Large-scale calculations are carried out for the 3p34So, 2Do, and 2Po multiplets of Si- and the 3p23P multiplet of Si. We predict an anomalous isotope shift on the electron affinity, dominated by the specific mass shift, with a value of -0.66(6) m-1 for the 30-28 isotope pair. We also report hyperfine-structure parameters for the studied multiplets. We provide the values of level electric-field gradients at the nucleus that could be of interest in a study of the metastable silicon isotopes. Relativistic corrections are estimated using nonrelativistic orbitals in the Breit-Pauli and fully relativistic frameworks. © 2014 American Physical Society.
BibTeX: @article{Carette2014, author = {Carette, T. and Godefroid, M.R.}, title = {Theoretical study of the isotope effects on the detachment thresholds of Si-}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2014}, volume = {89}, number = {5}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.89.052513} }
Clarisse L, Coheur P-F, Theys N, Hurtmans D and Clerbaux C (2014), "The 2011 Nabro eruption, a SO2 plume height analysis using IASI measurements", Atmospheric Chemistry and Physics. Vol. 14(6), pp. 3095 – 3111. [Abstract] [BibTeX] [DOI]
Abstract: In the wake of the June 2011 Nabro eruption, large stratospheric plumes were observed by several instruments up to altitudes of 21 km, much higher than initial reported injection heights. It has been debated whether deep convection associated with the Asian Summer Monsoon anticyclone played a vital role in the vertical transport of the plume. Here we present a new and fast SO2 height retrieval algorithm for observations of the Infrared Atmospheric Sounding Interferometer (IASI). A comprehensive validation with forward trajectories and coincident CALIOP measurements is presented which indicates an accuracy better than 2 km for plumes below 20 km and SO2 columns up to the 1 DU level. We use this new product to analyse the Nabro eruption. Our findings indicate an initial plume located mainly between 15 and 17 km for which the lower parts underwent in succession rapid descent and uplift, within the Asian Monsoon anticyclone circulation, up to the stable thermal tropopause between 16 and 18 km, from where it slowly ascended further into the stratosphere. Evidence is presented that emissions in the first week of the eruption also contributed to the stratospheric sulfur input. This includes a second eruption between 15 and 17 km on the 16th and continuous emissions in the mid-troposphere of which some were also entrained and lifted within the anticyclonic circulation. © 2014 Author(s).
BibTeX: @article{Clarisse2014, author = {Clarisse, L. and Coheur, P.-F. and Theys, N. and Hurtmans, D. and Clerbaux, C.}, title = {The 2011 Nabro eruption, a SO2 plume height analysis using IASI measurements}, journal = {Atmospheric Chemistry and Physics}, year = {2014}, volume = {14}, number = {6}, pages = {3095 – 3111}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-14-3095-2014} }
Colin R and Bernath PF (2014), "Rotational analysis of the B2Σ+-X 2Σ+ transition of the 13C15N molecule", Journal of Molecular Spectroscopy. Vol. 302, pp. 34 – 35. [Abstract] [BibTeX] [DOI]
Abstract: The B2Σ+-X2Σ+ (violet system) electronic transition of the 13C15N free radical was recorded with a Fourier transform spectrometer. The 0-0, 1-1, 1-0, 0-1 and 1-2 bands were rotationally analyzed to obtain spectroscopic constants. There have been no previous measurements of any electronic transitions for the 13C15N isotopologue. © 2014 Elsevier Inc. All rights reserved.
BibTeX: @article{Colin2014, author = {Colin, Reginald and Bernath, Peter F.}, title = {Rotational analysis of the B2Σ+-X 2Σ+ transition of the 13C15N molecule}, journal = {Journal of Molecular Spectroscopy}, year = {2014}, volume = {302}, pages = {34 – 35}, doi = {10.1016/j.jms.2014.06.006} }
Cooper M, Martin RV, Wespes C, Coheur P-F, Clerbaux C and Murray LT (2014), "Tropospheric nitric acid columns from the IASI satellite instrument interpreted with a chemical transport model: Implications for parameterizations of nitric oxide production by lightning", Journal of Geophysical Research: Atmospheres. Vol. 119(16), pp. 10068 – 10079. [Abstract] [BibTeX] [DOI]
Abstract: This paper interprets tropical tropospheric nitric acid columns from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument with a global chemical transport model (GEOS-Chem). GEOS-Chemand IASI columns generally agree over the tropical ocean to within 10%. However, the GEOS-Chem simulation underestimates IASI nitric acid over Southeast Asia by a factor of 2. The regional nitric acid bias is confirmed by comparing the GEOS-Chem simulation with additional satellite (High Resolution Dynamics Limb Sounder, Atmospheric Chemistry Experiment Fourier Transform Spectrometer) and aircraft (Pacific Exploratory Mission (PEM)-Tropics A and PEM-West B) observations of the middle and upper troposphere. This bias appears to be driven by the lightning NOx parameterization, both in terms of the magnitude of the NOx source and the ozone production efficiency of concentrated lightning NOx plumes. We tested a subgrid lightning plume parameterization and found that an ozone production efficiency of 15 mol/mol in lightning plumes over Southeast Asia in conjunction with an additional 0.5 Tg N would reduce the regional nitric acid bias from 92% to 6% without perturbing the rest of the tropics. Other sensitivity studies such as modified NOx yield per flash, increased altitude of lightning NOx emissions, decreased convective mass flux, or increased scavenging of nitric acid required unrealistic changes to reduce the bias. © 2014. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Cooper2014, author = {Cooper, Matthew and Martin, Randall V. and Wespes, Catherine and Coheur, Pierre-Francois and Clerbaux, Cathy and Murray, Lee T.}, title = {Tropospheric nitric acid columns from the IASI satellite instrument interpreted with a chemical transport model: Implications for parameterizations of nitric oxide production by lightning}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2014}, volume = {119}, number = {16}, pages = {10068 – 10079}, note = {All Open Access, Green Open Access}, doi = {10.1002/2014JD021907} }
Crevoisier C, Clerbaux C, Guidard V, Phulpin T, Armante R, Barret B, Camy-Peyret C, Chaboureau J-P, Coheur P-F, Crépeau L, Dufour G, Labonnote L, Lavanant L, Hadji-Lazaro J, Herbin H, Jacquinet-Husson N, Payan S, Péquignot E, Pierangelo C, Sellitto P and Stubenrauch C (2014), "Towards IASI-New Generation (IASI-NG): Impact of improved spectral resolution and radiometric noise on the retrieval of thermodynamic, chemistry and climate variables", Atmospheric Measurement Techniques. Vol. 7(12), pp. 4367 – 4385. [Abstract] [BibTeX] [DOI]
Abstract: Besides their strong contribution to weather forecast improvement through data assimilation, thermal infrared sounders onboard polar-orbiting platforms are now playing a key role for monitoring atmospheric composition changes. The Infrared Atmospheric Sounding Interferometer (IASI) instrument developed by the French space agency (CNES) and launched by EUMETSAT onboard the Metop satellite series is providing essential inputs for weather forecasting and pollution/climate monitoring owing to its smart combination of large horizontal swath, good spectral resolution and high radiometric performance. EUMETSAT is currently preparing the next polar-orbiting program (EPS-SG) with the Metop-SG satellite series that should be launched around 2020. In this framework, CNES is studying the concept of a new instrument, the IASI-New Generation (IASI-NG), characterized by an improvement of both spectral and radiometric characteristics as compared to IASI, with three objectives: (i) continuity of the IASI/Metop series; (ii) improvement of vertical resolution; and (iii) improvement of the accuracy and detection threshold for atmospheric and surface components. In this paper, we show that an improvement of spectral resolution and radiometric noise fulfil these objectives by leading to (i) a better vertical coverage in the lower part of the troposphere, thanks to the increase in spectral resolution; and (ii) an increase in the accuracy of the retrieval of several thermodynamic, climate and chemistry variables, thanks to the improved signal-to-noise ratio as well as less interference between the signatures of the absorbing species in the measured radiances. The detection limit of several atmospheric species is also improved. We conclude that IASI-NG has the potential to strongly benefit the numerical weather prediction, chemistry and climate communities now connected through the European GMES/Copernicus initiative. © Author(s) 2014.
BibTeX: @article{Crevoisier2014, author = {Crevoisier, C. and Clerbaux, C. and Guidard, V. and Phulpin, T. and Armante, R. and Barret, B. and Camy-Peyret, C. and Chaboureau, J.-P. and Coheur, P.-F. and Crépeau, L. and Dufour, G. and Labonnote, L. and Lavanant, L. and Hadji-Lazaro, J. and Herbin, H. and Jacquinet-Husson, N. and Payan, S. and Péquignot, E. and Pierangelo, C. and Sellitto, P. and Stubenrauch, C.}, title = {Towards IASI-New Generation (IASI-NG): Impact of improved spectral resolution and radiometric noise on the retrieval of thermodynamic, chemistry and climate variables}, journal = {Atmospheric Measurement Techniques}, year = {2014}, volume = {7}, number = {12}, pages = {4367 – 4385}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-7-4367-2014} }
Daneshvar L, Földes T, Buldyreva J and Auwera JV (2014), "Infrared absorption by pure CO2 near 3340cm-1: Measurements and analysis of collisional coefficients and line-mixing effects at subatmospheric pressures", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 149, pp. 258 – 274. [Abstract] [BibTeX] [DOI]
Abstract: High resolution Fourier transform spectra of the 21102-00001 band of 12C16O2 near 3340cm-1 have been recorded and analyzed to extract isolated-line intensities and collisional parameters, and first-order line-mixing coefficients. Voigt, hard-collision Rautian and Sobel'man, and quadratic-speed-dependent Voigt profiles have been used. The line-mixing coefficients measured for the three branches have also been evaluated using an Energy-Corrected Sudden approach employing a symmetric metric in the Liouville space. These coefficients compare very favorably with the experimental results and estimations with an algorithm available in the literature. Results of straightforward ECS-modeling of complete band shapes have been compared to the recorded spectra and future improvements of this model required at subatmospheric pressures have been outlined. © 2014 Elsevier Ltd.
BibTeX: @article{Daneshvar2014, author = {Daneshvar, L. and Földes, T. and Buldyreva, J. and Auwera, J. Vander}, title = {Infrared absorption by pure CO2 near 3340cm-1: Measurements and analysis of collisional coefficients and line-mixing effects at subatmospheric pressures}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2014}, volume = {149}, pages = {258 – 274}, doi = {10.1016/j.jqsrt.2014.08.007} }
Ekman J, Godefroid MR and Hartman H (2014), "Validation and implementation of uncertainty estimates of calculated transition rates", Atoms. Vol. 2(2), pp. 215 – 224. [Abstract] [BibTeX] [DOI]
Abstract: Uncertainties of calculated transition rates in LS-allowed electric dipole transitions in boron-like O IV and carbon-like Fe XXI are estimated using an approach in which differences in line strengths calculated in length and velocity gauges are utilized. Estimated uncertainties are compared and validated against several high-quality theoretical data sets in O IV, and implemented in large scale calculations in Fe XXI. © 2014 by the authors.
BibTeX: @article{Ekman2014a, author = {Ekman, Jörgen and Godefroid, Michel R. and Hartman, Henrik}, title = {Validation and implementation of uncertainty estimates of calculated transition rates}, journal = {Atoms}, year = {2014}, volume = {2}, number = {2}, pages = {215 – 224}, note = {All Open Access, Gold Open Access}, doi = {10.3390/atoms2020215} }
Ekman J, Jönsson P, Gustafsson S, Hartman H, Gaigalas G, Godefroid M and Froese Fischer C (2014), "Calculations with spectroscopic accuracy: Energies, transition rates,and Lande gJ-factors in the carbon isoelectronic sequence from Ar XIII to Zn XXV", Astronomy and Astrophysics. Vol. 564 [Abstract] [BibTeX] [DOI]
Abstract: Extensive self-consistent multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and subsequent relativistic configuration interaction calculations are performed for 262 states belonging to the 15 configurations 2s 22p2, 2s2p3, 2p4, 2s 22p3l, 2s2p23l, 2p33l and 2s22p4l(l = 0,1,2) in selected carbon-like ions from Ar XIII to Zn XXV. Electron correlation effects are accounted for through large configuration state function expansions. Calculated energy levels are compared with existing theoretical calculations and data from the Chianti and NIST databases. In addition, Landé gJ-factors and radiative electric dipole transition rates are given for all ions. The accuracy of the calculations are high enough to facilitate the identification of observed spectral lines. © 2014 ESO.
BibTeX: @article{Ekman2014, author = {Ekman, J. and Jönsson, P. and Gustafsson, S. and Hartman, H. and Gaigalas, G. and Godefroid, M.R. and Froese Fischer, C.}, title = {Calculations with spectroscopic accuracy: Energies, transition rates,and Lande gJ-factors in the carbon isoelectronic sequence from Ar XIII to Zn XXV}, journal = {Astronomy and Astrophysics}, year = {2014}, volume = {564}, note = {All Open Access, Bronze Open Access}, doi = {10.1051/0004-6361/201323163} }
Filippin L, Godefroid M and Baye D (2014), "Relativistic polarizabilities with the Lagrange-mesh method", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 90(5) [Abstract] [BibTeX] [DOI]
Abstract: Relativistic dipolar to hexadecapolar polarizabilities of the ground state and some excited states of hydrogenic atoms are calculated by using numerically exact energies and wave functions obtained from the Dirac equation with the Lagrange-mesh method. This approach is an approximate variational method taking the form of equations on a grid because of the use of a Gauss quadrature approximation. The partial polarizabilities conserving the absolute value of the quantum number κ are also numerically exact with small numbers of mesh points. The ones where \|κ\| changes are very accurate when using three different meshes for the initial and final wave functions and for the calculation of matrix elements. The polarizabilities of the n=2 excited states of hydrogenic atoms are also studied with a separate treatment of the final states that are degenerate at the nonrelativistic approximation. The method provides high accuracies for polarizabilities of a particle in a Yukawa potential and is applied to a hydrogen atom embedded in a Debye plasma. © 2014 American Physical Society.
BibTeX: @article{Filippin2014, author = {Filippin, Livio and Godefroid, Michel and Baye, Daniel}, title = {Relativistic polarizabilities with the Lagrange-mesh method}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2014}, volume = {90}, number = {5}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.90.052520} }
Földes T, Golebiowski D, Herman M, Softley T, Di Lonardo G and Fusina L (2014), "Low-temperature high-resolution absorption spectrum of 14NH3 in the v1+v3 band region (1.51 μm)", Molecular Physics. Vol. 112(18), pp. 2407 – 2418. [Abstract] [BibTeX] [DOI]
Abstract: Jet-cooled spectra of 14NH3 and 15NH3 in natural abundance were recorded using cavity ring-down (CRDS, 6584-6670 cm-1) and cavity enhanced absorption (CEAS, 6530-6700 cm-1) spectroscopy. Line broadening effects in the CRDS spectrum allowed lines with J'-values between 0 and 3 to be identified. Intensity ratios in 14NH3 between the jet-cooled CRDS and literature room-temperature data from Sung et al. (J. Quant. Spectrosc. Radiat. Transfer, 113 (2012), 1066) further assisted the line assignments. Ground state combination differences were extensively used to support the assignments, providing reliable values for J, K and inversion symmetry of the ground state vibrational levels. CEAS data helped in this respect for the lowest J lines, some of which are saturated in the CRDS spectrum. Further information on a/s doublets arose from the observed spectral structures. Thirty-two transitions of 14NH3 were assigned in this way and a limited but significant number (19) of changes in the assignments results, compared to Sung et al. or to Cacciani et al. (J. Quant. Spectrosc. Radiat. Transfer, 113 (2012), 1084). Sixteen known and 25 new low-J transitions were identified for 15NH3 in the CRDS spectrum but the much scarcer literature information did not allow for any more refined assignment. The present line position measurements improve on literature values published for 15NH3 and on some line positions for 14NH3. © 2014 Taylor & Francis.
BibTeX: @article{Foeldes2014a, author = {Földes, T. and Golebiowski, D. and Herman, M. and Softley, T.P. and Di Lonardo, G. and Fusina, L.}, title = {Low-temperature high-resolution absorption spectrum of 14NH3 in the v1+v3 band region (1.51 μm)}, journal = {Molecular Physics}, year = {2014}, volume = {112}, number = {18}, pages = {2407 – 2418}, doi = {10.1080/00268976.2014.904944} }
Földes T, Vanfleteren T and Herman M (2014), "Communication: A rotationally resolved (2OH) overtone band in the water dimer (H2O)2", Journal of Chemical Physics. Vol. 141(11) [Abstract] [BibTeX] [DOI]
Abstract: Cw-CRDS spectra of water-rare gas supersonic expansions were recorded between 7229 and 7262 cm-1. The effective absorption pathlength was about 1 km in jet-cooled gas and the resolution about 1 × 10-4cm-1. Many well-resolved structures are observed that could be assigned from experimental evidence to H2O-Ar/Kr bands. Eight broader unresolved features are more specifically reported and assigned to small H2O multimers, in good agreement and refining previous observations by Nizkorodov et al. [J. Chem. Phys. 122, 194316 (2005)]. Among these, the band at 7256.5 cm-1is shown to be a Q branch of the water dimer with accompanying R and very weak P lines. The band is assigned to a Ka= 0 → 1 transition and rotationally analyzed, leading to a restricted set of upper state rotational constants. The upper state lifetime (60 ± 3 ps) is extracted from the linewidths. © 2014 AIP Publishing LLC.
BibTeX: @article{Foeldes2014, author = {Földes, T. and Vanfleteren, T. and Herman, M.}, title = {Communication: A rotationally resolved (2OH) overtone band in the water dimer (H2O)2}, journal = {Journal of Chemical Physics}, year = {2014}, volume = {141}, number = {11}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.4896163} }
Golebiowski D, de Ghellinck d'Elseghem Vaernewijck X, Herman M, Auwera JV and Fayt A (2014), "High sensitivity (femto-FT-CEAS) spectra of carbonyl sulphide between 6200 and 8200cm-1, and new energy pattern in the global rovibrational analysis of 16O12C32S", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 149, pp. 184 – 203. [Abstract] [BibTeX] [DOI]
Abstract: We have recorded Fourier transform spectra of OCS between 6170 and 6680cm-1, and between 7700 and 8160cm-1 using a femto/OPO laser absorption source and cavity enhanced spectroscopy. Equivalent absorption path lengths varying between 7 and 13km were obtained depending on the specific spectral region. In the lower and higher energy ranges, 7 and 12 new bands were observed, respectively, while improved results were gained on those previously reported in the literature. Some of these data brought significant, new information on the rovibrational energy pattern in OCS that triggered an update of the latest published global polyad model (Rbaihi et al. J Mol Spectrosc 1998;191:32 [15]). The new fit includes for the first time all overtone data since published in the literature, covering the range 6200-13950cm-1, as well as all known lower energy ones. All data selected for the global analysis of carbonyl sulphide 16O12C32S are provided as supplementary information. The previous polyad model was extended to include the inter-polyad anharmonic k1113 and Coriolis C11222 interactions, leading to simultaneously deal with sets of nine interacting polyad matrices at a time, each polyad defined by N=2v1+v2+4v3 (with 1-3 the conventional normal modes in OCS). We have obtained a statistical agreement with all experimental data with an estimated standard deviation better than unity (σ=0.7568). The fit produced 141 molecular parameters, of which 4 concern the new inter-polyad resonances. They have been used to calculate effective rovibrational parameters for all sub-states up to more than 12,000cm-1, listed in a Depository (Appendix B). A list of line parameters, covering the measured spectral ranges and including line intensities determined using previously recorded Fourier transform spectra of the two strongest bands observed in the present work, was generated in HITRAN format. It is also provided as supplementary information. © 2014 Elsevier Ltd.
BibTeX: @article{Golebiowski2014, author = {Golebiowski, D. and de Ghellinck d'Elseghem Vaernewijck, X. and Herman, M. and Auwera, J. Vander and Fayt, A.}, title = {High sensitivity (femto-FT-CEAS) spectra of carbonyl sulphide between 6200 and 8200cm-1, and new energy pattern in the global rovibrational analysis of 16O12C32S}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2014}, volume = {149}, pages = {184 – 203}, doi = {10.1016/j.jqsrt.2014.07.005} }
Hartmann J-M, Boulet C, Auwera JV, El Hamzaoui H, Capoen B and Bouazaoui M (2014), "Line broadening of confined CO gas: From molecule-wall to molecule-molecule collisions with pressure", Journal of Chemical Physics. Vol. 140(6) [Abstract] [BibTeX] [DOI]
Abstract: The infrared absorption in the fundamental band of CO gas confined in porous silica xerogel has been recorded at room temperature for pressures between about 5 and 920 hPa using a high resolution Fourier transform spectrometer. The widths of individual lines are determined from fits of measured spectra and compared with ab initio predictions obtained from requantized classical molecular dynamics simulations. Good agreement is obtained from the low pressure regime where the line shapes are governed by molecule-wall collisions to high pressures where the influence of molecule-molecule interactions dominates. These results, together with those obtained with a simple analytical model, indicate that both mechanisms contribute in a practically additive way to the observed linewidths. They also confirm that a single collision of a molecule with a wall changes its rotational state. These results are of interest for the determination of some characteristics of the opened porosity of porous materials through optical soundings. © 2014 AIP Publishing LLC.
BibTeX: @article{Hartmann2014, author = {Hartmann, J.-M. and Boulet, C. and Auwera, J. Vander and El Hamzaoui, H. and Capoen, B. and Bouazaoui, M.}, title = {Line broadening of confined CO gas: From molecule-wall to molecule-molecule collisions with pressure}, journal = {Journal of Chemical Physics}, year = {2014}, volume = {140}, number = {6}, doi = {10.1063/1.4864205} }
Hassler B, Petropavlovskikh I, Staehelin J, August T, Bhartia P, Clerbaux C, Degenstein D, De Mazière M, Dinelli B, Dudhia A, Dufour G, Frith S, Froidevaux L, Godin-Beekmann S, Granville J, Harris N, Hoppel K, Hubert D, Kasai Y, Kurylo M, Kyrölä E, Levelt P, McElroy C, McPeters R, Munro R, Nakajima H, Parrish A, Raspollini P, Remsberg E, Rosenlof K, Rozanov A, Sano T, Sasano Y, Shiotani M, Smit H, Stiller G, Tamminen J, Tarasick D, Urban J, Van Der A R, Veefkind J, Vigouroux C, Von Clarmann T, Von Savigny C, Walker K, Weber M, Wild J and Zawodny J (2014), "Past changes in the vertical distribution of ozone – Part 1: Measurement techniques, uncertainties and availability", Atmospheric Measurement Techniques. Vol. 7(5), pp. 1395 – 1427. [Abstract] [BibTeX] [DOI]
Abstract: Peak stratospheric chlorofluorocarbon (CFC) and other ozone depleting substance (ODS) concentrations were reached in the mid-to late 1990s. Detection and attribution of the expected recovery of the stratospheric ozone layer in an atmosphere with reduced ODSs as well as efforts to understand the evolution of stratospheric ozone in the presence of increasing greenhouse gases are key current research topics. These require a critical examination of the ozone changes with an accurate knowledge of the spatial (geographical and vertical) and temporal ozone response. For such an examination, it is vital that the quality of the measurements used be as high as possible and measurement uncertainties well quantified. In preparation for the 2014 United Nations Environment Programme (UNEP)/World Meteorological Organization (WMO) Scientific Assessment of Ozone Depletion, the SPARC/IO3C/IGACO-O3/NDACC (SI2N) Initiative was designed to study and document changes in the global ozone profile distribution. This requires assessing long-term ozone profile data sets in regards to measurement stability and uncertainty characteristics. The ultimate goal is to establish suitability for estimating long-term ozone trends to contribute to ozone recovery studies. Some of the data sets have been improved as part of this initiative with updated versions now available. This summary presents an overview of stratospheric ozone profile measurement data sets (ground and satellite based) available for ozone recovery studies. Here we document measurement techniques, spatial and temporal coverage, vertical resolution, native units and measurement uncertainties. In addition, the latest data versions are briefly described (including data version updates as well as detailing multiple retrievals when available for a given satellite instrument). Archive location information for each data set is also given. © Author(s) 2014.
BibTeX: @article{Hassler2014, author = {Hassler, B. and Petropavlovskikh, I. and Staehelin, J. and August, T. and Bhartia, P.K. and Clerbaux, C. and Degenstein, D. and De Mazière, M. and Dinelli, B.M. and Dudhia, A. and Dufour, G. and Frith, S.M. and Froidevaux, L. and Godin-Beekmann, S. and Granville, J. and Harris, N.R.P. and Hoppel, K. and Hubert, D. and Kasai, Y. and Kurylo, M.J. and Kyrölä, E. and Levelt, P.F. and McElroy, C.T. and McPeters, R.D. and Munro, R. and Nakajima, H. and Parrish, A. and Raspollini, P. and Remsberg, E.E. and Rosenlof, K.H. and Rozanov, A. and Sano, T. and Sasano, Y. and Shiotani, M. and Smit, H.G.J. and Stiller, G. and Tamminen, J. and Tarasick, D.W. and Urban, J. and Van Der A, R.J. and Veefkind, J.P. and Vigouroux, C. and Von Clarmann, T. and Von Savigny, C. and Walker, K.A. and Weber, M. and Wild, J. and Zawodny, J.M.}, title = {Past changes in the vertical distribution of ozone – Part 1: Measurement techniques, uncertainties and availability}, journal = {Atmospheric Measurement Techniques}, year = {2014}, volume = {7}, number = {5}, pages = {1395 – 1427}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-7-1395-2014} }
Hoffmann L, Alexander M, Clerbaux C, Grimsdell A, Meyer C, Rößler T and Tournier B (2014), "Intercomparison of stratospheric gravity wave observations with AIRS and IASI", Atmospheric Measurement Techniques. Vol. 7(12), pp. 4517 – 4537. [Abstract] [BibTeX] [DOI]
Abstract: Gravity waves are an important driver for the atmospheric circulation and have substantial impact on weather and climate. Satellite instruments offer excellent opportunities to study gravity waves on a global scale. This study focuses on observations from the Atmospheric Infrared Sounder (AIRS) onboard the National Aeronautics and Space Administration Aqua satellite and the Infrared Atmospheric Sounding Interferometer (IASI) onboard the European MetOp satellites. The main aim of this study is an intercomparison of stratospheric gravity wave observations of both instruments. In particular, we analyzed AIRS and IASI 4.3 μm brightness temperature measurements, which directly relate to stratospheric temperature. Three case studies showed that AIRS and IASI provide a clear and consistent picture of the temporal development of individual gravity wave events. Statistical comparisons based on a 5-year period of measurements (2008-2012) showed similar spatial and temporal patterns of gravity wave activity. However, the statistical comparisons also revealed systematic differences of variances between AIRS and IASI that we attribute to the different spatial measurement characteristics of both instruments. We also found differences between day- and nighttime data that are partly due to the local time variations of the gravity wave sources. While AIRS has been used successfully in many previous gravity wave studies, IASI data are applied here for the first time for that purpose. Our study shows that gravity wave observations from different hyperspectral infrared sounders such as AIRS and IASI can be directly related to each other, if instrument-specific characteristics such as different noise levels and spatial resolution and sampling are carefully considered. The ability to combine observations from different satellites provides an opportunity to create a long-term record, which is an exciting prospect for future climatological studies of stratospheric gravity wave activity. © Author(s) 2014.
BibTeX: @article{Hoffmann2014, author = {Hoffmann, L. and Alexander, M.J. and Clerbaux, C. and Grimsdell, A.W. and Meyer, C.I. and Rößler, T. and Tournier, B.}, title = {Intercomparison of stratospheric gravity wave observations with AIRS and IASI}, journal = {Atmospheric Measurement Techniques}, year = {2014}, volume = {7}, number = {12}, pages = {4517 – 4537}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-7-4517-2014} }
Keller A, Rackwitz J, Cauët E, Liévin J, Körzdörfer T, Rotaru A, Gothelf KV, Besenbacher F and Bald I (2014), "Sequence dependence of electron-induced DNA strand breakage revealed by DNA nanoarrays", Scientific Reports. Vol. 4 [Abstract] [BibTeX] [DOI]
Abstract: The electronic structure of DNA is determined by its nucleotide sequence, which is for instance exploited in molecular electronics. Here we demonstrate that also the DNA strand breakage induced by low-energy electrons (18 eV) depends on the nucleotide sequence. To determine the absolute cross sections for electron induced single strand breaks in specific 13 mer oligonucleotides we used atomic force microscopy analysis of DNA origami based DNA nanoarrays. We investigated the DNA sequences 5′-TT(XYX) 3 TT with X = A, G, C and Y = T, BrU 5-bromouracil and found absolute strand break cross sections between 2.66 · 10-14 cm2 and 7.06 · 10-14 cm2. The highest cross section was found for 5 2-TT(ATA) 3 TT and 5 2-TT(ABrUA) 3 TT, respectively. BrU is a radiosensitizer, which was discussed to be used in cancer radiation therapy. The replacement of T by BrU into the investigated DNA sequences leads to a slight increase of the absolute strand break cross sections resulting in sequence-dependent enhancement factors between 1.14 and 1.66. Nevertheless, the variation of strand break cross sections due to the specific nucleotide sequence is considerably higher. Thus, the present results suggest the development of targeted radiosensitizers for cancer radiation therapy.
BibTeX: @article{Keller2014, author = {Keller, Adrian and Rackwitz, Jenny and Cauët, Emilie and Liévin, Jacques and Körzdörfer, Thomas and Rotaru, Alexandru and Gothelf, Kurt V. and Besenbacher, Flemming and Bald, Ilko}, title = {Sequence dependence of electron-induced DNA strand breakage revealed by DNA nanoarrays}, journal = {Scientific Reports}, year = {2014}, volume = {4}, note = {All Open Access, Gold Open Access}, doi = {10.1038/srep07391} }
Konovalov I, Berezin E, Ciais P, Broquet G, Beekmann M, Hadji-Lazaro J, Clerbaux C, Andreae M, Kaiser J and Schulze E-D (2014), "Constraining CO2emissions from open biomass burning by satellite observations of co-emitted species: A method and its application to wildfires in Siberia", Atmospheric Chemistry and Physics. Vol. 14(19), pp. 10383 – 10410. [Abstract] [BibTeX] [DOI]
Abstract: A method to constrain carbon dioxide (CO2) emissions from open biomass burning by using satellite observations of co-emitted species and a chemistry-transport model (CTM) is proposed and applied to the case of wildfires in Siberia. CO2emissions are assessed by means of an emission model assuming a direct relationship between the biomass burning rate (BBR) and the fire radiative power (FRP) derived from MODIS measurements. The key features of the method are (1) estimating the FRP-to-BBR conversion factors (α) for different vegetative land cover types by assimilating the satellite observations of co-emitted species into the CTM, (2) optimal combination of the estimates of α derived independently from satellite observations of different species (CO and aerosol in this study), and (3) estimation of the diurnal cycle of the fire emissions directly from the FRP measurements. Values of α for forest and grassland fires in Siberia and their uncertainties are estimated using the Infrared Atmospheric Sounding Interferometer (IASI) carbon monoxide (CO) retrievals and MODIS aerosol optical depth (AOD) measurements combined with outputs from the CHIMERE mesoscale chemistry-transport model. The constrained CO emissions are validated through comparison of the respective simulations with independent data of ground-based CO measurements at the ZOTTO site. Using our optimal regional-scale estimates of the conversion factors (which are found to be in agreement with earlier published estimates obtained from local measurements of experimental fires), the total CO2emissions from wildfires in Siberia in 2012 are estimated to be in the range from 280 to 550 Tg C, with the optimal (maximum likelihood) value of 392 Tg C. Sensitivity test cases featuring different assumptions regarding the injection height and diurnal variations of emissions indicate that the derived estimates of the total CO2emissions in Siberia are robust with respect to the modeling options (the different estimates vary within less than 15% of their magnitude). The CO2emission estimates obtained for several years are compared with independent estimates provided by the GFED3.1 and GFASv1.0 global emission inventories. It is found that our "top-down" estimates for the total annual biomass burning CO2emissions in the period from 2007 to 2011 in Siberia are by factors of 2.5 and 1.8 larger than the respective bottom-up estimates; these discrepancies cannot be fully explained by uncertainties in our estimates. There are also considerable differences in the spatial distribution of the different emission estimates; some of those differences have a systematic character and require further analysis. © Author(s) 2014. CC Attribution 3.0 License.
BibTeX: @article{Konovalov2014, author = {Konovalov, I.B. and Berezin, E.V. and Ciais, P. and Broquet, G. and Beekmann, M. and Hadji-Lazaro, J. and Clerbaux, C. and Andreae, M.O. and Kaiser, J.W. and Schulze, E.-D.}, title = {Constraining CO2emissions from open biomass burning by satellite observations of co-emitted species: A method and its application to wildfires in Siberia}, journal = {Atmospheric Chemistry and Physics}, year = {2014}, volume = {14}, number = {19}, pages = {10383 – 10410}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-14-10383-2014} }
Koukouli ME, Clarisse L, Carboni E, Van Gent J, Spinetti C, Balis D, Dimopoulos S, Grainger R, Theys N, Tampellini L and Zehner C (2014), "Intercomparison of Metop-A SO2 measurements during the 2010- 2011 Icelandic eruptions", Annals of Geophysics. Vol. 57(FastTrack2) [Abstract] [BibTeX] [DOI]
Abstract: The European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards, was introduced after the eruption of the Icelandic volcano Eyjafjallajökull in the spring of 2010 to facilitate the development of an optimal EndtoEnd System for Volcanic Ash Plume Monitoring and Prediction. The Eyjafjallajökull plume drifted towards Europe and caused major disruptions of European air traffic for several weeks affecting the everyday life of millions of people. The limitations in volcanic plume monitoring and prediction capabilities gave birth to this observational system which is based on comprehensive satellitederived ash plume and sulphur dioxide [SO2] level estimates, as well as a widespread validation using supplementary satellite, aircraft and groundbased measurements. Intercomparison of the volcanic total SO2 column and plume height observed by GOME2/MetopA and IASI/MetopA are shown before, during and after the Eyjafjallajökull 2010 eruptions as well as for the 2011 Grímsvötn eruption. Colocated groundbased Brewer Spectrophotometer data extracted from the World Ozone and Ultraviolet Radiation Data Centre for de Bilt, the Netherlands, are also compared to the different satellite estimates. Promising agreement is found for the two different types of instrument for the SO2 columns with linear regression coefficients ranging around from 0.64 when comparing the different instruments and 0.85 when comparing the two different IASI algorithms. The agreement for the plume height is lower, possibly due to the major differences between the height retrieval part of the GOME2 and IASI algorithms. The comparisons with the Brewer groundbased station in de Bilt, The Netherlands show good qualitative agreement for the peak of the event however stronger eruptive signals are required for a longer quantitative comparison. © 2014, Editrice Compositori s.r.l., All rights reserved.
BibTeX: @article{Koukouli2014, author = {Koukouli, Maria Elissavet and Clarisse, Lieven and Carboni, Elisa and Van Gent, Jeroen and Spinetti, Claudia and Balis, Dimitris and Dimopoulos, Spyros and Grainger, Roy and Theys, Nicolas and Tampellini, Lucia and Zehner, Claus}, title = {Intercomparison of Metop-A SO2 measurements during the 2010- 2011 Icelandic eruptions}, journal = {Annals of Geophysics}, year = {2014}, volume = {57}, number = {FastTrack2}, note = {All Open Access, Gold Open Access}, doi = {10.4401/ag-6613} }
Laeng A, Grabowski U, Von Clarmann T, Stiller G, Glatthor N, Höpfner M, Kellmann S, Kiefer M, Linden A, Lossow S, Sofieva V, Petropavlovskikh I, Hubert D, Bathgate T, Bernath P, Boone C, Clerbaux C, Coheur P, Damadeo R, Degenstein D, Frith S, Froidevaux L, Gille J, Hoppel K, Mchugh M, Kasai Y, Lumpe J, Rahpoe N, Toon G, Sano T, Suzuki M, Tamminen J, Urban J, Walker K, Weber M and Zawodny J (2014), "Validation of MIPAS IMK/IAA V5R-O3-224 ozone profiles", Atmospheric Measurement Techniques. Vol. 7(11), pp. 3971 – 3987. [Abstract] [BibTeX] [DOI]
Abstract: We present the results of an extensive validation program of the most recent version of ozone vertical profiles retrieved with the IMK/IAA (Institute for Meteorology and Climate Research/Instituto de Astrofísica de Andalucía) MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) research level 2 processor from version 5 spectral level 1 data. The time period covered corresponds to the reduced spectral resolution period of the MIPAS instrument, i.e., January 2005-April 2012. The comparison with satellite instruments includes all post-2005 satellite limb and occultation sensors that have measured the vertical profiles of tropospheric and stratospheric ozone: ACE-FTS, GOMOS, HALOE, HIRDLS, MLS, OSIRIS, POAM, SAGE II, SCIAMACHY, SMILES, and SMR. In addition, balloon-borne MkIV solar occultation measurements and ground-based Umkehr measurements have been included, as well as two nadir sensors: IASI and SBUV. For each reference data set, bias determination and precision assessment are performed. Better agreement with reference instruments than for the previous data version, V5R-O3-220 (Laeng et al., 2014), is found: the known high bias around the ozone vmr (volume mixing ratio) peak is significantly reduced and the vertical resolution at 35 km has been improved. The agreement with limb and solar occultation reference instruments that have a known small bias vs. ozonesondes is within 7% in the lower and middle stratosphere and 5% in the upper troposphere. Around the ozone vmr peak, the agreement with most of the satellite reference instruments is within 5%; this bias is as low as 3% for ACE-FTS, MLS, OSIRIS, POAM and SBUV. © Author(s) 2014.
BibTeX: @article{Laeng2014, author = {Laeng, A. and Grabowski, U. and Von Clarmann, T. and Stiller, G. and Glatthor, N. and Höpfner, M. and Kellmann, S. and Kiefer, M. and Linden, A. and Lossow, S. and Sofieva, V. and Petropavlovskikh, I. and Hubert, D. and Bathgate, T. and Bernath, P. and Boone, C.D. and Clerbaux, C. and Coheur, P. and Damadeo, R. and Degenstein, D. and Frith, S. and Froidevaux, L. and Gille, J. and Hoppel, K. and Mchugh, M. and Kasai, Y. and Lumpe, J. and Rahpoe, N. and Toon, G. and Sano, T. and Suzuki, M. and Tamminen, J. and Urban, J. and Walker, K. and Weber, M. and Zawodny, J.}, title = {Validation of MIPAS IMK/IAA V5R-O3-224 ozone profiles}, journal = {Atmospheric Measurement Techniques}, year = {2014}, volume = {7}, number = {11}, pages = {3971 – 3987}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-7-3971-2014} }
Loreau J, Liévin J, Scribano Y and Van Der Avoird A (2014), "Potential energy surface and bound states of the NH3-Ar and ND3-Ar complexes", Journal of Chemical Physics. Vol. 141(22) [Abstract] [BibTeX] [DOI]
Abstract: A new, four-dimensional potential energy surface for the interaction of NH3 and ND3 with Ar is computed using the coupled-cluster method with single, double, and perturbative triple excitations and large basis sets. The umbrella motion of the ammonia molecule is explicitly taken into account. The bound states of both NH3-Ar and ND3-Ar are calculated on this potential for total angular momentum values from J = 0 to 10, with the inclusion of Coriolis interactions. The energies and splittings of the rovibrational levels are in excellent agreement with the extensive high-resolution spectroscopic data accumulated over the years in the infrared and microwave regions for both complexes, which demonstrates the quality of the potential energy surface. © 2014 AIP Publishing LLC.
BibTeX: @article{Loreau2014a, author = {Loreau, J. and Liévin, J. and Scribano, Y. and Van Der Avoird, A.}, title = {Potential energy surface and bound states of the NH3-Ar and ND3-Ar complexes}, journal = {Journal of Chemical Physics}, year = {2014}, volume = {141}, number = {22}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.4903047} }
Loreau J, Ryabchenko S and Vaeck N (2014), "Charge transfer in proton-helium collisions from low to high energy", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 47(13) [Abstract] [BibTeX] [DOI]
Abstract: The cross section for charge transfer in proton-helium collisions has been computed in the energy range from 10eV/u up to 10 MeV/u. Four different methods (full quantal time-independent and time-dependent methods, molecular and atomic basis set semi-classical approaches) valid in different energy regimes have been used to calculate the partial and total cross section for single-electron capture. The results are compared with previous theoretical calculations and experimental measurements and the different theoretical methods used are shown to be complementary for describing the charge transfer reaction. A fit of the cross section, valid for collision energies from 10eV/u up to 10 MeV/u is presented based on these results. © 2014 IOP Publishing Ltd.
BibTeX: @article{Loreau2014, author = {Loreau, J. and Ryabchenko, S. and Vaeck, N.}, title = {Charge transfer in proton-helium collisions from low to high energy}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2014}, volume = {47}, number = {13}, doi = {10.1088/0953-4075/47/13/135204} }
Lyulin O, Mondelain D, Béguier S, Kassi S, Vander Auwera J and Campargue A (2014), "High-sensitivity CRDS absorption spectroscopy of acetylene between 5851 and 6341 cm-1", Molecular Physics. Vol. 112(18), pp. 2433 – 2444. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of acetylene has been recorded at room temperature (297 K) using high-sensitivity cavity ring-down spectroscopy (αmin ∼ 5×10-11 cm-1) in the 5851 and 6341 cm-1 interval corresponding to a region of very weak absorption. A list of about 10,700 absorption features with estimated absolute line intensities was constructed. The smallest intensities are of the order of 5×10-29 cm molecule-1. The line list includes about 2500 absorption lines of ethylene present at the ppm level in the acetylene sample and identified on the basis of a high-resolution Fourier transform spectrum specifically recorded. A total of more than 2700 lines of 12C2H2 were rovibrationally assigned in comparison with accurate predictions provided by a global effective operator model. Overall, the present effort adds about 2260 new assignments to the set of about 500 assigned transitions available in the literature. The new assignments correspond to 45 new bands and 17 already-known bands, for which additional J lines were assigned. Spectroscopic parameters were derived for the upper vibrational levels from a band by band fit of the line positions (typical root mean square deviation values are of the order of 0.001 cm-1). A few of the analysed bands were found to be affected by rovibrational perturbations, which are discussed. The new data will be valuable to refine the parameters of the global effective Hamiltonian and dipole moments of 12C2H2. © 2014 Taylor & Francis.
BibTeX: @article{Lyulin2014, author = {Lyulin, O.M. and Mondelain, D. and Béguier, S. and Kassi, S. and Vander Auwera, J. and Campargue, A.}, title = {High-sensitivity CRDS absorption spectroscopy of acetylene between 5851 and 6341 cm-1}, journal = {Molecular Physics}, year = {2014}, volume = {112}, number = {18}, pages = {2433 – 2444}, doi = {10.1080/00268976.2014.906677} }
Mahieu E, Chipperfield M, Notholt J, Reddmann T, Anderson J, Bernath P, Blumenstock T, Coffey M, Dhomse S, Feng W, Franco B, Froidevaux L, Griffith D, Hannigan J, Hase F, Hossaini R, Jones N, Morino I, Murata I, Nakajima H, Palm M, Paton-Walsh C, Russell J, Schneider M, Servais C, Smale D and Walker K (2014), "Recent Northern Hemisphere stratospheric HCl increase due to atmospheric circulation changes", Nature. Vol. 515(7525), pp. 104 – 107. [Abstract] [BibTeX] [DOI]
Abstract: The abundance of chlorine in the Earth's atmosphere increased considerably during the 1970s to 1990s, following large emissions of anthropogenic long-lived chlorine-containing source gases, notably the chlorofluorocarbons. The chemical inertness of chlorofluorocarbons allows their transport and mixing throughout the troposphere on a global scale, before they reach the stratosphere where they release chlorine atoms that cause ozone depletion. The large ozone loss over Antarctica was the key observation that stimulated the definition and signing in 1987 of the Montreal Protocol, an international treaty establishing a schedule to reduce the production of the major chlorine- and bromine-containing halocarbons. Owing to its implementation, the near-surface total chlorine concentration showed a maximum in 1993, followed by a decrease of half a per cent to one per cent per year, in line with expectations. Remote-sensing data have revealed a peak in stratospheric chlorine after 1996, then a decrease of close to one per cent per year, in agreement with the surface observations of the chlorine source gases and model calculations. Here we present ground-based and satellite data that show a recent and significant increase, at the 2σ level, in hydrogen chloride (HCl), the main stratospheric chlorine reservoir, starting around 2007 in the lower stratosphere of the Northern Hemisphere, in contrast with the ongoing monotonic decrease of near-surface source gases. Using model simulations, we attribute this trend anomaly to a slowdown in the Northern Hemisphere atmospheric circulation, occurring over several consecutive years, transporting more aged air to the lower stratosphere, and characterized by a larger relative conversion of source gases to HCl. This short-term dynamical variability will also affect other stratospheric tracers and needs to be accounted for when studying the evolution of the stratospheric ozone layer. ©2014 Macmillan Publishers Limited. All rights reserved.
BibTeX: @article{Mahieu2014, author = {Mahieu, E. and Chipperfield, M.P. and Notholt, J. and Reddmann, T. and Anderson, J. and Bernath, P.F. and Blumenstock, T. and Coffey, M.T. and Dhomse, S.S. and Feng, W. and Franco, B. and Froidevaux, L. and Griffith, D.W.T. and Hannigan, J.W. and Hase, F. and Hossaini, R. and Jones, N.B. and Morino, I. and Murata, I. and Nakajima, H. and Palm, M. and Paton-Walsh, C. and Russell, J.M. and Schneider, M. and Servais, C. and Smale, D. and Walker, K.A.}, title = {Recent Northern Hemisphere stratospheric HCl increase due to atmospheric circulation changes}, journal = {Nature}, year = {2014}, volume = {515}, number = {7525}, pages = {104 – 107}, doi = {10.1038/nature13857} }
Masseron T, Plez B, Van Eck S, Colin R, Daoutidis I, Godefroid M, Coheur P-F, Bernath P, Jorissen A and Christlieb N (2014), "CH in stellar atmospheres: An extensive linelist", Astronomy and Astrophysics. Vol. 571 [Abstract] [BibTeX] [DOI]
Abstract: The advent of high-resolution spectrographs and detailed stellar atmosphere modelling has strengthened the need for accurate molecular data. Carbon-enhanced metal-poor (CEMP) stars spectra are interesting objects with which to study transitions from the CH molecule. We combine programs for spectral analysis of molecules and stellar-radiative transfer codes to build an extensive CH linelist, including predissociation broadening as well as newly identified levels. We show examples of strong predissociation CH lines in CEMP stars, and we stress the important role played by the CH features in the Bond-Neff feature depressing the spectra of barium stars by as much as 0.2 mag in the λ = 3000-5500 Å range. Because of the extreme thermodynamic conditions prevailing in stellar atmospheres (compared to the laboratory), molecular transitions with high energy levels can be observed. Stellar spectra can thus be used to constrain and improve molecular data. © 2014 ESO.
BibTeX: @article{Masseron2014, author = {Masseron, T. and Plez, B. and Van Eck, S. and Colin, R. and Daoutidis, I. and Godefroid, M. and Coheur, P.-F. and Bernath, P. and Jorissen, A. and Christlieb, N.}, title = {CH in stellar atmospheres: An extensive linelist}, journal = {Astronomy and Astrophysics}, year = {2014}, volume = {571}, note = {All Open Access, Bronze Open Access}, doi = {10.1051/0004-6361/201423956} }
Moxnes E, Kristiansen N, Stohl A, Clarisse L, Durant A, Weber K and Vogel A (2014), "Separation of ash and sulfur dioxide during the 2011 Grímsvötn eruption", Journal of Geophysical Research: Atmospheres. Vol. 119(12), pp. 7477 – 7501. [Abstract] [BibTeX] [DOI]
Abstract: Modeling the transport of volcanic ash and gases released during volcanic eruptions is crucially dependent on knowledge of the source term of the eruption, that is, the source strength as a function of altitude and time. For the first time, an inversion method is used to estimate the source terms of both volcanic sulfur dioxide (SO2) and ash. It was applied to the explosive volcanic eruption of Grímsvötn, Iceland, in May 2011. The method uses input from the particle dispersion model, FLEXPART (flexible particle dispersion model), a priori source estimates, and satellite observations of SO2 or ash total columns from Infrared Atmospheric Sounding Interferometer to separately obtain the source terms for volcanic SO2 and fine ash. The estimated source terms show that SO2 was emitted mostly to high altitudes (5 to 13 km) during about 18 h (22 May, 00-18 UTC) while fine ash was emitted mostly to low altitudes (below 4 km) during roughly 24 h (22 May 06 UTC to 23 May 06 UTC). FLEXPART simulations using the estimated source terms show a clear separation of SO2 (transported mostly northwestward) and the fine ash (transported mostly southeastward). This corresponds well with independent satellite observations and measured aerosol mass concentrations and lidar measurements at surface stations in Scandinavia. Aircraft measurements above Iceland and Germany confirmed that the ash was located in the lower atmosphere. This demonstrates that the inversion method, in this case, is able to distinguish between emission heights of SO2 and ash and can capture resulting differences in transport patterns. Key Points Ash and SO2 source terms estimated using inverse techniques and satellite data The transport and separation of ash and SO2 are modeled Model simulations correspond well with a range of independent observations ©2014. The Authors.
BibTeX: @article{Moxnes2014, author = {Moxnes, E.D. and Kristiansen, N.I. and Stohl, A. and Clarisse, L. and Durant, A. and Weber, K. and Vogel, A.}, title = {Separation of ash and sulfur dioxide during the 2011 Grímsvötn eruption}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2014}, volume = {119}, number = {12}, pages = {7477 – 7501}, note = {All Open Access, Green Open Access}, doi = {10.1002/2013JD021129} }
Nazé C, Verdebout S, Rynkun P, Gaigalas G, Godefroid M and Jönsson P (2014), "Isotope shifts in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations", Atomic Data and Nuclear Data Tables. Vol. 100(5), pp. 1197 – 1249. [Abstract] [BibTeX] [DOI]
Abstract: Energy levels, normal and specific mass shift parameters as well as electronic densities at the nucleus are reported for numerous states along the beryllium, boron, carbon, and nitrogen isoelectronic sequences. Combined with nuclear data, these electronic parameters can be used to determine values of level and transition isotope shifts. The calculation of the electronic parameters is done using first-order perturbation theory with relativistic configuration interaction wavefunctions that account for valence, core-valence, and core-core correlation effects as zero-order functions. Results are compared with experimental and other theoretical values, when available. © 2014 Elsevier Inc.
BibTeX: @article{Naze2014, author = {Nazé, C. and Verdebout, S. and Rynkun, P. and Gaigalas, G. and Godefroid, M. and Jönsson, P.}, title = {Isotope shifts in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations}, journal = {Atomic Data and Nuclear Data Tables}, year = {2014}, volume = {100}, number = {5}, pages = {1197 – 1249}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.adt.2014.02.004} }
Oetjen H, Payne V, Kulawik S, Eldering A, Worden J, Edwards D, Francis G, Worden H, Clerbaux C, Hadji-Lazaro J and Hurtmans D (2014), "Extending the satellite data record of tropospheric ozone profiles from Aura-TES to MetOp-IASI: Characterisation of optimal estimation retrievals", Atmospheric Measurement Techniques. Vol. 7(12), pp. 4223 – 4236. [Abstract] [BibTeX] [DOI]
Abstract: We apply the Tropospheric Emission Spectrometer (TES) ozone retrieval algorithm to Infrared Atmospheric Sounding Instrument (IASI) radiances and characterise the uncertainties and information content of the retrieved ozone profiles. This study focuses on mid-latitudes for the year 2008. We validate our results by comparing the IASI ozone profiles to ozone sondes. In the sonde comparisons, we find a negative bias (1-10%) in the IASI profiles in the lower to mid-troposphere and a positive bias (up to 14%) in the upper troposphere/lower stratosphere (UTLS) region. For the described cases, the degrees of freedom for signal are on average 3.2, 0.3, 0.8, and 0.9 for the columns 0 km - top of atmosphere, (0-6), (0-11), and (8-16) km, respectively. We find that our biases with respect to sondes and our degrees of freedom for signal for ozone are comparable to previously published results from other IASI ozone algorithms. In addition to evaluating biases, we validate the retrieval errors by comparing predicted errors to the sample covariance matrix of the IASI observations themselves. For the predicted versus empirical error comparison, we find that these errors are consistent and that the measurement noise and the interference of temperature and water vapour on the retrieval together mostly explain the empirically derived random errors. In general, the precision of the IASI ozone profiles is better than 20%. © 2014 Author(s).
BibTeX: @article{Oetjen2014, author = {Oetjen, H. and Payne, V.H. and Kulawik, S.S. and Eldering, A. and Worden, J. and Edwards, D.P. and Francis, G.L. and Worden, H.M. and Clerbaux, C. and Hadji-Lazaro, J. and Hurtmans, D.}, title = {Extending the satellite data record of tropospheric ozone profiles from Aura-TES to MetOp-IASI: Characterisation of optimal estimation retrievals}, journal = {Atmospheric Measurement Techniques}, year = {2014}, volume = {7}, number = {12}, pages = {4223 – 4236}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-7-4223-2014} }
Pommier M, Lacour J-L, Risi C, Bréon F, Clerbaux C, Coheur P-F, Gribanov K, Hurtmans D, Jouzel J and Zakharov V (2014), "Observation of tropospheric δd by IASI over western Siberia: Comparison with a general circulation model", Atmospheric Measurement Techniques. Vol. 7(6), pp. 1581 – 1595. [Abstract] [BibTeX] [DOI]
Abstract: This study presents the joint H2 16O and HDO retrieval from Infrared Atmospheric Sounding Interferometer (IASI) spectra over western Siberia. IASI is an instrument on board the MetOp-A European satellite. The global coverage of the instrument and the good signal-to-noise ratio allow us to provide information on δD over this remote region. We show that IASI measurements may be used to estimate integrated δD between the surface and 3 km altitude or from 1 to 5 km depending on the thermal contrast, with observational errors lower than 4% and 7 %, respectively. The retrieved data are compared to simulations from an isotopic general circulation model, LMDZ-iso for 2011. The satellite measurements and the model agree well and they reproduce well the seasonal and day-to-day variations for δD, presenting a good correlation (r up to 0.8 with the smoothed data in summer). The IASI-based retrievals also show the seasonal variation of the specific humidity in both altitude ranges. © Author(s) 2014.
BibTeX: @article{Pommier2014, author = {Pommier, M. and Lacour, J.-L. and Risi, C. and Bréon, F.M. and Clerbaux, C. and Coheur, P.-F. and Gribanov, K. and Hurtmans, D. and Jouzel, J. and Zakharov, V.}, title = {Observation of tropospheric δd by IASI over western Siberia: Comparison with a general circulation model}, journal = {Atmospheric Measurement Techniques}, year = {2014}, volume = {7}, number = {6}, pages = {1581 – 1595}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-7-1581-2014} }
Riffet V, Jacquemin D, Cauët E and Frison G (2014), "Benchmarking DFT and TD-DFT functionals for the ground and excited states of hydrogen-rich peptide radicals", Journal of Chemical Theory and Computation. Vol. 10(8), pp. 3308 – 3318. [Abstract] [BibTeX] [DOI]
Abstract: We assess the pros and cons of a large panel of DFT exchange-correlation functionals for the prediction of the electronic structure of hydrogen-rich peptide radicals formed after electron attachment on a protonated peptide. Indeed, despite its importance in the understanding of the chemical changes associated with the reduction step, the question of the attachment site of an electron and, more generally, of the reduced species formed in the gas phase through electron-induced dissociation (ExD) processes in mass spectrometry is still a matter of debate. For hydrogen-rich peptide radicals in which several positive groups and low-lying π* orbitals can capture the incoming electron in ExD, inclusion of full Hartree-Fock exchange at long-range interelectronic distance is a prerequisite for an accurate description of the electronic states, thereby excluding several popular exchange-correlation functionals, e.g., B3LYP, M06-2X, or CAM-B3LYP. However, we show that this condition is not sufficient by comparing the results obtained with asymptotically correct range-separated hybrids (M11, LC-BLYP, LC-BPW91, ωB97, ωB97X, and ωB97X-D) and with reference CASSCF-MRCI and EOM-CCSD calculations. The attenuation parameter ω significantly tunes the spin density distribution and the excited states vertical energies. The investigated model structures, ranging from methylammonium to hexapeptide, allow us to obtain a description of the nature and energy of the electronic states, depending on (i) the presence of hydrogen bond(s) around the cationic site(s), (ii) the presence of π* molecular orbitals (MOs), and (iii) the selected DFT approach. It turns out that, in the present framework, LC-BLYP and ωB97 yields the most accurate results. © 2014 American Chemical Society.
BibTeX: @article{Riffet2014, author = {Riffet, Vanessa and Jacquemin, Denis and Cauët, Emilie and Frison, Gilles}, title = {Benchmarking DFT and TD-DFT functionals for the ground and excited states of hydrogen-rich peptide radicals}, journal = {Journal of Chemical Theory and Computation}, year = {2014}, volume = {10}, number = {8}, pages = {3308 – 3318}, doi = {10.1021/ct5004912} }
Safieddine S, Boynard A, Coheur P-F, Hurtmans D, Pfister G, Quennehen B, Thomas J, Raut J-C, Law K, Klimont Z, Hadji-Lazaro J, George M and Clerbaux C (2014), "Summertime tropospheric ozone assessment over the Mediterranean region using the thermal infrared IASI/MetOp sounder and the WRF-Chem model", Atmospheric Chemistry and Physics. Vol. 14(18), pp. 10119 – 10131. [Abstract] [BibTeX] [DOI]
Abstract: Over the Mediterranean region, elevated tropospheric ozone (O3) values are recorded, especially in summer. We use the thermal Infrared Atmospheric Sounding Interferometer (IASI) and the Weather Research and Forecasting Model with Chemistry (WRF-Chem) to understand and interpret the factors and emission sources responsible for the high O3concentrations observed in the Mediterranean troposphere. Six years (2008-2013) of IASI data have been analyzed and results show consistent maxima during summer, with an increase of up to 22% in the [0-8] km O3column in the eastern part of the basin compared to the middle of the basin. We focus on summer 2010 to investigate the processes that contribute to these summer maxima. Using two modeled O3tracers (inflow to the model domain and local anthropogenic emissions), we show that, between the surface and 2 km, O3is mostly formed from anthropogenic emissions, while above 4 km it is mostly transported from outside the domain or from stratospheric origins. Evidence of stratosphere-to-troposphere exchange (STE) events in the eastern part of the basin is shown, and corresponds to a low water vapor mixing ratio and high potential vorticity. © 2014 Author(s).
BibTeX: @article{Safieddine2014, author = {Safieddine, S. and Boynard, A. and Coheur, P.-F. and Hurtmans, D. and Pfister, G. and Quennehen, B. and Thomas, J.L. and Raut, J.-C. and Law, K.S. and Klimont, Z. and Hadji-Lazaro, J. and George, M. and Clerbaux, C.}, title = {Summertime tropospheric ozone assessment over the Mediterranean region using the thermal infrared IASI/MetOp sounder and the WRF-Chem model}, journal = {Atmospheric Chemistry and Physics}, year = {2014}, volume = {14}, number = {18}, pages = {10119 – 10131}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-14-10119-2014} }
Softley TP, Császár AG, De Natale P, Herman M and Quack M (2014), "Special issue: 23rd Colloquium on High Resolution Molecular Spectroscopy", Molecular Physics. Vol. 112(18), pp. 2373. [BibTeX] [DOI]
BibTeX: @article{Softley2014, author = {Softley, Timothy P. and Császár, Attila G. and De Natale, Paolo and Herman, Michel and Quack, Martin}, title = {Special issue: 23rd Colloquium on High Resolution Molecular Spectroscopy}, journal = {Molecular Physics}, year = {2014}, volume = {112}, number = {18}, pages = {2373}, note = {All Open Access, Bronze Open Access}, doi = {10.1080/00268976.2014.943982} }
Spinetti C, Salerno GG, Caltabiano T, Carboni E, Clarisse L, Corradini S, Grainger RG, Hedelt PA, Koukouli ME, Merucci L, Siddans R, Tampellini L, Theys N, Valks P and Zehner C (2014), "Volcanic SO2 by UV-TIR satellite retrievals: Validation by using ground-based network at Mt. Etna", Annals of Geophysics. Vol. 57(FastTrack2) [Abstract] [BibTeX] [DOI]
Abstract: Mt. Etna volcano in Italy is one of the most active degassing volcanoes worldwide, emitting a mean of 1.7 Mt/year of Sulphur Dioxide (SO2) in quiescent periods. In this work, SO2 measurements retrieved by Moderate Resolution Imaging Spectroradiometer (MODIS), hyper-spectral Infrared Atmospheric Sounding Interferometer (IASI) and the second Global Ozone Monitoring Experiment (GOME-2) data are compared with the ground-based data from the FLux Automatic MEasurement monitoring network (FLAME). Among the eighteen lava fountain episodes occurring at Mt. Etna in 2011, the 10 April paroxysmal event has been selected as a case-study for the simultaneous observation of the SO2 cloud by satellite and ground-based sensors. For each data-set two retrieval techniques were adopted and the measurements of SO2 mass and flux with their respective uncertainty were obtained. With respect to the FLAME SO2 mass of 4.5 Gg, MODIS, IASI and GOME-2 differ by about 10%, 15% and 30%, respectively. The SO2 flux correlation coefficient between MODIS and FLAME is 0.84. All the retrievals within the respective errors are in agreement with the ground-based measurements supporting the validity of these space measurements. © 2014, Editrice Compositori s.r.l. All rights reserved.
BibTeX: @article{Spinetti2014, author = {Spinetti, Claudia and Salerno, Giuseppe Giovanni and Caltabiano, Tommaso and Carboni, Elisa and Clarisse, Lieven and Corradini, Stefano and Grainger, Roy Gordon and Hedelt, Pascal Andre and Koukouli, Maria Elissavet and Merucci, Luca and Siddans, Richard and Tampellini, Lucia and Theys, Nicolas and Valks, Pieter and Zehner, Claus}, title = {Volcanic SO2 by UV-TIR satellite retrievals: Validation by using ground-based network at Mt. Etna}, journal = {Annals of Geophysics}, year = {2014}, volume = {57}, number = {FastTrack2}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.4401/ag-6641} }
Stein O, Schultz M, Bouarar I, Clark H, Huijnen V, Gaudel A, George M and Clerbaux C (2014), "On the wintertime low bias of Northern Hemisphere carbon monoxide found in global model simulations", Atmospheric Chemistry and Physics. Vol. 14(17), pp. 9295 – 9316. [Abstract] [BibTeX] [DOI]
Abstract: Despite the developments in the global modelling of chemistry and of the parameterization of the physical processes, carbon monoxide (CO) concentrations remain underestimated during Northern Hemisphere (NH) winter by most state-of-the-art chemistry transport models. The consequential model bias can in principle originate from either an underestimation of CO sources or an overestimation of its sinks. We address both the role of surface sources and sinks with a series of MOZART (Model for Ozone And Related Tracers) model sensitivity studies for the year 2008 and compare our results to observational data from ground-based stations, satellite observations, and vertical profiles from measurements on passenger aircraft. In our base case simulation using MACCity (Monitoring Atmospheric Composition and Climate project) anthropogenic emissions, the near-surface CO mixing ratios are underestimated in the Northern Hemisphere by more than 20 ppb from December to April, with the largest bias of up to 75 ppb over Europe in January. An increase in global biomass burning or biogenic emissions of CO or volatile organic compounds (VOCs) is not able to reduce the annual course of the model bias and yields concentrations over the Southern Hemisphere which are too high. Raising global annual anthropogenic emissions with a simple scaling factor results in overestimations of surface mixing ratios in most regions all year round. Instead, our results indicate that anthropogenic CO and, possibly, VOC emissions in the MACCity inventory are too low for the industrialized countries only during winter and spring. Reasonable agreement with observations can only be achieved if the CO emissions are adjusted seasonally with regionally varying scaling factors. A part of the model bias could also be eliminated by exchanging the original resistance-type dry deposition scheme with a parameterization for CO uptake by oxidation from soil bacteria and microbes, which reduces the boreal winter dry deposition fluxes. The best match to surface observations, satellite retrievals, and aircraft observations was achieved when the modified dry deposition scheme was combined with increased wintertime road traffic emissions over Europe and North America (factors up to 4.5 and 2, respectively). One reason for the apparent underestimation of emissions may be an exaggerated downward trend in the Representative Concentration Pathway (RCP) 8.5 scenario in these regions between 2000 and 2010, as this scenario was used to extrapolate the MACCity emissions from their base year 2000. This factor is potentially amplified by a lack of knowledge about the seasonality of emissions. A methane lifetime of 9.7 yr for our basic model and 9.8 yr for the optimized simulation agrees well with current estimates of global OH, but we cannot fully exclude a potential effect from errors in the geographical and seasonal distribution of OH concentrations on the modelled CO. © Author(s) 2014. CC Attribution 3.0 License.
BibTeX: @article{Stein2014, author = {Stein, O. and Schultz, M.G. and Bouarar, I. and Clark, H. and Huijnen, V. and Gaudel, A. and George, M. and Clerbaux, C.}, title = {On the wintertime low bias of Northern Hemisphere carbon monoxide found in global model simulations}, journal = {Atmospheric Chemistry and Physics}, year = {2014}, volume = {14}, number = {17}, pages = {9295 – 9316}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-14-9295-2014} }
Sugny D, Vranckx S, Ndong M, Vaeck N, Atabek O and Desouter-Lecomte M (2014), "Control of molecular dynamics with zero-area fields: Application to molecular orientation and photofragmentation", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 90(5) [Abstract] [BibTeX] [DOI]
Abstract: The constraint of time-integrated zero area on the laser field is a fundamental requirement, both theoretically and experimentally, in the control of molecular dynamics. By using techniques of local and optimal control theory, we show how to enforce this constraint in two benchmark control problems, namely, molecular orientation and photofragmentation. The origin and the physical implications for the dynamics of this zero-area control field are discussed. © 2014 American Physical Society.
BibTeX: @article{Sugny2014, author = {Sugny, Dominique and Vranckx, Stéphane and Ndong, Mamadou and Vaeck, Nathalie and Atabek, Osman and Desouter-Lecomte, Michèle}, title = {Control of molecular dynamics with zero-area fields: Application to molecular orientation and photofragmentation}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2014}, volume = {90}, number = {5}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.90.053404} }
Sutcliffe BT and Woolley RG (2014), "Comment on "on the quantum theory of molecules" [J. Chem. Phys. 137, 22A544 (2012)]", Journal of Chemical Physics. Vol. 140(3) [Abstract] [BibTeX] [DOI]
Abstract: In our previous paper [B. T. Sutcliffe and R. G. Woolley, J. Chem. Phys. 137, 22A544 (2012)] we argued that the Born-Oppenheimer approximation could not be based on an exact transformation of the molecular Schrödinger equation. In this Comment we suggest that the fundamental reason for the approximate nature of the Born-Oppenheimer model is the lack of a complete set of functions for the electronic space, and the need to describe the continuous spectrum using spectral projection. © 2014 AIP Publishing LLC.
BibTeX: @article{Sutcliffe2014, author = {Sutcliffe, Brian T. and Woolley, R. Guy}, title = {Comment on "on the quantum theory of molecules" [J. Chem. Phys. 137, 22A544 (2012)]}, journal = {Journal of Chemical Physics}, year = {2014}, volume = {140}, number = {3}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1063/1.4861897} }
Theys N, De Smedt I, Van Roozendael M, Froidevaux L, Clarisse L and Hendrick F (2014), "First satellite detection of volcanic OClO after the eruption of Puyehue-Cordõn Caulle", Geophysical Research Letters. Vol. 41(2), pp. 667 – 672. [Abstract] [BibTeX] [DOI]
Abstract: Volcanoes release large amounts of halogen species such as HCl and HBr, which can be converted into reactive halogens by heterogeneous photochemical reactions that are currently not fully characterized. Here we report on the first satellite detection of volcanic chlorine dioxide (OClO). Measurements were performed using the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography instrument for the ash-laden plume emitted after the 2011 eruption of Puyehue-Cordõn Caulle in Chile. We also identified volcanic BrO using the Ozone Monitoring Instrument, as well as enhanced HCl in data of the Microwave Limb Sounder instrument. These observations suggest that OClO was formed in the plume by the ClO + BrO reaction in presence of a large excess of ClO. The present satellite data set could help better understand reactive halogen chemistry in volcanic plumes and its impact on atmospheric composition. ©2013. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Theys2014, author = {Theys, Nicolas and De Smedt, Isabelle and Van Roozendael, Michel and Froidevaux, Lucien and Clarisse, Lieven and Hendrick, François}, title = {First satellite detection of volcanic OClO after the eruption of Puyehue-Cordõn Caulle}, journal = {Geophysical Research Letters}, year = {2014}, volume = {41}, number = {2}, pages = {667 – 672}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2013GL058416} }
Van Damme M, Clarisse L, Heald C, Hurtmans D, Ngadi Y, Clerbaux C, Dolman A, Erisman J and Coheur P (2014), "Global distributions, time series and error characterization of atmospheric ammonia (NH3) from IASI satellite observations", Atmospheric Chemistry and Physics. Vol. 14(6), pp. 2905 – 2922. [Abstract] [BibTeX] [DOI]
Abstract: Ammonia (NH3) emissions in the atmosphere have increased substantially over the past decades, largely because of intensive livestock production and use of fertilizers. As a short-lived species, NH3 is highly variable in the atmosphere and its concentration is generally small, except near local sources. While ground-based measurements are possible, they are challenging and sparse. Advanced infrared sounders in orbit have recently demonstrated their capability to measure NH3, offering a new tool to refine global and regional budgets. In this paper we describe an improved retrieval scheme of NH3 total columns from the measurements of the Infrared Atmospheric Sounding Interferometer (IASI). It exploits the hyperspectral character of this instrument by using an extended spectral range (800-1200 cm-1) where NH3 is optically active. This scheme consists of the calculation of a dimensionless spectral index from the IASI level1C radiances, which is subsequently converted to a total NH3 column using look-up tables built from forward radiative transfer model simulations. We show how to retrieve the NH3 total columns from IASI quasi-globally and twice daily above both land and sea without large computational resources and with an improved detection limit. The retrieval also includes error characterization of the retrieved columns. Five years of IASI measurements (1 November 2007 to 31 October 2012) have been processed to acquire the first global and multiple-year data set of NH3 total columns, which are evaluated and compared to similar products from other retrieval methods. Spatial distributions from the five years data set are provided and analyzed at global and regional scales. In particular, we show the ability of this method to identify smaller emission sources than those previously reported, as well as transport patterns over the ocean. The five-year time series is further examined in terms of seasonality and interannual variability (in particular as a function of fire activity) separately for the Northern and Southern Hemispheres. © Author(s) 2014.
BibTeX: @article{VanDamme2014a, author = {Van Damme, M. and Clarisse, L. and Heald, C.L. and Hurtmans, D. and Ngadi, Y. and Clerbaux, C. and Dolman, A.J. and Erisman, J.W. and Coheur, P.F.}, title = {Global distributions, time series and error characterization of atmospheric ammonia (NH3) from IASI satellite observations}, journal = {Atmospheric Chemistry and Physics}, year = {2014}, volume = {14}, number = {6}, pages = {2905 – 2922}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-14-2905-2014} }
Van Damme M, Wichink Kruit R, Schaap M, Clarisse L, Clerbaux C, Coheur P-F, Dammers E, Dolman A and Erisman J (2014), "Evaluating 4 years of atmospheric ammonia (NH3) over Europe using IASI satellite observations and LOTOS-EUROS model results", Journal of Geophysical Research. Vol. 119(15), pp. 9549 – 9566. [Abstract] [BibTeX] [DOI]
Abstract: Monitoring ammonia (NH3) concentrations on a global to regional scale is a challenge. Due to the limited availability of reliable ground-based measurements, the determination of NH3 distributions generally relies on model calculations. Novel remotely sensed NH3 burdens provide valuable insights to complement traditional assessments for clear-sky conditions. This paper presents a first quantitative comparison between Atmospheric Sounding Interferometer (IASI) satellite observations and LOTOS-EUROS model results over Europe and Western Russia. A methodology to account for the variable retrieval sensitivity of the measurements is described. Four years of data (2008–2011) highlight three main agricultural hot spot areas in Europe: the Po Valley, the continental part of Northwestern Europe, and the Ebro Valley. The spatial comparison reveals a good overall agreement of the NH3 distributions not only in these source regions but also over remote areas and over sea when transport is observed. On average, the measured columns exceed the modeled ones, except for a few cases. Large discrepancies over several industrial areas in Eastern Europe and Russia point to underestimated emissions in the underlying inventories. The temporal analysis over the three hot spot areas reveals that the seasonality is well captured by the model when the lower sensitivity of the satellite measurements in the colder months is taken into account. Comparison of the daily time series indicates possible misrepresentations of the timing and magnitude of the emissions. Finally, specific attention to biomass burning events shows that modeled plumes are less spread out than the observed ones. This is confirmed for the 2010 Russian fires with a comparison using in situ observations. © 2014. American Geophysical Union. All Rights Reserved.
BibTeX: @article{VanDamme2014, author = {Van Damme, M. and Wichink Kruit, R.J. and Schaap, M. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Dammers, E. and Dolman, A.J. and Erisman, J.W.}, title = {Evaluating 4 years of atmospheric ammonia (NH3) over Europe using IASI satellite observations and LOTOS-EUROS model results}, journal = {Journal of Geophysical Research}, year = {2014}, volume = {119}, number = {15}, pages = {9549 – 9566}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2014JD021911} }
Vander Auwera J, Fayt A, Tudorie M, Rotger M, Boudon V, Franco B and Mahieu E (2014), "Self-broadening coefficients and improved line intensities for the ν7 band of ethylene near 10.5 μm, and impact on ethylene retrievals from Jungfraujoch solar spectra", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 148, pp. 177 – 185. [Abstract] [BibTeX] [DOI]
Abstract: Relying on high-resolution Fourier transform infrared (FTIR) spectra, the present work involved extensive measurements of individual line intensities and self-broadening coefficients for the ν7 band of 12C2H4. The measured self-broadening coefficients exhibit a dependence on both J and Ka. Compared to the corresponding information available in the latest edition of the HITRAN spectroscopic database, the measured line intensities were found to be higher by about 10% for high J lines in the P branch and lower by about 5% for high J lines of the R branch, varying between these two limits roughly linearly with the line positions. The impact of the presently measured line intensities on retrievals of atmospheric ethylene in the 949.0-952.0cm-1 microwindow was evaluated using a subset of ground-based high-resolution FTIR solar spectra recorded at the Jungfraujoch station. The use of HITRAN 2012 with line intensities modified to match the present measurements led to a systematic reduction of the measured total columns of ethylene by -4.1 ± 0.1 %. © 2014 Elsevier Ltd.
BibTeX: @article{VanderAuwera2014, author = {Vander Auwera, J. and Fayt, A. and Tudorie, M. and Rotger, M. and Boudon, V. and Franco, B. and Mahieu, E.}, title = {Self-broadening coefficients and improved line intensities for the ν7 band of ethylene near 10.5 μm, and impact on ethylene retrievals from Jungfraujoch solar spectra}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2014}, volume = {148}, pages = {177 – 185}, doi = {10.1016/j.jqsrt.2014.07.003} }
Verdebout S, Nazé C, Jönsson P, Rynkun P, Godefroid M and Gaigalas G (2014), "Hyperfine structures and Landé gJ-factors for n=2 states in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations", Atomic Data and Nuclear Data Tables. Vol. 100(5), pp. 1111 – 1155. [Abstract] [BibTeX] [DOI]
Abstract: Energy levels, hyperfine interaction constants, and Landé gJ-factors are reported for n=2 states in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations. Valence, core-valence, and core-core correlation effects are taken into account through single and double-excitations from multireference expansions to increasing sets of active orbitals. A systematic comparison of the calculated hyperfine interaction constants is made with values from the available literature. © 2014 Elsevier Inc.
BibTeX: @article{Verdebout2014, author = {Verdebout, S. and Nazé, C. and Jönsson, P. and Rynkun, P. and Godefroid, M. and Gaigalas, G.}, title = {Hyperfine structures and Landé gJ-factors for n=2 states in beryllium-, boron-, carbon-, and nitrogen-like ions from relativistic configuration interaction calculations}, journal = {Atomic Data and Nuclear Data Tables}, year = {2014}, volume = {100}, number = {5}, pages = {1111 – 1155}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.adt.2014.05.001} }
Berger G, Gelbcke M, Cauët E, Luhmer M, Nève J and Dufrasne F (2013), "Synthesis of 15N-labeled vicinal diamines through N-activated chiral aziridines: Tools for the NMR study of platinum-based anticancer compounds", Tetrahedron Letters. Vol. 54(6), pp. 545 – 548. [Abstract] [BibTeX] [DOI]
Abstract: A new method for the synthesis of 15N-labeled chiral β-diamines from a common precursor, either optically pure amino acids or anti-β-amino alcohols, is reported. The two diastereomeric series of vicinal diamines are produced through the nucleophilic ring opening of activated chiral aziridines. 15N was introduced by means of [ 15N]-benzylamine, prepared from 15NH4Cl. The final compounds are highly valuable because [1H-15N] NMR is considered a powerful tool for studying the chemical properties of platinum-based complexes. © 2012 Published by Elsevier Ltd.
BibTeX: @article{Berger2013, author = {Berger, Gilles and Gelbcke, Michel and Cauët, Emilie and Luhmer, Michel and Nève, Jean and Dufrasne, François}, title = {Synthesis of 15N-labeled vicinal diamines through N-activated chiral aziridines: Tools for the NMR study of platinum-based anticancer compounds}, journal = {Tetrahedron Letters}, year = {2013}, volume = {54}, number = {6}, pages = {545 – 548}, doi = {10.1016/j.tetlet.2012.11.079} }
Bogatko S, Cauët E, Bylaska E, Schenter G, Fulton J and Weare J (2013), "The aqueous Ca2+ system, in comparison with Zn2+, Fe3 +, and Al3 +: An ab initio molecular dynamics study", Chemistry - A European Journal. Vol. 19(9), pp. 3047 – 3060. [Abstract] [BibTeX] [DOI]
Abstract: Herein, we report on the structure and dynamics of the aqueous Ca 2+ system studied by using ab initio molecular dynamics (AIMD) simulations. Our detailed study revealed the formation of well-formed hydration shells with characteristics that were significantly different to those of bulk water. To facilitate a robust comparison with state-of-the-art X-ray absorption fine structure (XAFS) data, we employ a 1st principles MD-XAFS procedure and directly compare simulated and experimental XAFS spectra. A comparison of the data for the aqueous Ca2+ system with those of the recently reported Zn2+, Fe3+, and Al3+ species showed that many of their structural characteristics correlated well with charge density on the cation. Some very important exceptions were found, which indicated a strong sensitivity of the solvent structure towards the cation′s valence electronic structure. Average dipole moments for the 2nd shell of all cations were suppressed relative to bulk water. Like a duck to water: An investigation into the solvent structure and dynamics around the Ca2+ cation was validated by comparison with XAFS data. A comparison with ab initio molecular dynamics studies of aqueous Zn2+, Fe3+, and Al 3+ was used to discuss general trends in the ability of these solvated cations to form extended structures. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
BibTeX: @article{Bogatko2013b, author = {Bogatko, Stuart and Cauët, Emilie and Bylaska, Eric and Schenter, Gregory and Fulton, John and Weare, John}, title = {The aqueous Ca2+ system, in comparison with Zn2+, Fe3 +, and Al3 +: An ab initio molecular dynamics study}, journal = {Chemistry - A European Journal}, year = {2013}, volume = {19}, number = {9}, pages = {3047 – 3060}, doi = {10.1002/chem.201202821} }
Bogatko S, Cauët E and Geerlings P (2013), "Improved DFT-based interpretation of ESI-MS of aqueous metal cations", Journal of the American Society for Mass Spectrometry. Vol. 24(6), pp. 926 – 931. [Abstract] [BibTeX] [DOI]
Abstract: We present results showing that our recently developed density functional theory (DFT)-based speciation model of the aqueous Al3+ system has the potential to improve the interpretations of ESI-MS studies of aqueous metal cation hydrolytic speciation. The main advantages of our method are that (1) it allows for the calculation of the relative abundance of a given species which may be directly assigned to the signal intensity in a mass spectrum; (2) in cases where species with identical m/z ratios may coexist, the assignment can be unambiguously assigned based on their theoretical relative abundances. As a demonstration of its application, we study four pairs of monomer and dimer aqueous Al3+ species, each with identical m/z ratio. For some of these pairs our method predicts that the dominant species changes from the monomer to the dimer species under varying pH conditions. [Figure not available: see fulltext.] © 2013 American Society for Mass Spectrometry.
BibTeX: @article{Bogatko2013a, author = {Bogatko, Stuart and Cauët, Emilie and Geerlings, Paul}, title = {Improved DFT-based interpretation of ESI-MS of aqueous metal cations}, journal = {Journal of the American Society for Mass Spectrometry}, year = {2013}, volume = {24}, number = {6}, pages = {926 – 931}, doi = {10.1007/s13361-013-0617-x} }
Bogatko S, Cauët E and Geerlings P (2013), "Rydberg electron capture by neutral Al hydrolysis products", Physical Chemistry Chemical Physics. Vol. 15(37), pp. 15309 – 15311. [Abstract] [BibTeX] [DOI]
Abstract: We predict that electron attachment may be used with ESI-MS techniques to observe neutral Al metal aqua-oxo-hydroxo species and the complex polymerization and precipitation reactions in which they participate. Neutral aqueous metal species have, so far, been invisible to ESI-MS techniques. This journal is © 2013 the Owner Societies.
BibTeX: @article{Bogatko2013, author = {Bogatko, Stuart and Cauët, Emilie and Geerlings, Paul}, title = {Rydberg electron capture by neutral Al hydrolysis products}, journal = {Physical Chemistry Chemical Physics}, year = {2013}, volume = {15}, number = {37}, pages = {15309 – 15311}, doi = {10.1039/c3cp51935j} }
Boichu M, Menut L, Khvorostyanov D, Clarisse L, Clerbaux C and Turquety S (2013), "Inverting for volcanic SO2 flux at high temporal resolution using spaceborne plume imagery and chemistry-transport modelling: the 2010 Eyjafjallajökull eruption case study", Atmospheric Chemistry and Physics. Vol. 13(17), pp. 8569 – 8584. [Abstract] [BibTeX] [DOI]
Abstract: Depending on the magnitude of their eruptions, volcanoes impact the atmosphere at various temporal and spatial scales. The volcanic source remains a major unknown to rigorously assess these impacts. At the scale of an eruption, the limited knowledge of source parameters, including time variations of erupted mass flux and emission profile, currently represents the greatest issue that limits the reliability of volcanic cloud forecasts. Today, a growing number of satellite and remote sensing observations of distant plumes are becoming available, bringing indirect information on these source terms. Here, we develop an inverse modelling approach combining satellite observations of the volcanic plume with an Eulerian regional chemistry-transport model (CHIMERE) to characterise the volcanic SO2 emissions during an eruptive crisis. The May 2010 eruption of Eyjafjallajökull is a perfect case study to apply this method as the volcano emitted substantial amounts of SO2 during more than a month. We take advantage of the SO2 column amounts provided by a vast set of IASI (Infrared Atmospheric Sounding Interferometer) satellite images to reconstruct retrospectively the time series of the mid-tropospheric SO2 flux emitted by the volcano with a temporal resolution of ∼2 h, spanning the period from 1 to 12 May 2010. We show that no a priori knowledge on the SO2 flux is required for this reconstruction. The initialisation of chemistry-transport modelling with this reconstructed source allows for reliable simulation of the evolution of the long-lived tropospheric SO2 cloud over thousands of kilometres. Heterogeneities within the plume, which mainly result from the temporal variability of the emissions, are correctly tracked over a timescale of a week. The robustness of our approach is also demonstrated by the broad similarities between the SO2 flux history determined by this study and the ash discharge behaviour estimated by other means during the phases of high explosive activity at Eyjafjallajö kull in May 2010. Finally, we show how a sequential IASI data assimilation allows for a substantial improvement in the forecasts of the location and concentration of the plume compared to an approach assuming constant flux at the source. As the SO2 flux is an important indicator of the volcanic activity, this approach is also of interest to monitor poorly instrumented volcanoes from space. © Author(s) 2013.
BibTeX: @article{Boichu2013, author = {Boichu, M. and Menut, L. and Khvorostyanov, D. and Clarisse, L. and Clerbaux, C. and Turquety, S.}, title = {Inverting for volcanic SO2 flux at high temporal resolution using spaceborne plume imagery and chemistry-transport modelling: the 2010 Eyjafjallajökull eruption case study}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {17}, pages = {8569 – 8584}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-13-8569-2013} }
Carette T and Godefroid M (2013), "Isotope shift on the chlorine electron affinity revisited by an MCHF/CI approach", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 46(9) [Abstract] [BibTeX] [DOI]
Abstract: Today, the electron affinity is experimentally well known for most of the elements and is a useful guideline for developing ab initio computational methods. However, the measurements of isotope shifts on the electron affinity are limited by both resolution and sensitivity. In this context, theory is of great help to further our knowledge and understanding of atomic structures, even though correlation plays a dominant role in negative ions' properties and, particularly, in the calculation of the specific mass shift contribution. This study solves the longstanding discrepancy between calculated and measured specific mass shifts on the electron affinity of chlorine (Berzinsh et al 1995 Phys. Rev. A 51 231). © 2013 IOP Publishing Ltd.
BibTeX: @article{Carette2013a, author = {Carette, T. and Godefroid, M.R.}, title = {Isotope shift on the chlorine electron affinity revisited by an MCHF/CI approach}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2013}, volume = {46}, number = {9}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/46/9/095003} }
Carette T, Nemouchi M, Li J and Godefroid M (2013), "Relativistic effects on the hyperfine structures of 2p4(3P) 3p2Do,4Do, and 4Po in 19F i", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 88(4) [Abstract] [BibTeX] [DOI]
Abstract: The hyperfine interaction constants of the 2p4(3P)3p 2D3/2,5/2o, 4D1/2-7/2o, and 4P1/2-5/2o levels in neutral fluorine are investigated theoretically. Large-scale calculations are carried out using the multiconfiguration Hartree-Fock (MCHF) and Dirac-Hartree-Fock (MCDHF) methods. In the framework of the MCHF approach, the relativistic effects are taken into account in the Breit-Pauli approximation using nonrelativistic orbitals. In the fully relativistic approach, the orbitals are optimized using the Dirac-Coulomb Hamiltonian with correlation models inspired by the nonrelativistic calculations. Higher-order excitations are captured through multireference configuration interaction calculations including the Breit interaction. In a third (intermediate) approach, the Dirac-Coulomb-Breit Hamiltonian matrix is diagonalized in a relativistic configuration space built with nonrelativistic MCHF radial functions converted into Dirac spinors using the Pauli approximation. The magnetic dipole hyperfine-structure constants calculated with the three relativistic models are consistent and reveal unexpectedly large effects of relativity for 2D5/2o, 4P3/2o, and 4P5/2o. The agreement with the few available experimental values is satisfactory. The strong J dependence of relativistic corrections on the hyperfine constants is investigated through the detailed analysis of the orbital, spin-dipole, and contact relative contributions calculated with the nonrelativistic magnetic dipole operator. © 2013 American Physical Society.
BibTeX: @article{Carette2013, author = {Carette, Thomas and Nemouchi, Messaoud and Li, Jiguang and Godefroid, Michel}, title = {Relativistic effects on the hyperfine structures of 2p4(3P) 3p2Do,4Do, and 4Po in 19F i}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2013}, volume = {88}, number = {4}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.88.042501} }
Cassam-Chenaï P and Liévin J (2013), "An improved third order dipole moment surface for methane", Journal of Molecular Spectroscopy. Vol. 291, pp. 77 – 84. [Abstract] [BibTeX] [DOI]
Abstract: In a previous article a dipole moment surface (DMS) of full-electron, multi-reference configuration interaction (MRCI) quality was obtained and used to calculate the rotational spectrum of methane vibrational ground state, by means of a combination of the mean field configuration interaction method (VMFCI) with a generalized perturbation theory. The theoretical line intensities were matching the experimental ones obtained at the SOLEIL synchrotron well within experimental uncertainties. However, not all third order terms were included in this DMS. In the present work, additional DMS points have been calculated and fitted using a complete third order expansion. The new results give R-branch intensities systematically smaller by about 1% compared to those previously obtained by using the same ab initio method, so still within experimental errors. The relevance of this DMS to calculate intensities for excited vibrational states, in particular for the dyad, is addressed. © 2013 Elsevier Inc. All rights reserved.
BibTeX: @article{CassamChenai2013, author = {Cassam-Chenaï, P. and Liévin, J.}, title = {An improved third order dipole moment surface for methane}, journal = {Journal of Molecular Spectroscopy}, year = {2013}, volume = {291}, pages = {77 – 84}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jms.2013.07.004} }
Cauët E, Bogatko S, Liévin J, De Proft F and Geerlings P (2013), "Electron-attachment-induced DNA damage: Instantaneous strand breaks", Journal of Physical Chemistry B. Vol. 117(33), pp. 9669 – 9676. [Abstract] [BibTeX] [DOI]
Abstract: Low energy electron-attachment-induced damage in DNA, where dissociation channels may involve multiple bonds including complex bond rearrangements and significant nuclear motions, is analyzed here. Quantum mechanics/molecular mechanics (QM/MM) calculations reveal how rearrangements of electron density after vertical electron attachment modulate the position and dynamics of the atomic nuclei in DNA. The nuclear motions involve the elongation of the P-O (P-O3′ and P-O5′) and C-C (C3′-C4′ and C4′-C5′) bonds for which the acquired kinetic energy becomes high enough so that the neighboring C3′-O3′ or C5′-O5′ phosphodiester bond may break almost immediately. Such dynamic behavior should happen on a very short time scale, within 15-30 fs, which is of the same order of magnitude as the time scale predicted for the excess electron to localize around the nucleobases. This result indicates that the C-O phosphodiester bonds can break before electron transfer from the backbone to the base. © 2013 American Chemical Society.
BibTeX: @article{Cauet2013, author = {Cauët, Emilie and Bogatko, Stuart and Liévin, Jacques and De Proft, Frank and Geerlings, Paul}, title = {Electron-attachment-induced DNA damage: Instantaneous strand breaks}, journal = {Journal of Physical Chemistry B}, year = {2013}, volume = {117}, number = {33}, pages = {9669 – 9676}, doi = {10.1021/jp406320g} }
Clarisse L, Coheur P-F, Prata F, Hadji-Lazaro J, Hurtmans D and Clerbaux C (2013), "A unified approach to infrared aerosol remote sensing and type specification", Atmospheric Chemistry and Physics. Vol. 13(4), pp. 2195 – 2221. [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric aerosols impact air quality and global climate. Space based measurements are the best way to observe their spatial and temporal distributions, and can also be used to gain better understanding of their chemical, physical and optical properties. Aerosol composition is the key parameter affecting the refractive index, which determines how much radiation is scattered and absorbed. Composition of aerosols is unfortunately not measured by state of the art satellite remote sounders. Here we use high resolution infrared measurements for aerosol type differentiation, exploiting, in that part of spectrum, the dependency of their refractive index on wavelength. We review existing detection methods and present a unified detection method based on linear discrimination analysis. We demonstrate this method on measurements of the Infrared Atmospheric Sounding Interferometer (IASI) and five different aerosol types, namely volcanic ash, windblown sand, sulfuric acid droplets, ammonium sulfate and smoke particles. We compare these with traditional MODIS AOD measurements. The detection of the last three types is unprecedented in the infrared in nadir mode, but is very promising, especially for sulfuric acid droplets which are detected in the lower troposphere and up to 6 months after injection in the upper troposphere/lower stratosphere. © 2013 Author(s).
BibTeX: @article{Clarisse2013, author = {Clarisse, L. and Coheur, P.-F. and Prata, F. and Hadji-Lazaro, J. and Hurtmans, D. and Clerbaux, C.}, title = {A unified approach to infrared aerosol remote sensing and type specification}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {4}, pages = {2195 – 2221}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-13-2195-2013} }
Clerbaux C and Crevoisier C (2013), "New Directions: Infrared remote sensing of the troposphere from satellite: Less, but better", Atmospheric Environment. Vol. 72, pp. 24 – 26. [BibTeX] [DOI]
BibTeX: @article{Clerbaux2013, author = {Clerbaux, Cathy and Crevoisier, Cyril}, title = {New Directions: Infrared remote sensing of the troposphere from satellite: Less, but better}, journal = {Atmospheric Environment}, year = {2013}, volume = {72}, pages = {24 – 26}, doi = {10.1016/j.atmosenv.2013.01.057} }
Didriche K, Földes T, Vanfleteren T and Herman M (2013), "Communication: Overtone (2NH) spectroscopy of NH3-Ar", Journal of Chemical Physics. Vol. 138(18) [Abstract] [BibTeX] [DOI]
Abstract: The Π (11) ← Σ (00) 2NH (ν1+ν3) band of the NH3-Ar van der Waals complex formed in a supersonic jet expansion, with origin at 6628 cm -1 was recorded at high-resolution using cavity ring down spectroscopy. The analysis leads to upper state rotational constants and J-dependent predissociation lifetimes estimated from linewidth analysis, with a mean value about 0.6 ns. © 2013 AIP Publishing LLC.
BibTeX: @article{Didriche2013, author = {Didriche, K. and Földes, T. and Vanfleteren, T. and Herman, M.}, title = {Communication: Overtone (2NH) spectroscopy of NH3-Ar}, journal = {Journal of Chemical Physics}, year = {2013}, volume = {138}, number = {18}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.4804421} }
Duflot V, Hurtmans D, Clarisse L, R'honi Y, Vigouroux C, De Mazière M, Mahieu E, Servais C, Clerbaux C and Coheur P-F (2013), "Measurements of hydrogen cyanide (HCN) and acetylene (C2H 2) from the Infrared Atmospheric Sounding Interferometer (IASI)", Atmospheric Measurement Techniques. Vol. 6(4), pp. 917 – 925. [Abstract] [BibTeX] [DOI]
Abstract: Hydrogen cyanide (HCN) and acetylene (C2H2) are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm-1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO 2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E) and Jungfraujoch (46° N, 8° E) in 2009-2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI). A first order comparison with local ground-based Fourier transform infraRed (FTIR) measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values. © Author(s) 2013.
BibTeX: @article{Duflot2013, author = {Duflot, V. and Hurtmans, D. and Clarisse, L. and R'honi, Y. and Vigouroux, C. and De Mazière, M. and Mahieu, E. and Servais, C. and Clerbaux, C. and Coheur, P.-F.}, title = {Measurements of hydrogen cyanide (HCN) and acetylene (C2H 2) from the Infrared Atmospheric Sounding Interferometer (IASI)}, journal = {Atmospheric Measurement Techniques}, year = {2013}, volume = {6}, number = {4}, pages = {917 – 925}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-6-917-2013} }
Fettweis X, Franco B, Tedesco M, Van Angelen J, Lenaerts J, Van Den Broeke M and Gallée H (2013), "Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR", Cryosphere. Vol. 7(2), pp. 469 – 489. [Abstract] [BibTeX] [DOI]
Abstract: To estimate the sea level rise (SLR) originating from changes in surface mass balance (SMB) of the Greenland ice sheet (GrIS), we present 21st century climate projections obtained with the regional climate model MAR (Modèle Atmosphérique Régional), forced by output of three CMIP5 (Coupled Model Intercomparison Project Phase 5) general circulation models (GCMs). Our results indicate that in a warmer climate, mass gain from increased winter snowfall over the GrIS does not compensate mass loss through increased meltwater run-off in summer. Despite the large spread in the projected near-surface warming, all the MAR projections show similar non-linear increase of GrIS surface melt volume because no change is projected in the general atmospheric circulation over Greenland. By coarsely estimating the GrIS SMB changes from GCM output, we show that the uncertainty from the GCM-based forcing represents about half of the projected SMB changes. In 2100, the CMIP5 ensemble mean projects a GrIS SMB decrease equivalent to a mean SLR of +4±2cm and +9±4cm for the RCP (Representative Concentration Pathways) 4.5 and RCP 8.5 scenarios respectively. These estimates do not consider the positive melt-elevation feedback, although sensitivity experiments using perturbed ice sheet topographies consistent with the projected SMB changes demonstrate that this is a significant feedback, and highlight the importance of coupling regional climate models to an ice sheet model. Such a coupling will allow the assessment of future response of both surface processes and ice-dynamic changes to rising temperatures, as well as their mutual feedbacks. © Author(s) 2013. CC Attribution 3.0 License.
BibTeX: @article{Fettweis2013, author = {Fettweis, X. and Franco, B. and Tedesco, M. and Van Angelen, J.H. and Lenaerts, J.T.M. and Van Den Broeke, M.R. and Gallée, H.}, title = {Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR}, journal = {Cryosphere}, year = {2013}, volume = {7}, number = {2}, pages = {469 – 489}, note = {All Open Access, Gold Open Access}, doi = {10.5194/tc-7-469-2013} }
Franco B, Fettweis X and Erpicum M (2013), "Future projections of the Greenland ice sheet energy balance driving the surface melt", Cryosphere. Vol. 7(1), pp. 1 – 18. [Abstract] [BibTeX] [DOI]
Abstract: In this study, simulations at 25 km resolution are performed over the Greenland ice sheet (GrIS) throughout the 20th and 21st centuries, using the regional climate model MAR forced by four RCP scenarios from three CMIP5 global circulation models (GCMs), in order to investigate the projected changes of the surface energy balance (SEB) components driving the surface melt. Analysis of 2000-2100 melt anomalies compared to melt results over 1980-1999 reveals an exponential relationship of the GrIS surface melt rate simulated by MAR to the near-surface air temperature (TAS) anomalies, mainly due to the surface albedo positive feedback associated with the extension of bare ice areas in summer. On the GrIS margins, the future melt anomalies are preferentially driven by stronger sensible heat fluxes, induced by enhanced warm air advection over the ice sheet. Over the central dry snow zone, the surface albedo positive feedback induced by the increase in summer melt exceeds the negative feedback of heavier snowfall for TAS anomalies higher than 4 C. In addition to the incoming longwave flux increase associated with the atmosphere warming, GCM-forced MAR simulations project an increase of the cloud cover decreasing the ratio of the incoming shortwave versus longwave radiation and dampening the albedo feedback. However, it should be noted that this trend in the cloud cover is contrary to that simulated by ERA-Interim-forced MAR for recent climate conditions, where the observed melt increase since the 1990s seems mainly to be a consequence of more anticyclonic atmospheric conditions. Finally, no significant change is projected in the length of the melt season, which highlights the importance of solar radiation absorbed by the ice sheet surface in the melt SEB. © Author(s) 2013. CC Attribution 3.0 License.
BibTeX: @article{Franco2013, author = {Franco, B. and Fettweis, X. and Erpicum, M.}, title = {Future projections of the Greenland ice sheet energy balance driving the surface melt}, journal = {Cryosphere}, year = {2013}, volume = {7}, number = {1}, pages = {1 – 18}, note = {All Open Access, Gold Open Access}, doi = {10.5194/tc-7-1-2013} }
Froese Fischer C, Verdebout S, Godefroid M, Rynkun P, Jönsson P and Gaigalas G (2013), "Doublet-quartet energy separation in boron: A partitioned-correlation- function-interaction method", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 88(6) [Abstract] [BibTeX] [DOI]
Abstract: No lines have been observed for transitions between the doublet and quartet levels of B i. Consequently, energy levels based on observation for the latter are obtained through extrapolation of wavelengths along the isoelectronic sequence for the 2s22p 2P3/2o - 2s2p2 4P5/2 transition. In this paper, accurate theoretical excitation energies from a partitioned-correlation- function-interaction (PCFI) method are reported for B i that include both relativistic effects in the Breit-Pauli approximation and a finite mass correction. Results are compared with extrapolated values from observed data. For B i our estimate of the excitation energy 28 959 ± 5 cm-1 is in better agreement with the values obtained by Edlén (1969) than those reported by Kramida and Ryabtsev (2007). Our method is validated by applying the same procedure to the separation of these levels in C ii. © 2013 American Physical Society.
BibTeX: @article{FroeseFischer2013, author = {Froese Fischer, Charlotte and Verdebout, Simon and Godefroid, Michel and Rynkun, Pavel and Jönsson, Per and Gaigalas, Gediminas}, title = {Doublet-quartet energy separation in boron: A partitioned-correlation- function-interaction method}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2013}, volume = {88}, number = {6}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.88.062506} }
Gazeaux J, Clerbaux C, George M, Hadji-Lazaro J, Kuttippurath J, Coheur P-F, Hurtmans D, Deshler T, Kovilakam M, Campbell P, Guidard V, Rabier F and Thépaut J-N (2013), "Intercomparison of polar ozone profiles by IASI/MetOp sounder with 2010 Concordiasi ozonesonde observations", Atmospheric Measurement Techniques. Vol. 6(3), pp. 613 – 620. [Abstract] [BibTeX] [DOI]
Abstract: Validation of ozone profiles measured from a nadir looking satellite instrument over Antarctica is a challenging task due to differences in their vertical sensitivity with ozonesonde measurements. In this paper, ozone observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) instrument onboard the polar-orbiting satellite MetOp are compared with ozone profiles collected between August and October 2010 at McMurdo Station, Antarctica, during the Concordiasi measurement campaign. The main objective of the campaign was the satellite data validation. With this aim 20 zero-pressure sounding balloons carrying ozonesondes were launched during this period when the MetOp satellite was passing above McMurdo. This makes the dataset relevant for comparison, especially because the balloons covered the entire altitude range of IASI profiles. The validation methodology and the collocation criteria vary according to the availability of global positioning system auxiliary data with each electro-chemical cell ozonesonde observation. The relative mean difference is shown to depend on the vertical range investigated. The analysis shows a good agreement in the troposphere (below 10 km) and middle stratosphere (25-40 km), where the differences are lower than 10%. However a significant positive bias of about 10-26% is estimated in the lower stratosphere at 10-25 km, depending on altitude. The positive bias in the 10-25 km range is consistent with previously reported studies comparing in situ data with thermal infrared satellite measurements. This study allows for a better characterization of IASI-retrieved ozone over the polar region during ozone depletion/recovery processes. © Author(s) 2013.
BibTeX: @article{Gazeaux2013, author = {Gazeaux, J. and Clerbaux, C. and George, M. and Hadji-Lazaro, J. and Kuttippurath, J. and Coheur, P.-F. and Hurtmans, D. and Deshler, T. and Kovilakam, M. and Campbell, P. and Guidard, V. and Rabier, F. and Thépaut, J.-N.}, title = {Intercomparison of polar ozone profiles by IASI/MetOp sounder with 2010 Concordiasi ozonesonde observations}, journal = {Atmospheric Measurement Techniques}, year = {2013}, volume = {6}, number = {3}, pages = {613 – 620}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-6-613-2013} }
Golebiowski D, Herman M and Lyulin O (2013), "16O12C17O and 18O 12C17O spectroscopy in the 1.2-1.25 νm region", Canadian Journal of Physics. Vol. 91(11), pp. 963 – 965. [Abstract] [BibTeX] [DOI]
Abstract: Near-infrared absorption spectra of a carbon dioxide sample enriched with oxygen-17 were recorded in the spectral range 1.2-1.25 νm. A high-resolution continuous scan Fourier transform interferometer fitted with a femto OPO/Idler laser source and cavity-enhanced absorption was used. The optimal root mean squared noise equivalent absorption was 1.2 × 10-10 cm -1Hz-1/2 per spectral element, corresponding to αmin = 10-8 cm-1. Two cold bands in 17O12C18O and one hot band in 16O12C17O were newly identified and rotationally analyzed. More lines than previously published (Lyulin et al. J. Quant. Spectrosc. Radiat. Transfer, 113, 2167 (2012)), were assigned in the observed bands of 12C17O2 and 16O12C17O. New upper state rotational constants were obtained from a band-by-band analysis. © 2013 Published by NRC Research Press.
BibTeX: @article{Golebiowski2013, author = {Golebiowski, D. and Herman, M. and Lyulin, O.}, title = {16O12C17O and 18O 12C17O spectroscopy in the 1.2-1.25 νm region}, journal = {Canadian Journal of Physics}, year = {2013}, volume = {91}, number = {11}, pages = {963 – 965}, doi = {10.1139/cjp-2012-0482} }
Griffin D, Walker K, Franklin J, Parrington M, Whaley C, Hopper J, Drummond J, Palmer P, Strong K, Duck T, Abboud I, Bernath P, Clerbaux C, Coheur P-F, Curry K, Dan L, Hyer E, Kliever J, Lesins G, Maurice M, Saha A, Tereszchuk K and Weaver D (2013), "Investigation of CO, C2H6 and aerosols in a boreal fire plume over eastern Canada during BORTAS 2011 using ground-and satellite-based observations and model simulations", Atmospheric Chemistry and Physics. Vol. 13(20), pp. 10227 – 10241. [Abstract] [BibTeX] [DOI]
Abstract: We present the results of total column measurements of CO, C2H6 and fine-mode aerosol optical depth (AOD) during the "Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites" (BORTAS-B) campaign over eastern Canada. Ground-based observations, using Fourier transform spectrometers (FTSs) and sun photometers, were carried out in July and August 2011. These measurements were taken in Halifax, Nova Scotia, which is an ideal location to monitor the outflow of boreal fires from North America, and also in Toronto, Ontario. Measurements of fine-mode AOD enhancements were highly correlated with enhancements in coincident trace gas (CO and C2H6) observations between 19 and 21 July 2011, which is typical for a smoke plume event. In this paper, we focus on the identification of the origin and the transport of this smoke plume. We use back trajectories calculated by the Canadian Meteorological Centre as well as FLEXPART forward trajectories to demonstrate that the enhanced CO, C2H6 and fine-mode AOD seen near Halifax and Toronto originated from forest fires in northwestern Ontario that occurred between 17 and 19 July 2011. In addition, total column measurements of CO from the satellite-borne Infrared Atmospheric Sounding Interferometer (IASI) have been used to trace the smoke plume and to confirm the origin of the CO enhancement. Furthermore, the enhancement ratio-that is, in this case equivalent to the emission ratio (ERC2H6/CO)-was estimated from these ground-based observations. These C2H6 emission results from boreal fires in northwestern Ontario agree well with C2H6 emission measurements from other boreal regions, and are relatively high compared to fires from other geographical regions. The ground-based CO and C2H6 observations were compared with outputs from the 3-D global chemical transport model GEOS-Chem, using the Fire Locating And Modeling of Burning Emissions (FLAMBE) inventory. Agreement within the stated measurement uncertainty (∼3% for CO and ∼8% for C2H6) was found for the magnitude of the enhancement of the CO and C2H6 total columns between the measured and modelled results. However, there is a small shift in time (of approximately 6 h) of arrival of the plume over Halifax between the results. © Author(s) 2013.
BibTeX: @article{Griffin2013, author = {Griffin, D. and Walker, K.A. and Franklin, J.E. and Parrington, M. and Whaley, C. and Hopper, J. and Drummond, J.R. and Palmer, P.I. and Strong, K. and Duck, T.J. and Abboud, I. and Bernath, P.F. and Clerbaux, C. and Coheur, P.-F. and Curry, K.R. and Dan, L. and Hyer, E. and Kliever, J. and Lesins, G. and Maurice, M. and Saha, A. and Tereszchuk, K. and Weaver, D.}, title = {Investigation of CO, C2H6 and aerosols in a boreal fire plume over eastern Canada during BORTAS 2011 using ground-and satellite-based observations and model simulations}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {20}, pages = {10227 – 10241}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-13-10227-2013} }
Herman M and Perry DS (2013), "Molecular spectroscopy and dynamics: A polyad-based perspective", Physical Chemistry Chemical Physics. Vol. 15(25), pp. 9970 – 9993. [Abstract] [BibTeX] [DOI]
Abstract: The efficiency and insight of global, polyad-based modeling in overtone spectroscopy and dynamics is demonstrated. Both vibration and vibration-rotation polyads are considered. The spectroscopic implications of polyad Hamiltonians derive from their ability to account for the detailed line positions and intensities of spectral features and their unique predictive power. The dynamical implications of polyad Hamiltonians include classical bifurcations that lead to the birth of new vibrational modes and intramolecular vibrational-rotational energy redistribution over multiple timescales. The literature is reviewed, with emphasis on acetylene results. © 2013 the Owner Societies.
BibTeX: @article{Herman2013, author = {Herman, Michel and Perry, David S.}, title = {Molecular spectroscopy and dynamics: A polyad-based perspective}, journal = {Physical Chemistry Chemical Physics}, year = {2013}, volume = {15}, number = {25}, pages = {9970 – 9993}, doi = {10.1039/c3cp50463h} }
Inness A, Baier F, Benedetti A, Bouarar I, Chabrillat S, Clark H, Clerbaux C, Coheur P, Engelen R, Errera Q, Flemming J, George M, Granier C, Hadji-Lazaro J, Huijnen V, Hurtmans D, Jones L, Kaiser J, Kapsomenakis J, Lefever K, Leitão J, Razinger M, Richter A, Schultz M, Simmons A, Suttie M, Stein O, Thépaut J-N, Thouret V, Vrekoussis M and Zerefos C (2013), "The MACC reanalysis: An 8 yr data set of atmospheric composition", Atmospheric Chemistry and Physics. Vol. 13(8), pp. 4073 – 4109. [Abstract] [BibTeX] [DOI]
Abstract: An eight-year long reanalysis of atmospheric composition data covering the period 2003-2010 was constructed as part of the FP7-funded Monitoring Atmospheric Composition and Climate project by assimilating satellite data into a global model and data assimilation system. This reanalysis provides fields of chemically reactive gases, namely carbon monoxide, ozone, nitrogen oxides, and formaldehyde, as well as aerosols and greenhouse gases globally at a horizontal resolution of about 80 km for both the troposphere and the stratosphere. This paper describes the assimilation system for the reactive gases and presents validation results for the reactive gas analysis fields to document the data set and to give a first indication of its quality. Tropospheric CO values from the MACC reanalysis are on average 10-20% lower than routine observations from commercial aircrafts over airports through most of the troposphere, and have larger negative biases in the boundary layer at urban sites affected by air pollution, possibly due to an underestimation of CO or precursor emissions. Stratospheric ozone fields from the MACC reanalysis agree with ozonesondes and ACE-FTS data to within ±10% in most seasons and regions. In the troposphere the reanalysis shows biases of -5% to +10% with respect to ozonesondes and aircraft data in the extratropics, but has larger negative biases in the tropics. Area-averaged total column ozone agrees with ozone fields from a multi-sensor reanalysis data set to within a few percent. NO2 fields from the reanalysis show the right seasonality over polluted urban areas of the NH and over tropical biomass burning areas, but underestimate wintertime NO2 maxima over anthropogenic pollution regions and overestimate NO2 in northern and southern Africa during the tropical biomass burning seasons. Tropospheric HCHO is well simulated in the MACC reanalysis even though no satellite data are assimilated. It shows good agreement with independent SCIAMACHY retrievals over regions dominated by biogenic emissions with some anthropogenic input, such as the eastern US and China, and also over African regions influenced by biogenic sources and biomass burning. © Author(s) 2013.
BibTeX: @article{Inness2013, author = {Inness, A. and Baier, F. and Benedetti, A. and Bouarar, I. and Chabrillat, S. and Clark, H. and Clerbaux, C. and Coheur, P. and Engelen, R.J. and Errera, Q. and Flemming, J. and George, M. and Granier, C. and Hadji-Lazaro, J. and Huijnen, V. and Hurtmans, D. and Jones, L. and Kaiser, J.W. and Kapsomenakis, J. and Lefever, K. and Leitão, J. and Razinger, M. and Richter, A. and Schultz, M.G. and Simmons, A.J. and Suttie, M. and Stein, O. and Thépaut, J.-N. and Thouret, V. and Vrekoussis, M. and Zerefos, C.}, title = {The MACC reanalysis: An 8 yr data set of atmospheric composition}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {8}, pages = {4073 – 4109}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-13-4073-2013} }
Jégou F, Berthet G, Brogniez C, Renard J-B, François P, Haywood J, Jones A, Bourgeois Q, Lurton T, Auriol F, Godin-Beekmann S, Guimbaud C, Krysztofiak G, Gaubicher B, Chartier M, Clarisse L, Clerbaux C, Balois J, Verwaerde C and Daugeron D (2013), "Stratospheric aerosols from the Sarychev volcano eruption in the 2009 Arctic summer", Atmospheric Chemistry and Physics. Vol. 13(13), pp. 6533 – 6552. [Abstract] [BibTeX] [DOI]
Abstract: Aerosols from the Sarychev volcano eruption (Kuril Islands, northeast of Japan) were observed in the Arctic lower stratosphere a few days after the strongest SO2 injection which occurred on 15 and 16 June 2009. From the observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) an estimated 0.9 Tg of sulphur dioxide was injected into the upper troposphere and lower stratosphere (UTLS). The resultant stratospheric sulphate aerosols were detected from satellites by the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb sounder and by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and from the surface by the Network for the Detection of Atmospheric Composition Changes (NDACC) lidar deployed at OHP (Observatoire de Haute-Provence, France). By the first week of July the aerosol plume had spread out over the entire Arctic region. The Sarychev-induced stratospheric aerosol over the Kiruna region (north of Sweden) was measured by the Stratospheric and Tropospheric Aerosol Counter (STAC) during eight balloon flights planned in August and September 2009. During this balloon campaign the Micro Radiomètre Ballon (MicroRADIBAL) and the Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et NOx (SALOMON) remote-sensing instruments also observed these aerosols. Aerosol concentrations returned to near-background levels by spring 2010. The effective radius, the surface area density (SAD), the aerosol extinction, and the total sulphur mass from STAC in situ measurements are enhanced with mean values in the range 0.15-0.21 μm, 5.5-14.7 μm2 cm-3, 5.5-29.5 × 10-4 km-1, and 4.9-12.6 × 10-10 kg[S] kg-1[air], respectively, between 14 km and 18 km. The observed and modelled e-folding time of sulphate aerosols from the Sarychev eruption is around 70-80 days, a value much shorter than the 12-14 months calculated for aerosols from the 1991 eruption of Mt Pinatubo. The OSIRIS stratospheric aerosol optical depth (AOD) at 750 nm is enhanced by a factor of 6, with a value of 0.02 in late July compared to 0.0035 before the eruption. The HadGEM2 and MIMOSA model outputs indicate that aerosol layers in polar region up to 14-15 km are largely modulated by stratosphere-troposphere exchange processes. The spatial extent of the Sarychev plume is well represented in the HadGEM2 model with lower altitudes of the plume being controlled by upper tropospheric troughs which displace the plume downward and upper altitudes around 18-20 km, in agreement with lidar observations. Good consistency is found between the HadGEM2 sulphur mass density and the value inferred from the STAC observations, with a maximum located about 1 km above the tropopause ranging from 1 to 2 × 10 -9 kg[S] kg-1[air], which is one order of magnitude higher than the background level. © Author(s) 2013.
BibTeX: @article{Jegou2013, author = {Jégou, F. and Berthet, G. and Brogniez, C. and Renard, J.-B. and François, P. and Haywood, J.M. and Jones, A. and Bourgeois, Q. and Lurton, T. and Auriol, F. and Godin-Beekmann, S. and Guimbaud, C. and Krysztofiak, G. and Gaubicher, B. and Chartier, M. and Clarisse, L. and Clerbaux, C. and Balois, J.Y. and Verwaerde, C. and Daugeron, D.}, title = {Stratospheric aerosols from the Sarychev volcano eruption in the 2009 Arctic summer}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {13}, pages = {6533 – 6552}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-13-6533-2013} }
Jönsson P, Ekman J, Gustafsson S, Hartman H, Karlsson L, Du Rietz R, Gaigalas G, Godefroid M and Froese Fischer C (2013), "Energy levels and transition rates for the boron isoelectronic sequence: Si X, Ti XVIII-Cu XXV", Astronomy and Astrophysics. Vol. 559 [Abstract] [BibTeX] [DOI]
Abstract: Relativistic configuration interaction (RCI) calculations are performed for 291 states belonging to the configurations 1s22s22p, 1s22s2p2, 1s22p3, 1s 22s23l, 1s22s2p3l, 1s22p 23l, 1s22s24l′, 1s 22s2p4l′, and 1s22p24l′ (l = 0,1,2 and l′ = 0,1,2,3) in boron-like ions Si X and Ti XVIII to Cu XXV. Electron correlation effects are represented in the wave functions by large configuration state function (CSF) expansions. States are transformed from jj-coupling to LS-coupling, and the LS-percentage compositions are used for labeling the levels. Radiative electric dipole transition rates are given for all ions, leading to massive data sets. Calculated energy levels are compared with other theoretical predictions and crosschecked against the Chianti database, NIST recommended values, and other observations. The accuracy of the calculations are high enough to facilitate the identification of observed spectral lines. © 2013 ESO.
BibTeX: @article{Joensson2013, author = {Jönsson, P. and Ekman, J. and Gustafsson, S. and Hartman, H. and Karlsson, L.B. and Du Rietz, R. and Gaigalas, G. and Godefroid, M.R. and Froese Fischer, C.}, title = {Energy levels and transition rates for the boron isoelectronic sequence: Si X, Ti XVIII-Cu XXV}, journal = {Astronomy and Astrophysics}, year = {2013}, volume = {559}, note = {All Open Access, Bronze Open Access}, doi = {10.1051/0004-6361/201321893} }
Jönsson P, Godefroid M, Gaigalas G, Bieroń J and Brage T (2013), "Accurate transition probabilities from large-scale multiconfiguration calculations - A tribute to Charlotte Froese Fischer", AIP Conference Proceedings. Vol. 1545, pp. 266 – 278. [Abstract] [BibTeX] [DOI]
Abstract: The development of multiconfiguration computer packages for atomic structure calculations is reviewed with special attention to the work of Charlotte Froese Fischer. The underlying theory is described along with methodologies to choose basis expansions of configuration state functions. Calculations of energies and transitions rates are presented and the accuracy of the results is assessed. Limitations of multiconfiguration methods are discussed and it is shown how these limitations can be circumvented by a division of the original large-scale computational problem into a number of smaller problems. © 2013 AIP Publishing LLC.
BibTeX: @conference{Joensson2013a, author = {Jönsson, Per and Godefroid, Michel and Gaigalas, Gediminas and Bieroń, Jacek and Brage, Tomas}, title = {Accurate transition probabilities from large-scale multiconfiguration calculations - A tribute to Charlotte Froese Fischer}, journal = {AIP Conference Proceedings}, year = {2013}, volume = {1545}, pages = {266 – 278}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.4815863} }
Krol M, Peters W, Hooghiemstra P, George M, Clerbaux C, Hurtmans D, McInerney D, Sedano F, Bergamaschi P, El Hajj M, Kaiser J, Fisher D, Yershov V and Muller J-P (2013), "How much CO was emitted by the 2010 fires around Moscow?", Atmospheric Chemistry and Physics. Vol. 13(9), pp. 4737 – 4747. [Abstract] [BibTeX] [DOI]
Abstract: The fires around Moscow in July and August 2010 emitted a large amount of pollutants to the atmosphere. Here we estimate the carbon monoxide (CO) source strength of the Moscow fires in July and August by using the TM5-4DVAR system in combination with CO column observations of the Infrared Atmospheric Sounding Interferometer (IASI). It is shown that the IASI observations provide a strong constraint on the total emissions needed in the model. Irrespective of the prior emissions used, the optimised CO fire emission estimates from mid-July to mid-August 2010 amount to approximately 24TgCO. This estimate depends only weakly (< 15%) on the assumed diurnal variations and injection height of the emissions. However, the estimated emissions might depend on unaccounted model uncertainties such as vertical transport. Our emission estimate of 22-27 TgCO during roughly one month of intense burning is less than suggested by another recent study, but substantially larger than predicted by the bottom-up inventories. This latter discrepancy suggests that bottom-up emission estimates for extreme peat burning events require improvements. © Author(s) 2013.
BibTeX: @article{Krol2013, author = {Krol, M. and Peters, W. and Hooghiemstra, P. and George, M. and Clerbaux, C. and Hurtmans, D. and McInerney, D. and Sedano, F. and Bergamaschi, P. and El Hajj, M. and Kaiser, J.W. and Fisher, D. and Yershov, V. and Muller, J.-P.}, title = {How much CO was emitted by the 2010 fires around Moscow?}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {9}, pages = {4737 – 4747}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-13-4737-2013} }
Lauzin C, Coudert LH, Herman M and Liévin J (2013), "Ab initio intermolecular potential of Ar-C2H2 refined using high-resolution spectroscopic data", Journal of Physical Chemistry A. Vol. 117(50), pp. 13767 – 13774. [Abstract] [BibTeX] [DOI]
Abstract: The high-resolution infrared spectra of the ν1 + ν3 (2CH) band of the Ar-C2H2 complex has been recorded from 6544 to 6566 cm-1. The previously reported K a = 1 ← 0, 2 ← 1, and 0 ← 1 subbands were observed and the Ka = 1 ← 2, 2 ← 3, and 3 ← 2 subbands were assigned for the first time. The intermolecular potential energy surface of this complex has been calculated ab initio and optimized by fitting the new high-resolution data. Refined intermolecular potential energy surfaces have been obtained for the ground vibrational state and for the excited v1 = v3 = 1 stretching state. For the former state, the results of the analysis are satisfactory and the microwave transitions of the complex are reproduced with a root-mean-square deviation of 5 MHz. For the latter state, systematic discrepancies arise in the analysis. © 2013 American Chemical Society.
BibTeX: @article{Lauzin2013, author = {Lauzin, Clément and Coudert, Laurent H. and Herman, Michel and Liévin, Jacques}, title = {Ab initio intermolecular potential of Ar-C2H2 refined using high-resolution spectroscopic data}, journal = {Journal of Physical Chemistry A}, year = {2013}, volume = {117}, number = {50}, pages = {13767 – 13774}, doi = {10.1021/jp408013n} }
Loreau J, Vranckx S, Desouter-Lecomte M, Vaeck N and Dalgarno A (2013), "Photodissociation and radiative association of HeH+ in the metastable triplet state", Journal of Physical Chemistry A. Vol. 117(39), pp. 9486 – 9492. [Abstract] [BibTeX] [DOI]
Abstract: We investigate the photodissociation of HeH+ in the metastable triplet state as well as its formation through the inverse process, radiative association. In models of astrophysical plasmas, HeH+ is assumed to be present only in the ground state, and the influence of the triplet state has not been explored. It may be formed by radiative association during collisions between a proton and metastable helium, which are present in significant concentrations in nebulae. The triplet state can also be formed by association of He+ and H, although this process is less likely to occur. We compute the cross sections and rate coefficients corresponding to the photodissociation of the triplet state by UV photons from a central star using a wave packet method. We show that the photodissociation cross sections depend strongly on the initial vibrational state and that the effects of excited electronic states and nonadiabatic couplings cannot be neglected. We then calculate the cross section and rate coefficient for the radiative association of HeH+ in the metastable triplet state. © 2013 American Chemical Society.
BibTeX: @article{Loreau2013, author = {Loreau, J. and Vranckx, S. and Desouter-Lecomte, M. and Vaeck, N. and Dalgarno, A.}, title = {Photodissociation and radiative association of HeH+ in the metastable triplet state}, journal = {Journal of Physical Chemistry A}, year = {2013}, volume = {117}, number = {39}, pages = {9486 – 9492}, note = {All Open Access, Green Open Access}, doi = {10.1021/jp312007q} }
Nazé C, Gaidamauskas E, Gaigalas G, Godefroid M and Jönsson P (2013), "Ris3: A program for relativistic isotope shift calculations", Computer Physics Communications. Vol. 184(9), pp. 2187 – 2196. [Abstract] [BibTeX] [DOI]
Abstract: An atomic spectral line is characteristic of the element producing the spectrum. The line also depends on the isotope. The program ris3 (Relativistic Isotope Shift) calculates the electron density at the origin and the normal and specific mass shift parameters. Combining these electronic quantities with available nuclear data, isotope-dependent energy level shifts are determined. © 2013 Elsevier B.V. All rights reserved.
BibTeX: @article{Naze2013, author = {Nazé, C. and Gaidamauskas, E. and Gaigalas, G. and Godefroid, M. and Jönsson, P.}, title = {Ris3: A program for relativistic isotope shift calculations}, journal = {Computer Physics Communications}, year = {2013}, volume = {184}, number = {9}, pages = {2187 – 2196}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.cpc.2013.02.015} }
Oudot C, Clerbaux C, Lazaro JH, George M, Safieddine S, Clarisse L, Hurtmans D and Coheur P (2013), "IASI/MetOp sounder contribution for atmospheric composition monitoring: 4-year study of radiance data", AIP Conference Proceedings. Vol. 1531, pp. 212 – 215. [Abstract] [BibTeX] [DOI]
Abstract: During the last decades, remote sensing sounders have demonstrated their capability for monitoring atmospheric composition and pollution. With now 5 years of continuous observations of IASI instrument, flying on board of MetOp-A platform, we are able to analyze long term variations of atmospheric molecules. This article involves new tendencies for CO and CO2 molecules based on IASI LIC radiances. Comparisons with total columns are also provided. © 2013 AIP Publishing LLC.
BibTeX: @conference{Oudot2013, author = {Oudot, C. and Clerbaux, C. and Lazaro, J. Hadji and George, M. and Safieddine, S. and Clarisse, L. and Hurtmans, D. and Coheur, P.}, title = {IASI/MetOp sounder contribution for atmospheric composition monitoring: 4-year study of radiance data}, journal = {AIP Conference Proceedings}, year = {2013}, volume = {1531}, pages = {212 – 215}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.4804744} }
R'Honi Y, Clarisse L, Clerbaux C, Hurtmans D, Duflot V, Turquety S, Ngadi Y and Coheur P-F (2013), "Exceptional emissions of NH3 and HCOOH in the 2010 Russian wildfires", Atmospheric Chemistry and Physics. Vol. 13(1), pp. 4171 – 4181. [Abstract] [BibTeX] [DOI]
Abstract: In July 2010, several hundred forest and peat fires broke out across central Russia during its hottest summer on record. Here, we analyze these wildfires using observations of the Infrared Atmospheric Sounding Interferometer (IASI). Carbon monoxide (CO), ammonia (NH3) and formic acid (HCOOH) total columns are presented for the year 2010. Maximum total columns were found to be one order (for CO and HCOOH) and two orders (for NH3) of magnitude larger than typical background values. The temporal evolution of NH3 and HCOOH enhancement ratios relative to CO are presented. Evidence of secondary formation of HCOOH is found, with enhancement ratios exceeding reported emission ratios in fresh plumes. We estimate the total emitted masses for the period July-August 2010 over the center of western Russia; they are 19-33 Tg (CO), 0.7-2.6 Tg (NH3) and 0.9-3.9 Tg (HCOOH). For NH3 and HCOOH, these quantities are comparable to what is emitted in the course of a whole year by all extratropical forest fires. © Author(s) 2013.
BibTeX: @article{RHoni2013, author = {R'Honi, Y. and Clarisse, L. and Clerbaux, C. and Hurtmans, D. and Duflot, V. and Turquety, S. and Ngadi, Y. and Coheur, P.-F.}, title = {Exceptional emissions of NH3 and HCOOH in the 2010 Russian wildfires}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {1}, pages = {4171 – 4181}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-13-4171-2013} }
Robert S, Borkov YG, Vander Auwera J, Drummond R, Mahieux A, Wilquet V, Vandaele A, Perevalov V, Tashkun S and Bertaux J (2013), "Assignment and rotational analysis of new absorption bands of carbon dioxide isotopologues in Venus spectra", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 114, pp. 29 – 41. [Abstract] [BibTeX] [DOI]
Abstract: We present absorption bands of carbon dioxide isotopologues, detected by the Solar Occultation for the Infrared Range (SOIR) instrument on board the Venus Express Satellite. The SOIR instrument combines an echelle spectrometer and an Acousto-Optical Tunable Filter (AOTF) for order selection. It performs solar occultation measurements in the Venus atmosphere in the IR region (2.2-4.3μm), at a resolution of 0.12-0.18cm-1. The wavelength range probed by SOIR allows a detailed chemical inventory of the Venus atmosphere above the cloud layer (65-150km) to be made with emphasis on the vertical distributions of gases. Thanks to the SOIR spectral resolution, a new CO2 absorption band was identified: the 21101-01101 band of 16O12C18O with R branch up to J=31. Two other previously reported bands were observed dispelling any doubts about their identifications: the 20001-00001 band of 16O13C18O [Villanueva G, et al. J Quant Spectrosc Radiat Transfer 2008;109:883-894] and the 01111-00001 band of 16O12C18O [Villanueva G, et al. J Quant Spectrosc Radiat Transfer 2008;109:883-894 and Wilquet V, et al. J Quant Spectrosc Radiat Transfer 2008;109:895-905]. These bands were analyzed, and spectroscopic constants characterizing them were obtained. The rotational assignment of the 20001-00001 band was corrected. The present measurements are compared with data available in the HITRAN database. © 2012 Elsevier Ltd.
BibTeX: @article{Robert2013, author = {Robert, S. and Borkov, Yu. G. and Vander Auwera, J. and Drummond, R. and Mahieux, A. and Wilquet, V. and Vandaele, A.C. and Perevalov, V.I. and Tashkun, S.A. and Bertaux, J.L.}, title = {Assignment and rotational analysis of new absorption bands of carbon dioxide isotopologues in Venus spectra}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2013}, volume = {114}, pages = {29 – 41}, doi = {10.1016/j.jqsrt.2012.08.023} }
Servaty K, Cauët E, Thomas F, Lambermont J, Gerbaux P, De Winter J, Ovaere M, Volker L, Vaeck N, Van Meervelt L, Dehaen W, Moucheron C and Kirsch-De Mesmaeker A (2013), "Peculiar properties of homoleptic Cu complexes with dipyrromethene derivatives", Dalton Transactions. Vol. 42(39), pp. 14188 – 14199. [Abstract] [BibTeX] [DOI]
Abstract: In view of preparing Cu polynuclear complexes with dipyrromethene ligands, the mononuclear complexes [Cu(ii)(dipy)2] (dipyH = 5-phenyldipyrromethene) and [Cu(ii)(dpdipy)2] (dpdipyH = 1,5,9-triphenyldipyrromethene) have been prepared and characterized by X-ray crystallography, mass spectrometry and EPR spectroscopy. Their peculiar redox and spectroscopic (absorption/emission) behaviours are discussed. In contrast to CuII complexes of 1,1′-bidypyrrin, the reduction electrolysis of [Cu(ii)(dpdipy)2] leads to decomposition products on a time scale of a few hours. Moreover in relation to this observation, [Cu(i)(dpdipy) 2]- could not be synthesized in spite of the Cu I core protection by the phenyl substituents in ortho position of the nitrogen atoms. Theoretical calculations provide some explanations for this instability. Interestingly [Cu(ii)(dipy)2] and [Cu(ii)(dpdipy) 2] display weak luminescence at room temperature, attributed to a ligand centered emission. © 2013 The Royal Society of Chemistry.
BibTeX: @article{Servaty2013, author = {Servaty, Kathleen and Cauët, Emilie and Thomas, Fabrice and Lambermont, Javiera and Gerbaux, Pascal and De Winter, Julien and Ovaere, Margriet and Volker, Leen and Vaeck, Nathalie and Van Meervelt, Luc and Dehaen, Wim and Moucheron, Cécile and Kirsch-De Mesmaeker, Andrée}, title = {Peculiar properties of homoleptic Cu complexes with dipyrromethene derivatives}, journal = {Dalton Transactions}, year = {2013}, volume = {42}, number = {39}, pages = {14188 – 14199}, doi = {10.1039/c3dt51541a} }
Sigmarsson O, Haddadi B, Carn S, Moune S, Gudnason J, Yang K and Clarisse L (2013), "The sulfur budget of the 2011 Grímsvötn eruption, Iceland", Geophysical Research Letters. Vol. 40(23), pp. 6095 – 6100. [Abstract] [BibTeX] [DOI]
Abstract: Sulfur concentrations have been measured in 28 melt inclusions (MIs) in plagioclase, clinopyroxene, and olivine crystals extracted from tephra produced during the explosive eruption of Grímsvötn in May 2011. The results are compared to sulfur concentrations in the groundmass glass in order to estimate the mass of sulfur brought to surface during the eruption. Satellite measurements yield order of magnitude lower sulfur ( 0.2 Tg) in the eruption plume than estimated from the difference between MI and the groundmass glass. This sulfur "deficit" is readily explained by sulfur adhering to tephra grains but principally by sulfide globules caused by basalt-sulfide melt exsolution before degassing. A mass balance calculation reveals that approximately 0.8 Tg of SO2 is present as globules, representing 50% of the total sulfur budget. Most of the sulfide globules likely reside at depth due to their elevated density, for potential later remobilization by new magma or hydrothermal circulation. Key Points H2S and SO2 degassing is estimated for the 2011 eruption of Grímsvötn Satellite-based SO2 mass loading is lower than from mineral melt inclusions Half of S resides as sulfide globules; 25% enter the stratosphere ©2013. American Geophysical Union. All Rights Reserved.
BibTeX: @article{Sigmarsson2013, author = {Sigmarsson, Olgeir and Haddadi, Baptiste and Carn, Simon and Moune, Séverine and Gudnason, Jõnas and Yang, Kai and Clarisse, Lieven}, title = {The sulfur budget of the 2011 Grímsvötn eruption, Iceland}, journal = {Geophysical Research Letters}, year = {2013}, volume = {40}, number = {23}, pages = {6095 – 6100}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/2013GL057760} }
Stremme W, Grutter M, Rivera C, Bezanilla A, Garcia A, Ortega I, George M, Clerbaux C, Coheur P-F, Hurtmans D, Hannigan J and Coffey M (2013), "Top-down estimation of carbon monoxide emissions from the Mexico Megacity based on FTIR measurements from ground and space", Atmospheric Chemistry and Physics. Vol. 13(3), pp. 1357 – 1376. [Abstract] [BibTeX] [DOI]
Abstract: Continuous carbon monoxide (CO) total column densities above the Universidad Nacional Autónoma de México (UNAM) campus in Mexico City have been derived from solar absorption infrared spectroscopic measurements since October 2007. Its diurnal evolution is used in the present study in conjunction with other ground-based and satellite data to develop a top-down emission estimate of the annual CO emission of the Mexico City Metropolitan Area (MCMA). The growth-rate of the total column around noon under low ventilation conditions is calculated and allows us to derive the average surface emission-flux at UNAM, while similar measurements taken at the edge of the MCMA in Tecámac provide information on background CO levels in the Mexico basin. Based on 3 yr of measurements, CO column measurements from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument are used to reconstruct the spatial distribution of this anthropogenic pollutant over the MCMA. The agreement between the measured columns of the satellite and ground-based measurements is excellent, particularly when a comparison strategy based on time-displaced air masses is used. The annual emission of the Mexico Megacity is estimated to be (2.15 ± 0.5) Tg yr-1 for the year 2008, while the official inventory for that year reported 1.6 Tg yr -1. The difference is slightly higher than the conservative uncertainty estimated in this work suggesting that the emission might be underestimated by the conventional bottom-up method. A larger discrepancy is found in the spatial distribution of the emissions, when comparing the emission flux over UNAM (derived from the ground-based measurement) with that of the inventory integrated over a representative area. The methodology presented here represents a new and useful strategy to evaluate the contribution of megacities to the global anthropogenic gas emissions. Additionally, three different strategies to compare ground and space-based measurements above an inhomogeneous and strongly contaminated area like Mexico City are presented and discussed. © Author(s) 2013.
BibTeX: @article{Stremme2013, author = {Stremme, W. and Grutter, M. and Rivera, C. and Bezanilla, A. and Garcia, A.R. and Ortega, I. and George, M. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Hannigan, J.W. and Coffey, M.T.}, title = {Top-down estimation of carbon monoxide emissions from the Mexico Megacity based on FTIR measurements from ground and space}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {3}, pages = {1357 – 1376}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-13-1357-2013} }
Sutcliffe B and Woolley RG (2013), "The Potential Energy Surface in Molecular Quantum Mechanics", Progress in Theoretical Chemistry and Physics. Vol. 27, pp. 3 – 40. [Abstract] [BibTeX] [DOI]
Abstract: The idea of a Potential Energy Surface (PES) forms the basis of almost all accounts of the mechanisms of chemical reactions, and much of theoretical molecular spectroscopy. It is assumed that, in principle, the PES can be calculated by means of clamped-nuclei electronic structure calculations based upon the Schrödinger Coulomb Hamiltonian. This article is devoted to a discussion of the origin of the idea, its development in the context of the Old Quantum Theory, and its present status in the quantum mechanics of molecules. It is argued that its present status must be regarded as uncertain. © 2013, Springer International Publishing Switzerland.
BibTeX: @article{Sutcliffe2013, author = {Sutcliffe, Brian and Woolley, R. Guy}, title = {The Potential Energy Surface in Molecular Quantum Mechanics}, journal = {Progress in Theoretical Chemistry and Physics}, year = {2013}, volume = {27}, pages = {3 – 40}, doi = {10.1007/978-3-319-01529-3_1} }
Sutton MA, Reis S, Riddick SN, Dragosits U, Nemitz E, Theobald MR, Tang YS, Braban CF, Vieno M, Dore AJ, Mitchell RF, Wanless S, Daunt F, Fowler D, Blackall TD, Milford C, Flechard CR, Loubet B, Massad R, Cellier P, Personne E, Coheur PF, Clarisse L, Van Damme M, Ngadi Y, Clerbaux C, Skjøth CA, Geels C, Hertel O, Kruit RJW, Pinder RW, Bash JO, Walker JT, Simpson D, Horváth L, Misselbrook TH, Bleeker A, Dentener F and de Vries W (2013), "Towards a climate-dependent paradigm of ammonia emission and deposition", Philosophical Transactions of the Royal Society B: Biological Sciences. Vol. 368(1621) [Abstract] [BibTeX] [DOI]
Abstract: Existing descriptions of bi-directional ammonia (NH3) land-atmosphere exchange incorporate temperature and moisture controls, and are beginning to be used in regional chemical transport models. However, such models have typically applied simpler emission factors to upscale the main NH3 emission terms. While this approach has successfully simulated the main spatial patterns on local to global scales, it fails to address the environment- and climate- dependence of emissions. To handle these issues, we outline the basis for a new modelling paradigm where both NH3 emissions and deposition are calculated online according to diurnal, seasonal and spatial differences in meteorology. We show how measurements reveal a strong, but complex pattern of climatic dependence, which is increasingly being characterized using ground-based NH3 monitoring and satellite observations, while advances in process-based modelling are illustrated for agricultural and natural sources, including a global application for seabird colonies. A future architecture for NH3 emission-deposition modelling is proposed that integrates the spatio-temporal interactions, and provides the necessary © 2013 The Author(s) Published by the Royal Society. All rights reserved.
BibTeX: @article{Sutton2013, author = {Sutton, Mark A. and Reis, Stefan and Riddick, Stuart N. and Dragosits, Ulrike and Nemitz, Eiko and Theobald, Mark R. and Tang, Y. Sim and Braban, Christine F. and Vieno, Massimo and Dore, Anthony J. and Mitchell, Robert F. and Wanless, Sarah and Daunt, Francis and Fowler, David and Blackall, Trevor D. and Milford, Celia and Flechard, Chris R. and Loubet, Benjamin and Massad, Raia and Cellier, Pierre and Personne, Erwan and Coheur, Pierre F. and Clarisse, Lieven and Van Damme, Martin and Ngadi, Yasmine and Clerbaux, Cathy and Skjøth, Carsten Ambelas and Geels, Camilla and Hertel, Ole and Kruit, Roy J. Wichink and Pinder, Robert W. and Bash, Jesse O. and Walker, John T. and Simpson, David and Horváth, László and Misselbrook, Tom H. and Bleeker, Albert and Dentener, Frank and de Vries, Wim}, title = {Towards a climate-dependent paradigm of ammonia emission and deposition}, journal = {Philosophical Transactions of the Royal Society B: Biological Sciences}, year = {2013}, volume = {368}, number = {1621}, note = {All Open Access, Bronze Open Access}, doi = {10.1098/rstb.2013.0166} }
Tereszchuk K, González Abad G, Clerbaux C, Hadji-Lazaro J, Hurtmans D, Coheur P-F and Bernath P (2013), "ACE-FTS observations of pyrogenic trace species in boreal biomass burning plumes during BORTAS", Atmospheric Chemistry and Physics. Vol. 13(9), pp. 4529 – 4541. [Abstract] [BibTeX] [DOI]
Abstract: To further our understanding of the effects of biomass burning emissions on atmospheric composition, the BORTAS campaign (BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) was conducted on 12 July to 3 August 2011 during the boreal forest fire season in Canada. The simultaneous aerial, ground and satellite measurement campaign sought to record instances of boreal biomass burning to measure the tropo-spheric volume mixing ratios (VMRs) of short- and long-lived trace molecular species from biomass burning emissions. The goal was to investigate the connection between the composition and the distribution of these pyrogenic outflows and their resulting perturbation to atmospheric chemistry, with particular focus on oxidant species to determine the overall impact on the oxidizing capacity of the free troposphere. Measurements of pyrogenic trace species in boreal biomass burning plumes were made by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) onboard the Canadian Space Agency (CSA) SCISAT-1 satellite during the BORTAS campaign. Even though biomass burning emissions are typically confined to the boundary layer, outflows are often injected into the upper troposphere by isolated convection and fire-related convective processes, thus allowing space-borne instruments to measure these pyrogenic outflows. An extensive set of 14 molecules - CH 3OH, C2H2, C2H6, C 3H6O, CO, HCN, HCOOH, HNO3, H2CO, NO, NO2, OCS, O3, and PAN -have been analysed. Included in this analysis is the calculation of age-dependent sets of enhancement ratios for each of the species originating from fires in North America (Canada, Alaska) and Siberia for a period of up to 7 days. Ratio values for the shorter lived primary pyrogenic species decrease over time primarily due to oxidation by the OH radical as the plume ages and values for longer lived species such as HCN and C2H6 remain relatively unchanged. Increasing negative values are observed for the oxidant species, including O3, indicating a destruction process in the plume as it ages such that concentrations of the oxidant species have dropped below their off-plume values. Results from previous campaigns have indicated that values for the molar ratios of ΔO 3 / ΔCO obtained from the measurements of the pyrogenic outflow from boreal fires are highly variable and range from negative to positive, irrespective of plume age. This variability has been attributed to pollution effects where the pyrogenic outflows have mixed with either local urban NO x emissions or pyrogenic emissions from the long-range transport of older plumes, thus affecting the production of O3 within the plumes. The results from this study have identified another potential cause of the variability in O3 concentrations observed in the measurements of biomass burning emissions, where evidence of stratosphere-troposphere exchange due to the pyroconvective updrafts from fires has been identified. Perturbations caused by the lofted emissions in these fire-aided convective processes may result in the intrusion of stratospheric air masses into the free troposphere and subsequent mixing of stratospheric O3 into the pyrogenic outflows causing fluctuations in observed ΔO3/ΔCO molar ratios. © Author(s) 2013.
BibTeX: @article{Tereszchuk2013, author = {Tereszchuk, K.A. and González Abad, G. and Clerbaux, C. and Hadji-Lazaro, J. and Hurtmans, D. and Coheur, P.-F. and Bernath, P.F.}, title = {ACE-FTS observations of pyrogenic trace species in boreal biomass burning plumes during BORTAS}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {9}, pages = {4529 – 4541}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-13-4529-2013} }
Theys N, Campion R, Clarisse L, Brenot H, Van Gent J, Dils B, Corradini S, Merucci L, Coheur P-F, Van Roozendael M, Hurtmans D, Clerbaux C, Tait S and Ferrucci F (2013), "Volcanic SO2 fluxes derived from satellite data: A survey using OMI, GOME-2, IASI and MODIS", Atmospheric Chemistry and Physics. Vol. 13(12), pp. 5945 – 5968. [Abstract] [BibTeX] [DOI]
Abstract: Sulphur dioxide (SO2) fluxes of active degassing volcanoes are routinely measured with ground-based equipment to characterize and monitor volcanic activity. SO2 of unmonitored volcanoes or from explosive volcanic eruptions, can be measured with satellites. However, remote-sensing methods based on absorption spectroscopy generally provide integrated amounts of already dispersed plumes of SO2 and satellite derived flux estimates are rarely reported. Here we review a number of different techniques to derive volcanic SO2 fluxes using satellite measurements of plumes of SO 2 and investigate the temporal evolution of the total emissions of SO2 for three very different volcanic events in 2011: Puyehue-Cordón Caulle (Chile), Nyamulagira (DR Congo) and Nabro (Eritrea). High spectral resolution satellite instruments operating both in the ultraviolet-visible (OMI/Aura and GOME-2/MetOp-A) and thermal infrared (IASI/MetOp-A) spectral ranges, and multispectral satellite instruments operating in the thermal infrared (MODIS/Terra-Aqua) are used. We show that satellite data can provide fluxes with a sampling of a day or less (few hours in the best case). Generally the flux results from the different methods are consistent, and we discuss the advantages and weaknesses of each technique. Although the primary objective of this study is the calculation of SO 2 fluxes, it also enables us to assess the consistency of the SO 2 products from the different sensors used. © 2013 Author(s).
BibTeX: @article{Theys2013, author = {Theys, N. and Campion, R. and Clarisse, L. and Brenot, H. and Van Gent, J. and Dils, B. and Corradini, S. and Merucci, L. and Coheur, P.-F. and Van Roozendael, M. and Hurtmans, D. and Clerbaux, C. and Tait, S. and Ferrucci, F.}, title = {Volcanic SO2 fluxes derived from satellite data: A survey using OMI, GOME-2, IASI and MODIS}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {12}, pages = {5945 – 5968}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-13-5945-2013} }
Turquety S, Messina P, Stromatas S, Anav A, Menut L, Bessagnet B, Péré J-C, Drobinski P, Coheur P, Rhoni Y, Clerbaux C and Tanré D (2013), "Impact of Fire Emissions on Air Quality in the Euro-Mediterranean Region", NATO Science for Peace and Security Series C: Environmental Security. Vol. 137, pp. 363 – 367. [Abstract] [BibTeX] [DOI]
Abstract: We present a regional emission inventory constructed based on satellite observations of fire activity (MODIS) and the ORCHIDEE vegetation model, and its application to air quality forecasting. After a brief description of the variability of fire activity in the Euro-Mediterranean region during the past 8 years, a full evaluation of the emissions is performed for the case study of the summer of 2007, during the large Greek fires event. Therefore, regional simulations undertaken with the CHIMERE chemistry-transport model (CTM) are compared to surface and satellite observations of trace gases and aerosols. © Springer Science+Business Media Dordrecht 2014.
BibTeX: @article{Turquety2013, author = {Turquety, S. and Messina, P. and Stromatas, S. and Anav, A. and Menut, L. and Bessagnet, B. and Péré, J.-C. and Drobinski, P. and Coheur, P.F. and Rhoni, Y. and Clerbaux, C. and Tanré, D.}, title = {Impact of Fire Emissions on Air Quality in the Euro-Mediterranean Region}, journal = {NATO Science for Peace and Security Series C: Environmental Security}, year = {2013}, volume = {137}, pages = {363 – 367}, doi = {10.1007/978-94-007-5577-2_61} }
Vander Auwera J, Ngo N, El Hamzaoui H, Capoen B, Bouazaoui M, Ausset P, Boulet C and Hartmann J-M (2013), "Infrared absorption by molecular gases as a probe of nanoporous silica xerogel and molecule-surface collisions: Low-pressure results", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 88(4) [Abstract] [BibTeX] [DOI]
Abstract: Transmission spectra of gases confined (but not adsorbed) within the pores of a 1.4-cm-thick silica xerogel sample have been recorded between 2.5 and 5 μm using a high-resolution Fourier transform spectrometer. This was done for pure CO, CO2, N2O, H2O, and CH4 at room temperature and pressures of a few hectopascals. Least-squares fits of measured absorption lines provide the optical-path lengths within the confined (LC) and free (LF) gas inside the absorption cell and the half width at half maximum ΓC of the lines of the confined gases. The values of LC and LF retrieved using numerous transitions of all studied species are very consistent. Furthermore, LC is in satisfactory agreement with values obtained from independent measurements, thus showing that reliable information on the open porosity volume can be retrieved from an optical experiment. The values of ΓC, here resulting from collisions of the molecules with the inner surfaces of the xerogel pores, are practically independent of the line for each gas and inversely proportional to the square root of the probed-molecule molar mass. This is a strong indication that, for the studied transitions, a single collision of a molecule with a pore surface is sufficient to change its rotational state. A previously proposed simple model, used for the prediction of the line shape, leads to satisfactory agreement with the observations. It also enables a determination of the average pore size, bringing information complementary to that obtained from nitrogen adsorption porosimetry. © 2013 American Physical Society.
BibTeX: @article{VanderAuwera2013, author = {Vander Auwera, J. and Ngo, N.H. and El Hamzaoui, H. and Capoen, B. and Bouazaoui, M. and Ausset, P. and Boulet, C. and Hartmann, J.-M.}, title = {Infrared absorption by molecular gases as a probe of nanoporous silica xerogel and molecule-surface collisions: Low-pressure results}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2013}, volume = {88}, number = {4}, doi = {10.1103/PhysRevA.88.042506} }
Verdebout S, Rynkun P, Jönsson P, Gaigalas G, Fischer CF and Godefroid M (2013), "A partitioned correlation function interaction approach for describing electron correlation in atoms", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 46(8) [Abstract] [BibTeX] [DOI]
Abstract: The traditional multiconfiguration Hartree-Fock (MCHF) and configuration interaction (CI) methods are based on a single orthonormal orbital basis. For atoms with many closed core shells, or complicated shell structures, a large orbital basis is needed to saturate the different electron correlation effects such as valence, core-valence and correlation within the core shells. The large orbital basis leads to massive configuration state function (CSF) expansions that are difficult to handle, even on large computer systems. We show that it is possible to relax the orthonormality restriction on the orbital basis and break down the originally very large calculations into a series of smaller calculations that can be run in parallel. Each calculation determines a partitioned correlation function (PCF) that accounts for a specific correlation effect. The PCFs are built on optimally localized orbital sets and are added to a zero-order multireference (MR) function to form a total wave function. The expansion coefficients of the PCFs are determined from a low dimensional generalized eigenvalue problem. The interaction and overlap matrices are computed using a biorthonormal transformation technique (Verdebout et al 2010 J. Phys. B: At. Mol. Phys. 43 074017). The new method, called partitioned correlation function interaction (PCFI), converges rapidly with respect to the orbital basis and gives total energies that are lower than the ones from ordinary MCHF and CI calculations. The PCFI method is also very flexible when it comes to targeting different electron correlation effects. Focusing our attention on neutral lithium, we show that by dedicating a PCF to the single excitations from the core, spin- and orbital-polarization effects can be captured very efficiently, leading to highly improved convergence patterns for hyperfine parameters compared with MCHF calculations based on a single orthogonal radial orbital basis. By collecting separately optimized PCFs to correct the MR function, the variational degrees of freedom in the relative mixing coefficients of the CSFs building the PCFs are inhibited. The constraints on the mixing coefficients lead to small off-sets in computed properties such as hyperfine structure, isotope shift and transition rates, with respect to the correct values. By (partially) deconstraining the mixing coefficients one converges to the correct limits and keeps the tremendous advantage of improved convergence rates that comes from the use of several orbital sets. Reducing ultimately each PCF to a single CSF with its own orbital basis leads to a non-orthogonal CI approach. Various perspectives of the new method are given. © 2013 IOP Publishing Ltd.
BibTeX: @article{Verdebout2013, author = {Verdebout, S. and Rynkun, P. and Jönsson, P. and Gaigalas, G. and Fischer, C. Froese and Godefroid, M.}, title = {A partitioned correlation function interaction approach for describing electron correlation in atoms}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2013}, volume = {46}, number = {8}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/46/8/085003} }
Villa M, Fusina L, Di Lonardo G, De Ghellinck D'Elseghem Vaernewijck X and Herman M (2013), "Femto-FT-CEAS investigation of rare acetylene isotopologues (H 12C13CD, D12 C13 CH and D 12C13CD)", Molecular Physics. Vol. 111(14-15), pp. 1972 – 1976. [Abstract] [BibTeX] [DOI]
Abstract: The infrared spectrum of a sample containing 13C mono-substituted isotopologues of acetylene, H12C13CH, H12C13CD, D12C13CH and D 12C13 CD has been recorded in the 6130-6800 cm -1 region using a femto-Fourier transform-cavity enhanced absorption spectroscopy (femto-FT-CEAS) apparatus. Three bands for both H 12C13CD and D12C13CH were observed and analysed, namely 2ν1 - GS and associated hot bands from ν4 and ν5 . The assignment of the 2ν1 overtone already reported in the literature [J.L. Hardwick, Z.T. Martin, M.J. Pilkenton, E.N. Wolf, J. Mol. Spectrosc. 243, 10 (2007)] was considerably extended to higher J values. For the D12C13CD isotopologue, four bands were analysed, ν1 + ν2 + ν3 - GS and associated hot bands from ν4 and ν5 and 2ν1 + ν4 + ν5 - GS. © 2013 Taylor & Francis.
BibTeX: @article{Villa2013, author = {Villa, M. and Fusina, L. and Di Lonardo, G. and De Ghellinck D'Elseghem Vaernewijck, X. and Herman, M.}, title = {Femto-FT-CEAS investigation of rare acetylene isotopologues (H 12C13CD, D12 C13 CH and D 12C13CD)}, journal = {Molecular Physics}, year = {2013}, volume = {111}, number = {14-15}, pages = {1972 – 1976}, doi = {10.1080/00268976.2013.771805} }
Vranckx S, Loreau J, Desouter-Lecomte M and Vaeck N (2013), "Determination of photodissociation and radiative association cross sections from the same time-dependent calculation", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 46(15) [Abstract] [BibTeX] [DOI]
Abstract: We illustrate some of the difficulties that may be encountered when computing photodissociation and radiative association cross sections from the same time-dependent approach based on wavepacket propagation. The total and partial photodissociation cross sections from the 33 vibrational levels of the b 3Σ+ state of HeH+ towards the nine other 3Σ+ and 6 3Π n = 2, 3 higher lying electronic states are calculated, using the autocorrelation method introduced by Heller (1978 J. Chem. Phys. 68 3891) and the method based on the asymptotic behaviour of wavepackets introduced by Balint-Kurti et al (1990 J. Chem. Soc. Faraday Trans. 86 1741). The corresponding radiative association cross sections are extracted from the same calculations, and the photodissociation and radiative association rate constants are determined. © 2013 IOP Publishing Ltd.
BibTeX: @article{Vranckx2013, author = {Vranckx, S. and Loreau, J. and Desouter-Lecomte, M. and Vaeck, N.}, title = {Determination of photodissociation and radiative association cross sections from the same time-dependent calculation}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2013}, volume = {46}, number = {15}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/46/15/155201} }
Worden H, Deeter M, Frankenberg C, George M, Nichitiu F, Worden J, Aben I, Bowman K, Clerbaux C, Coheur P, De Laat A, Detweiler R, Drummond J, Edwards D, Gille J, Hurtmans D, Luo M, Martínez-Alonso S, Massie S, Pfister G and Warner J (2013), "Decadal record of satellite carbon monoxide observations", Atmospheric Chemistry and Physics. Vol. 13(2), pp. 837 – 850. [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric carbon monoxide (CO) distributions are controlled by anthropogenic emissions, biomass burning, transport and oxidation by reaction with the hydroxyl radical (OH). Quantifying trends in CO is therefore important for understanding changes related to all of these contributions. Here we present a comprehensive record of satellite observations from 2000 through 2011 of total column CO using the available measurements from nadir-viewing thermal infrared instruments: MOPITT, AIRS, TES and IASI. We examine trends for CO in the Northern and Southern Hemispheres along with regional trends for Eastern China, Eastern USA, Europe and India. We find that all the satellite observations are consistent with a modest decreasing trend ∼-1 % yr-1 in total column CO over the Northern Hemisphere for this time period and a less significant, but still decreasing trend in the Southern Hemisphere. Although decreasing trends in the United States and Europe have been observed from surface CO measurements, we also find a decrease in CO over E. China that, to our knowledge, has not been reported previously. Some of the interannual variability in the observations can be explained by global fire emissions, but the overall decrease needs further study to understand the implications for changes in anthropogenic emissions. © 2013 Author(s).
BibTeX: @article{Worden2013, author = {Worden, H.M. and Deeter, M.N. and Frankenberg, C. and George, M. and Nichitiu, F. and Worden, J. and Aben, I. and Bowman, K.W. and Clerbaux, C. and Coheur, P.F. and De Laat, A.T.J. and Detweiler, R. and Drummond, J.R. and Edwards, D.P. and Gille, J.C. and Hurtmans, D. and Luo, M. and Martínez-Alonso, S. and Massie, S. and Pfister, G. and Warner, J.X.}, title = {Decadal record of satellite carbon monoxide observations}, journal = {Atmospheric Chemistry and Physics}, year = {2013}, volume = {13}, number = {2}, pages = {837 – 850}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-13-837-2013} }
Astoreca R, Doxaran D, Ruddick K, Rousseau V and Lancelot C (2012), "Influence of suspended particle concentration, composition and size on the variability of inherent optical properties of the Southern North Sea", Continental Shelf Research. Vol. 35, pp. 117 – 128. [Abstract] [BibTeX] [DOI]
Abstract: Suspended particles play an important role in coastal waters by controlling to a large extent the variability of the water inherent optical properties (IOPs). In this study, focused on the complex waters of the Southern North Sea, the relationships between the concentration, composition and size of suspended particles and their optical properties (light absorption, and attenuation in the visible and near-infrared spectral regions) are investigated. Over a one-year period, field measurements were carried out along regular transects from the Belgian to the English coasts to cover a wide gradient of water masses. Results show that the area can be divided into three geographical zones, each one having specific biogeochemical and optical properties: Scheldt coastal zone (SCZ), Middle of the Southern North Sea (MSNS) and Thames coastal zone (TCZ). Concentrations of organic (inorganic) particles were always higher in the SCZ (TCZ). The MSNS was characterized by a high proportion of organic particles in low concentration. The spectral shape of particle attenuation reveals a wide range from negative to positive slopes. Particle size distributions reveal a power-law shape along the coasts (especially in the TCZ) and a bimodal distribution in the MSNS notably during the spring phytoplankton bloom. This bimodal size distribution and more precisely a size peak around 7 μm results in an unexpected negative spectral slope of the particle attenuation coefficient. Variations in the particulate mass-specific IOPs between the three regions were observed to predominate over seasonal variations. The implications in terms of inversion of IOPs into biogeochemical parameters, such as chlorophyll a and total suspended matter, in coastal waters are discussed. © 2012 Elsevier Ltd.
BibTeX: @article{Astoreca2012, author = {Astoreca, R. and Doxaran, D. and Ruddick, K. and Rousseau, V. and Lancelot, C.}, title = {Influence of suspended particle concentration, composition and size on the variability of inherent optical properties of the Southern North Sea}, journal = {Continental Shelf Research}, year = {2012}, volume = {35}, pages = {117 – 128}, doi = {10.1016/j.csr.2012.01.007} }
Borgoo A, Godefroid MR and Geerlings P (2012), "Atomic Density Functions: Atomic Physics Calculations Analyzed with Methods from Quantum Chemistry", Progress in Theoretical Chemistry and Physics. Vol. 22, pp. 139 – 171. [Abstract] [BibTeX] [DOI]
Abstract: This contribution reviews a selection of findings on atomic density functions and discusses ways for reading chemical information from them. First an expression for the density function for atoms in the multi-configuration Hartree–Fock scheme is established. The spherical harmonic content of the density function and ways to restore the spherical symmetry in a general open-shell case are treated. The evaluation of the density function is illustrated in a few examples. In the second part of the paper, atomic density functions are analyzed using quantum similarity measures. The comparison of atomic density functions is shown to be useful to obtain physical and chemical information. Finally, concepts from information theory are introduced and adopted for the comparison of density functions. In particular, based on the Kullback–Leibler form, a functional is constructed that reveals the periodicity in Mendeleev’s table. Finally a quantum similarity measure is constructed, based on the integrand of the Kullback–Leibler expression and the periodicity is regained in a different way. © 2012, Springer Science+Business Media B.V.
BibTeX: @article{Borgoo2012, author = {Borgoo, Alex and Godefroid, Michel R. and Geerlings, Paul}, title = {Atomic Density Functions: Atomic Physics Calculations Analyzed with Methods from Quantum Chemistry}, journal = {Progress in Theoretical Chemistry and Physics}, year = {2012}, volume = {22}, pages = {139 – 171}, doi = {10.1007/978-94-007-2076-3_9} }
Cassam-Chenaï P and Liévin J (2012), "Ab initio calculation of the rotational spectrum of methane vibrational ground state", Journal of Chemical Physics. Vol. 136(17) [Abstract] [BibTeX] [DOI]
Abstract: In a previous article we have introduced an alternative perturbation scheme to the traditional one starting from the harmonic oscillator, rigid rotator Hamiltonian, to find approximate solutions of the spectral problem for rotation-vibration molecular Hamiltonians. The convergence of our method for the methane vibrational ground state rotational energy levels was quicker than that of the traditional method, as expected, and our predictions were quantitative. In this second article, we study the convergence of the ab initio calculation of effective dipole moments for methane within the same theoretical frame. The first order of perturbation when applied to the electric dipole moment operator of a spherical top gives the expression used in previous spectroscopic studies. Higher orders of perturbation give corrections corresponding to higher centrifugal distortion contributions and are calculated accurately for the first time. Two potential energy surfaces of the literature have been used for solving the anharmonic vibrational problem by means of the vibrational mean field configuration interaction approach. Two corresponding dipole moment surfaces were calculated in this work at a high level of theory. The predicted intensities agree better with recent experimental values than their empirical fit. This suggests that our ab initio dipole moment surface and effective dipole moment operator are both highly accurate. © 2012 American Institute of Physics.
BibTeX: @article{CassamChenai2012, author = {Cassam-Chenaï, P. and Liévin, J.}, title = {Ab initio calculation of the rotational spectrum of methane vibrational ground state}, journal = {Journal of Chemical Physics}, year = {2012}, volume = {136}, number = {17}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.4705278} }
Cauët E, Bogatko SA, Bylaska EJ and Weare JH (2012), "Ion association in AlCl 3 aqueous solutions from constrained first-principles molecular dynamics", Inorganic Chemistry. Vol. 51(20), pp. 10856 – 10869. [Abstract] [BibTeX] [DOI]
Abstract: The Car-Parrinello-based molecular dynamics (CPMD) method was used to investigate the ion-pairing behavior between Cl - and Al 3+ ions in an aqueous AlCl 3 solution containing 63 water molecules. A series of constrained simulations was carried out at 300 K for up to 16 ps each, with the internuclear separation (r Al-Cl) between the Al 3+ ion and one of the Cl - ions held constant. The calculated potential of mean force (PMF) of the Al 3+-Cl - ion pair shows a global minimum at r Al-Cl = 2.3 Å corresponding to a contact ion pair (CIP). Two local minima assigned to solvent-separated ion pairs (SSIPs) are identified at r Al-Cl = 4.4 and 6.0 Å. The positions of the free energy minima coincide with the hydration-shell intervals of the Al 3+ cation, suggesting that the Cl - ion is inclined to reside in regions with low concentrations of water molecules, that is, between the first and second hydration shells of Al 3+ and between the second shell and the bulk. A detailed analysis of the solvent structure around the Al 3+ and Cl - ions as a function of r Al-Cl is presented. The results are compared to structural data from X-ray measurements and unconstrained CPMD simulations of single Al 3+ and Cl - ions and AlCl 3 solutions. The dipole moments of the water molecules in the first and second hydration shells of Al 3+ and in the bulk region and those of Cl - ions were calculated as a function of r Al-Cl. Major changes in the electronic structure of the system were found to result from the removal of Cl - from the first hydration shell of the Al 3+ cation. Finally, two unconstrained CPMD simulations of aqueous AlCl 3 solutions corresponding to CIP and SSIP configurations were performed (17 ps, 300 K). Only minor structural changes were observed in these systems, confirming their stability. © 2012 American Chemical Society.
BibTeX: @article{Cauet2012, author = {Cauët, Emilie and Bogatko, Stuart A. and Bylaska, Eric J. and Weare, John H.}, title = {Ion association in AlCl 3 aqueous solutions from constrained first-principles molecular dynamics}, journal = {Inorganic Chemistry}, year = {2012}, volume = {51}, number = {20}, pages = {10856 – 10869}, doi = {10.1021/ic301346k} }
Cauët E, Carette T, Lauzin C, Li J, Loreau J, Delsaut M, Nazé C, Verdebout S, Vranckx S, Godefroid M, Liévin J and Vaeck N (2012), "From atoms to biomolecules: A fruitful perspective", Theoretical Chemistry Accounts. Vol. 131(8), pp. 1 – 17. [Abstract] [BibTeX] [DOI]
Abstract: We present a summary of the research activities of the "Quantum Chemistry and Atomic Physics" theoretical group of the "Chimie Quantique et Photophysique" Laboratory at Université Libre de Bruxelles. We emphasize the links between the three orientations of the group: theoretical atomic spectroscopy, structure, and molecular dynamics and list the perspectives of our collaboration. © Springer-Verlag 2012.
BibTeX: @article{Cauet2012c, author = {Cauët, E. and Carette, T. and Lauzin, C. and Li, J.G. and Loreau, J. and Delsaut, M. and Nazé, C. and Verdebout, S. and Vranckx, S. and Godefroid, M. and Liévin, J. and Vaeck, N.}, title = {From atoms to biomolecules: A fruitful perspective}, journal = {Theoretical Chemistry Accounts}, year = {2012}, volume = {131}, number = {8}, pages = {1 – 17}, doi = {10.1007/s00214-012-1254-3} }
Cauët E and Jacquemin D (2012), "A theoretical spectroscopy investigation of oxosumanenes", Chemical Physics Letters. Vol. 519-520, pp. 49 – 53. [Abstract] [BibTeX] [DOI]
Abstract: Using Density Functional Theory approaches, we investigate the structure and spectroscopic signatures of sumanene, monooxosumanene and trioxosumanene, three synthesised bowl-shaped compounds. The simulated properties include geometries, charges, polarisabilities, infrared and UV/visible spectra as well as complexation energies. Refined approaches have been considered (anharmonic frequencies, state-specific solvent model, dispersion-corrected DFT...) and a valuable agreement with experimental reference values is reached for most properties. The evolution of the electronic features of sumanene upon oxidation has been rationalised. © 2011 Elsevier B.V. All rights reserved.
BibTeX: @article{Cauet2012b, author = {Cauët, Emilie and Jacquemin, Denis}, title = {A theoretical spectroscopy investigation of oxosumanenes}, journal = {Chemical Physics Letters}, year = {2012}, volume = {519-520}, pages = {49 – 53}, doi = {10.1016/j.cplett.2011.11.021} }
Cauët E, Valiev M, Weare J and Liévin J (2012), "Quantum mechanical calculations related to ionization and charge transfer in DNA", Journal of Physics: Conference Series. Vol. 373 [Abstract] [BibTeX] [DOI]
Abstract: Ionization and charge migration in DNA play crucial roles in mechanisms of DNA damage caused by ionizing radiation, oxidizing agents and photo-irradiation. Therefore, an evaluation of the ionization properties of the DNA bases is central to the full interpretation and understanding of the elementary reactive processes that occur at the molecular level during the initial exposure and afterwards. Ab initio quantum mechanical (QM) methods have been successful in providing highly accurate evaluations of key parameters, such as ionization energies (IE) of DNA bases. Hence, in this study, we performed high-level QM calculations to characterize the molecular energy levels and potential energy surfaces, which shed light on ionization and charge migration between DNA bases. In particular, we examined the IEs of guanine, the most easily oxidized base, isolated and embedded in base clusters, and investigated the mechanism of charge migration over two and three stacked guanines. The IE of guanine in the human telomere sequence has also been evaluated. We report a simple molecular orbital analysis to explain how modifications in the base sequence are expected to change the efficiency of the sequence as a hole trap. Finally, the application of a hybrid approach combining quantum mechanics with molecular mechanics brings an interesting discussion as to how the native aqueous DNA environment affects the IE threshold of nucleobases.
BibTeX: @conference{Cauet2012a, author = {Cauët, E. and Valiev, M. and Weare, J.H. and Liévin, J.}, title = {Quantum mechanical calculations related to ionization and charge transfer in DNA}, journal = {Journal of Physics: Conference Series}, year = {2012}, volume = {373}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/373/1/012003} }
Cerón-Carrasco JP, Jacquemin D and Cauët E (2012), "Cisplatin cytotoxicity: A theoretical study of induced mutations", Physical Chemistry Chemical Physics. Vol. 14(36), pp. 12457 – 12464. [Abstract] [BibTeX] [DOI]
Abstract: We investigate possible mutations in the genetic code induced by cisplatin with an approach combining molecular dynamics (MD) and hybrid quantum mechanics/molecular mechanics (QM/MM) calculations. Specifically, the impact of platination on the natural tautomeric equilibrium in guanine-cytosine (GC) base pairs is assessed to disclose the possible role played by non-canonical forms in anti-tumour activity. To obtain valuable predictions, the main interactions present in a real DNA environment, namely hydration and stacking, are simultaneously taken into account. According to our results, the Pt-DNA adduct promotes a single proton transfer reaction in GC in the DNA sequence AGGC. Such rare tautomers might play an important role in the cisplatin biological activity since they meet the stability requirements necessary to promote a permanent mutation. This journal is © the Owner Societies 2012.
BibTeX: @article{CeronCarrasco2012, author = {Cerón-Carrasco, José P. and Jacquemin, Denis and Cauët, Emilie}, title = {Cisplatin cytotoxicity: A theoretical study of induced mutations}, journal = {Physical Chemistry Chemical Physics}, year = {2012}, volume = {14}, number = {36}, pages = {12457 – 12464}, doi = {10.1039/c2cp40515f} }
Cich M, McRaven C, Lopez G, Sears T, Hurtmans D and Mantz A (2012), "Temperature-dependent pressure broadened line shape measurements in the ν 1+ν 3 band of acetylene using a diode laser referenced to a frequency comb", Applied Physics B: Lasers and Optics. Vol. 109(3), pp. 373 – 384. [Abstract] [BibTeX] [DOI]
Abstract: Using an extended cavity diode laser referenced to a femtosecond frequency comb, the P(11) absorption line in the ν 1+ν 3 combination band of the most abundant isotopologue of pure acetylene was studied at temperatures of 296, 240, 200, 175, 165, 160, 155, and 150 K to determine pressure-dependent line shape parameters at these temperatures. The laser emission profile, the instrumental resolution, is a Lorentz function characterized by a half width at half the maximum emission (HWHM) of 8.3×10-6 cm-1 (or 250 kHz) for these measurements. Six collision models were tested in fitting the experimental data: Voigt, speed-dependent Voigt, Rautian-Sobel'man, Galatry, and two Rautian-Galatry hybrid models (with and without speed-dependence). Only the speed-dependent Voigt model was able to fit the data to the experimental noise level at all temperatures and for pressures between 3 and nearly 360 torr. The variations of the speed-dependent Voigt profile line shape parameters with temperature were also characterized, and this model accurately reproduces the observations over their entire range of temperature and pressure. © 2011 Springer-Verlag.
BibTeX: @article{Cich2012, author = {Cich, M.J. and McRaven, C.P. and Lopez, G.V. and Sears, T.J. and Hurtmans, D. and Mantz, A.W.}, title = {Temperature-dependent pressure broadened line shape measurements in the ν 1+ν 3 band of acetylene using a diode laser referenced to a frequency comb}, journal = {Applied Physics B: Lasers and Optics}, year = {2012}, volume = {109}, number = {3}, pages = {373 – 384}, doi = {10.1007/s00340-011-4829-0} }
Clarisse L, Hurtmans D, Clerbaux C, Hadji-Lazaro J, Ngadi Y and Coheur P-F (2012), "Retrieval of sulphur dioxide from the infrared atmospheric sounding interferometer (IASI)", Atmospheric Measurement Techniques. Vol. 5(3), pp. 581 – 594. [Abstract] [BibTeX] [DOI]
Abstract: Thermal infrared sounding of sulphur dioxide (SO 2) from space has gained appreciation as a valuable complement to ultraviolet sounding. There are several strong absorption bands of SO 2 in the infrared, and atmospheric sounders, such as AIRS (Atmospheric Infrared Sounder), TES (Tropospheric Emission Spectrometer) and IASI (Infrared Atmospheric Sounding Interferometer) have the ability to globally monitor SO 2 abundances. Most of the observed SO 2 is found in volcanic plumes. In this paper we outline a novel algorithm for the sounding of SO 2 above ∼5 km altitude using high resolution infrared sounders and apply it to measurements of IASI. The main features of the algorithm are a wide applicable total column range (over 4 orders of magnitude, from 0.5 to 5000 dobson units), a low theoretical uncertainty (3-5%) and near real time applicability. We make an error analysis and demonstrate the algorithm on the recent eruptions of Sarychev, Kasatochi, Grimsvötn, Puyehue-Cordón Caulle and Nabro. © 2012 Author(s). CC Attribution 3.0 License.
BibTeX: @article{Clarisse2012, author = {Clarisse, L. and Hurtmans, D. and Clerbaux, C. and Hadji-Lazaro, J. and Ngadi, Y. and Coheur, P.-F.}, title = {Retrieval of sulphur dioxide from the infrared atmospheric sounding interferometer (IASI)}, journal = {Atmospheric Measurement Techniques}, year = {2012}, volume = {5}, number = {3}, pages = {581 – 594}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-5-581-2012} }
Colin R and Bernath PF (2012), "High resolution Fourier transform emission spectroscopy of the A 2Π-X 2Σ + and B 2Σ +-X 2Σ + systems of the 12C 15N free radical", Journal of Molecular Spectroscopy. Vol. 273(1), pp. 30 – 33. [Abstract] [BibTeX] [DOI]
Abstract: Emission spectra of the A 2Π-X 2Σ + (red) and B 2Σ +-X 2Σ + (violet) systems of the 12C 15N molecule have been investigated in the 4500-26 000 cm -1 spectral region at high resolution using a Fourier transform spectrometer. In all, 22 bands of the A-X system and six bands of the B-X system have been rotationally analyzed providing a set of molecular constants for the v″ = 0-5, v′ = 0-4 and v′ = 0-3 levels of the X, A and B states, respectively. © 2012 Elsevier B.V. All rights reserved.
BibTeX: @article{Colin2012, author = {Colin, Reginald and Bernath, Peter F.}, title = {High resolution Fourier transform emission spectroscopy of the A 2Π-X 2Σ + and B 2Σ +-X 2Σ + systems of the 12C 15N free radical}, journal = {Journal of Molecular Spectroscopy}, year = {2012}, volume = {273}, number = {1}, pages = {30 – 33}, doi = {10.1016/j.jms.2012.01.007} }
Daumont L, Jenouvrier A, Mikhailenko S, Carleer M, Hermans C, Fally S and Vandaele AC (2012), "High resolution Fourier transform spectroscopy of HD 16O: Line positions, absolute intensities and self broadening coefficients in the 8800-11,600cm -1 spectral region", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 113(11), pp. 878 – 888. [Abstract] [BibTeX] [DOI]
Abstract: High-resolution water vapor absorption spectra have been measured at room temperature in the 8800-11,600cm -1 spectral region. They were obtained using the mobile BRUKER IFS 120M Fourier transform spectrometer (FTS) from ULB-SCQP coupled to the 50m base long multiple reflection White type cell in GSMA laboratory. The absorption path was 600m and different H 2O/HDO/D 2O mixtures were used. Measurements of line positions, intensities and self-broadening coefficients were performed for the HD 16O isotopologue. 6464 rovibrational assignment of the observed lines was made on the basis of global variational predictions and allowed the identification of new energy levels. 3ν 3, 2ν 1+ν 3, 3ν 1+ν 2, ν 1+2ν 3 and 2ν 2+2ν 3 are the five strongest bands. The present paper provides a complementary data set on water vapor for atmospheric and astrophysical applications. © 2012 Elsevier Ltd.
BibTeX: @article{Daumont2012, author = {Daumont, Ludovic and Jenouvrier, Alain and Mikhailenko, Semen and Carleer, Michel and Hermans, Christian and Fally, Sophie and Vandaele, Ann Carine}, title = {High resolution Fourier transform spectroscopy of HD 16O: Line positions, absolute intensities and self broadening coefficients in the 8800-11,600cm -1 spectral region}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2012}, volume = {113}, number = {11}, pages = {878 – 888}, doi = {10.1016/j.jqsrt.2012.02.017} }
De Ghellinck D'Elseghem Vaernewijck X, Golebiowski D and Herman M (2012), "Femto-Fourier transform-cavity enhanced absorption spectroscopy in a supersonic expansion", Molecular Physics. Vol. 110(21-22), pp. 2735 – 2741. [Abstract] [BibTeX] [DOI]
Abstract: Proofs of principle spectra of C2H4, N2O and C2H2, including H12C13CH in natural abundance, are reported, recorded in the 1.6 mm range in an Ar supersonic expansion using femto-Fourier transform-cavity enhanced absorption spectroscopy. The effective absorption pathlength in the jet-cooled sample is up to 78m and the optimal S/N is over 2300. The data processing is detailed. Saturation effects are reported for the C2H2 bands. spectroscopy © 2012 Taylor and Francis.
BibTeX: @article{DeGhellinckDElseghemVaernewijck2012b, author = {De Ghellinck D'Elseghem Vaernewijck, X. and Golebiowski, D. and Herman, M.}, title = {Femto-Fourier transform-cavity enhanced absorption spectroscopy in a supersonic expansion}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2735 – 2741}, doi = {10.1080/00268976.2012.701342} }
De Ghellinck D'Elseghem Vaernewijck X, Kassi S and Herman M (2012), "17O12C17O and 18O 12C17O spectroscopy in the 1.6 μm region", Molecular Physics. Vol. 110(21-22), pp. 2665 – 2671. [Abstract] [BibTeX] [DOI]
Abstract: Near infrared spectra of a carbon dioxide sample enriched with oxygen-17 have been recorded using a highresolution continuous scan Fourier transform interferometer fitted with a femto OPO/Idler laser source. Cavity enhanced absorption has been achieved in a static gas cell allowing an optimal rms noise equivalent absorption of 1.2×10-10 cm-1 Hz -1/2 per spectral element to be reached, corresponding to αmin=10-8 cm-1. Spectra were calibrated against acetylene reference line positions. Three bands in the 3v 1+v3 tetrad in both 12C17O 2 and 12C17O18O have been identified and rotationally analyzed, as well as some related hot bands, eight of which are newly reported and three with their analysis updated compared with a preliminary report (X. de Ghellinck d'Elseghem Vaernewijck et al., Chem. Phys. Lett. 514, 29 (2011)). © 2012 Taylor and Francis.
BibTeX: @article{DeGhellinckDElseghemVaernewijck2012, author = {De Ghellinck D'Elseghem Vaernewijck, X. and Kassi, S. and Herman, M.}, title = {17O12C17O and 18O 12C17O spectroscopy in the 1.6 μm region}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2665 – 2671}, doi = {10.1080/00268976.2012.705346} }
De Ghellinck D'Elseghem Vaernewijck X, Kongolo Tshikala P, Lepère M and Herman M (2012), "Femto-FT-CEAS applied to carbon disulfide around 1.54 μm", Journal of Molecular Spectroscopy. Vol. 282(1), pp. 27 – 29. [Abstract] [BibTeX] [DOI]
Abstract: A femto-OPO laser fitted to a high-finesse cavity and a Fourier transform spectrometer to perform femto-FT-CEAS (for femto-Fourier transform-cavity enhanced spectroscopy) was used to record high overtones of carbon disulfide with a minimal rms equivalent absorption coefficient of 1.2 × 10 -11 cm-1 Hz-1/2 per spectral element. New vibrational states are reported for 12C32S2 and 12C32S34S and new or improved rotational constants are obtained, for the v1v2l2v3 = 3003, 2203, 0114 and 4003 states in 12C32S2 and 3003 state in 32S12C34S. © 2012 Elsevier Inc. All rights reserved.
BibTeX: @article{DeGhellinckDElseghemVaernewijck2012a, author = {De Ghellinck D'Elseghem Vaernewijck, Xavier and Kongolo Tshikala, Pardaillan and Lepère, Muriel and Herman, Michel}, title = {Femto-FT-CEAS applied to carbon disulfide around 1.54 μm}, journal = {Journal of Molecular Spectroscopy}, year = {2012}, volume = {282}, number = {1}, pages = {27 – 29}, doi = {10.1016/j.jms.2012.10.006} }
De Wachter E, Barret B, Le Flochmoën E, Pavelin E, Matricardi M, Clerbaux C, Hadji-Lazaro J, George M, Hurtmans D, Coheur P-F, Nedelec P and Cammas J (2012), "Retrieval of MetOp-A/IASI CO profiles and validation with MOZAIC data", Atmospheric Measurement Techniques. Vol. 5(11), pp. 2843 – 2857. [Abstract] [BibTeX] [DOI]
Abstract: The IASI (Infrared Atmospheric Sounding Interferometer) nadir-looking thermal infrared sounder onboard MetOp-A enables the monitoring of atmospheric constituents on a global scale. This paper presents a quality assessment of IASI CO profiles retrieved by the two different retrieval algorithms SOFRID and FORLI, by an intercomparison with airborne in-situ CO profiles from the MOZAIC program for the 2008-2009 period. Lower (surface-480 hPa) and upper tropospheric partial column (480-225 hPa) comparisons as well as profile comparisons are made. The retrieval errors of the IASI products are less than 21% in the lower troposphere and less than 10% in the upper troposphere. A statistical analysis shows similar correlation coefficients for the two retrieval algorithms and smoothed MOZAIC of r ∼ 0.8 and r ∼ 0.7 in the lower and upper troposphere respectively. Comparison with smoothed MOZAIC data of the temporal variation of the CO profiles at the airports of Frankfurt and Windhoek demonstrates that the IASI products are able to capture the seasonal variability at these sites. At Frankfurt SOFRID (respectively FORLI) is positively biased by 10.5% (13.0%) compared to smoothed MOZAIC in the upper (lower) troposphere, and the limited sensitivity of the IASI instrument to the boundary layer when thermal contrast is low is identified. At Windhoek, the impact of the vegetation fires in Southern Africa from July to November is captured by both SOFRID and FORLI, with an overestimation of the CO background values (fire maxima) by SOFRID (FORLI) by 12.8% (10%). Profile comparisons at Frankfurt and Windhoek show that the largest discrepancies are found between the two IASI products and MOZAIC for the nighttime retrievals. © 2012 Author(s).
BibTeX: @article{DeWachter2012, author = {De Wachter, E. and Barret, B. and Le Flochmoën, E. and Pavelin, E. and Matricardi, M. and Clerbaux, C. and Hadji-Lazaro, J. and George, M. and Hurtmans, D. and Coheur, P.-F. and Nedelec, P. and Cammas, J.P.}, title = {Retrieval of MetOp-A/IASI CO profiles and validation with MOZAIC data}, journal = {Atmospheric Measurement Techniques}, year = {2012}, volume = {5}, number = {11}, pages = {2843 – 2857}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-5-2843-2012} }
Di Lauro C, Lattanzi F, Brown LR, Sung K, Vander Auwera J, Mantz AW and Smith MAH (2012), "High resolution investigation of the 7 μm region of the ethane spectrum", Planetary and Space Science. Vol. 60(1), pp. 93 – 101. [Abstract] [BibTeX] [DOI]
Abstract: Building upon previous studies, we re-investigated the ethane spectrum between 1330 and 1610 cm -1 by combining unapodized spectra obtained at room temperature with a Bruker Fourier transform spectrometer (FTS) in Brussels and at 131 K with a Bruker FTS in Pasadena. The maximum optical path differences (MOPD) of the two datasets were 450 and 323.7 cm, corresponding to spectral resolutions of 0.0020 and 0.0028 cm -1, respectively. Of the 15,000 lines observed, over 4592 transitions were assigned to the ν 6 (at 1379 cm -1), ν 8 (at 1472 cm -1), ν 4ν 12 (at 1481 cm -1) and 2ν 4ν 9 (at 1388 cm -1) bands, and another 1044 transitions were located for the ν 4ν 8- ν 4 hot band (at 1472 cm -1). Our new analysis included an improved implementation of the Hamiltonian calculation needed to interpret the complex spectral structures caused by numerous interactions affecting these four modes of vibration. From these results, we created the first line-by-line database containing the molecular parameters for over 20,000 12C 2H 6 transitions at 7 μm. © 2011 Elsevier Ltd. All rights reserved.
BibTeX: @article{DiLauro2012, author = {Di Lauro, Carlo and Lattanzi, Franca and Brown, Linda R. and Sung, Keeyoon and Vander Auwera, Jean and Mantz, Arlan W. and Smith, Mary Ann H.}, title = {High resolution investigation of the 7 μm region of the ethane spectrum}, journal = {Planetary and Space Science}, year = {2012}, volume = {60}, number = {1}, pages = {93 – 101}, doi = {10.1016/j.pss.2011.01.008} }
Didriche K, Földes T, Lauzin C, Golebiowski D, Liévin J and Herman M (2012), "Experimental 2CH excitation in acetylene-containing van der Waals complexes", Molecular Physics. Vol. 110(21-22), pp. 2781 – 2796. [Abstract] [BibTeX] [DOI]
Abstract: Spectroscopic results are presented concerning the 2CH excitation around 1.5 mm in van der Waals complexes of acetylene (C2H2) with Ar, Kr, N2, CO2, N2O and C2H 2. Many are reviewed from the literature, with some updates. Previously unpublished results are also presented, concerning the mechanism of formation of C2H2-Ar in the supersonic jet, the assignment of new spectral structures in C2H2-N2O, and the first observation of 2CH excitation in C2H2-Ne, C 2H2-H2O, C2H2-D 2O and (C2H2)n. Lifetimes of these 2CH vibrationally excited dimers are discussed. © 2012 Taylor and Francis.
BibTeX: @article{Didriche2012a, author = {Didriche, K. and Földes, T. and Lauzin, C. and Golebiowski, D. and Liévin, J. and Herman, M.}, title = {Experimental 2CH excitation in acetylene-containing van der Waals complexes}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2781 – 2796}, doi = {10.1080/00268976.2012.705347} }
Didriche K, Földes T, Lauzin C and Herman M (2012), "The 2CH excitation band in C2H2-N2O and 2CH+torsion combination bands in C2H2-N2O and C2H2-CO2", Molecular Physics. Vol. 110(21-22), pp. 2773 – 2779. [Abstract] [BibTeX] [DOI]
Abstract: A preliminary analysis of the 2CH excitation band in C2H 2-N2O in the 1.5 mm range (K. Didriche, C. Lauzin, P. Macko, M. Herman and W.J. Lafferty, Chem. Phys. Letters 469, 35 (2009).), only considering 117 low J-, and Ka-vibration-rotation lines, is significantly extended thanks to the analysis of new spectra including very regular series of lines with J/Ka up to 31/15. 1271 b-type lines were assigned. Perturbations are briefly discussed. The rotational temperature in the experiments is estimated to be 20K and the upper state mean half-time is 1.6 ns for non perturbed levels. The previous analyses of the 2CH + torsion band in C2H2-N2O and in C2H 2-CO2 (C. Lauzin, K. Didriche, T. Földes and M. Herman, Mol. Phys. 109, 2105 (2011).), are also extended to include 286 and 234 lines, respectively, also correcting for calibration errors. New rotational constants are obtained using a rigid rotor Hamiltonian by simultaneously fitting the ground, 2CH and 2CH + torsion states in C2H2-N 2O, and the latter state, only, in C2H2-CO 2. © 2012 Taylor and Francis.
BibTeX: @article{Didriche2012, author = {Didriche, K. and Földes, T. and Lauzin, C. and Herman, M.}, title = {The 2CH excitation band in C2H2-N2O and 2CH+torsion combination bands in C2H2-N2O and C2H2-CO2}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2773 – 2779}, doi = {10.1080/00268976.2012.713523} }
Dufour G, Eremenko M, Griesfeller A, Barret B, Leflochmoën E, Clerbaux C, Hadji-Lazaro J, Coheur P-F and Hurtmans D (2012), "Validation of three different scientific ozone products retrieved from IASI spectra using ozonesondes", Atmospheric Measurement Techniques. Vol. 5(3), pp. 611 – 630. [Abstract] [BibTeX] [DOI]
Abstract: Three scientific ozone products from the Infrared Atmospheric Sounding Interferometer (IASI) aboard MetOp-A, retrieved in three different research teams (LA, LATMOS/ULB, LISA) with different retrieval schemes, are characterized and validated using ozonesondes measurements. The characteristics of the products are analyzed in terms of retrieval sensitivity, systematic and random errors, and ability to retrieve the natural variability of ozone and focus on different partial columns from the lower troposphere up to 30 km. The validation covers the midlatitudes and the tropics and the period from January to December 2008. The products present degrees of freedom (DOF) in the troposphere between 1 and 1.2 on average in the midlatitudes and between 1 and 1.4 in the tropics. The DOF are distributed differently on the vertical depending on the profiles and the season: summer leading to a better sensitivity to the lower troposphere, as expected. The error estimates range between 10 and 20% from the lower tropospheric partial columns (0-6 km and 0-8 km for the midlatitudes and the tropics respectively) to the UTLS partial columns (8-16 km and 11-20 km for the midlatitudes and the tropics respectively) for all the products and are about 5% in the stratosphere (16-30 km) and for the column up to 30 km. The main feature that arises from the comparison with the ozonesondes is a systematic overestimation of ozone in the UTLS (between 10 and 25%) by the three products in the midlatitudes and the tropics, attributed to the moderate vertical resolution of IASI and possibly to spectroscopic inconsistencies. The ability of the products to reproduce natural variability of tropospheric ozone is fairly good and depends on the considered season and region. © 2012 Author(s).
BibTeX: @article{Dufour2012, author = {Dufour, G. and Eremenko, M. and Griesfeller, A. and Barret, B. and Leflochmoën, E. and Clerbaux, C. and Hadji-Lazaro, J. and Coheur, P.-F. and Hurtmans, D.}, title = {Validation of three different scientific ozone products retrieved from IASI spectra using ozonesondes}, journal = {Atmospheric Measurement Techniques}, year = {2012}, volume = {5}, number = {3}, pages = {611 – 630}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/amt-5-611-2012} }
Franco B, Fettweis X, Lang C and Erpicum M (2012), "Impact of spatial resolution on the modelling of the Greenland ice sheet surface mass balance between 1990-2010, using the regional climate model MAR", Cryosphere. Vol. 6(3), pp. 695 – 711. [Abstract] [BibTeX] [DOI]
Abstract: With the aim to force an ice dynamical model, the Greenland ice sheet (GrIS) surface mass balance (SMB) was modelled at different spatial resolutions (15-50 km) for the period 1990-2010, using the regional climate model MAR (Modèle Atmosphérique Régional) forced by the ERA-INTERIM reanalysis. This comparison revealed that (i) the inter-annual variability of the SMB components is consistent within the different spatial resolutions investigated, (ii) the MAR model simulates heavier precipitation on average over the GrIS with decreasing spatial resolution, and (iii) the SMB components (except precipitation) can be derived from a simulation at lower resolution with an "intelligent" interpolation. This interpolation can also be used to approximate the SMB components over another topography/ice sheet mask of the GrIS. These results are important for the forcing of an ice dynamical model needed to enable future projections of the GrIS contribution to sea level rise over the coming centuries. © 2013 Author(s).
BibTeX: @article{Franco2012, author = {Franco, B. and Fettweis, X. and Lang, C. and Erpicum, M.}, title = {Impact of spatial resolution on the modelling of the Greenland ice sheet surface mass balance between 1990-2010, using the regional climate model MAR}, journal = {Cryosphere}, year = {2012}, volume = {6}, number = {3}, pages = {695 – 711}, note = {All Open Access, Gold Open Access}, doi = {10.5194/tc-6-695-2012} }
Fulton JL, Bylaska EJ, Bogatko S, Balasubramanian M, Cauët E, Schenter GK and Weare JH (2012), "Near-quantitative agreement of model-free DFT-MD predictions with XAFS observations of the hydration structure of highly charged transition-metal ions", Journal of Physical Chemistry Letters. Vol. 3(18), pp. 2588 – 2593. [Abstract] [BibTeX] [DOI]
Abstract: First-principles dynamics simulations (DFT, PBE96, and PBE0) and electron scattering calculations (FEFF9) provide near-quantitative agreement with new and existing XAFS measurements for a series of transition-metal ions interacting with their hydration shells via complex mechanisms (high spin, covalency, charge transfer, etc.). This analysis does not require either the development of empirical interparticle interaction potentials or structural models of hydration. However, it provides consistent parameter-free analysis and improved agreement with the higher-R scattering region (first- and second-shell structure, symmetry, dynamic disorder, and multiple scattering) for this comprehensive series of ions. DFT+GGA MD methods provide a high level of agreement. However, improvements are observed when exact exchange is included. Higher accuracy in the pseudopotential description of the atomic potential, including core polarization and reducing core radii, was necessary for very detailed agreement. The first-principles nature of this approach supports its application to more complex systems. © 2012 American Chemical Society.
BibTeX: @article{Fulton2012, author = {Fulton, John L. and Bylaska, Eric J. and Bogatko, Stuart and Balasubramanian, Mahalingam and Cauët, Emilie and Schenter, Gregory K. and Weare, John H.}, title = {Near-quantitative agreement of model-free DFT-MD predictions with XAFS observations of the hydration structure of highly charged transition-metal ions}, journal = {Journal of Physical Chemistry Letters}, year = {2012}, volume = {3}, number = {18}, pages = {2588 – 2593}, doi = {10.1021/jz3008497} }
Ginoux P, Clarisse L, Clerbaux C, Coheur P-F, Dubovik O, Hsu N and Van Damme M (2012), "Mixing of dust and NH 3 observed globally over anthropogenic dust sources", Atmospheric Chemistry and Physics. Vol. 12(16), pp. 7351 – 7363. [Abstract] [BibTeX] [DOI]
Abstract: The global distribution of dust column burden derived from MODIS Deep Blue aerosol products is compared to NH 3 column burden retrieved from IASI infrared spectra. We found similarities in their spatial distributions, in particular their hot spots are often collocated over croplands and to a lesser extent pastures. Globally, we found 22% of dust burden collocated with NH 3, with only 1% difference between land-use databases. This confirms the importance of anthropogenic dust from agriculture. Regionally, the Indian subcontinent has the highest amount of dust mixed with NH 3 (26%), mostly over cropland and during the pre-monsoon season. North Africa represents 50% of total dust burden but accounts for only 4% of mixed dust, which is found over croplands and pastures in Sahel and the coastal region of the Mediterranean. In order to evaluate the radiative effect of this mixing on dust optical properties, we derive the mass extinction efficiency for various mixtures of dust and NH 3, using AERONET sunphotometers data. We found that for dusty days the coarse mode mass extinction efficiency decreases from 0.62 to 0.48 m 2 g -1 as NH 3 burden increases from 0 to 40 mg m -2. The fine mode extinction efficiency, ranging from 4 to 16 m 2 g -1, does not appear to depend on NH 3 concentration or relative humidity but rather on mineralogical composition and mixing with other aerosols. Our results imply that a significant amount of dust is already mixed with ammonium salt before its long range transport. This in turn will affect dust lifetime, and its interactions with radiation and cloud properties. © 2012 Author(s).
BibTeX: @article{Ginoux2012, author = {Ginoux, P. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Dubovik, O. and Hsu, N.C. and Van Damme, M.}, title = {Mixing of dust and NH 3 observed globally over anthropogenic dust sources}, journal = {Atmospheric Chemistry and Physics}, year = {2012}, volume = {12}, number = {16}, pages = {7351 – 7363}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-12-7351-2012} }
Heald C, Collett J, Lee T, Benedict K, Schwandner F, Li Y, Clarisse L, Hurtmans D, Van Damme M, Clerbaux C, Coheur P-F, Philip S, Martin R and Pye H (2012), "Atmospheric ammonia and particulate inorganic nitrogen over the United States", Atmospheric Chemistry and Physics. Vol. 12(21), pp. 10295 – 10312. [Abstract] [BibTeX] [DOI]
Abstract: We use in situ observations from the Interagency Monitoring of PROtected Visual Environments (IMPROVE) network, the Midwest Ammonia Monitoring Project, 11 surface site campaigns as well as Infrared Atmospheric Sounding Interferometer (IASI) satellite measurements with the GEOS-Chem model to investigate inorganic aerosol loading and atmospheric ammonia concentrations over the United States. IASI observations suggest that current ammonia emissions are underestimated in California and in the springtime in the Midwest. In California this underestimate likely drives the underestimate in nitrate formation in the GEOS-Chem model. However in the remaining continental United States we find that the nitrate simulation is biased high (normalized mean bias > Combining double low line 1.0) year-round, except in Spring (due to the underestimate in ammonia in this season). None of the uncertainties in precursor emissions, the uptake efficiency of N2O5 on aerosols, OH concentrations, the reaction rate for the formation of nitric acid, or the dry deposition velocity of nitric acid are able to explain this bias. We find that reducing nitric acid concentrations to 75% of their simulated values corrects the bias in nitrate (as well as ammonium) in the US. However the mechanism for this potential reduction is unclear and may be a combination of errors in chemistry, deposition and sub-grid near-surface gradients. This "updated" simulation reproduces PM and ammonia loading and captures the strong seasonal and spatial gradients in gas-particle partitioning across the United States. We estimate that nitrogen makes up 15-35% of inorganic fine PM mass over the US, and that this fraction is likely to increase in the coming decade, both with decreases in sulfur emissions and increases in ammonia emissions. © 2012 Author(s).
BibTeX: @article{Heald2012, author = {Heald, C.L. and Collett, J.L. and Lee, T. and Benedict, K.B. and Schwandner, F.M. and Li, Y. and Clarisse, L. and Hurtmans, D.R. and Van Damme, M. and Clerbaux, C. and Coheur, P.-F. and Philip, S. and Martin, R.V. and Pye, H.O.T.}, title = {Atmospheric ammonia and particulate inorganic nitrogen over the United States}, journal = {Atmospheric Chemistry and Physics}, year = {2012}, volume = {12}, number = {21}, pages = {10295 – 10312}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-12-10295-2012} }
Heard IPC, Manning AJ, Haywood JM, Witham C, Redington A, Jones A, Clarisse L and Bourassa A (2012), "A comparison of atmospheric dispersion model predictions with observations of SO2 and sulphate aerosol from volcanic eruptions", Journal of Geophysical Research Atmospheres. Vol. 117(6) [Abstract] [BibTeX] [DOI]
Abstract: The UK Met Office's Numerical Atmospheric-dispersion Modeling Environment (NAME) is used both operationally and for research investigations. It has previously been used to model volcanic ash at the London Volcanic Ash Advisory Centre (VAAC), including that from the eruptions in Iceland of Eyjafjallajökull in 2010 and Grímsvtn in 2011. In this paper, the ability of NAME to model the release and dispersion of volcanic SO2, the chemical processes leading to the production of sulphate aerosol, and the subsequent dispersion of sulphate aerosol, has been investigated. Sensitivity tests were carried out to investigate the suitability of the NAME chemistry scheme for use in both the troposphere and the stratosphere. The eruptions of Sarychev in 2009, Kasatochi in 2008 and Eyjafjallajökull in 2010 were simulated and results for SO2 column density and sulphate aerosol optical depth (AOD) were compared with satellite retrievals. NAME results compare favorably with available observations in terms of both geographical distribution and magnitude for all three cases. The NAME modeled values of SO2 show a correlation of 0.8 with the corresponding observations for Sarychev. Ninety percent of modeled values of northern hemisphere averaged sulphate AOD are within a factor of 2 of those observed for Kasatochi and 71% are within a factor of 2 of those observed for Sarychev. Although significant uncertainties are present in both the model and observations, this work demonstrates that NAME's current chemistry scheme shows promise as a tool for modeling SO2 and sulphate from volcanoes. © 2012 by the American Geophysical Union.
BibTeX: @article{Heard2012, author = {Heard, Imogen P. C. and Manning, Alistair J. and Haywood, James M. and Witham, Claire and Redington, Alison and Jones, Andy and Clarisse, Lieven and Bourassa, Adam}, title = {A comparison of atmospheric dispersion model predictions with observations of SO2 and sulphate aerosol from volcanic eruptions}, journal = {Journal of Geophysical Research Atmospheres}, year = {2012}, volume = {117}, number = {6}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2011JD016791} }
Herman M (2012), "Foreword", Molecular Physics. Vol. 110(21-22), pp. 2619 – 2620. [BibTeX] [DOI]
BibTeX: @article{Herman2012, author = {Herman, Michel}, title = {Foreword}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2619 – 2620}, doi = {10.1080/00268976.2012.707015} }
Hilton F, Armante R, August T, Barnet C, Bouchard A, Camy-Peyret C, Capelle V, Clarisse L, Clerbaux C, Coheur P-F, Collard A, Crevoisier C, Dufour G, Edwards D, Faijan F, Fourrié N, Gambacorta A, Goldberg M, Guidard V, Hurtmans D, Illingworth S, Jacquinet-Husson N, Kerzenmacher T, Klaes D, Lavanant L, Masiello G, Matricardi M, McNally A, Newman S, Pavelin E, Payan S, Péquignot E, Peyridieu S, Phulpin T, Remedios J, Schlüssel P, Serio C, Strow L, Stubenrauch C, Taylor J, Tobin D, Wolf W and Zhou D (2012), "Hyperspectral earth observation from IASI", Bulletin of the American Meteorological Society. Vol. 93(3), pp. 347 – 370. [Abstract] [BibTeX] [DOI]
Abstract: The first Infrared Atmospheric Sounding Interferometer (IASI) was launched in October 2006 on the European Organization for the Exploitation of Meteorological Satellites' (EUMETSAT) Meteorological Operation (MetOp)-A satellite. The instrument and its successors will continue to operate until 2020 on the current MetOp platform and two follow-on satellites. The stability of the instrument is monitored routinely by the CNES Technical Expertise Center, using onboard measurements, and by EUMETSAT, where stable, clear fields of view are compared with simulated radiances from numerical weather prediction model output. Routine monitoring of IASI data and calibration and validation activities by CNES and EUMETSAT ensure full characterization of the instrument and verify that the performance meets the requirements. In-depth evaluation is routinely performed by comparing IASI with other instruments, such as AVHRR and the High Resolution Infrared Radiation Sounder (HIRS) on the MetOp platform.
BibTeX: @article{Hilton2012, author = {Hilton, Fiona and Armante, Raymond and August, Thomas and Barnet, Chris and Bouchard, Aurelie and Camy-Peyret, Claude and Capelle, Virginie and Clarisse, Lieven and Clerbaux, Cathy and Coheur, Pierre-Francois and Collard, Andrew and Crevoisier, Cyril and Dufour, Gaelle and Edwards, David and Faijan, Francois and Fourrié, Nadia and Gambacorta, Antonia and Goldberg, Mitchell and Guidard, Vincent and Hurtmans, Daniel and Illingworth, Samuel and Jacquinet-Husson, Nicole and Kerzenmacher, Tobias and Klaes, Dieter and Lavanant, Lydie and Masiello, Guido and Matricardi, Marco and McNally, Anthony and Newman, Stuart and Pavelin, Edward and Payan, Sebastien and Péquignot, Eric and Peyridieu, Sophie and Phulpin, Thierry and Remedios, John and Schlüssel, Peter and Serio, Carmine and Strow, Larrabee and Stubenrauch, Claudia and Taylor, Jonathan and Tobin, David and Wolf, Walter and Zhou, Daniel}, title = {Hyperspectral earth observation from IASI}, journal = {Bulletin of the American Meteorological Society}, year = {2012}, volume = {93}, number = {3}, pages = {347 – 370}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1175/BAMS-D-11-00027.1} }
Hurtmans D, Coheur P-F, Wespes C, Clarisse L, Scharf O, Clerbaux C, Hadji-Lazaro J, George M and Turquety S (2012), "FORLI radiative transfer and retrieval code for IASI", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 113(11), pp. 1391 – 1408. [Abstract] [BibTeX] [DOI]
Abstract: This paper lays down the theoretical bases and the methods used in the Fast Optimal Retrievals on Layers for IASI (FORLI) software, which is developed and maintained at the "Université Libre de Bruxelles" (ULB) with the support of the "Laboratoire Atmosphères, Milieux, Observations Spatiales" (LATMOS) to process radiance spectra from the Infrared Atmospheric Sounding Interferometer (IASI) in the perspective of local to global chemistry applications. The forward radiative transfer model (RTM) and the retrieval approaches are formulated and numerical approximations are described. The aim of FORLI is near-real-time provision of global scale concentrations of trace gases from IASI, either integrated over the altitude range of the atmosphere (total columns) or vertically resolved. To this end, FORLI uses precalculated table of absorbances. At the time of writing three gas-specific versions of this algorithm have been set up: FORLI-CO, FORLI-O 3 and FORLI-HNO 3. The performances of each are reviewed and illustrations of results and early validations are provided, making the link to recent scientific publications. In this paper we stress the challenges raised by near-real-time processing of IASI, shortly describe the processing chain set up at ULB and draw perspectives for future developments and applications. © 2012 Elsevier Ltd.
BibTeX: @article{Hurtmans2012, author = {Hurtmans, D. and Coheur, P.-F. and Wespes, C. and Clarisse, L. and Scharf, O. and Clerbaux, C. and Hadji-Lazaro, J. and George, M. and Turquety, S.}, title = {FORLI radiative transfer and retrieval code for IASI}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2012}, volume = {113}, number = {11}, pages = {1391 – 1408}, doi = {10.1016/j.jqsrt.2012.02.036} }
Keller A, Bald I, Rotaru A, Cauët E, Gothelf KV and Besenbacher F (2012), "Probing electron-induced bond cleavage at the single-molecule level using DNA origami templates", ACS Nano. Vol. 6(5), pp. 4392 – 4399. [Abstract] [BibTeX] [DOI]
Abstract: Low-energy electrons (LEEs) play an important role in nanolithography, atmospheric chemistry, and DNA radiation damage. Previously, the cleavage of specific chemical bonds triggered by LEEs has been demonstrated in a variety of small organic molecules such as halogenated benzenes and DNA nucleobases. Here we present a strategy that allows for the first time to visualize the electron-induced dissociation of single chemical bonds within complex, but well-defined self-assembled DNA nanostructures. We employ atomic force microscopy to image and quantify LEE-induced bond dissociations within specifically designed oligonucleotide targets that are attached to DNA origami templates. In this way, we use a highly selective approach to compare the efficiency of the electron-induced dissociation of a single disulfide bond with the more complex cleavage of the DNA backbone within a Π dinucleotide sequence. This novel technique enables the fast and parallel determination of DNA strand break yields with unprecedented control over the DNA's primary and secondary structure. Thus the detailed investigation of DNA radiation damage in its most natural environment, e.g., DNA nucleosomes constituting the chromatin, now becomes feasible. © 2012 American Chemical Society.
BibTeX: @article{Keller2012, author = {Keller, Adrian and Bald, Ilko and Rotaru, Alexandru and Cauët, Emilie and Gothelf, Kurt V. and Besenbacher, Flemming}, title = {Probing electron-induced bond cleavage at the single-molecule level using DNA origami templates}, journal = {ACS Nano}, year = {2012}, volume = {6}, number = {5}, pages = {4392 – 4399}, doi = {10.1021/nn3010747} }
Kerzenmacher T, Dils B, Kumps N, Blumenstock T, Clerbaux C, Coheur P-F, Demoulin P, García O, George M, Griffith D, Hase F, Hadji-Lazaro J, Hurtmans D, Jones N, Mahieu E, Notholt J, Paton-Walsh C, Raffalski U, Ridder T, Schneider M, Servais C and De Mazière M (2012), "Validation of IASI FORLI carbon monoxide retrievals using FTIR data from NDACC", Atmospheric Measurement Techniques. Vol. 5(11), pp. 2751 – 2761. [Abstract] [BibTeX] [DOI]
Abstract: Carbon monoxide (CO) is retrieved daily and globally from space-borne IASI radiance spectra using the Fast Optimal Retrievals on Layers for IASI (FORLI) software developed at the Université Libre de Bruxelles (ULB). The IASI CO total column product for 2008 from the most recent FORLI retrieval version (20100815) is evaluated using correlative CO profile products retrieved from ground-based solar absorption Fourier transform infrared (FTIR) observations at the following FTIR spectrometer sites from the Network for the Detection of Atmospheric Composition Change (NDACC): Ny-Ã..lesund, Kiruna, Bremen, Jungfraujoch, Izaña and Wollongong. In order to have good statistics for the comparisons, we included all IASI data from the same day, within a 100 km radius around the ground-based stations. The individual ground-based data were adjusted to the lowest altitude of the co-located IASI CO profiles. To account for the different vertical resolutions and sensitivities of the ground-based and satellite measurements, the averaging kernels associated with the various retrieved products have been used to properly smooth coincident data products. It has been found that the IASI CO total column products compare well on average with the co-located ground-based FTIR total columns at the selected NDACC sites and that there is no significant bias for the mean values at all stations. © 2012 Author(s).
BibTeX: @article{Kerzenmacher2012, author = {Kerzenmacher, T. and Dils, B. and Kumps, N. and Blumenstock, T. and Clerbaux, C. and Coheur, P.-F. and Demoulin, P. and García, O. and George, M. and Griffith, D.W.T. and Hase, F. and Hadji-Lazaro, J. and Hurtmans, D. and Jones, N. and Mahieu, E. and Notholt, J. and Paton-Walsh, C. and Raffalski, U. and Ridder, T. and Schneider, M. and Servais, C. and De Mazière, M.}, title = {Validation of IASI FORLI carbon monoxide retrievals using FTIR data from NDACC}, journal = {Atmospheric Measurement Techniques}, year = {2012}, volume = {5}, number = {11}, pages = {2751 – 2761}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-5-2751-2012} }
Klonecki A, Pommier M, Clerbaux C, Ancellet G, Cammas J-P, Coheur P-F, Cozic A, Diskin G, Hadji-Lazaro J, Hauglustaine D, Hurtmans D, Khattatov B, Lamarque J-F, Law K, Nedelec P, Paris J-D, Podolske J, Prunet P, Schlager H, Szopa S and Turquety S (2012), "Assimilation of IASI satellite CO fields into a global chemistry transport model for validation against aircraft measurements", Atmospheric Chemistry and Physics. Vol. 12(10), pp. 4493 – 4512. [Abstract] [BibTeX] [DOI]
Abstract: This work evaluates the IASI CO product against independent in-situ aircraft data from the MOZAIC program and the POLARCAT aircraft campaign. The validation is carried out by analysing the impact of assimilation of eight months of IASI CO columns retrieved for the period of May to December 2008 into the global chemistry transport model LMDz-INCA. A modelling system based on a sub-optimal Kalman filter was developed and a specific treatment that takes into account the representativeness of observations at the scale of the model grid is applied to the IASI CO columns and associated errors before their assimilation in the model. Comparisons of the assimilated CO profiles with in situ CO measurements indicate that the assimilation leads to a considerable improvement of the model simulations in the middle troposphere as compared with a control run with no assimilation. Model biases in the simulation of background values are reduced and improvement in the simulation of very high concentrations is observed. The improvement is due to the transport by the model of the information present in the IASI CO retrievals. Our analysis also shows the impact of assimilation of CO on the representation of transport into the Arctic region during the POLARCAT summer campaign. A considerable increase in CO mixing ratios over the Asian source region was observed when assimilation was used leading to much higher values of CO during the cross-pole transport episode. These higher values are in good agreement with data from the POLARCAT flights that sampled this plume. © 2012 Author(s).
BibTeX: @article{Klonecki2012, author = {Klonecki, A. and Pommier, M. and Clerbaux, C. and Ancellet, G. and Cammas, J.-P. and Coheur, P.-F. and Cozic, A. and Diskin, G.S. and Hadji-Lazaro, J. and Hauglustaine, D.A. and Hurtmans, D. and Khattatov, B. and Lamarque, J.-F. and Law, K.S. and Nedelec, P. and Paris, J.-D. and Podolske, J.R. and Prunet, P. and Schlager, H. and Szopa, S. and Turquety, S.}, title = {Assimilation of IASI satellite CO fields into a global chemistry transport model for validation against aircraft measurements}, journal = {Atmospheric Chemistry and Physics}, year = {2012}, volume = {12}, number = {10}, pages = {4493 – 4512}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-12-4493-2012} }
Krysztofiak G, Thiéblemont R, Huret N, Catoire V, Té Y, Jégou F, Coheur P, Clerbaux C, Payan S, Drouin M, Robert C, Jeseck P, Attié J-L and Camy-Peyret C (2012), "Detection in the summer polar stratosphere of pollution plume from East Asia and North America by balloon-borne in situ CO measurements", Atmospheric Chemistry and Physics. Vol. 12(24), pp. 11889 – 11906. [Abstract] [BibTeX] [DOI]
Abstract: The SPIRALE and SWIR balloon-borne instruments were launched in the Arctic polar region (near Kiruna, Sweden, 67.9° N-21.1° E) during summer on 7 and 24 August 2009 and on 14 August 2009, respectively. The SPIRALE instrument performed in situ measurements of several trace gases including CO and O 3 at altitudes between 9 and 34 km, with very high vertical resolution (∼ 5 m). The SWIR-balloon instrument measured total and partial column of several species including CO. The CO stratospheric profile from SPIRALE for 7 August 2009 shows some specific structures with large concentrations in the low levels (potential temperatures between 320 and 380 K, i.e. 10-14 km height). These structures are not present in the CO vertical profile of SPIRALE for 24 August 2009, for which the volume mixing ratios are typical from polar latitudes (∼ 30 ppb). CO total columns retrieved from the IASI-MetOp satellite sounder for the three dates of flights are used to understand this CO variability. SPIRALE and SWIR CO partial columns between 9 and 34 km are compared, allowing us to confirm that the enhancement of CO is localised in the stratosphere. The measurements are also investigated in terms of CO:O3 correlations and using several modelling approaches (trajectory calculations, potential vorticity fields, results of chemistry transport model) in order to characterize the origin of the air masses sampled. The emission sources are qualified in terms of source type (fires, urban pollution) using NH3 and CO measurements from IASI-MetOp and fires detection from MODIS on board the TERRA/AQUA satellite. The results give strong evidence that the unusual abundance of CO on 7 August is due to surface pollution plumes from East Asia and North America transporting to the upper troposphere and then entering the lower stratosphere by isentropic advection. This study strengthens evidence that the composition of low polar stratosphere in summer may be affected by anthropogenic surface emissions through long-range transport. © 2012 Author(s).
BibTeX: @article{Krysztofiak2012, author = {Krysztofiak, G. and Thiéblemont, R. and Huret, N. and Catoire, V. and Té, Y. and Jégou, F. and Coheur, P.F. and Clerbaux, C. and Payan, S. and Drouin, M.A. and Robert, C. and Jeseck, P. and Attié, J.-L. and Camy-Peyret, C.}, title = {Detection in the summer polar stratosphere of pollution plume from East Asia and North America by balloon-borne in situ CO measurements}, journal = {Atmospheric Chemistry and Physics}, year = {2012}, volume = {12}, number = {24}, pages = {11889 – 11906}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-12-11889-2012} }
Lacour J-L, Risi C, Clarisse L, Bony S, Hurtmans D, Clerbaux C and Coheur P-F (2012), "Mid-tropospheric δd observations from IASI/MetOp at high spatial and temporal resolution", Atmospheric Chemistry and Physics. Vol. 12(22), pp. 10817 – 10832. [Abstract] [BibTeX] [DOI]
Abstract: In this paper we retrieve atmospheric HDO, H2O concentrations and their ratio δD from IASI radiances spectra. Our method relies on an existing radiative transfer model (Atmosphit) and an optimal estimation inversion scheme, but goes further than our previous work by explicitly considering correlations between the two species. A global HDO and H 2O a priori profile together with a covariance matrix were built from daily LMDz-iso model simulations of HDO and H2O profiles over the whole globe and a whole year. The retrieval parameters are described and characterized in terms of errors. We show that IASI is mostly sensitive to δD in the middle troposphere and allows retrieving δD for an integrated 3-6 km column with an error of 38‰ on an individual measurement basis. We examine the performance of the retrieval to capture the temporal (seasonal and short-term) and spatial variations of δD for one year of measurement at two dedicated sites (Darwin and Izan∼a) and a latitudinal band from g-60° to 60° for a 15 day period in January. We report a generally good agreement between IASI and the model and indicate the capabilities of IASI to reproduce the large scale variations of δD (seasonal cycle and latitudinal gradient) with good accuracy. In particular, we show that there is no systematic significant bias in the retrieved δD values in comparison with the model, and that the retrieved variability is similar to the one in the model even though there are certain local differences. Moreover, the noticeable differences between IASI and the model are briefly examined and suggest modeling issues instead of retrieval effects. Finally, the results further reveal the unprecedented capabilities of IASI to capture short-term variations in δD, highlighting the added value of the sounder for monitoring hydrological processes. © 2012 Author(s).
BibTeX: @article{Lacour2012, author = {Lacour, J.-L. and Risi, C. and Clarisse, L. and Bony, S. and Hurtmans, D. and Clerbaux, C. and Coheur, P.-F.}, title = {Mid-tropospheric δd observations from IASI/MetOp at high spatial and temporal resolution}, journal = {Atmospheric Chemistry and Physics}, year = {2012}, volume = {12}, number = {22}, pages = {10817 – 10832}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-12-10817-2012} }
Lauzin C, Cauët E, Demaison J, Herman M, Stoll H and Liévina J (2012), "Accurate ground-state potential energy surfaces of the C2H 2-Kr and C2H2-Xe van der Waals complexes", Molecular Physics. Vol. 110(21-22), pp. 2751 – 2760. [Abstract] [BibTeX] [DOI]
Abstract: Accurate ab initio intermolecular potential energy surfaces (IPES) have been obtained for the first time for the ground electronic state of the C 2H2-Kr and C2H2-Xe van der Waals complexes. Extensive tests, including complete basis set and all-electron scalar relativistic results, support their calculation at the CCSD(T) level of theory, using small-core relativistic pseudopotentials for the rare-gas atoms and aug-cc-pVQZ basis sets extended with a set of 3s3p2d1f1g mid-bond functions. All results are corrected for the basis set superposition error. The importance of the scalar relativistic and rare-gas outer-core (n.1)d correlation effects is investigated. The calculated IPES, adjusted to analytical functions, are characterized by global minima corresponding to skew T-shaped geometries, in which the Jacobi vector positioning the rare-gas atom with respect to the center of mass of the C2H2 moiety corresponds to distances of 4.064 and 4.229Å, and angles of 65.22° and 68.67° for C 2H2-Kr and C2H2-Xe, respectively. The interaction energy of both complexes is estimated to be -151.88 (1.817 kJ mol-1) and -182.76 cm-1 (2.186 kJ mol-1), respectively. The evolution of the topology of the IPES as a function of the rare-gas atom, from He to Xe, is also discussed. © 2012 Taylor and Francis.
BibTeX: @article{Lauzin2012, author = {Lauzin, C. and Cauët, E. and Demaison, J. and Herman, M. and Stoll, H. and Liévina, J.}, title = {Accurate ground-state potential energy surfaces of the C2H 2-Kr and C2H2-Xe van der Waals complexes}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2751 – 2760}, doi = {10.1080/00268976.2012.713524} }
Li J, Jönsson P, Godefroid M, Dong C and Gaigalas G (2012), "Effects of the electron correlation and Breit and hyperfine interactions on the lifetime of the 2p53s states in neutral neon", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 86(5) [Abstract] [BibTeX] [DOI]
Abstract: In the framework of the multiconfiguration Dirac-Hartree-Fock method, we investigate the transition properties of four excited states in the 2p53s configuration of neutral neon. The electron correlation effects are taken into account systematically by using the active space approach. The effect of higher-order correlation on fine structures is shown. We also study the influence of the Breit interaction and find that it reduces the oscillator strength of the 3P1o-1S0 transition by 17%. It turns out that the inclusion of the Breit interaction is essential even for such a light atomic system. Our ab initio calculated line strengths, oscillator strengths, and transition rates are compared with other theoretical values and experimental measurements. Good agreement is found except for the 3P2o-1S0 M2 transition for which discrepancies of around 15% between theories and experiments remain. In addition, the impact of hyperfine interactions on the lifetimes of the 3P0o and 3P2o metastable states is investigated for the 21Ne isotope (I=3/2). We find that hyperfine interactions reduce the lifetimes drastically. For the 3P0o state the lifetime is decreased by a factor of 630. © 2012 American Physical Society.
BibTeX: @article{Li2012b, author = {Li, Jiguang and Jönsson, Per and Godefroid, Michel and Dong, Chenzhong and Gaigalas, Gediminas}, title = {Effects of the electron correlation and Breit and hyperfine interactions on the lifetime of the 2p53s states in neutral neon}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2012}, volume = {86}, number = {5}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.86.052523} }
Li J, Nazé C, Godefroid M, Fritzsche S, Gaigalas G, Indelicato P and Jönsson P (2012), "Mass- and field-shift isotope parameters for the 2s-2p resonance doublet of lithiumlike ions", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 86(2) [Abstract] [BibTeX] [DOI]
Abstract: It was recently shown that dielectronic recombination measurements can be used for accurately inferring changes in the nuclear mean-square charge radii of highly charged lithiumlike neodymium. To make use of this method to derive information about the nuclear charge distribution for other elements and isotopes, accurate electronic isotope shift parameters are required. In this work, we calculate and discuss the relativistic mass- and field-shift factors for the two 2s2S 1/2-2p2P1/2,3/2o transitions along the lithium isoelectronic sequence. Based on the multiconfiguration Dirac-Hartree-Fock method, the electron correlation and the Breit interaction are taken into account systematically. The analysis of the isotope shifts for these two transitions along the isoelectronic sequence demonstrates the importance and competition between the mass shifts and the field shifts. © 2012 American Physical Society.
BibTeX: @article{Li2012, author = {Li, Jiguang and Nazé, Cédric and Godefroid, Michel and Fritzsche, Stephan and Gaigalas, Gediminas and Indelicato, Paul and Jönsson, Per}, title = {Mass- and field-shift isotope parameters for the 2s-2p resonance doublet of lithiumlike ions}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2012}, volume = {86}, number = {2}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.86.022518} }
Li J, Nazé C, Godefroid M, Gaigalas G and Jönsson P (2012), "On the breakdown of the Dirac kinetic energy operator for estimating normal mass shifts", European Physical Journal D. Vol. 66(11) [Abstract] [BibTeX] [DOI]
Abstract: The Dirac kinetic energy (DKE) form of the normal mass shift operator (me/M ∑i=1N Ti), which is an approximation of the (1/2M ∑i=1N pi 2) operator built on the relativistic electron momenta, is widely used in relativistic atomic structure calculations. In the present paper, we illustrate the progressive breakdown of the Dirac kinetic energy form relatively to the momentum form when increasing the nuclear charge along the lithium isoelectronic sequence. Both forms are incorrect in the relativistic case but the DKE operator provides expectation values that are closer to the results obtained with the more complete relativistic recoil operator. © EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2012.
BibTeX: @article{Li2012a, author = {Li, J.G. and Nazé, C. and Godefroid, M. and Gaigalas, G. and Jönsson, P.}, title = {On the breakdown of the Dirac kinetic energy operator for estimating normal mass shifts}, journal = {European Physical Journal D}, year = {2012}, volume = {66}, number = {11}, doi = {10.1140/epjd/e2012-30328-5} }
Li J, Verdebout S and Godefroid M (2012), "Ab-initio multi-configuration Dirac-Hartree-Fock calculation on the lifetimes of levels in 2p53s configuration of neutral neon", Journal of Physics: Conference Series. Vol. 388(PART 15) [Abstract] [BibTeX] [DOI]
Abstract: Large-scale calculations have been performed using the GRASP2K package to accurately determine the lifetime of levels in 2p53s configuration of neutral neon. In particular, we calculated the hyperfine-induced transition rates from two metastable levels 3P20,0 to the ground state for odd Ne isotopes. It was found that hyperfine interactions drastically quench the lifetime of these two levels.
BibTeX: @conference{Li2012c, author = {Li, J.G. and Verdebout, S. and Godefroid, M.}, title = {Ab-initio multi-configuration Dirac-Hartree-Fock calculation on the lifetimes of levels in 2p53s configuration of neutral neon}, journal = {Journal of Physics: Conference Series}, year = {2012}, volume = {388}, number = {PART 15}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/388/15/152007} }
Martínez-Alonso S, Deeter MN, Worden HM, Clerbaux C, Mao D and Gille JC (2012), "First satellite identification of volcanic carbon monoxide", Geophysical Research Letters. Vol. 39(21) [Abstract] [BibTeX] [DOI]
Abstract: Volcanic degassing produces abundant H2O and CO2, as well as SO2, HCl, H2S, S2, H2, HF, CO, and SiF4. Volcanic SO2, HCl, and H2S have been detected from satellites in the past; the remaining species are analyzed in situ or using airborne instruments, with all the consequent limitations in safety and sampling, and at elevated costs. We report identification of high CO concentrations consistent with a volcanic origin (the 2010 Eyjafjallajkull and 2011 Grímsvtn eruptions in Iceland) in data from the Measurements of Pollution in the Troposphere instrument (MOPITT) onboard EOS/Terra. The high CO values coincide spatially and temporally with ash plumes emanating from the eruptive centers, with elevated SO2 and aerosol optical thickness, as well as with high CO values in data from the Infrared Atmospheric Sounding Interferometer (IASI), onboard MetOp-A. CO has a positive indirect radiative forcing; climate models currently do not account for volcanic CO emissions. Given global volcanic CO2 emissions between 130 and 440 Tg/year and volcanic CO:CO2 ratios from the literature, we estimate that average global volcanic CO emissions may be on the order of ∼5.5 Tg/year, equivalent to the CO emissions caused by combined fossil fuel and biofuel combustion in Australia. © 2012. American Geophysical Union. All Rights Reserved.
BibTeX: @article{MartinezAlonso2012, author = {Martínez-Alonso, Sara and Deeter, Merritt N. and Worden, Helen M. and Clerbaux, Cathy and Mao, Debbie and Gille, John C.}, title = {First satellite identification of volcanic carbon monoxide}, journal = {Geophysical Research Letters}, year = {2012}, volume = {39}, number = {21}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1029/2012GL053275} }
Nazé C, Li J and Godefroid M (2012), "Relativistic calculations on isotope shifts in barium", Journal of Physics: Conference Series. Vol. 388(PART 15) [Abstract] [BibTeX] [DOI]
Abstract: When the effects of the finite mass of the nucleus and the spatial nuclear charge distribution are taken into account in the Hamiltonian describing an atomic system, the isotopes of an element have different electronic energy levels. In the present work, we are investigating these mass and field effects in neutral barium, hoping to shed some light on the surprising observed deviation of isotope shifts from their expected behavior for odd isotopes in an analysis based on King-plots.
BibTeX: @conference{Naze2012, author = {Nazé, C. and Li, J.G. and Godefroid, M.}, title = {Relativistic calculations on isotope shifts in barium}, journal = {Journal of Physics: Conference Series}, year = {2012}, volume = {388}, number = {PART 15}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/388/15/152008} }
Nekermans G, Loisel H, Meriaux X, Astoreca R and McKee D (2012), "In situ variability of mass-specific beam attenuation and backscattering of marine particles with respect to particle size, density, and composition", Limnology and Oceanography. Vol. 57(1), pp. 124 – 144. [Abstract] [BibTeX] [DOI]
Abstract: This study analyzes relationships between concentration of suspended particles represented by dry mass, [SPM], or area, [AC], and optical properties including particulate beam attenuation (cp), side scattering (bs), and backscattering (bbp), obtained from an intensive sampling program in coastal and offshore waters around Europe and French Guyana. First-order optical properties are driven by particle concentration with best predictions of [SPM] by bbp and bs, and of [AC] by cp. Second-order variability is investigated with respect to particle size, apparent density (dry weight-to-wet-volume ratio), and composition. Overall, the mass-specific particulate backscattering coefficient, bmp (=bbp: [SPM]), is relatively well constrained, with variability of a factor of 3-4. This coefficient is well correlated with particle composition, with inorganic particles having values about three times greater (brmp= 0.012 m2 g_1) than organic particles (brmp= 0.005 m2 g_1). The mass-specific particulate attenuation coefficient, cm (= cp: [SPM]), on the other hand, varies over one order of magnitude and is strongly driven (77% of the variability explained) by particle apparent density. In this data set particle size does not affect cm and affects b bmp only weakly in clear (case 1) waters, despite size variations over one order of magnitude. A significant fraction (40-60%) of the variability in bmp remains unexplained. Possible causes are the limitation of the measured size distributions to the 2-302-mm range and effects of particle shape and internal structure that affect bbp more than cp and were not accounted for. © 2012, by the Association for the Sciences of Limnology and Oceanography, Inc.
BibTeX: @article{Nekermans2012, author = {Nekermans, Grier and Loisel, Hubert and Meriaux, Xavier and Astoreca, Rosa and McKee, David}, title = {In situ variability of mass-specific beam attenuation and backscattering of marine particles with respect to particle size, density, and composition}, journal = {Limnology and Oceanography}, year = {2012}, volume = {57}, number = {1}, pages = {124 – 144}, doi = {10.4319/lo.2011.57.1.0124} }
Newman SM, Clarisse L, Hurtmans D, Marenco F, Johnson B, Turnbull K, Havemann S, Baran AJ, O'Sullivan D and Haywood J (2012), "A case study of observations of volcanic ash from the Eyjafjallajökull eruption: 2. Airborne and satellite radiative measurements", Journal of Geophysical Research Atmospheres. Vol. 117(4) [Abstract] [BibTeX] [DOI]
Abstract: An extensive set of airborne and satellite observations of volcanic ash from the Eyjafjallajökull Icelandic eruption are analyzed for a case study on 17 May 2010. Data collected from particle scattering probes and backscatter lidar on the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 aircraft allow estimates of ash concentration to be derived. Using radiative transfer simulations we show that airborne and satellite infrared radiances can be accurately modeled based on the in situ measured size distribution and a mineral dust refractive index. Furthermore, airborne irradiance measurements in the 0.3-1.7 m range are well modeled with these properties. Retrievals of ash mass column loading using Infrared Atmospheric Sounding Interferometer (IASI) observations are shown to be in accord with lidar-derived mass estimates, giving for the first time an independent verification of a hyperspectral ash variational retrieval method. The agreement of the observed and modeled solar and terrestrial irradiances suggests a reasonable degree of radiative closure implying that the physical and optical properties of volcanic ash can be relatively well constrained using data from state-of-the-science airborne platforms such as the FAAM BAe 146 aircraft. Comparisons with IASI measurements during recent Grímsvötn and Puyehue volcanic eruptions demonstrate the importance of accurately specifying the refractive index when modeling the observed spectra.
BibTeX: @article{Newman2012, author = {Newman, Stuart M. and Clarisse, Lieven and Hurtmans, Daniel and Marenco, Franco and Johnson, Ben and Turnbull, Kate and Havemann, Stephan and Baran, Anthony J. and O'Sullivan, Debbie and Haywood, Jim}, title = {A case study of observations of volcanic ash from the Eyjafjallajökull eruption: 2. Airborne and satellite radiative measurements}, journal = {Journal of Geophysical Research Atmospheres}, year = {2012}, volume = {117}, number = {4}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2011JD016780} }
Parrington M, Palmer P, Henze D, Tarasick D, Hyer E, Owen R, Helmig D, Clerbaux C, Bowman K, Deeter M, Barratt E, Coheur P-F, Hurtmans D, Jiang Z, George M and Worden J (2012), "The influence of boreal biomass burning emissions on the distribution of tropospheric ozone over North America and the North Atlantic during 2010", Atmospheric Chemistry and Physics. Vol. 12(4), pp. 2077 – 2098. [Abstract] [BibTeX] [DOI]
Abstract: We have analysed the sensitivity of the tropospheric ozone distribution over North America and the North Atlantic to boreal biomass burning emissions during the summer of 2010 using the GEOS-Chem 3-D global tropospheric chemical transport model and observations from in situ and satellite instruments. We show that the model ozone distribution is consistent with observations from the Pico Mountain Observatory in the Azores, ozonesondes across Canada, and the Tropospheric Emission Spectrometer (TES) and Infrared Atmospheric Sounding Instrument (IASI) satellite instruments. Mean biases between the model and observed ozone mixing ratio in the free troposphere were less than 10 ppbv. We used the adjoint of GEOS-Chem to show the model ozone distribution in the free troposphere over Maritime Canada is largely sensitive to NOx emissions from biomass burning sources in Central Canada, lightning sources in the central US, and anthropogenic sources in the eastern US and south-eastern Canada. We also used the adjoint of GEOS-Chem to evaluate the Fire Locating And Monitoring of Burning Emissions (FLAMBE) inventory through assimilation of CO observations from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument. The CO inversion showed that, on average, the FLAMBE emissions needed to be reduced to 89% of their original values, with scaling factors ranging from 12% to 102%, to fit the MOPITT observations in the boreal regions. Applying the CO scaling factors to all species emitted from boreal biomass burning sources led to a decrease of the model tropospheric distributions of CO, PAN, and NOx by as much as -20 ppbv, -50 pptv, and -20 pptv respectively. The modification of the biomass burning emission estimates reduced the model ozone distribution by approximately -3 ppbv (-8%) and on average improved the agreement of the model ozone distribution compared to the observations throughout the free troposphere, reducing the mean model bias from 5.5 to 4.0 ppbv for the Pico Mountain Observatory, 3.0 to 0.9 ppbv for ozonesondes, 2.0 to 0.9 ppbv for TES, and 2.8 to 1.4 ppbv for IASI. © 2012 Author(s).
BibTeX: @article{Parrington2012, author = {Parrington, M. and Palmer, P.I. and Henze, D.K. and Tarasick, D.W. and Hyer, E.J. and Owen, R.C. and Helmig, D. and Clerbaux, C. and Bowman, K.W. and Deeter, M.N. and Barratt, E.M. and Coheur, P.-F. and Hurtmans, D. and Jiang, Z. and George, M. and Worden, J.R.}, title = {The influence of boreal biomass burning emissions on the distribution of tropospheric ozone over North America and the North Atlantic during 2010}, journal = {Atmospheric Chemistry and Physics}, year = {2012}, volume = {12}, number = {4}, pages = {2077 – 2098}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-12-2077-2012} }
Perry DS, Martens J, Amyay B and Herman M (2012), "Hierarchies of intramolecular vibration-rotation dynamical processes in acetylene up to 13,000 cm-1", Molecular Physics. Vol. 110(21-22), pp. 2687 – 2705. [Abstract] [BibTeX] [DOI]
Abstract: The vibration-rotation dynamics of X̃1Σ +g acetylene are computed from a spectroscopic Hamiltonian with 468 parameters fit to 19,582 vibration-rotation transitions up to 13,000 cm-1 of vibrational energy. In this energy range, both the bending and the CH stretching vibrations can reach large amplitudes, but the maximum energy remains below the threshold for isomerization to vinylidene. In contrast to the behavior at energies below 5000 cm-1 [Mol. Phys. 108, 1115 (2010)], excitation of single bright states leads, in almost all cases, to computed intramolecular vibrational redistribution (IVR) that is irreversible on the timescales investigated. Hierarchies of IVR processes on timescales ranging from 20 fs to 20 ps result when different bright states are excited. Different parts of the vibrational quantum number space are explored as a result of the four different classes of coupling terms: vibrational l-type resonance, anharmonic resonances, the rotational l-type resonance, and Coriolis couplings. The initial IVR rates are very different depending on whether the bright states are bending states or stretching states, normal modes or local modes, edge states or interior states. However, the rates of the rotationally mediated couplings do not depend substantially on these distinctions. © 2012 Taylor and Francis.
BibTeX: @article{Perry2012, author = {Perry, David S. and Martens, Jonathan and Amyay, Badr and Herman, Michel}, title = {Hierarchies of intramolecular vibration-rotation dynamical processes in acetylene up to 13,000 cm-1}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2687 – 2705}, doi = {10.1080/00268976.2012.711493} }
Pommier M, Clerbaux C, Law K, Ancellet G, Bernath P, Coheur P-F, Hadji-Lazaro J, Hurtmans D, Nédélec P, Paris J-D, Ravetta F, Ryerson T, Schlager H and Weinheimer A (2012), "Analysis of IASI tropospheric O3 data over the Arctic during POLARCAT campaigns in 2008", Atmospheric Chemistry and Physics. Vol. 12(16), pp. 7371 – 7389. [Abstract] [BibTeX] [DOI]
Abstract: Ozone data retrieved in the Arctic region from infrared radiance spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI) on board the MetOp-A European satellite are presented. They are compared with in situ and lidar observations obtained during a series of aircraft measurement campaigns as part of the International Polar Year POLARCAT activities in spring and summer 2008. Different air masses were sampled during the campaigns including clean air, polluted plumes originating from anthropogenic sources, forest fire plumes from the three northern continents, and stratospheric-influenced air masses. The comparison between IASI O3 [0-8 km], [0-12 km] partial columns and profiles with collocated aircraft observations is achieved by taking into account the different sensitivity and geometry of the sounding instruments. A detailed analysis is provided and the agreement is discussed in terms of vertical sensitivity and surface properties at the location of the observations. Overall, IASI O3 profiles are found to be in relatively good agreement with smoothed in situ and lidar profiles in the free troposphere with differences of less than 40% (25% over sea for both seasons) and 10%, respectively. The correlation between IASI O3 retrieved partial columns and the smoothed aircraft partial columns is good with DC-8 in situ data in spring over North America (r= Combining double low line 0.68), and over Greenland with ATR-42 lidar measurements in summer (r= Combining double low line 0.67). Correlations with other data are less significant highlighting the difficulty of IASI to capture precisely the O3 variability in the Arctic upper troposphere and lower stratosphere (UTLS). This is particularly noted in comparison with the [0-12 km] partial columns. The IASI [0-8 km] partial columns display a low negative bias (by less than 26% over snow) compared to columns derived from in situ measurements. Despite the relatively high biases of the IASI retrievals in the Arctic UTLS, our analysis shows that IASI can be used to identify, using O3/CO ratios, stratospheric intrusions. © 2012 Author(s).
BibTeX: @article{Pommier2012, author = {Pommier, M. and Clerbaux, C. and Law, K.S. and Ancellet, G. and Bernath, P. and Coheur, P.-F. and Hadji-Lazaro, J. and Hurtmans, D. and Nédélec, P. and Paris, J.-D. and Ravetta, F. and Ryerson, T.B. and Schlager, H. and Weinheimer, A.J.}, title = {Analysis of IASI tropospheric O3 data over the Arctic during POLARCAT campaigns in 2008}, journal = {Atmospheric Chemistry and Physics}, year = {2012}, volume = {12}, number = {16}, pages = {7371 – 7389}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-12-7371-2012} }
Povey C, Predoi-Cross A and Hurtmans DR (2012), "Low-pressure line shape study of acetylene transitions in the v1 + v2 + v4 + v5 band over a range of temperatures", Molecular Physics. Vol. 110(21-22), pp. 2633 – 2644. [Abstract] [BibTeX] [DOI]
Abstract: In this study we have retrieved the self-broadened widths, self-pressure-induced shifts, and Dicke narrowing coefficients for 20 R-branch transitions in the v1+v2+v4+v5 band of acetylene. The spectra were recorded using a three-channel diode laser spectrometer, a temperature-controlled cell of fixed length and a second, room temperature cell. The soft collision (Galatry) and hard collision (Rautian) profiles with inclusion of line mixing effects were used to retrieve the line parameters. We determined the temperature dependencies for line broadening, shift, and Dicke narrowing coefficients. We performed comparisons between our retrieved line parameters and published line parameters for acetylene transitions. © 2012 Taylor and Francis.
BibTeX: @article{Povey2012, author = {Povey, Chad and Predoi-Cross, Adriana and Hurtmans, Daniel R.}, title = {Low-pressure line shape study of acetylene transitions in the v1 + v2 + v4 + v5 band over a range of temperatures}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2633 – 2644}, doi = {10.1080/00268976.2012.705908} }
Predoi-Cross A, Herman M, Fusina L and Di Lonardo G (2012), "The far infrared spectrum of trans-formic acid: An extension up to 175cm-1 ", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 113(11), pp. 1134 – 1137. [Abstract] [BibTeX] [DOI]
Abstract: The far infrared spectrum of HCOOH was recorded at a high resolution (0.0009cm-1) and long path length (72m) at the far-infrared beamline, Canadian Light Source. Spectra were recorded in the region 62-300cm-1, showing transitions from the trans-isomer.Ground state rotational transitions with Ka up to 30, were identified up to 175cm-1, extending the observation reported in the literature. A total of 3321 transitions were assigned and fitted together with previous (4149) published data. An improved set of rotational parameters was obtained adopting the symmetric top (A) reduction of the rotational Hamiltonian in the Ir representation. The newly measured far infrared transitions allowed the determination of all diagonal and off diagonal 8th order parameters L and of some of the diagonal 10th order parameters P. © 2012 Elsevier Ltd.
BibTeX: @article{PredoiCross2012, author = {Predoi-Cross, Adriana and Herman, Michel and Fusina, Luciano and Di Lonardo, Gianfranco}, title = {The far infrared spectrum of trans-formic acid: An extension up to 175cm-1 }, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2012}, volume = {113}, number = {11}, pages = {1134 – 1137}, doi = {10.1016/j.jqsrt.2012.01.026} }
Predoi-Cross A, Herman M, Fusina L and Di Lonardo G (2012), "The infrared spectrum of 13C2H2 in the 60-2600 cm-1 region: Bending states up to v4+v 5=4", Molecular Physics. Vol. 110(21-22), pp. 2621 – 2632. [Abstract] [BibTeX] [DOI]
Abstract: The vibration-rotation spectra of 13C substituted acetylene, 13C2H2, have been recorded in the region between 60 and 2600 cm-1 at an effective resolution ranging from 0.001 to 0.006 cm-1. Three different instruments were used to collect the experimental data in the extended spectral interval investigated. In total 9529 rotation vibration transitions have been assigned to 101 bands involving the bending states up to vtot=v4=v-1=4, allowing the characterization of the ground state and of 33 vibrationally excited states. All the bands involving states up to vtot=3 have been analyzed simultaneously by adopting a model Hamiltonian which takes into account the vibration and rotation l-type resonances. The derived spectroscopic parameters reproduce the transition wavenumbers with a RMS value of the order of the experimental uncertainty. Using the same model, larger discrepancies between observed and calculated values have been obtained for transitions involving states with vtot=4. These could be satisfactorily reproduced only by adopting a set of effective constants for each vibrational manifold, in addition to the previously determined parameters, which were constrained in the analysis. © 2012 Taylor and Francis.
BibTeX: @article{PredoiCross2012a, author = {Predoi-Cross, Adriana and Herman, Michel and Fusina, Luciano and Di Lonardo, Gianfranco}, title = {The infrared spectrum of 13C2H2 in the 60-2600 cm-1 region: Bending states up to v4+v 5=4}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2621 – 2632}, doi = {10.1080/00268976.2012.705345} }
Rozario H, Garber J, Povey C, Hurtmans D, Buldyreva J and Predoi-Cross A (2012), "Experimental and theoretical study of N2-broadened acetylene line parameters in the v1+v3 band over a range of temperatures", Molecular Physics. Vol. 110(21-22), pp. 2645 – 2663. [Abstract] [BibTeX] [DOI]
Abstract: N2-broadened line widths and N2-pressure induced line shifts have been measured for transitions in the v1+v3 band of acetylene at seven temperatures in the range 213-333K to obtain the temperature dependences of broadening and shift coefficients. For the room-temperature spectra the line mixing effects have been also investigated. The Voigt and hard-collision line profile models were used to retrieve the line parameters. All spectra were recorded using a 3-channel tuneable diode laser spectrometer. The line-broadening and line-shifting coefficients as well as their temperature-dependence parameters have been also evaluated theoretically, in the frame of a semi-classical approach based on an exponential representation of the scattering operator, an intermolecular potential composed of electrostatic quadrupole-quadrupole and pairwise atom-atom interactions as well as on exact trajectories driven by an effective isotropic potential. © 2012 Taylor and Francis.
BibTeX: @article{Rozario2012, author = {Rozario, Hoimonti and Garber, Jolene and Povey, Chad and Hurtmans, Daniel and Buldyreva, Jeanna and Predoi-Cross, Adriana}, title = {Experimental and theoretical study of N2-broadened acetylene line parameters in the v1+v3 band over a range of temperatures}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2645 – 2663}, doi = {10.1080/00268976.2012.720040} }
Sanzharov M, Vander Auwera J, Pirali O, Roy P, Brubach J-B, Manceron L, Gabard T and Boudon V (2012), "Self and N 2 collisional broadening of far-infrared methane lines measured at the SOLEIL synchrotron", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 113(15), pp. 1874 – 1886. [Abstract] [BibTeX] [DOI]
Abstract: Following our recent study devoted to measurements of intensities of pure rotation lines of methane, room temperature far infrared spectra of methane diluted in nitrogen at five total pressures between 100 and 800hPa have been recorded at the AILES beamline of the SOLEIL synchrotron. One hundred and five N 2 broadening coefficients of methane pure rotation lines have been measured in the 83-261cm -1 spectral range using multi-spectrum non-linear least squares fitting of Voigt profiles. Pressure-induced line shifts were not needed to fit the spectra to the noise level and line mixing effects were neglected. One hundred and seventy-six self broadening coefficients have also been measured in the 59-288cm -1 spectral range using the pure methane spectra recorded in our previous work. The measured N 2 broadening coefficients were compared to semi-classical calculations. © 2012 Elsevier Ltd.
BibTeX: @article{Sanzharov2012, author = {Sanzharov, M. and Vander Auwera, J. and Pirali, O. and Roy, P. and Brubach, J.-B. and Manceron, L. and Gabard, T. and Boudon, V.}, title = {Self and N 2 collisional broadening of far-infrared methane lines measured at the SOLEIL synchrotron}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2012}, volume = {113}, number = {15}, pages = {1874 – 1886}, doi = {10.1016/j.jqsrt.2012.06.001} }
Saunois M, Emmons L, Lamarque J-F, Tilmes S, Wespes C, Thouret V and Schultz M (2012), "Impact of sampling frequency in the analysis of tropospheric ozone observations", Atmospheric Chemistry and Physics. Vol. 12(15), pp. 6757 – 6773. [Abstract] [BibTeX] [DOI]
Abstract: Measurements of ozone vertical profiles are valuable for the evaluation of atmospheric chemistry models and contribute to the understanding of the processes controlling the distribution of tropospheric ozone. The longest record of ozone vertical profiles is provided by ozone sondes, which have a typical frequency of 4 to 12 profiles a month. Here we quantify the uncertainty introduced by low frequency sampling in the determination of means and trends. To do this, the high frequency MOZAIC (Measurements of OZone, water vapor, carbon monoxide and nitrogen oxides by in-service AIrbus airCraft) profiles over airports, such as Frankfurt, have been subsampled at two typical ozone sonde frequencies of 4 and 12 profiles per month. We found the lowest sampling uncertainty on seasonal means at 700 hPa over Frankfurt, with around 5% for a frequency of 12 profiles per month and 10% for a 4 profile-a-month frequency. However the uncertainty can reach up to 15 and 29% at the lowest altitude levels. As a consequence, the sampling uncertainty at the lowest frequency could be higher than the typical 10% accuracy of the ozone sondes and should be carefully considered for observation comparison and model evaluation. We found that the 95% confidence limit on the seasonal mean derived from the subsample created is similar to the sampling uncertainty and suggest to use it as an estimate of the sampling uncertainty. Similar results are found at six other Northern Hemisphere sites. We show that the sampling substantially impacts on the inter-annual variability and the trend derived over the period 1998-2008 both in magnitude and in sign throughout the troposphere. Also, a tropical case is discussed using the MOZAIC profiles taken over Windhoek, Namibia between 2005 and 2008. For this site, we found that the sampling uncertainty in the free troposphere is around 8 and 12% at 12 and 4 profiles a month respectively. © 2012 Author(s).
BibTeX: @article{Saunois2012, author = {Saunois, M. and Emmons, L. and Lamarque, J.-F. and Tilmes, S. and Wespes, C. and Thouret, V. and Schultz, M.}, title = {Impact of sampling frequency in the analysis of tropospheric ozone observations}, journal = {Atmospheric Chemistry and Physics}, year = {2012}, volume = {12}, number = {15}, pages = {6757 – 6773}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-12-6757-2012} }
Scannell C, Hurtmans D, Boynard A, Hadji-Lazaro J, George M, Delcloo A, Tuinder O, Coheur P-F and Clerbaux C (2012), "Antarctic ozone hole as observed by IASI/MetOp for 2008-2010", Atmospheric Measurement Techniques. Vol. 5(1), pp. 123 – 139. [Abstract] [BibTeX] [DOI]
Abstract: In this paper we present a study of the ozone hole as observed by the Infrared Atmospheric Sounding Interferometer (IASI) on-board the MetOp-A European satellite platform from the beginning of data dissemination, August 2008, to the end of December 2010. Here we demonstrate IASI's ability to capture the seasonal characteristics of the ozone hole, in particular during polar night. We compare IASI ozone total columns and vertical profiles with those of the Global Ozone Monitoring Experiment 2 (GOME-2, also on-board MetOp-A) and electrochemical concentration cell (ECC) ozone sonde measurements. Total ozone column from IASI and GOME-2 were found to be in excellent agreement for this region with a correlation coefficient of 0.97, for September, October and November 2009. On average IASI exhibits a positive bias of approximately 7% compared to the GOME-2 measurements over the entire ozone hole period. Comparisons between IASI and ozone sonde measurements were also found to be in good agreement with the difference between both ozone profile measurements being less than ±30% over the altitude range of 0-40 km. The vertical structure of the ozone profile inside the ozone hole is captured remarkably well by IASI. © Author(s) 2012.
BibTeX: @article{Scannell2012, author = {Scannell, C. and Hurtmans, D. and Boynard, A. and Hadji-Lazaro, J. and George, M. and Delcloo, A. and Tuinder, O. and Coheur, P.-F. and Clerbaux, C.}, title = {Antarctic ozone hole as observed by IASI/MetOp for 2008-2010}, journal = {Atmospheric Measurement Techniques}, year = {2012}, volume = {5}, number = {1}, pages = {123 – 139}, note = {All Open Access, Gold Open Access}, doi = {10.5194/amt-5-123-2012} }
Stavrakou T, Müller J-F, Peeters J, Razavi A, Clarisse L, Clerbaux C, Coheur P-F, Hurtmans D, De Mazière M, Vigouroux C, Deutscher N, Griffith D, Jones N and Paton-Walsh C (2012), "Satellite evidence for a large source of formic acid from boreal and tropical forests", Nature Geoscience. Vol. 5(1), pp. 26 – 30. [Abstract] [BibTeX] [DOI]
Abstract: Formic acid contributes significantly to acid rain in remote environments. Direct sources of formic acid include human activities, biomass burning and plant leaves. Aside from these direct sources, sunlight-induced oxidation of non-methane hydrocarbons (largely of biogenic origin) is probably the largest source. However, model simulations substantially underpredict atmospheric formic acid levels, indicating that not all sources have been included in the models. Here, we use satellite measurements of formic acid concentrations to constrain model simulations of the global formic acid budget. According to our simulations, 100- 120Tg of formic acid is produced annually, which is two to three times more than that estimated from known sources. We show that 90% of the formic acid produced is biogenic in origin, and largely sourced from tropical and boreal forests. We suggest that terpenoids- volatile organic compounds released by plants- are the predominant precursors. Model comparisons with independent observations of formic acid strengthen our conclusions, and provide indirect validation for the satellite measurements. Finally, we show that the larger formic acid emissions have a substantial impact on rainwater acidity, especially over boreal forests in the summer, where formic acid reduces pH by 0.25- 0.5.
BibTeX: @article{Stavrakou2012, author = {Stavrakou, T. and Müller, J.-F. and Peeters, J. and Razavi, A. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and De Mazière, M. and Vigouroux, C. and Deutscher, N.M. and Griffith, D.W.T. and Jones, N. and Paton-Walsh, C.}, title = {Satellite evidence for a large source of formic acid from boreal and tropical forests}, journal = {Nature Geoscience}, year = {2012}, volume = {5}, number = {1}, pages = {26 – 30}, doi = {10.1038/ngeo1354} }
Surono, Jousset P, Pallister J, Boichu M, Buongiorno MF, Budisantoso A, Costa F, Andreastuti S, Prata F, Schneider D, Clarisse L, Humaida H, Sumarti S, Bignami C, Griswold J, Carn S, Oppenheimer C and Lavigne F (2012), "The 2010 explosive eruption of Java's Merapi volcano-A '100-year' event", Journal of Volcanology and Geothermal Research. Vol. 241-242, pp. 121 – 135. [Abstract] [BibTeX] [DOI]
Abstract: Merapi volcano (Indonesia) is one of the most active and hazardous volcanoes in the world. It is known for frequent small to moderate eruptions, pyroclastic flows produced by lava dome collapse, and the large population settled on and around the flanks of the volcano that is at risk. Its usual behavior for the last decades abruptly changed in late October and early November 2010, when the volcano produced its largest and most explosive eruptions in more than a century, displacing at least a third of a million people, and claiming nearly 400 lives. Despite the challenges involved in forecasting this 'hundred year eruption', we show that the magnitude of precursory signals (seismicity, ground deformation, gas emissions) was proportional to the large size and intensity of the eruption. In addition and for the first time, near-real-time satellite radar imagery played an equal role with seismic, geodetic, and gas observations in monitoring eruptive activity during a major volcanic crisis. The Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) issued timely forecasts of the magnitude of the eruption phases, saving 10,000-20,000 lives. In addition to reporting on aspects of the crisis management, we report the first synthesis of scientific observations of the eruption. Our monitoring and petrologic data show that the 2010 eruption was fed by rapid ascent of magma from depths ranging from 5 to 30km. Magma reached the surface with variable gas content resulting in alternating explosive and rapid effusive eruptions, and released a total of 0.44Tg of SO2. The eruptive behavior seems also related to the seismicity along a tectonic fault more than 40km from the volcano, highlighting both the complex stress pattern of the Merapi region of Java and the role of magmatic pressurization in activating regional faults. We suggest a dynamic triggering of the main explosions on 3 and 4 November by the passing seismic waves generated by regional earthquakes on these days. © 2012 Elsevier B.V.
BibTeX: @article{Surono2012, author = {Surono and Jousset, Philippe and Pallister, John and Boichu, Marie and Buongiorno, M. Fabrizia and Budisantoso, Agus and Costa, Fidel and Andreastuti, Supriyati and Prata, Fred and Schneider, David and Clarisse, Lieven and Humaida, Hanik and Sumarti, Sri and Bignami, Christian and Griswold, Julie and Carn, Simon and Oppenheimer, Clive and Lavigne, Franck}, title = {The 2010 explosive eruption of Java's Merapi volcano-A '100-year' event}, journal = {Journal of Volcanology and Geothermal Research}, year = {2012}, volume = {241-242}, pages = {121 – 135}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jvolgeores.2012.06.018} }
Sutcliffe B (2012), "Is there an exact potential energy surface?", Theoretical Chemistry Accounts. Vol. 131(4), pp. 1 – 11. [Abstract] [BibTeX] [DOI]
Abstract: Transition state theory was introduced in the 1930s to account for chemical reactions. Central to this theory is the idea of a potential energy surface (PES). It was assumed that quantum mechanical computation, when it became possible, would yield such surfaces, but for the time being they would have to be constructed empirically. The approach was very successful. Nowadays, quantum mechanical ab initio electronic structure calculations are possible and from their results PESs can be constructed. Such surfaces are now widely used in the explanation of chemical reactions in place of the traditional empirical ones. It is argued here that theoretical basis of such PESs is not quite as clear as is usually assumed and that, from a quantum mechanical perspective, certain puzzles remain. © 2012 Springer-Verlag.
BibTeX: @article{Sutcliffe2012e, author = {Sutcliffe, Brian}, title = {Is there an exact potential energy surface?}, journal = {Theoretical Chemistry Accounts}, year = {2012}, volume = {131}, number = {4}, pages = {1 – 11}, doi = {10.1007/s00214-012-1215-x} }
Sutcliffe B (2012), "Some difficulties in considering rotation motion within the Born-Oppenheimer approximation for polyatomic molecules", International Journal of Quantum Chemistry. Vol. 112(17), pp. 2894 – 2903. [Abstract] [BibTeX] [DOI]
Abstract: The original account of the Born-Oppenheimer approximation is not mathematically secure because it is not legitimate to use perturbation theory in its development. It is necessary to use an asymptotic expansion based upon an electronic Hamiltonian defined in terms of a fiber bundle. Although with this approach it has been possible account for the traditional results for a diatomic molecule, rotational motion in the polyatomic case has not so far been accounted for. It is argued here that it is not generally possible to provide a mathematically secure account of the Born-Oppenheimer approximation for polyatomic molecules, in which rotation can be considered as a separable motion. © 2012 Wiley Periodicals, Inc. Copyright © 2012 Wiley Periodicals, Inc.
BibTeX: @article{Sutcliffe2012b, author = {Sutcliffe, Brian}, title = {Some difficulties in considering rotation motion within the Born-Oppenheimer approximation for polyatomic molecules}, journal = {International Journal of Quantum Chemistry}, year = {2012}, volume = {112}, number = {17}, pages = {2894 – 2903}, doi = {10.1002/qua.24021} }
Sutcliffe B and Woolley RG (2012), "The position of the clamped nuclei electronic hamiltonian in quantum mechanics", Handbook of Computational Chemistry. , pp. 13 – 54. [Abstract] [BibTeX] [DOI]
Abstract: Arguments are advanced to support the view that at present it is not possible to derive molecular structure from the full quantum mechanical Coulomb Hamiltonian associated with a given molecular formula that is customarily regarded as representing the molecule in terms of its constituent electrons and nuclei. However molecular structure may be identified provided that some additional chemically motivated assumptions that lead to the clamped nuclei Hamiltonian are added to the quantum mechanical account. © Springer Science+Business Media B.V. 2012.
BibTeX: @book{Sutcliffe2012d, author = {Sutcliffe, Brian and Woolley, R. Guy}, title = {The position of the clamped nuclei electronic hamiltonian in quantum mechanics}, journal = {Handbook of Computational Chemistry}, year = {2012}, pages = {13 – 54}, doi = {10.1007/978-94-007-0711-5_2} }
Sutcliffe BT (2012), "Chemistry as a "manifestation of quantum phenomena" and the Born-Oppenheimer approximation?", Structure and Bonding. Vol. 143, pp. 101 – 120. [Abstract] [BibTeX] [DOI]
Abstract: When considering the work of Carl Ballhausen on vibrational spectra, it is suggested that his use of the Born-Oppenheimer approximation is capable of some refinement and extension in the light of later developments. A consideration of the potential energy surface in the context of a full Coulomb Schrödinger Hamiltonian in which translational and rotational motions are explicitly considered would seem to require a reformulation of the Born-Oppenheimer approach. The resulting potential surface for vibrational motion should be treated, allowing for the rotational motion and the nuclear permutational symmetry of the molecule. © 2011 Springer-Verlag Berlin Heidelberg.
BibTeX: @article{Sutcliffe2012a, author = {Sutcliffe, Brian T.}, title = {Chemistry as a "manifestation of quantum phenomena" and the Born-Oppenheimer approximation?}, journal = {Structure and Bonding}, year = {2012}, volume = {143}, pages = {101 – 120}, doi = {10.1007/430_2011_44} }
Sutcliffe BT and Guy Woolley R (2012), "Atoms and molecules in classical chemistry and quantum mechanics", Philosophy of Chemistry. , pp. 387 – 426. [Abstract] [BibTeX] [DOI]
Abstract: This chapter starts by giving a brief account of the development of the atomic-molecular conception of chemistry. An essential backdrop to the whole discussion is the importance throughout human history of the practical chemical arts that have informed the production of the whole range of useful materials and stimulated enquiry into the theoretical aspects of chemical processes. Chemistry is concerned with the composition and properties of matter, and with the transformations of matter that can occur spontaneously or under the action of heat, radiation or other sources of energy. From the results of chemical experiments the chemist singles out a particular class of materials that have characteristic and invariant properties. Such materials are called pure substances and may be of two kinds, viz: compounds and elements. Elements may be defined as substances which have not been converted either by the action of heat, radiation, or chemical reaction with other substances, or small electrical voltages, into any simpler substance. Compounds are formed from the chemical combination of the elements, and have properties that are invariably different from the properties of the constituent elements; they are also homogeneous. This characteristic chemical notion of a pure substance is based on an ideal conception of the chemical and physical properties of matter and their changes under specified experimental conditions. © 2012 Elsevier B.V. All rights reserved.
BibTeX: @book{Sutcliffe2012c, author = {Sutcliffe, Brian T. and Guy Woolley, R.}, title = {Atoms and molecules in classical chemistry and quantum mechanics}, journal = {Philosophy of Chemistry}, year = {2012}, pages = {387 – 426}, doi = {10.1016/B978-0-444-51675-6.50028-1} }
Sutcliffe BT and Woolley RG (2012), "On the quantum theory of molecules", Journal of Chemical Physics. Vol. 137(22) [Abstract] [BibTeX] [DOI]
Abstract: Transition state theory was introduced in 1930s to account for chemical reactions. Central to this theory is the idea of a potential energy surface (PES). It was assumed that such a surface could be constructed using eigensolutions of the Schrödinger equation for the molecular (Coulomb) Hamiltonian but at that time such calculations were not possible. Nowadays quantum mechanical ab initio electronic structure calculations are routine and from their results PESs can be constructed which are believed to approximate those assumed derivable from the eigensolutions. It is argued here that this belief is unfounded. It is suggested that the potential energy surface construction is more appropriately regarded as a legitimate and effective modification of quantum mechanics for chemical purposes. © 2012 American Institute of Physics.
BibTeX: @article{Sutcliffe2012, author = {Sutcliffe, Brian T. and Woolley, R. Guy}, title = {On the quantum theory of molecules}, journal = {Journal of Chemical Physics}, year = {2012}, volume = {137}, number = {22}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.4755287} }
Té YV, Dieudonné E, Jeseck P, Hase F, Hadji-Lazaro J, Clerbaux C, Ravetta F, Payan S, Pépin I, Hurtmans D, Pelon J and Camy-Peyret C (2012), "Carbon monoxide urban emission monitoring: A ground-based FTIR case study", Journal of Atmospheric and Oceanic Technology. Vol. 29(7), pp. 911 – 921. [Abstract] [BibTeX] [DOI]
Abstract: The characterization and the precise measurements of atmospheric pollutant's concentration are essential to improve the understanding and modeling of urban air pollution processes. The QualAir platform at the Université Pierre et Marie Curie (UPMC) is an experimental research platform dedicated to urban air quality and pollution studies. As one of the major instruments, the ground-based QualAir Fourier transform spectrometer (FTS) provides information on the air composition of a megacity like Paris, France. Operating in solar infrared absorption, it enables the monitoring of several important pollutants involved in tropospheric chemistry and atmospheric transport around the Ile de France region. Results on nitrous oxide (N 2O), methane (CH 4), and carbon monoxide (CO) will be presented in this paper, as well as the CO measurements comparison with satellite and in situ measurements showing the capabilities and strengths of this groundbased FTS with the other instruments of the QualAir platform. © 2012 American Meteorological Society.
BibTeX: @article{Te2012, author = {Té, Yao Veng and Dieudonné, E. and Jeseck, P. and Hase, F. and Hadji-Lazaro, J. and Clerbaux, C. and Ravetta, F. and Payan, S. and Pépin, I. and Hurtmans, D. and Pelon, J. and Camy-Peyret, C.}, title = {Carbon monoxide urban emission monitoring: A ground-based FTIR case study}, journal = {Journal of Atmospheric and Oceanic Technology}, year = {2012}, volume = {29}, number = {7}, pages = {911 – 921}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1175/JTECH-D-11-00040.1} }
Toledano C, Bennouna Y, Cachorro V, Ortiz de Galisteo J, Stohl A, Stebel K, Kristiansen N, Olmo F, Lyamani H, Obregón M, Estellés V, Wagner F, Baldasano J, González-Castanedo Y, Clarisse L and de Frutos A (2012), "Aerosol properties of the Eyjafjallajökull ash derived from sun photometer and satellite observations over the Iberian Peninsula", Atmospheric Environment. Vol. 48, pp. 22 – 32. [Abstract] [BibTeX] [DOI]
Abstract: The Eyjafjallajökull ash that crossed over Spain and Portugal on 6-12 May 2010 has been monitored by a set of operational sun photometer sites within AERONET-RIMA and satellite sensors. The sun photometer observations (aerosol optical depth, coarse mode concentrations) and ash products from IASI and SEVIRI satellite sensors, together with FLEXPART simulations of particle transport, allow identifying the volcanic aerosols. The aerosol columnar properties derived from inversions were investigated, indicating specific properties, especially regarding the absorption. The single scattering albedo was high (0.95 at 440nm) and nearly wavelength independent, although with slight decrease with wavelength. Other parameters, like the fine mode fraction of the volume size distributions (0.20-0.80) or the portion of spherical particles (15-90%), were very variable among the sites and indicated that the various ash clouds were inhomogeneous with respect to particle size and shape. © 2011 Elsevier Ltd.
BibTeX: @article{Toledano2012, author = {Toledano, C. and Bennouna, Y. and Cachorro, V. and Ortiz de Galisteo, J.P. and Stohl, A. and Stebel, K. and Kristiansen, N.I. and Olmo, F.J. and Lyamani, H. and Obregón, M.A. and Estellés, V. and Wagner, F. and Baldasano, J.M. and González-Castanedo, Y. and Clarisse, L. and de Frutos, A.M.}, title = {Aerosol properties of the Eyjafjallajökull ash derived from sun photometer and satellite observations over the Iberian Peninsula}, journal = {Atmospheric Environment}, year = {2012}, volume = {48}, pages = {22 – 32}, doi = {10.1016/j.atmosenv.2011.09.072} }
Tudorie M, Földes T, Vandaele A and Vander Auwera J (2012), "CO 2 pressure broadening and shift coefficients for the 1-0 band of HCl and DCl", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 113(11), pp. 1092 – 1101. [Abstract] [BibTeX] [DOI]
Abstract: CO 2 broadened spectra of the 1-0 band of H 35Cl and H 37Cl, observed near 2886cm -1, and the 1-0 band of D 35Cl and D 37Cl, located near 2089cm -1, have been recorded at room temperature and five total pressures between 150 and 700Torr, using a Bruker IFS125HR Fourier transform spectrometer. Spectra of pure HCl were also recorded. CO 2 broadening and shift coefficients of HCl and DCl have been measured using multi-spectrum non-linear least squares fitting of Voigt profiles. The analysis of the 1-0 band of DCl was complicated by the presence of overlapping CO 2 bands, which were included in the treatment as absorption coefficients calculated taking line-mixing effects into account. © 2012 Elsevier Ltd.
BibTeX: @article{Tudorie2012a, author = {Tudorie, M. and Földes, T. and Vandaele, A.C. and Vander Auwera, J.}, title = {CO 2 pressure broadening and shift coefficients for the 1-0 band of HCl and DCl}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2012}, volume = {113}, number = {11}, pages = {1092 – 1101}, doi = {10.1016/j.jqsrt.2012.01.025} }
Tudorie M, Ilyushin V, Auwera JV, Pirali O, Roy P and Huet T (2012), "Synchrotron FTIR spectroscopy of weak torsional bands: A case study of cis-methyl formate", Journal of Chemical Physics. Vol. 137(6) [Abstract] [BibTeX] [DOI]
Abstract: The far infrared spectrum of cis-methyl formate has been recorded on the AILES beamline of the synchrotron SOLEIL using a Fourier transform infrared spectrometer coupled to a long path cell. The very weak fundamental band associated with the methyl-top torsion mode (ν 18) was observed. The frequency analysis was performed using the rho axis method, and the microwave and millimeter-wave data from the literature. A precise determination of the band origins (ν18A 132.4303 cm -1 and ν18E 131.8445 cm -1) and of the barrier height V 3 370.7398 (58) cm -1 have been obtained. The intensity of the ν 18 fundamental band was determined to be 3.4 × 10 -21 cm -1(molecule cm -2) at 297 K, equally shared among A-A and E-E transitions, thus leading to a dipole moment component μ c (3) equal to 0.0483 D. The results were compared with the ab initio calcula-tions of Senent [Astrophys. J. 627, 567 (2005)]10.1086/430201. © 2012 American Institute of Physics.
BibTeX: @article{Tudorie2012, author = {Tudorie, M. and Ilyushin, V. and Auwera, J. Vander and Pirali, O. and Roy, P. and Huet, T.R.}, title = {Synchrotron FTIR spectroscopy of weak torsional bands: A case study of cis-methyl formate}, journal = {Journal of Chemical Physics}, year = {2012}, volume = {137}, number = {6}, doi = {10.1063/1.4740250} }
Urbain X, Lecointre J, Loreau J and Vaeck N (2012), "Photodissociation from the ground state of HeH+: Comparison with experiment", Journal of Physics: Conference Series. Vol. 388(PART 2) [Abstract] [BibTeX] [DOI]
Abstract: We investigate the photodissociation process for both hot and cold HeH + ions. Detailed comparison with experiments performed at FLASH is made possible by experimentally determining the ro-vibrational distribution of the ions under identical source conditions, and averaging the theoretical cross sections accordingly. © Published under licence by IOP Publishing Ltd.
BibTeX: @conference{Urbain2012, author = {Urbain, X. and Lecointre, J. and Loreau, J. and Vaeck, N.}, title = {Photodissociation from the ground state of HeH+: Comparison with experiment}, journal = {Journal of Physics: Conference Series}, year = {2012}, volume = {388}, number = {PART 2}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/388/2/022107} }
Verdebout S, Rynkun P, Jönsson P, Gaigalast G, Froese Fischer C and Godefroid M (2012), "Interaction of variational localised correlation functions for atomic properties of Be I", Journal of Physics: Conference Series. Vol. 388(PART 15) [Abstract] [BibTeX] [DOI]
Abstract: We present some progress associated to the localised correlation function interaction (LCFI) method. In this report, the LCFI method is tested not only for total energy but also for the specific mass shift operator, the hyperfine structure parameters and the transition probabilities. These properties are computed for the three lowest electronic states of the beryllium atom. These calculations illustrate the importance of the contraction effects.
BibTeX: @conference{Verdebout2012, author = {Verdebout, S. and Rynkun, P. and Jönsson, P. and Gaigalast, G. and Froese Fischer, C. and Godefroid, M.}, title = {Interaction of variational localised correlation functions for atomic properties of Be I}, journal = {Journal of Physics: Conference Series}, year = {2012}, volume = {388}, number = {PART 15}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/388/15/152006} }
Vieira Mendes LA, Boyé-Péronne S, Jacovella U, Liévin J and Gauyacq D (2012), "Rydberg states of cyanoacetylene investigated by (3+1) REMPI spectroscopy in the 77,000.90,000 cm-1 energy range", Molecular Physics. Vol. 110(21-22), pp. 2829 – 2842. [Abstract] [BibTeX] [DOI]
Abstract: (3+1) resonantly enhanced multiphoton ionization (REMPI) spectroscopy coupled to photoelectron spectroscopy (REMPI-PES) has been carried out to study the Rydberg states of HC3N in the 77,000.90,000 cm-1 region. Ab initio calculations (energies and optimized equilibrium geometries) have been performed for the first time for the low-lying X̃2Π, Ã 2Σ+ and B̃2Π states of the cation HC3N+ in order to help the analysis. Thanks to the combination of the three-photon REMPI spectra, one-photon spectrum and photoelectron spectra, unambiguous assignments of the Rydberg series and their vibrationally excited members are proposed. The electronic Rydberg structure of cyanoacetylene is very similar to that of C2H2 and HCN (almost identical quantum defects), fully supporting the present analysis. New three-photon allowed Rydberg series are identified belonging to ns and nd series. The three-photon vibrational band assignments, confirmed by the photoelectrons spectra, reveal excitation of only one or two quanta of the v1 (C≅N) mode. Apparent discrepancies between the three-photon REMPI spectrum and the one-photon absorption spectrum are removed via a minor re-assignment of the absorption spectrum previously analysed by Connors et al. J. Chem. Phys. 60(12), 5011 (1974). Finally the observed analogy with C 2H2 and HCN can be rationalized by a partial relocalization of the 2π electrons upon excitation to Rydberg states converging to the X̃2Π state of HC3N+, as predicted by the present ab initio calculations on the cation core. © 2012 Taylor and Francis.
BibTeX: @article{VieiraMendes2012, author = {Vieira Mendes, Luiz A. and Boyé-Péronne, Séverine and Jacovella, Ugo and Liévin, Jacques and Gauyacq, Dolores}, title = {Rydberg states of cyanoacetylene investigated by (3+1) REMPI spectroscopy in the 77,000.90,000 cm-1 energy range}, journal = {Molecular Physics}, year = {2012}, volume = {110}, number = {21-22}, pages = {2829 – 2842}, doi = {10.1080/00268976.2012.706327} }
Villa M, Fusina L, Nivellini G, Didriche K, De Ghellinck D'Elseghem Vaernewijck X and Herman M (2012), "The infrared spectrum of propyne in the range 6200-6700 cm -1 ", Chemical Physics. Vol. 402, pp. 14 – 21. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of propyne (CH 3CCH) has been investigated in the range 6200-6700 cm -1. Data were obtained using three different experimental techniques: conventional FTIR experiments (room temperature, 0.018 cm -1 resolution, 10 m absorption path), FTIR experiments using a femtosecond broadband absorption source and a build up cavity (room temperature, 0.02 cm -1 resolution, absorption path between 1500 and 12,000 m), cavity ring down spectroscopy to probe a propyne/Ar supersonic expansion (T rot ≈ 20 K, sub-Doppler resolution, 720 m effective absorption path length). The analysis focused on one perpendicular ( ν1+ν6±1) and four parallel (2ν 1, ν 1 + ν 2, ν 1 + ν 3 + ν 5, ν1+ ν3+2ν90) bands, all perturbed by a complex system of Coriolis and anharmonic interactions. A model Hamiltonian was built, including all symmetry allowed perturbations between the upper levels of the studied bands but not accounting for additional interacting states. In total 1176 rovibrational transitions have been assigned and simultaneously fitted (σ = 0.0029 cm -1), leading to a set of effective rovibrational parameters. The resulting polyad structure is discussed and additional bands identified in the spectral range are tentatively assigned. © 2012 Elsevier B.V. All rights reserved.
BibTeX: @article{Villa2012, author = {Villa, Mattia and Fusina, Luciano and Nivellini, Giandomenico and Didriche, Keevin and De Ghellinck D'Elseghem Vaernewijck, Xavier and Herman, Michel}, title = {The infrared spectrum of propyne in the range 6200-6700 cm -1 }, journal = {Chemical Physics}, year = {2012}, volume = {402}, pages = {14 – 21}, doi = {10.1016/j.chemphys.2012.03.020} }
Vranckx S, Loreau J, Desouter-Lecomte M and Vaeck N (2012), "Radiative stabilization and photodissociation of HeH+ in its two lowest 3Σ+ states", Journal of Physics: Conference Series. Vol. 388(PART 2) [Abstract] [BibTeX] [DOI]
Abstract: Although it is thought to play an important role in the chemistry of some extra-terrestrial environments, the HeH+ cation has not been detected in space so far. We suggest it could be observed in its triplets rather than singlet states and we study the formation by radiative stabiliation and the destruction by photodissociation of the two lowest states of this symmetry. © Published under licence by IOP Publishing Ltd.
BibTeX: @conference{Vranckx2012, author = {Vranckx, Stéphane and Loreau, Jérôme and Desouter-Lecomte, Michèle and Vaeck, Nathalie}, title = {Radiative stabilization and photodissociation of HeH+ in its two lowest 3Σ+ states}, journal = {Journal of Physics: Conference Series}, year = {2012}, volume = {388}, number = {PART 2}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/388/2/022109} }
Vranckx S, Meier C, Bomble L, Chenel A, Desouter-Lecomte M and Vaeck N (2012), "Local control of nonadiabatic photodissociation dynamics using Moller operators", Journal of Physics: Conference Series. Vol. 388(PART 11) [Abstract] [BibTeX] [DOI]
Abstract: We implement a local control strategy based on the use of Moller operators and use it to control the photodissociation of diatomic molecules in the presence of nonadiabatic interactions.
BibTeX: @conference{Vranckx2012a, author = {Vranckx, Stéphane and Meier, Christoph and Bomble, Laetitia and Chenel, Aurélie and Desouter-Lecomte, Michèle and Vaeck, Nathalie}, title = {Local control of nonadiabatic photodissociation dynamics using Moller operators}, journal = {Journal of Physics: Conference Series}, year = {2012}, volume = {388}, number = {PART 11}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/388/11/112009} }
Wang Q, Li J, Fritzsche S, Godefroid M, Chang Z and Dong C (2012), "Theoretical study of hyperfine structure constants of Ga isotopes", Journal of Physics: Conference Series. Vol. 388(PART 15) [Abstract] [BibTeX] [DOI]
Abstract: The hyperfine structure constants for the ground 4s24p 2P°3/2 and lowest excited states 4s25s 2S1/2 of 71Ga are calculated using the GRASP2K package based on the multi-configuration Dirac-Hartree-Fock method. Furthermore, the magnetic dipole (μ) and the electric quadrupole (Q) moments of the Ga isotopes from 67Ga to 81Ga are derived.
BibTeX: @conference{Wang2012, author = {Wang, Q.M. and Li, J.G. and Fritzsche, S. and Godefroid, M. and Chang, Z.W. and Dong, C.Z.}, title = {Theoretical study of hyperfine structure constants of Ga isotopes}, journal = {Journal of Physics: Conference Series}, year = {2012}, volume = {388}, number = {PART 15}, note = {All Open Access, Gold Open Access}, doi = {10.1088/1742-6596/388/15/152009} }
Wells K, Millet D, Hu L, Cady-Pereira K, Xiao Y, Shephard M, Clerbaux C, Clarisse L, Coheur P-F, Apel E, De Gouw J, Warneke C, Singh H, Goldstein A and Sive B (2012), "Tropospheric methanol observations from space: Retrieval evaluation and constraints on the seasonality of biogenic emissions", Atmospheric Chemistry and Physics. Vol. 12(13), pp. 5897 – 5912. [Abstract] [BibTeX] [DOI]
Abstract: Methanol retrievals from nadir-viewing space-based sensors offer powerful new information for quantifying methanol emissions on a global scale. Here we apply an ensemble of aircraft observations over North America to evaluate new methanol measurements from the Tropospheric Emission Spectrometer (TES) on the Aura satellite, and combine the TES data with observations from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A satellite to investigate the seasonality of methanol emissions from northern midlatitude ecosystems. Using the GEOS-Chem chemical transport model as an intercomparison platform, we find that the TES retrieval performs well when the degrees of freedom for signal (DOFS) are above 0.5, in which case the model:TES regressions are generally consistent with the model:aircraft comparisons. Including retrievals with DOFS below 0.5 degrades the comparisons, as these are excessively influenced by the a priori. The comparisons suggest DOFS >0.5 as a minimum threshold for interpreting retrievals of trace gases with a weak tropospheric signal. We analyze one full year of satellite observations and find that GEOS-Chem, driven with MEGANv2.1 biogenic emissions, underestimates observed methanol concentrations throughout the midlatitudes in springtime, with the timing of the seasonal peak in model emissions 1-2 months too late. We attribute this discrepancy to an underestimate of emissions from new leaves in MEGAN, and apply the satellite data to better quantify the seasonal change in methanol emissions for midlatitude ecosystems. The derived parameters (relative emission factors of 11.0, 0.26, 0.12 and 3.0 for new, growing, mature, and old leaves, respectively, plus a leaf area index activity factor of 0.5 for expanding canopies with leaf area index <1.2) provide a more realistic simulation of seasonal methanol concentrations in midlatitudes on the basis of both the IASI and TES measurements. © 2012 Author(s).
BibTeX: @article{Wells2012, author = {Wells, K.C. and Millet, D.B. and Hu, L. and Cady-Pereira, K.E. and Xiao, Y. and Shephard, M.W. and Clerbaux, C.L. and Clarisse, L. and Coheur, P.-F. and Apel, E.C. and De Gouw, J. and Warneke, C. and Singh, H.B. and Goldstein, A.H. and Sive, B.C.}, title = {Tropospheric methanol observations from space: Retrieval evaluation and constraints on the seasonality of biogenic emissions}, journal = {Atmospheric Chemistry and Physics}, year = {2012}, volume = {12}, number = {13}, pages = {5897 – 5912}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-12-5897-2012} }
Wespes C, Emmons L, Edwards D, Hannigan J, Hurtmans D, Saunois M, Coheur P-F, Clerbaux C, Coffey M, Batchelor R, Lindenmaier R, Strong K, Weinheimer A, Nowak J, Ryerson T, Crounse J and Wennberg P (2012), "Analysis of ozone and nitric acid in spring and summer Arctic pollution using aircraft, ground-based, satellite observations and MOZART-4 model: Source attribution and partitioning", Atmospheric Chemistry and Physics. Vol. 12(1), pp. 237 – 259. [Abstract] [BibTeX] [DOI]
Abstract: In this paper, we analyze tropospheric O3 together with HNO3 during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) program, combining observations and model results. Aircraft observations from the NASA ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) and NOAA ARCPAC (Aerosol, Radiation and Cloud Processes affecting Arctic Climate) campaigns during spring and summer of 2008 are used together with the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) to assist in the interpretation of the observations in terms of the source attribution and transport of O3 and HNO3 into the Arctic (north of 60°N). The MOZART-4 simulations reproduce the aircraft observations generally well (within 15%), but some discrepancies in the model are identified and discussed. The observed correlation of O3 with HNO 3 is exploited to evaluate the MOZART-4 model performance for different air mass types (fresh plumes, free troposphere and stratospheric-contaminated air masses). Based on model simulations of O 3 and HNO3 tagged by source type and region, we find that the anthropogenic pollution from the Northern Hemisphere is the dominant source of O3 and HNO3 in the Arctic at pressures greater than 400 hPa, and that the stratospheric influence is the principal contribution at pressures less 400 hPa. During the summer, intense Russian fire emissions contribute some amount to the tropospheric columns of both gases over the American sector of the Arctic. North American fire emissions (California and Canada) also show an important impact on tropospheric ozone in the Arctic boundary layer. Additional analysis of tropospheric O3 measurements from ground-based FTIR and from the IASI satellite sounder made at the Eureka (Canada) and Thule (Greenland) polar sites during POLARCAT has been performed using the tagged contributions. It demonstrates the capability of these instruments for observing pollution at northern high latitudes. Differences between contributions from the sources to the tropospheric columns as measured by FTIR and IASI are discussed in terms of vertical sensitivity associated with these instruments. The first analysis of O3 tropospheric columns observed by the IASI satellite instrument over the Arctic is also provided. Despite its limited vertical sensitivity in the lowermost atmospheric layers, we demonstrate that IASI is capable of detecting low-altitude pollution transported into the Arctic with some limitations. © 2012 Author(s).
BibTeX: @article{Wespes2012, author = {Wespes, C. and Emmons, L. and Edwards, D.P. and Hannigan, J. and Hurtmans, D. and Saunois, M. and Coheur, P.-F. and Clerbaux, C. and Coffey, M.T. and Batchelor, R.L. and Lindenmaier, R. and Strong, K. and Weinheimer, A.J. and Nowak, J.B. and Ryerson, T.B. and Crounse, J.D. and Wennberg, P.O.}, title = {Analysis of ozone and nitric acid in spring and summer Arctic pollution using aircraft, ground-based, satellite observations and MOZART-4 model: Source attribution and partitioning}, journal = {Atmospheric Chemistry and Physics}, year = {2012}, volume = {12}, number = {1}, pages = {237 – 259}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-12-237-2012} }
Amyay B, Fayt A and Herman M (2011), "Accurate partition function for acetylene, 12C 2H 2, and related thermodynamical quantities", Journal of Chemical Physics. Vol. 135(23) [Abstract] [BibTeX] [DOI]
Abstract: The internal partition function (Q int) of ethyne (acetylene), 12C 2H 2, is calculated by explicit summation of the contribution of all individual vibration-rotation energy levels up to 15 000 cm -1. The corresponding energies are predicted from a global model and constants reproducing within 3σ all 18 415 published vibration-rotation lines in the literature involving vibrational states up to 8900 cm -1, as produced by Amyay J. Mol. Spectrosc. 267, 80 (2011). Values of Q int, with distinct calculations for para and ortho species are provided from 1 to 2000 K, in step of 1 K. The total internal partition function at 298.15 K is 104.224387(47) or 416.89755(19), with the nuclear degeneracy spin factors taken as 1/4: 3/4 (astronomer convention) or 1:3 (atmospheric convention), respectively, for para:ortho species. The Helmholtz function, Gibbs enthalpy function, entropy, and specific heat at constant pressure are also calculated over the same temperature range. Accuracies as well as the missing contribution of the vinylidene isomer of acetylene in the calculations are discussed. © 2011 American Institute of Physics.
BibTeX: @article{Amyay2011, author = {Amyay, B. and Fayt, A. and Herman, M.}, title = {Accurate partition function for acetylene, 12C 2H 2, and related thermodynamical quantities}, journal = {Journal of Chemical Physics}, year = {2011}, volume = {135}, number = {23}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.3664626} }
Amyay B, Herman M, Fayt A, Campargue A and Kassi S (2011), "Acetylene, 12C2H2: Refined analysis of CRDS spectra around 1.52 μm", Journal of Molecular Spectroscopy. Vol. 267(1-2), pp. 80 – 91. [Abstract] [BibTeX] [DOI]
Abstract: The analysis of CW-cavity ring down absorption spectra of 12C2H2 previously reported by Robert et al. (Mol. Phys. 106 (2008) 2581) was improved in the range 6667-7015 cm -1. Some 1825 lines were newly assigned. They either belong to 105 new sub-bands, involving 69 previously unreported sub-states, or extend assignments in 35 already known sub-bands. A global fit procedure of line positions from the full 12C2H2 database containing 18 415 lines, including those newly assigned, was performed, accessing vibrational states up to 8900 cm-1. Coriolis interactions were systematically introduced in the global Hamiltonian, which also accounted for higher order vibrational constants and considered the role of higher excited bending states than before. The dimensionless standard deviation of the fit was 1.07 and 396 effective vibration-rotation parameters were determined. Two local, interpolyad couplings were evidenced for the first time. A set of 121 new lines from 12CH13CH present in natural abundance in the gas sample were also assigned. © 2011 Elsevier Inc. All rights reserved.
BibTeX: @article{Amyay2011a, author = {Amyay, B. and Herman, M. and Fayt, A. and Campargue, A. and Kassi, S.}, title = {Acetylene, 12C2H2: Refined analysis of CRDS spectra around 1.52 μm}, journal = {Journal of Molecular Spectroscopy}, year = {2011}, volume = {267}, number = {1-2}, pages = {80 – 91}, doi = {10.1016/j.jms.2011.02.015} }
Antón M, Loyola D, Clerbaux C, López M, Vilaplana J, Bañón M, Hadji-Lazaro J, Valks P, Hao N, Zimmer W, Coheur P, Hurtmans D and Alados-Arboledas L (2011), "Validation of the MetOp-A total ozone data from GOME-2 and IASI using reference ground-based measurements at the Iberian Peninsula", Remote Sensing of Environment. Vol. 115(6), pp. 1380 – 1386. [Abstract] [BibTeX] [DOI]
Abstract: One of the most important atmospheric composition products derived from the first EUMETSAT Meteorological Operational satellite (MetOp-A) is the total ozone column (TOC). For this purpose, MetOp-A has two instruments on board: the Global Ozone Monitoring Experiment 2 (GOME-2) that retrieves the TOC data from the backscattered solar ultraviolet-visible (UV-Vis) radiance, and the Infrared Atmospheric Sounding Interferometer (IASI) that uses the thermal infrared radiance to derive TOC data. This paper focuses on the simultaneous validation of the TOC data provided by these two MetOp-A instruments using the measurements recorded by five well-calibrated Brewer UV spectrophotometers located at the Iberian Peninsula during the complete 2009. The results show an excellent correlation between the ground-based data and the GOME-2 and IASI satellite observations (R2 higher than 0.91). Differences between the ground-based and satellite TOC data show that the IASI instrument significantly overestimates the Brewer measurements (about 4.4% when all five ground-based stations are jointly used). In contrast, the GOME-2 instrument shows a slight underestimation ( 1.6%). In addition, the absolute relative differences between the Brewer and GOME-2 data are quite smaller (about a factor higher than 2) than the Brewer-IASI absolute differences. The satellite viewing geometry (solar zenith angle and the view zenith angle) has no significant influence on the Brewer-satellite relative differences. Moreover, the analysis of these relative differences with respect to the ground-based TOC data indicates that GOME-2 instrument presents a slight underestimation for high TOC values. Finally, the IASI-GOME-2 correlation is high (R2 0.92), but with a mean relative difference of about ±6% which could be associated with the bias between UV-Vis and infrared spectroscopy used in the retrieval processes. © 2011 Elsevier Inc.
BibTeX: @article{Anton2011, author = {Antón, M. and Loyola, D. and Clerbaux, C. and López, M. and Vilaplana, J.M. and Bañón, M. and Hadji-Lazaro, J. and Valks, P. and Hao, N. and Zimmer, W. and Coheur, P.F. and Hurtmans, D. and Alados-Arboledas, L.}, title = {Validation of the MetOp-A total ozone data from GOME-2 and IASI using reference ground-based measurements at the Iberian Peninsula}, journal = {Remote Sensing of Environment}, year = {2011}, volume = {115}, number = {6}, pages = {1380 – 1386}, doi = {10.1016/j.rse.2011.01.018} }
Bogatko S, Cauët E and Geerlings P (2011), "Influence of F- coordination on Al3+ hydrolysis reactions from density functional theory calculations", Journal of Physical Chemistry C. Vol. 115(14), pp. 6910 – 6921. [Abstract] [BibTeX] [DOI]
Abstract: Aqua/hydroxo mononuclear Al3+ species coordinated by F - in aqueous solution are investigated using density functional theory (DFT B3LYP/6-311++G(d,p)) and the polarized continuum model (PCM). Optimized gas-phase geometries have been obtained for the species AlF(OH) n(H2O)m(2-n)+ in which n = 0, 1, 2, or 3 while (n + m) = 3, 4, or 5. Analysis of the Al-F, Al-O, and O-H bond lengths and the Al, F, O, and H natural charges of these complexes reveals clear trends that suggest increased acidity with decreasing coordination number (CN) and decreased water stability with increased hydrolysis. These observations are supported by the calculation and analysis of the dehydration and hydrolysis reaction Gibbs free energies δGaqueous dehydration and δGaqueous hydrolysis of the AlF(OH)n(H2O)m(2-n) + complexes, which clearly show a strong correlation between increased hydrolysis and a preference to coordinate fewer water molecules. The combination of the appropriate δGaqueous dehydration and δGaqueous hydrolysis values generate the aqueous Gibbs free energies relative to AlF(H2O)52+ and demonstrate the clear transition from a 6 to 5 to 4 coordinate species as a function of ligand hydrolysis. Calculation of the equilibrium mole fraction of each species as a function of pH shows that this system is largely dominated by the AlF(OH) 1(H2O)41+ and AlF(OH) 31- species. A comparison of structural and electronic data with the aqueous Al3+ complexes shows a remarkable similarity when plotted against the number negative ligands (F- or OH -), suggesting that the F- anion coordinates the Al 3+ cation in a similar way to the remaining OH- anions. The comparison of the calculated equilibrium mole fractions of each species displays important changes in the composition of our model system upon Al 3+ coordination by F- in the direction of increased acidity of these complexes. Our predicted decreased stability of the Al-water bond is in complete agreement with experimental NMR observations of an increased water exchange rate upon F- coordination of aqueous aluminum complexes. Our prediction of stable hydroxide ternary complexes is not in agreement with recent NMR data, which indicate that these complexes do not readily form. An explanation for this may lie in the increased lability of these complexes, which may lead to difficulties in NMR detection. © 2011 American Chemical Society.
BibTeX: @article{Bogatko2011, author = {Bogatko, Stuart and Cauët, Emilie and Geerlings, Paul}, title = {Influence of F- coordination on Al3+ hydrolysis reactions from density functional theory calculations}, journal = {Journal of Physical Chemistry C}, year = {2011}, volume = {115}, number = {14}, pages = {6910 – 6921}, doi = {10.1021/jp112076r} }
Boudon V, Gabard T, Pirali O, Roy P, Brubach J-B, Manceron L, Vander Auwera J, Coustenis A and Lellouch E (2011), "The far infrared spectrum of methane in the Titan's atmosphere; [Le spectre infrarouge lointain du méthane dans l'atmosphère de Titan]", Actualite Chimique. (356-357), pp. 97 – 99. [Abstract] [BibTeX]
Abstract: The far infrared spectrum of methane is observed in emission in the stratosphere of Titan, Saturn's main satellite, allowing to determine its concentration in this environment. However this spectrum, which has a very low intensity because it is induced by the centrifugal distortion of the molecule only, was poorly characterized up to now. For the first time, it has been recorded, in absorption and at high resolution, at the AILES beamline of the SOLEIL synchrotron. Measurements have been performed for both pure methane and methanenitrogen mixtures. The intensities of methane lines and coefficients characterizing the broadening of these lines induced by collisions with nitrogen have been accurately determined. These new spectroscopic data, essential to analyze measurements in planetology, will most probably improve our understanding of physicochemical processes in planetary atmospheres where methane is often present.
BibTeX: @article{Boudon2011, author = {Boudon, Vincent and Gabard, Tony and Pirali, Olivier and Roy, Pascale and Brubach, Jean-Blaise and Manceron, Laurent and Vander Auwera, Jean and Coustenis, Athena and Lellouch, Emmanuel}, title = {The far infrared spectrum of methane in the Titan's atmosphere; [Le spectre infrarouge lointain du méthane dans l'atmosphère de Titan]}, journal = {Actualite Chimique}, year = {2011}, number = {356-357}, pages = {97 – 99} }
Carette T and Godefroid M (2011), "Ab initio calculations of the 33S 3p4 3PJ and 33S-/37, 35Cl 3p5 2PoJ hyperfine structures", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 44(10) [Abstract] [BibTeX] [DOI]
Abstract: We present highly correlated multi-configuration Hartree-Fock (MCHF) calculations of the hyperfine structure of the 3p5 2P oJ levels of 33S- and 35, 37Cl. We obtain good agreement with observation. The hyperfine structure of the neutral sulphur 33S 3p4 3PJ lowest multiplet that has never been measured to the knowledge of the authors is also estimated theoretically. We discuss some interesting observations made on the description of the atomic core in MCHF theory. © 2011 IOP Publishing Ltd.
BibTeX: @article{Carette2011a, author = {Carette, T. and Godefroid, M.R.}, title = {Ab initio calculations of the 33S 3p4 3PJ and 33S-/37, 35Cl 3p5 2PoJ hyperfine structures}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2011}, volume = {44}, number = {10}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/44/10/105001} }
Carette T and Godefroid M (2011), "Theoretical study of the C- 4S3/2o and 2D3/2,5/2o bound states and C ground configuration: Fine and hyperfine structures, isotope shifts, and transition probabilities", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 83(6) [Abstract] [BibTeX] [DOI]
Abstract: This work is an ab initio study of the 2p34S3/2o, and 2D3/2,5/2o states of C- and 2p23P0,1,2, 1D2, and 1S0 states of neutral carbon. We use the multiconfiguration Hartree-Fock approach, focusing on the accuracy of the wave function itself. We obtain all C - detachment thresholds, including correlation effects to about 0.5%. Isotope shifts and hyperfine structures are calculated. The achieved accuracy of the latter is of the order of 0.1 MHz. Intraconfiguration transition probabilities are also estimated. © 2011 American Physical Society.
BibTeX: @article{Carette2011, author = {Carette, T. and Godefroid, M.R.}, title = {Theoretical study of the C- 4S3/2o and 2D3/2,5/2o bound states and C ground configuration: Fine and hyperfine structures, isotope shifts, and transition probabilities}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2011}, volume = {83}, number = {6}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.83.062505} }
Cauët E (2011), "Quantum mechanical methods related to ionization of nucleic acid bases", DNA Microarrays, Synthesis and Synthetic DNA. , pp. 255 – 284. [Abstract] [BibTeX]
Abstract: Ab initio quantum mechanical methods provide microscopic insights into DNA characteristics and are, today, essential to the full interpretation and understanding of results obtained by experimental techniques. In this chapter we summarize the contributions of modern quantum chemicalcalculations to the determination of the electronic properties of DNA bases, isolated or embedded in base clusters. In particular, the calculations discussed concern the characterization of the molecular energy levels and potential energy surfaces, which shed light on ionization and charge migration along DNA molecules. We mainly consider the estimation of key parameters, such as ionization potentials (IPs) of DNA bases, which govern the charge injection into DNA. The effects of the stacking and H-bonding DNA base interactions and the solvation of DNA on these quantities are described. We also discuss the mechanisms of charge migration over stacked DNA bases. These aspects are illustrated by a survey of the literature and by our own selected recent results. © 2012 by Nova Science Publishers, Inc. All rights reserved.
BibTeX: @book{Cauet2011, author = {Cauët, Emilie}, title = {Quantum mechanical methods related to ionization of nucleic acid bases}, journal = {DNA Microarrays, Synthesis and Synthetic DNA}, year = {2011}, pages = {255 – 284} }
Cauët E (2011), "Unique hole-trapping property of the human telomere sequence", Journal of Biomolecular Structure and Dynamics. Vol. 29(3), pp. 557 – 561. [Abstract] [BibTeX] [DOI]
Abstract: The hypothetical protection of genes from oxidative damage provided by the G-rich telomeric overhangs located at the end of chromosomes, which consist, in humans, of single strands of TTAGGG sequence repeats, is investigated here. First principle Møller-Plesset perturbation theory calculations reveal that the TTAGGG human telomere sequence is particularly prone to oxidation and can act as a profound hole trap as deep as a sequence of five consecutive guanines. In addition, we show that the sequence dependence is very important and that modifications in the human telomeric sequence can induce crucial changes in the electronic structure of the sequence, with concomitant increase of the ionization energy. These theoretical results provide, for the first time, quantitative data indicating a high and unique efficiency of the human telomeric sequence as a trap in long-range hole migration which will aid in the design of subsequent experiments. © 2011 Taylor & Francis Group, LLC.
BibTeX: @article{Cauet2011a, author = {Cauët, Emilie}, title = {Unique hole-trapping property of the human telomere sequence}, journal = {Journal of Biomolecular Structure and Dynamics}, year = {2011}, volume = {29}, number = {3}, pages = {557 – 561}, doi = {10.1080/07391102.2011.10507405} }
Clarisse L, Coheur P-F, Chefdeville S, Lacour J-L, Hurtmans D and Clerbaux C (2011), "Infrared satellite observations of hydrogen sulfide in the volcanic plume of the August 2008 Kasatochi eruption", Geophysical Research Letters. Vol. 38(10) [Abstract] [BibTeX] [DOI]
Abstract: Hydrogen sulphide (H2S) is one of the main trace gases released from volcanoes with yearly global emissions estimated between 1 and 37 Tg. With sulfur dioxide (SO2, 15-21 Tg/year), it dominates the volcanic sulfur budget, and the emission ratio H2S:SO2 is an important geochemical probe for studying source conditions, sulfur chemistry and magma-water interactions. Contrary to SO2, measurements of H 2S are sparse and difficult. Here we report the first measurements of a large H2S plume from space. Observations were made with the infrared sounder IASI of the volcanic plume released after the 7-8 August 2008 eruption of Kasatochi volcano. The eruption was characterized by 5 consecutive explosive events. The first events were phreatomagmatic producing a plume rich in water vapor and poor in ash and SO2. We show that the observed H2S plume, calculated at 29±10 kT with integrated columns exceeding 140±25 Dobson Units (DU), is likely associated with these first explosions. H2S:SO2 ratios with maximum values of 12±2 are found, representative of redox conditions in the hydrothermal envelop. With a detection threshold of 25 DU, future space observations of H2S plumes are certain. These will be important for improving the atmospheric sulfur budget and characterizing the H2S:SO2 fingerprint of different eruptions. Copyright 2011 by the American Geophysical Union.
BibTeX: @article{Clarisse2011b, author = {Clarisse, Lieven and Coheur, Pierre-Franois and Chefdeville, Simon and Lacour, Jean-Lionel and Hurtmans, Daniel and Clerbaux, Cathy}, title = {Infrared satellite observations of hydrogen sulfide in the volcanic plume of the August 2008 Kasatochi eruption}, journal = {Geophysical Research Letters}, year = {2011}, volume = {38}, number = {10}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2011GL047402} }
Clarisse L, Fromm M, Ngadi Y, Emmons L, Clerbaux C, Hurtmans D and Coheur P-F (2011), "Intercontinental transport of anthropogenic sulfur dioxide and other pollutants: An infrared remote sensing case study", Geophysical Research Letters. Vol. 38(19) [Abstract] [BibTeX] [DOI]
Abstract: Using 3 years worth of IASI (the Infrared Atmospheric Sounder Interferometer aboard METOP-A) measurements, we have identified 24 major events of uplift and transport of anthropogenic sulfur dioxide. These were all first observed over East Asia, and could be traced for over 60 hours. On 7 November 2010 a sulfur dioxide plume was observed over Northeast China and tracked for five days to North America. We discuss this event in detail with respect to build up; uplift and in-plume chemistry. We found a host of trace gas enhancements in the plume (SO2, CO, PAN, CH3OH, HCOOH and C2H2). A reasonable to very good agreement was found with MOZART-4 modeled ambient columns for all species except methanol, which was underestimated by the model by an order of magnitude. We calculate correlations of the different species and give observational evidence of secondary in-plume formation of methanol and PAN. Copyright 2011 by the American Geophysical Union.
BibTeX: @article{Clarisse2011a, author = {Clarisse, Lieven and Fromm, Michael and Ngadi, Yasmine and Emmons, Louisa and Clerbaux, Cathy and Hurtmans, Daniel and Coheur, Pierre-Franois}, title = {Intercontinental transport of anthropogenic sulfur dioxide and other pollutants: An infrared remote sensing case study}, journal = {Geophysical Research Letters}, year = {2011}, volume = {38}, number = {19}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1029/2011GL048976} }
Clarisse L, R'Honi Y, Coheur P-F, Hurtmans D and Clerbaux C (2011), "Thermal infrared nadir observations of 24 atmospheric gases", Geophysical Research Letters. Vol. 38(10) [Abstract] [BibTeX] [DOI]
Abstract: [1] Thermal infrared nadir sounders are ideal for observing total columns or vertical profiles of atmospheric gases such as water, carbon dioxide and ozone. High resolution sounders with a spectral resolution below 5 cm -1 can distinguish fine spectral features of trace gases. Forty years after the launch of the first hyperspectral sounder IRIS, we have now several state of the art instruments in orbit, with improved instrumental specifications. In this letter we give an overview of the trace gases which have been observed by infrared nadir sounders, focusing on new observations of the Infrared Atmospheric Sounding Interferometer (IASI). We present typical observations of 14 rare reactive trace gas species. Several species are reported here for the first time in nadir view, including nitrous acid, furan, acetylene, propylene, acetic acid, formaldehyde and hydrogen cyanide, observations which were made in a pyrocumulus cloud from the Australian bush fires of February 2009. Being able to observe this large number of reactive trace gases will likely improve our knowledge of source emissions and their impact on the environment and climate.
BibTeX: @article{Clarisse2011, author = {Clarisse, Lieven and R'Honi, Yasmina and Coheur, Pierre-François and Hurtmans, Daniel and Clerbaux, Cathy}, title = {Thermal infrared nadir observations of 24 atmospheric gases}, journal = {Geophysical Research Letters}, year = {2011}, volume = {38}, number = {10}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2011GL047271} }
Cooper M, Martin RV, Sauvage B, Boone CD, Walker KA, Bernath PF, McLinden CA, Degenstein DA, Volz-Thomas A and Wespes C (2011), "Evaluation of ACE-FTS and OSIRIS Satellite retrievals of ozone and nitric acid in the tropical upper troposphere: Application to ozone production efficiency", Journal of Geophysical Research Atmospheres. Vol. 116(12) [Abstract] [BibTeX] [DOI]
Abstract: We evaluate climatologies of upper tropospheric ozone and nitric acid retrieved from two satellite instruments (ACE-FTS and OSIRIS) with long-term in situ measurements from aircraft (MOZAIC, CR-AVE, PRE-AVE, PEM Tropics, and TC4) and ozonesondes. A global chemical transport model (GEOS-Chem) is used to guide the evaluation and to relate sparse in situ measurements with the satellite retrievals. Both satellite retrievals generally reproduce broad ozone features in the upper troposphere such as summer enhancements in the northern subtropics and larger concentrations over the tropical Atlantic versus the tropical Pacific. These comparisons indicate biases in annual, tropical mean ozone concentrations from both ACE-FTS (10-13%) and OSIRIS (5%) relative to aircraft and ozonesonde observations. More uncertain evidence suggests that nitric acid from ACE-FTS has a positive mean bias of 15%. We demonstrate that an upper limit on the ozone production efficiency in the upper troposphere can be determined using ACE-FTS satellite measurements of O3 and HNO3. The resulting value of 196 (+34, -61) mol/mol is in broad agreement with model simulations. Higher OPE values inferred from ACE-FTS over the tropical Pacific (249 (+21, -68) mol/mol) than the tropical Atlantic (146 (+16, -41) mol/mol) reflect increasing ozone production efficiency with decreasing pollution. This analysis indicates a new capability of satellite observations to provide insight into ozone production in the tropical troposphere. Copyright 2011 by the American Geophysical Union.
BibTeX: @article{Cooper2011, author = {Cooper, Matthew and Martin, Randall V. and Sauvage, Bastien and Boone, Chris D. and Walker, Kaley A. and Bernath, Peter F. and McLinden, Chris A. and Degenstein, Doug A. and Volz-Thomas, Andreas and Wespes, Catherine}, title = {Evaluation of ACE-FTS and OSIRIS Satellite retrievals of ozone and nitric acid in the tropical upper troposphere: Application to ozone production efficiency}, journal = {Journal of Geophysical Research Atmospheres}, year = {2011}, volume = {116}, number = {12}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2010JD015056} }
Dacre H, Grant A, Hogan R, Belcher S, Thomson D, Devenish B, Marenco F, Hort M, Haywood J, Ansmann A, Mattis I and Clarisse L (2011), "Evaluating the structure and magnitude of the ash plume during the initial phase of the 2010 Eyjafjallajökull eruption using lidar observations and NAME simulations", Journal of Geophysical Research Atmospheres. Vol. 116(14) [Abstract] [BibTeX] [DOI]
Abstract: The Eyjafjallajökull volcano in Iceland erupted explosively on 14 April 2010, emitting a plume of ash into the atmosphere. The ash was transported from Iceland toward Europe where mostly cloud-free skies allowed ground-based lidars at Chilbolton in England and Leipzig in Germany to estimate the mass concentration in the ash cloud as it passed overhead. The UK Met Office's Numerical Atmospheric-dispersion Modeling Environment (NAME) has been used to simulate the evolution of the ash cloud from the Eyjafjallajökull volcano during the initial phase of the ash emissions, 14-16 April 2010. NAME captures the timing and sloped structure of the ash layer observed over Leipzig, close to the central axis of the ash cloud. Relatively small errors in the ash cloud position, probably caused by the cumulative effect of errors in the driving meteorology en route, result in a timing error at distances far from the central axis of the ash cloud. Taking the timing error into account, NAME is able to capture the sloped ash layer over the UK. Comparison of the lidar observations and NAME simulations has allowed an estimation of the plume height time series to be made. It is necessary to include in the model input the large variations in plume height in order to accurately predict the ash cloud structure at long range. Quantitative comparison with the mass concentrations at Leipzig and Chilbolton suggest that around 3% of the total emitted mass is transported as far as these sites by small (<100 μm diameter) ash particles. Copyright 2011 by the American Geophysical Union.
BibTeX: @article{Dacre2011, author = {Dacre, H.F. and Grant, A.L.M. and Hogan, R.J. and Belcher, S.E. and Thomson, D.J. and Devenish, B.J. and Marenco, F. and Hort, M.C. and Haywood, J.M. and Ansmann, A. and Mattis, I. and Clarisse, L.}, title = {Evaluating the structure and magnitude of the ash plume during the initial phase of the 2010 Eyjafjallajökull eruption using lidar observations and NAME simulations}, journal = {Journal of Geophysical Research Atmospheres}, year = {2011}, volume = {116}, number = {14}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2011JD015608} }
De Ghellinck D'Elseghem Vaernewijck X, Kassi S and Herman M (2011), "17O12C17O and 18O 12C17O overtone spectroscopy in the 1.64 μm region", Chemical Physics Letters. Vol. 514(1-3), pp. 29 – 31. [Abstract] [BibTeX] [DOI]
Abstract: Near infrared spectra of a carbon dioxide sample enriched with oxygen-17 have been recorded using a high resolution continuous scan Fourier transform interferometer fitted with a femto OPO laser source. Cavity enhanced absorption has been achieved in a static gas cell allowing for an optimal rms noise equivalent absorption of 4.4 × 10-9 cm-1 Hz -1/2 per spectral element to be reached, corresponding to αmin = 3 × 10-7 cm-1. The 3ν1 + ν3 and related hot bands in 12C17O2 and the 3ν1 + ν3 R-branch in 12C17O18O have been identified and rotationally analyzed. © 2011 Elsevier B.V. All rights reserved.
BibTeX: @article{DeGhellinckDElseghemVaernewijck2011, author = {De Ghellinck D'Elseghem Vaernewijck, X. and Kassi, S. and Herman, M.}, title = {17O12C17O and 18O 12C17O overtone spectroscopy in the 1.64 μm region}, journal = {Chemical Physics Letters}, year = {2011}, volume = {514}, number = {1-3}, pages = {29 – 31}, doi = {10.1016/j.cplett.2011.08.025} }
Didriche K, Lauzin C, Földes T, Golebiowski D, Herman M and Leforestier C (2011), "High resolution overtone spectroscopy of the acetylene van der Waals dimer, (12C2H2)2", Physical Chemistry Chemical Physics. Vol. 13(31), pp. 14010 – 14018. [Abstract] [BibTeX] [DOI]
Abstract: CW-cavity ring down spectroscopy was used to record in a free jet expansion the spectrum of the absorption band in (12C2H 2)2 with origin at 6547.6 cm-1. It is a perpendicular band and corresponds to 2CH excitation in the hat unit of the T-shaped dimer. Calibration (better than ±1 × 10-3 cm-1 accuracy) and ring-down time (130 μs) were improved compared to a previous contribution (Didriche et al. Mol. Phys., 2010, 108, 2158-2164). A line-by-line analysis was achieved. Three series of lines were identified involving levels with A1+, E+ and B 1+ ground state tunneling symmetries, confirming the spectral and symmetry analyses reported in the literature for the 1CH excitation band (Fraser et al. J. Chem. Phys., 1988, 89, 6028-6045). 164 vibration-rotation-tunneling lines were assigned in the K′a- K″a= 2-3,0-1,2-1 and 4-3 sub-bands and effective rigid rotor vibration-rotation constants were obtained by simultaneously fitting 1CH and 2CH lines with the same symmetry series. Perturbations affecting the Ka stacks, in particular, are reported. The tunneling frequency in 2CH is estimated to be ν2CHtunn = 270 MHz for the Ka = 0 stack. The rotational temperature is determined to be 23 K from relative line intensities and the lifetime of the dimer in the 2CH hat state is estimated to be 1 ns from individual line widths. © the Owner Societies 2011.
BibTeX: @article{Didriche2011, author = {Didriche, K. and Lauzin, C. and Földes, T. and Golebiowski, D. and Herman, M. and Leforestier, C.}, title = {High resolution overtone spectroscopy of the acetylene van der Waals dimer, (12C2H2)2}, journal = {Physical Chemistry Chemical Physics}, year = {2011}, volume = {13}, number = {31}, pages = {14010 – 14018}, doi = {10.1039/c1cp20561g} }
Fortems-Cheiney A, Chevallier F, Pison I, Bousquet P, Szopa S, Deeter M and Clerbaux C (2011), "Ten years of CO emissions as seen from Measurements of Pollution in the Troposphere (MOPITT)", Journal of Geophysical Research Atmospheres. Vol. 116(5) [Abstract] [BibTeX] [DOI]
Abstract: The Measurements of Pollution in the Troposphere (MOPITT) retrievals are used as top-down constraints in an inversion for global CO emissions, for the past 10 years (from March 2000 to December 2009), at 8 day and 3.75° × 2.75° (longitude, latitude) resolution. The method updates a standard prior inventory and yields large increments in terms of annual regional budgets and seasonality. Our validation strategy consists in comparing our posterior-modeled concentrations with several sets of independent measurements: surface measurements, aircraft, and satellite. The posterior emissions, with a global 10 year average of 1430 TgCO/yr, are 37% higher than the prior ones, built from the EDGAR 3.2 and the GFEDv2 inventories (1038 TgCO/yr on average). In addition, they present some significant seasonal variations in the Northern Hemisphere that are not present in our prior nor in others' major inventories. Our results also exhibit some large interannual variability due to biomass burning emissions, climate, and socioeconomic factors; CO emissions range from 1504 TgCO (in 2007) to 1318 TgCO (in 2009). Copyright 2011 by the American Geophysical Union.
BibTeX: @article{FortemsCheiney2011, author = {Fortems-Cheiney, A. and Chevallier, F. and Pison, I. and Bousquet, P. and Szopa, S. and Deeter, M.N. and Clerbaux, C.}, title = {Ten years of CO emissions as seen from Measurements of Pollution in the Troposphere (MOPITT)}, journal = {Journal of Geophysical Research Atmospheres}, year = {2011}, volume = {116}, number = {5}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1029/2010JD014416} }
Franco B, Fettweis X, Erpicum M and Nicolay S (2011), "Present and future climates of the Greenland ice sheet according to the IPCC AR4 models", Climate Dynamics. Vol. 36(9-10), pp. 1897 – 1918. [Abstract] [BibTeX] [DOI]
Abstract: The atmosphere-ocean general circulation models (AOGCMs) used for the IPCC 4th Assessment Report (IPCC AR4) are evaluated for the Greenland ice sheet (GrIS) current climate modelling. The most suited AOGCMs for Greenland climate simulation are then selected on the basis of comparison between the 1970-1999 outputs of the Climate of the twentieth Century experiment (20C3M) and reanalyses (ECMWF, NCEP/NCAR). This comparison indicates that the representation quality of surface parameters such as temperature and precipitation are highly correlated to the atmospheric circulation (500 hPa geopotential height) and its interannual variability (North Atlantic oscillation). The outputs of the three most suitable AOGCMs for present-day climate simulation are then used to assess the changes estimated by three IPCC greenhouse gas emissions scenarios (SRES) over the GrIS for the 2070-2099 period. Future atmospheric circulation changes are projected to dampen the zonal flow, enhance the meridional fluxes and therefore provide additional heat and moisture to the GrIS, increasing temperature over the whole ice sheet and precipitation over its northeastern area. We also show that the GrIS surface mass balance anomalies from the SRES A1B scenario amount to -300 km3/year with respect to the 1970-1999 period, leading to a global sea-level rise of 5 cm by the end of the 21st century. This work can help to select the boundaries conditions for AOGCMs-based downscaled future projections. © 2010 Springer-Verlag.
BibTeX: @article{Franco2011, author = {Franco, Bruno and Fettweis, Xavier and Erpicum, Michel and Nicolay, Samuel}, title = {Present and future climates of the Greenland ice sheet according to the IPCC AR4 models}, journal = {Climate Dynamics}, year = {2011}, volume = {36}, number = {9-10}, pages = {1897 – 1918}, doi = {10.1007/s00382-010-0779-1} }
Gaidamauskas E, Nazé C, Rynkun P, Gaigalas G, Jönsson P and Godefroid M (2011), "Tensorial form and matrix elements of the relativistic nuclear recoil operator", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 44(17) [Abstract] [BibTeX] [DOI]
Abstract: Within the lowest-order relativistic approximation (∼v 2/c2) and to first order in me/M, the tensorial form of the relativistic corrections of the nuclear recoil Hamiltonian is derived, opening interesting perspectives for calculating isotope shifts in the multiconfiguration Dirac-Hartree-Fock framework. Their calculation is illustrated for selected Li-, B- and C-like ions. This work underlines the fact that the relativistic corrections to the nuclear recoil are definitively necessary for obtaining reliable isotope shift values. © 2011 IOP Publishing Ltd.
BibTeX: @article{Gaidamauskas2011, author = {Gaidamauskas, E. and Nazé, C. and Rynkun, P. and Gaigalas, G. and Jönsson, P. and Godefroid, M.}, title = {Tensorial form and matrix elements of the relativistic nuclear recoil operator}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2011}, volume = {44}, number = {17}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/44/17/175003} }
Jacquinet-Husson N, Crepeau L, Armante R, Boutammine C, Chédin A, Scott N, Crevoisier C, Capelle V, Boone C, Poulet-Crovisier N, Barbe A, Campargue A, Chris Benner D, Benilan Y, Bézard B, Boudon V, Brown L, Coudert L, Coustenis A, Dana V, Devi V, Fally S, Fayt A, Flaud J-M, Goldman A, Herman M, Harris G, Jacquemart D, Jolly A, Kleiner I, Kleinböhl A, Kwabia-Tchana F, Lavrentieva N, Lacome N, Xu L-H, Lyulin O, Mandin J-Y, Maki A, Mikhailenko S, Miller C, Mishina T, Moazzen-Ahmadi N, Müller H, Nikitin A, Orphal J, Perevalov V, Perrin A, Petkie D, Predoi-Cross A, Rinsland C, Remedios J, Rotger M, Smith M, Sung K, Tashkun S, Tennyson J, Toth R, Vandaele A-C and Vander Auwera J (2011), "The 2009 edition of the GEISA spectroscopic database", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 112(15), pp. 2395 – 2445. [Abstract] [BibTeX] [DOI]
Abstract: The updated 2009 edition of the spectroscopic database GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques; Management and Study of Atmospheric Spectroscopic Information) is described in this paper. GEISA is a computer-accessible system comprising three independent sub-databases devoted, respectively, to: line parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols. In this edition, 50 molecules are involved in the line parameters sub-database, including 111 isotopologues, for a total of 3,807,997 entries, in the spectral range from 10-6 to 35,877.031cm-1.The successful performances of the new generation of hyperspectral sounders depend ultimately on the accuracy to which the spectroscopic parameters of the optically active atmospheric gases are known, since they constitute an essential input to the forward radiative transfer models that are used to interpret their observations. Currently, GEISA is involved in activities related to the assessment of the capabilities of IASI (Infrared Atmospheric Sounding Interferometer; http://smsc.cnes.fr/IASI/index.htm) on board the METOP European satellite through the GEISA/IASI database derived from GEISA. Since the Metop-A (http://www.eumetsat.int) launch (19 October 2006), GEISA is the reference spectroscopic database for the validation of the level-1 IASI data. Also, GEISA is involved in planetary research, i.e., modeling of Titan's atmosphere, in the comparison with observations performed by Voyager, or by ground-based telescopes, and by the instruments on board the Cassini-Huygens mission.GEISA, continuously developed and maintained at LMD (Laboratoire de Météorologie Dynamique, France) since 1976, is implemented on the IPSL/CNRS (France) "Ether" Products and Services Centre WEB site (http://ether.ipsl.jussieu.fr), where all archived spectroscopic data can be handled through general and user friendly associated management software facilities. More than 350 researchers are registered for on line use of GEISA. © 2011 Elsevier Ltd.
BibTeX: @article{JacquinetHusson2011, author = {Jacquinet-Husson, N. and Crepeau, L. and Armante, R. and Boutammine, C. and Chédin, A. and Scott, N.A. and Crevoisier, C. and Capelle, V. and Boone, C. and Poulet-Crovisier, N. and Barbe, A. and Campargue, A. and Chris Benner, D. and Benilan, Y. and Bézard, B. and Boudon, V. and Brown, L.R. and Coudert, L.H. and Coustenis, A. and Dana, V. and Devi, V.M. and Fally, S. and Fayt, A. and Flaud, J.-M. and Goldman, A. and Herman, M. and Harris, G.J. and Jacquemart, D. and Jolly, A. and Kleiner, I. and Kleinböhl, A. and Kwabia-Tchana, F. and Lavrentieva, N. and Lacome, N. and Xu, Li-Hong and Lyulin, O.M. and Mandin, J.-Y. and Maki, A. and Mikhailenko, S. and Miller, C.E. and Mishina, T. and Moazzen-Ahmadi, N. and Müller, H.S.P. and Nikitin, A. and Orphal, J. and Perevalov, V. and Perrin, A. and Petkie, D.T. and Predoi-Cross, A. and Rinsland, C.P. and Remedios, J.J. and Rotger, M. and Smith, M.A.H. and Sung, K. and Tashkun, S. and Tennyson, J. and Toth, R.A. and Vandaele, A.-C. and Vander Auwera, J.}, title = {The 2009 edition of the GEISA spectroscopic database}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2011}, volume = {112}, number = {15}, pages = {2395 – 2445}, doi = {10.1016/j.jqsrt.2011.06.004} }
Lattanzi F, Di Lauro C and Auwera JV (2011), "Extended analysis of the high resolution spectrum of C 2H 6 near 7μm: The v 6, v 8, v 4+ v 12, 2v 4+v 9 vibrational system, and associated hot transitions", Molecular Physics. Vol. 109(17-18), pp. 2219 – 2235. [Abstract] [BibTeX] [DOI]
Abstract: The room temperature high resolution infrared spectrum of C 2H 6 between 1330 and 1610cm -1, the region of the 6 and 8 fundamentals, has been re-investigated owing to the relevance of this spectral region in atmospheric and planetary applied research. The assignments of transitions from the ground vibrational state to the upper states v 6, v 8, v 4+v 12 and 2v 4+v 9 (4592 in total) and from the lower state v 4 to the upper state v 4+v 8 (1090 lines) have been considerably extended with respect to our previous work [F. Lattanzi, C. di Lauro and J. Vander Auwera, J. Mol. Spectrosc. 248 (2008) 134-145], especially for the hot transitions. In particular, three new series of perturbation activated transitions were found, with ΔK=±2, made observable by the resonance of the type l(Δl=±2, ΔK=±1) within v 8. Also, new P-transitions to v 6 were found, made observable by the x,y-Coriolis resonance with v 8, at the values of K from 15 to 18. The extension of the assignments in the high frequency wing of v 8 and their analysis allowed the discovery of two additional resonance interactions. The first interaction, a higher order Coriolis-type between v 8(±K, l=±1) and v 6(K±2, l=0), induces a few detectable transitions to v 6 with ΔK=3. The second interaction, of the type l(Δl=±2, ΔK=±1), comes to resonance between v 8(k=19, ±l=±1) and 2v 4+v 9 (k=±20, l=±1). This last resonance and the x,y-Coriolis resonance of v 6 and 2v 4+v 9 allows one to observe several transitions to the 2v 4+v 9 vibrational state. The extension of the assignments in the (v 4+v 8)-v 4 hot band allowed discovery of a resonance interaction of the type l(Δl=±2, ΔK=±1) between the states v 4+v 8 and 2v 4+v 12, in addition to their well known Fermi-type interaction. The K-values before and after the level crossing could be determined for both interactions. Better values were also determined for the J-structure parameters B, D J and D JK in the v 4 state, from 410 selected combination differences. Least squares fit calculations, performed on 2084 upper state energy levels for the cold system (RMS of 3.69×10 -3cm -1) and 500 for the hot system (RMS of 6.62×10 -3cm -1), required a more sophisticated Hamiltonian model than in our previous work. Copyright © 2011 Taylor and Francis Group, LLC.
BibTeX: @article{Lattanzi2011, author = {Lattanzi, F. and Di Lauro, C. and Auwera, J. Vander}, title = {Extended analysis of the high resolution spectrum of C 2H 6 near 7μm: The v 6, v 8, v 4+ v 12, 2v 4+v 9 vibrational system, and associated hot transitions}, journal = {Molecular Physics}, year = {2011}, volume = {109}, number = {17-18}, pages = {2219 – 2235}, doi = {10.1080/00268976.2011.604353} }
Lattanzi F, Di Lauro C and Vander Auwera J (2011), "Toward the understanding of the high resolution infrared spectrum of C 2H6 near 3.3 μm", Journal of Molecular Spectroscopy. Vol. 267(1-2), pp. 71 – 79. [Abstract] [BibTeX] [DOI]
Abstract: The Fourier transform infrared spectrum of ethane between 2860 and 3060 cm-1 has been re-investigated under high resolution at 229 K. The infrared absorption in this region is due mainly to the CH stretching fundamentals ν5 (parallel band) and ν7 (degenerate perpendicular band), and to the parallel combination system ν8 + ν11 (A4s, A3s). All the relevant perturbation mechanisms affecting the observed absorption patterns have been clarified. In particular, the main perturbers of the ν7 state are identified to be the degenerate vibrational combination states ν8 + ν11 (l-type interaction) and ν3 + 2ν4 + ν8 (Fermi-type interaction). Because of the last interaction, the K″ΔK = -6 transitions occur with intensities comparable to both the infrared active fundamental ν7 and the almost dark combination ν3 + 2ν4 + ν8. The parallel combination system ν8 + ν11 (A 4s, A3s) is overlapped and heavily perturbed by the nearby parallel system ν4 + ν11 + ν12 (A4s, A3s), whose K-structure is spread by the strong z-Coriolis interaction of its two vibrational components. In this work, 95 new transitions to the perturbers of ν7 have been assigned. They belong mostly to the degenerate vibrational states ν8 + ν11 (E1d) and ν3 + 2ν4 + ν8 (E1d), and to the parallel system ν8 + ν11 (A4s, A3s). A least squares fit calculation, limited to the ν7 degenerate fundamental and its degenerate perturbers ν8 + ν11, ν3 + 2ν4 + ν8, ν4 + ν11 + ν12, and ν3 + 3ν4 + ν12 was performed. From the results of this fit, we created a line-by-line database containing the molecular parameters for 4969 transitions in these five bands of 12C2H6. Finally, we identified the degenerate combination band ν2 + ν8 (62 observed transitions) to be the main perturber (x, y-Coriolis-type interaction) of the parallel fundamental ν5. © 2011 Elsevier Inc. All rights reserved.
BibTeX: @article{Lattanzi2011a, author = {Lattanzi, F. and Di Lauro, C. and Vander Auwera, J.}, title = {Toward the understanding of the high resolution infrared spectrum of C 2H6 near 3.3 μm}, journal = {Journal of Molecular Spectroscopy}, year = {2011}, volume = {267}, number = {1-2}, pages = {71 – 79}, doi = {10.1016/j.jms.2011.02.003} }
Lauzin C, Didriche K, Földes T and Herman M (2011), "Torsional excitation in the 2CH vibrational overtone of the C 2H 2-CO 2 and C 2H 2-N 2O van der Waals complexes", Molecular Physics. Vol. 109(17-18), pp. 2105 – 2109. [Abstract] [BibTeX] [DOI]
Abstract: Infrared spectra of the weakly-bound C 2H 2-CO 2 and C 2H 2-N 2O complexes in the region of the 2CH acetylene overtone band (∼1.52μm) were recorded using CW-cavity ring down spectroscopy in a continuous supersonic expansion. A new, c-type combination band is observed in each case. The rotational analysis of low J, K lines is performed and rotational constants are obtained. The band origins are 40.491(2) and 40.778(2) cm -1 higher in energy than the 2CH excitation bands for C 2H 2-CO 2 and C 2H 2-N 2O, respectively. The combination band is assigned in each case as involving intermolecular torsional excitation combined to 2CH. The values of the torsional vibrational frequency and of the x CH/torsion anharmonicity constant are briefly discussed. Copyright © 2011 Taylor and Francis Group, LLC.
BibTeX: @article{Lauzin2011, author = {Lauzin, C. and Didriche, K. and Földes, T. and Herman, M.}, title = {Torsional excitation in the 2CH vibrational overtone of the C 2H 2-CO 2 and C 2H 2-N 2O van der Waals complexes}, journal = {Molecular Physics}, year = {2011}, volume = {109}, number = {17-18}, pages = {2105 – 2109}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268976.2011.593572} }
Leforestier C, Tekin A, Jansen G and Herman M (2011), "First principles potential for the acetylene dimer and refinement by fitting to experiments", Journal of Chemical Physics. Vol. 135(23) [Abstract] [BibTeX] [DOI]
Abstract: We report the definition and refinement of a new first principles potential for the acetylene dimer. The ab initio calculations were performed with the DFT-SAPT combination of symmetry-adapted intermolecular perturbation method and density functional theory, and fitted to a model site-site functional form. Comparison of the calculated microwave spectrum with experimental data revealed that the barriers to isomerization were too low. This potential was refined by fitting the model parameters in order to reproduce the observed transitions, an excellent agreement within ∼1 MHz being achieved. © 2011 American Institute of Physics.
BibTeX: @article{Leforestier2011, author = {Leforestier, Claude and Tekin, Adem and Jansen, Georg and Herman, Michel}, title = {First principles potential for the acetylene dimer and refinement by fitting to experiments}, journal = {Journal of Chemical Physics}, year = {2011}, volume = {135}, number = {23}, doi = {10.1063/1.3668283} }
Liévin J, Demaison J, Herman M, Fayt A and Puzzarini C (2011), "Comparison of the experimental, semi-experimental and ab initio equilibrium structures of acetylene: Influence of relativisitic effects and of the diagonal Born-Oppenheimer corrections", Journal of Chemical Physics. Vol. 134(6) [Abstract] [BibTeX] [DOI]
Abstract: The equilibrium structure of acetylene (also named ethyne) has been reinvestigated to resolve the small discrepancies noted between different determinations. The size of the system as well as the large amount of available experimental data provides the quite unique opportunity to check the magnitude and relevance of various contributions to equilibrium structure as well as to verify the accuracy of experimental results. With respect to pure theoretical investigation, quantum-chemical calculations at the coupled-cluster level have been employed together with extrapolation to the basis set limit, consideration of higher excitations in the cluster operator, inclusion of core correlation effects as well as relativistic and diagonal Born-Oppenheimer corrections. In particular, it is found that the extrapolation to the complete basis set limit, the inclusion of higher excitations in the electronic-correlation treatment and the relativistic corrections are of the same order of magnitude. It also appears that a basis set as large as a core-valence quintuple-zeta set is required for accurately accounting for the inner-shell correlation contribution. From a pure experimental point of view, the equilibrium structure has been determined using very accurate rotational constants recently obtained by a global analysis (that is to say that all non-negligible interactions are explicitely included in the Hamiltonian matrix) of rovibrational spectra. Finally, a semi-experimental equilibrium structure (where the equilibrium rotational constants are obtained from the experimental ground state rotational constants and computed rovibrational corrections) has been obtained from the available experimental ground-state rotational constants for ten isotopic species corrected for computed vibrational corrections. Such a determination led to the revision of the ground-state rotational constants of two isotopologues, thus showing that structural determination is a good method to identify errors in experimental rotational constants. The three structures are found in a very good agreement, and our recommended values are rCC 120.2958(7) pm and rCH 106.164(1) pm. © 2011 American Institute of Physics.
BibTeX: @article{Lievin2011, author = {Liévin, J. and Demaison, J. and Herman, M. and Fayt, A. and Puzzarini, C.}, title = {Comparison of the experimental, semi-experimental and ab initio equilibrium structures of acetylene: Influence of relativisitic effects and of the diagonal Born-Oppenheimer corrections}, journal = {Journal of Chemical Physics}, year = {2011}, volume = {134}, number = {6}, doi = {10.1063/1.3553203} }
Loreau J, Lecointre J, Urbain X and Vaeck N (2011), "Rovibrational analysis of the XUV photodissociation of HeH+ ions", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 84(5) [Abstract] [BibTeX] [DOI]
Abstract: We investigate the dynamics of the photodissociation of the helium hydride ion HeH+ by XUV radiation with the aim to establish a detailed comparison with a recent experimental work carried out at the FLASH free electron laser using both vibrationally hot and cold ions. We determine the corresponding rovibrational distributions using a dissociative charge transfer setup and the same source conditions as in the FLASH experiment. Using a nonadiabatic time-dependent wave-packet method, we calculate the partial photodissociation cross sections for the n=1-3 coupled electronic states of HeH+. We find good agreement with the experiment for the cross section into the He + H+ dissociative channel. On the other hand, we show that the experimental observation of the importance of the electronic states with n>3 cannot be well explained theoretically, especially for cold (v=0) ions. We find a good agreement with the experiment on the relative contribution of the Σ and Π states to the cross section for the He + + H channel, but only a qualitative one for the He + H+ channel. We discuss the factors that could explain the remaining discrepancies between theory and experiment. © 2011 American Physical Society.
BibTeX: @article{Loreau2011, author = {Loreau, J. and Lecointre, J. and Urbain, X. and Vaeck, N.}, title = {Rovibrational analysis of the XUV photodissociation of HeH+ ions}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2011}, volume = {84}, number = {5}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.84.053412} }
Loreau J, Ryabchenko S, Dalgarno A and Vaeck N (2011), "Isotope effect in charge-transfer collisions of H with He+", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 84(5) [Abstract] [BibTeX] [DOI]
Abstract: We present a theoretical study of the isotope effect arising from the replacement of H by T in the charge-transfer collision H(n=2) + He +(1s) at low energy. Using a quasimolecular approach and a time-dependent wave-packet method, we compute the cross sections for the reaction including the effects of the nonadiabatic radial and rotational couplings. For H(2s) + He+(1s) collisions, we find a strong isotope effect at energies below 1 eV/amu for both singlet and triplet states. We find a much smaller isotopic dependence of the cross section for H(2p) + He +(1s) collisions in triplet states, and no isotope effect in singlet states. We explain the isotope effect on the basis of the potential energy curves and the nonadiabatic couplings, and we evaluate the importance of the isotope effect on the charge-transfer rate coefficients. © 2011 American Physical Society.
BibTeX: @article{Loreau2011a, author = {Loreau, J. and Ryabchenko, S. and Dalgarno, A. and Vaeck, N.}, title = {Isotope effect in charge-transfer collisions of H with He+}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2011}, volume = {84}, number = {5}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.84.052720} }
McRaven C, Cich M, Lopez G, Sears TJ, Hurtmans D and Mantz A (2011), "Frequency comb-referenced measurements of self- and nitrogen-broadening in the ν1 + ν3 band of acetylene", Journal of Molecular Spectroscopy. Vol. 266(1), pp. 43 – 51. [Abstract] [BibTeX] [DOI]
Abstract: We report measurements of self- and nitrogen-pressure broadening of the P(11) line in the ν1 + ν3 combination band of acetylene at 195 739.649 5135(80) GHz by absorption of radiation emitted by an extended cavity diode laser referenced to a femtosecond frequency comb. Broadening, shift and narrowing parameters were determined at 296 K. For the most appropriate, hard collision, model in units of cm-1/atm, we find 0.146317(27), 0.047271(104) and -0.0070819(22) for the acetylene self-broadening, narrowing and shift, and 0.081129(35), 0.022940(74) and -0.0088913(25) respectively, for the nitrogen-broadening parameters. The uncertainties are expressed as one standard deviation (in parenthesis) in units of the last digit reported. These parameters are 2-3 orders of magnitude more precise than those reported in previous measurements. Similar analyses of the experimental data using soft collision and simple Voigt lineshape models were made for comparison. © 2011 Elsevier Inc. All rights reserved.
BibTeX: @article{McRaven2011, author = {McRaven, C.P. and Cich, M.J. and Lopez, G.V. and Sears, Trevor J. and Hurtmans, Daniel and Mantz, A.W.}, title = {Frequency comb-referenced measurements of self- and nitrogen-broadening in the ν1 + ν3 band of acetylene}, journal = {Journal of Molecular Spectroscopy}, year = {2011}, volume = {266}, number = {1}, pages = {43 – 51}, doi = {10.1016/j.jms.2011.02.016} }
Moudens A, Georges R, Benidar A, Amyay B, Herman M, Fayt A and Plez B (2011), "Emission spectroscopy from optically thick laboratory acetylene samples at high temperature", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 112(3), pp. 540 – 549. [Abstract] [BibTeX] [DOI]
Abstract: Recently, a high temperature source has been used to produce high temperature emission spectra of acetylene in the 3 γm spectral range, under Doppler limited resolution, and the complete spectral assignment has been performed using a global rovibrational Hamiltonian [Amyay B, Robert S, Herman M, Fayt A, Raghavendra B, Moudens A et al. Vibration-rotation pattern in acetylene (II): Introduction to Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 γm. J Chem Phys 2009;131:114301]. The present investigation focuses on the relative emission line intensities which are observed to be affected. The strongest lines intensity may be considerably reduced for high column density acetylene samples, hence affecting the 3:1 ortho:para intensity ratio. A radiative model is developed to take into account the effects generated by the strong opacity of the acetylene samples including self-absorption and absorption of the radiation emitted by the hot environment. The model is used to extract the absolute concentration of the high temperature acetylene samples from the observed relative spectral intensities. The relevance of the procedure for infrared remote sensing in high temperature astrophysical environments, such as circumstellar envelopes of cool carbon rich evolved stars, is discussed. © 2010 Elsevier Ltd.
BibTeX: @article{Moudens2011, author = {Moudens, Audrey and Georges, Robert and Benidar, Abdessamad and Amyay, Badr and Herman, M. and Fayt, André and Plez, Bertrand}, title = {Emission spectroscopy from optically thick laboratory acetylene samples at high temperature}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2011}, volume = {112}, number = {3}, pages = {540 – 549}, doi = {10.1016/j.jqsrt.2010.10.012} }
Povey C, Predoi-Cross A and Hurtmans DR (2011), "Line shape study of acetylene transitions in the ν1 + ν2 + ν4 + ν5 band over a range of temperatures", Journal of Molecular Spectroscopy. Vol. 268(1-2), pp. 177 – 188. [Abstract] [BibTeX] [DOI]
Abstract: In this study we have retrieved the line intensities, self broadened widths, pressure-induced shifts and selected line mixing coefficients for 20 R-branch transitions in the ν1 + ν2 + ν4 + ν5 band of acetylene. The spectra were recorded using our 3-channels diode laser spectrometer, a temperature controlled cell of fixed length and a second, room temperature cell. The Voigt and speed-dependent Voigt profiles with inclusion of line mixing effects were used to retrieve the line parameters. We determined the temperature dependencies for line broadening, shift and line mixing coefficients. © 2011 Elsevier Inc. All rights reserved.
BibTeX: @article{Povey2011, author = {Povey, Chad and Predoi-Cross, Adriana and Hurtmans, Daniel R.}, title = {Line shape study of acetylene transitions in the ν1 + ν2 + ν4 + ν5 band over a range of temperatures}, journal = {Journal of Molecular Spectroscopy}, year = {2011}, volume = {268}, number = {1-2}, pages = {177 – 188}, doi = {10.1016/j.jms.2011.04.020} }
Predoi-Cross A, Herman M, Fusina L and Di Lonardo G (2011), "The far-infrared spectrum of 12C2HD", Molecular Physics. Vol. 109(4), pp. 559 – 563. [Abstract] [BibTeX] [DOI]
Abstract: The infrared spectrum of 12C2HD has been studied using synchrotron radiation at the far-infrared beam line, Canadian Light Source, Saskatoon, Canada. The spectra were recorded at a resolution of 0.00096 cm-1 in the 60 to 360 cm-1 range using a Bruker IFS 125 Fourier transform spectrometer. In total, 821 vibration rotation lines were observed and assigned to the P(J), Q(J) and R(J) transitions of the v 5←v4 difference band and associated hot bands with J up to 35 and (v4+v5) up to 3. These new transitions were analysed together with 4518 transitions involving bending states with (v I+v5) up to 3 available in the literature. The spectroscopic parameters obtained from the fit reproduce 4909 transitions with a standard deviation of 0.00028 cm-1. The v5←v 4 bands of 13CH12CD and 12CH 13CD were also detected and analysed. © 2011 Taylor & Francis.
BibTeX: @article{PredoiCross2011, author = {Predoi-Cross, A. and Herman, M. and Fusina, L. and Di Lonardo, G.}, title = {The far-infrared spectrum of 12C2HD}, journal = {Molecular Physics}, year = {2011}, volume = {109}, number = {4}, pages = {559 – 563}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268976.2010.536170} }
Razavi A, Karagulian F, Clarisse L, Hurtmans D, Coheur P, Clerbaux C, Müller J and Stavrakou T (2011), "Global distributions of methanol and formic acid retrieved for the first time from the IASI/MetOp thermal infrared sounder", Atmospheric Chemistry and Physics. Vol. 11(2), pp. 857 – 872. [Abstract] [BibTeX] [DOI]
Abstract: Methanol (CH3OH) and formic acid (HCOOH) are among the most abundant volatile organic compounds present in the atmosphere. In this work, we derive the global distributions of these two organic species using for the first time the Infrared Atmospheric Sounding Interferometer (IASI) launched onboard the MetOp-A satellite in 2006. This paper describes the method used and provides a first critical analysis of the retrieved products. The retrieval process follows a two-step approach in which global distributions are first obtained on the basis of a simple radiance indexing (transformed into brightness temperatures), and then mapped onto column abundances using suitable conversion factors. For methanol, the factors were calculated using a complete retrieval approach in selected regions. In the case of formic acid, a different approach, which uses a set of forward simulations for representative atmospheres, has been used. In both cases, the main error sources are carefully determined: the average relative error on the column for both species is estimated to be about 50%, increasing to about 100% for the least favorable conditions. The distributions for the year 2009 are discussed in terms of seasonality and source identification. Time series comparing methanol, formic acid and carbon monoxide in different regions are also presented. © 2011 Author(s).
BibTeX: @article{Razavi2011, author = {Razavi, A. and Karagulian, F. and Clarisse, L. and Hurtmans, D. and Coheur, P.F. and Clerbaux, C. and Müller, J.F. and Stavrakou, T.}, title = {Global distributions of methanol and formic acid retrieved for the first time from the IASI/MetOp thermal infrared sounder}, journal = {Atmospheric Chemistry and Physics}, year = {2011}, volume = {11}, number = {2}, pages = {857 – 872}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-11-857-2011} }
Rooman M, Cauët E, Liévin J and Wintjens R (2011), "Conformations consistent with charge migration observed in dna and rna x-ray structures", Journal of Biomolecular Structure and Dynamics. Vol. 28(6), pp. 949 – 954. [Abstract] [BibTeX] [DOI]
Abstract: Electron holes are known to migrate along the DNA or RNA duplexes and to localize preferentially on successive guanines. The stationary point conformations of Gua pairs that can trap or let pass these holes have been characterized by quantum chemistry calculations. Here we show their recurrent occurrence in DNA and RNA X-ray structures, often in quadruplex conformations or in interaction with proteins, ligands or metal ions. These findings give support to the biological, possibly regulatory, roles of charge migration in cell functioning. © 2011 Taylor & Francis Group, LLC.
BibTeX: @article{Rooman2011, author = {Rooman, Marianne and Cauët, Emilie and Liévin, Jacques and Wintjens, René}, title = {Conformations consistent with charge migration observed in dna and rna x-ray structures}, journal = {Journal of Biomolecular Structure and Dynamics}, year = {2011}, volume = {28}, number = {6}, pages = {949 – 954}, note = {All Open Access, Bronze Open Access}, doi = {10.1080/073911011010524985} }
Shephard M, Cady-Pereira K, Luo M, Henze D, Pinder R, Walker J, Rinsland C, Bash J, Zhu L, Payne V and Clarisse L (2011), "TES ammonia retrieval strategy and global observations of the spatial and seasonal variability of ammonia", Atmospheric Chemistry and Physics. Vol. 11(20), pp. 10743 – 10763. [Abstract] [BibTeX] [DOI]
Abstract: Presently only limited sets of tropospheric ammonia (NH3) measurements in the Earth's atmosphere have been reported from satellite and surface station measurements, despite the well-documented negative impact of NH3 on the environment and human health. Presented here is a detailed description of the satellite retrieval strategy and analysis for the Tropospheric Emission Spectrometer (TES) using simulations and measurements. These results show that: (i) the level of detectability for a representative boundary layer TES NH3 mixing ratio value is ∼0.4 ppbv, which typically corresponds to a profile that contains a maximum level value of ∼1 ppbv; (ii) TES NH3 retrievals generally provide at most one degree of freedom for signal (DOFS), with peak sensitivity between 700 and 900 mbar; (iii) TES NH3 retrievals show significant spatial and seasonal variability of NH3 globally; (iv) initial comparisons of TES observations with GEOS-CHEM estimates show TES values being higher overall. Important differences and similarities between modeled and observed seasonal and spatial trends are noted, with discrepancies indicating areas where the timing and magnitude of modeled NH3 emissions from agricultural sources, and to lesser extent biomass burning sources, need further study. © Author(s) 2011. CC Attribution 3.0 License.
BibTeX: @article{Shephard2011, author = {Shephard, M.W. and Cady-Pereira, K.E. and Luo, M. and Henze, D.K. and Pinder, R.W. and Walker, J.T. and Rinsland, C.P. and Bash, J.O. and Zhu, L. and Payne, V.H. and Clarisse, L.}, title = {TES ammonia retrieval strategy and global observations of the spatial and seasonal variability of ammonia}, journal = {Atmospheric Chemistry and Physics}, year = {2011}, volume = {11}, number = {20}, pages = {10743 – 10763}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-11-10743-2011} }
Sodemann H, Pommier M, Arnold S, Monks S, Stebel K, Burkhart J, Hair J, Diskin G, Clerbaux C, Coheur P-F, Hurtmans D, Schlager H, Blechschmidt A-M, Kristjánsson J and Stohl A (2011), "Episodes of cross-polar transport in the Arctic troposphere during July 2008 as seen from models, satellite, and aircraft observations", Atmospheric Chemistry and Physics. Vol. 11(8), pp. 3631 – 3651. [Abstract] [BibTeX] [DOI]
Abstract: During the POLARCAT summer campaign in 2008, two episodes (2g-5 July and 7g-10 July 2008) occurred where low-pressure systems traveled from Siberia across the Arctic Ocean towards the North Pole. The two cyclones had extensive smoke plumes from Siberian forest fires and anthropogenic sources in East Asia embedded in their associated air masses, creating an excellent opportunity to use satellite and aircraft observations to validate the performance of atmospheric transport models in the Arctic, which is a challenging model domain due to numerical and other complications. Here we compare transport simulations of carbon monoxide (CO) from the Lagrangian transport model FLEXPART and the Eulerian chemical transport model TOMCAT with retrievals of total column CO from the IASI passive infrared sensor onboard the MetOp-A satellite. The main aspect of the comparison is how realistic horizontal and vertical structures are represented in the model simulations. Analysis of CALIPSO lidar curtains and in situ aircraft measurements provide further independent reference points to assess how reliable the model simulations are and what the main limitations are. The horizontal structure of mid-latitude pollution plumes agrees well between the IASI total column CO and the model simulations. However, finer-scale structures are too quickly diffused in the Eulerian model. Applying the IASI averaging kernels to the model data is essential for a meaningful comparison. Using aircraft data as a reference suggests that the satellite data are biased high, while TOMCAT is biased low. FLEXPART fits the aircraft data rather well, but due to added background concentrations the simulation is not independent from observations. The multi-data, multi-model approach allows separating the influences of meteorological fields, model realisation, and grid type on the plume structure. In addition to the very good agreement between simulated and observed total column CO fields, the results also highlight the difficulty to identify a data set that most realistically represents the actual pollution state of the Arctic atmosphere. © 2011 Adis Data Information BV. All rights reserved.
BibTeX: @article{Sodemann2011, author = {Sodemann, H. and Pommier, M. and Arnold, S.R. and Monks, S.A. and Stebel, K. and Burkhart, J.F. and Hair, J.W. and Diskin, G.S. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Schlager, H. and Blechschmidt, A.-M. and Kristjánsson, J.E. and Stohl, A.}, title = {Episodes of cross-polar transport in the Arctic troposphere during July 2008 as seen from models, satellite, and aircraft observations}, journal = {Atmospheric Chemistry and Physics}, year = {2011}, volume = {11}, number = {8}, pages = {3631 – 3651}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-11-3631-2011} }
Softley TP, Boudon V, De Natale P, Fusina L, Herman M and Quack M (2011), "22nd Colloquium on High Resolution Molecular Spectroscopy: Special Issue dedicated to Gianfranco di Lonardo", Molecular Physics. Vol. 109(17-18), pp. 2069 – 2070. [BibTeX] [DOI]
BibTeX: @article{Softley2011, author = {Softley, Timothy P. and Boudon, Vincent and De Natale, Paolo and Fusina, Luciano and Herman, Michel and Quack, Martin}, title = {22nd Colloquium on High Resolution Molecular Spectroscopy: Special Issue dedicated to Gianfranco di Lonardo}, journal = {Molecular Physics}, year = {2011}, volume = {109}, number = {17-18}, pages = {2069 – 2070}, doi = {10.1080/00268976.2011.620772} }
Soorkia S, Shafizadeh N, Liévin J, Gaveau M-A, Pothier C, Mestdagh J-M, Soep B and Field RW (2011), "Determination of the ground electronic state in transition metal halides: ZrF", Journal of Physical Chemistry A. Vol. 115(34), pp. 9620 – 9632. [Abstract] [BibTeX] [DOI]
Abstract: The spectroscopy of the ZrF radical, produced by a laser ablation-molecular beam experimental setup, has been investigated for the first time using a two-color two-photon (1 + 1′) REMPI scheme and time-of-flight (TOF) mass spectrometry detection. The region of intense bands 400-470 nm has been studied, based upon the first spectroscopic observations of the isovalent ZrCl radical by Carroll and Daly.(1)The overall spectrum observed is complex. However, simultaneous and individual ion detection of the five naturally occurring isotopologues of ZrF has provided a crucial means of identifying band origins and characterization via the isotopic shift, δ iso, of the numerous vibronic transitions recorded. Hence, five (0-0) transitions, of which only two were free of overlap with other transitions, have been identified. The most intense (0-0) transition at 23113 cm -1 presented an unambiguously characteristic RQP rotational structure. From rotational contour simulations of the observed spectra, the nature of the ground electronic state is found to be unambiguously of 2Δ symmetry, leading to the assignment of this band as (0-0) 2Δ ← X 2Δ at 23113 cm -1. A set of transitions (1-0) 2Δ ← X 2Δ at 22105 cm -1 and (2-0) 2 ← X 2Δ at 22944 cm -1 involving the X 2Δ state has also been identified and analyzed. Furthermore, a second series of transitions with lesser intensity has also been related to the long-lived metastable 4Σ - state: (3-0) 4Π -1/2 ← 4Σ - at 21801 cm -1, (2-0) 4Π -1/2 ← 4Σ - at 21285 cm -1 and (2-0) 4Σ - ← 4Σ - at 23568 cm -1. These spectroscopic assignments are supported by MRCI ab initio calculations, performed using the MOLPRO quantum chemistry package, and show that the low-lying excited states of the ZrF radical are the 4Σ - and 4 states lying at 2383 and 4179 cm -1 respectively above the ground X 2Δ state. The difference in the nature of ground state and ordering of the first electronic states with TiF (X 4)(2-4)and ZrCl,(5)respectively, is examined in terms of the ligand field theory (LFT)(7)applied to diatomic molecules. These results give a precise description of the electronic structure of the low lying electronic states of the ZrF transition metal radical. © 2011 American Chemical Society.
BibTeX: @article{Soorkia2011, author = {Soorkia, Satchin and Shafizadeh, Niloufar and Liévin, Jacques and Gaveau, Marc-André and Pothier, Christophe and Mestdagh, Jean-Michel and Soep, Benoît and Field, Robert W.}, title = {Determination of the ground electronic state in transition metal halides: ZrF}, journal = {Journal of Physical Chemistry A}, year = {2011}, volume = {115}, number = {34}, pages = {9620 – 9632}, doi = {10.1021/jp2004997} }
Stavrakou T, Guenther A, Razavi A, Clarisse L, Clerbaux C, Coheur P-F, Hurtmans D, Karagulian F, De MaziÃ̈re M, Vigouroux C, Amelynck C, Schoon N, Laffineur Q, Heinesch B, Aubinet M, Rinsland C and Müller J-F (2011), "First space-based derivation of the global atmospheric methanol emission fluxes", Atmospheric Chemistry and Physics. Vol. 11(10), pp. 4873 – 4898. [Abstract] [BibTeX] [DOI]
Abstract: This study provides improved methanol emission estimates on the global scale, in particular for the largest methanol source, the terrestrial biosphere, and for biomass burning. To this purpose, one complete year of spaceborne measurements of tropospheric methanol columns retrieved for the first time by the thermal infrared sensor IASI aboard the MetOp satellite are compared with distributions calculated by the IMAGESv2 global chemistry-transport model. Two model simulations are performed using a priori biogenic methanol emissions either from the new MEGANv2.1 emission model, which is fully described in this work and is based on net ecosystem flux measurements, or from a previous parameterization based on net primary production by Jacob et al. (2005). A significantly better model performance in terms of both amplitude and seasonality is achieved through the use of MEGANv2.1 in most world regions, with respect to IASI data, and to surface- and air-based methanol measurements, even though important discrepancies over several regions are still present. As a second step of this study, we combine the MEGANv2.1 and the IASI column abundances over continents in an inverse modelling scheme based on the adjoint of the IMAGESv2 model to generate an improved global methanol emission source. The global optimized source totals 187 Tg yr−1 with a contribution of 100 Tg yr−1 from plants, only slightly lower than the a priori MEGANv2.1 value of 105 Tg yr−1. Large decreases with respect to the MEGANv2.1 biogenic source are inferred over Amazonia (up to 55 %) and Indonesia (up to 58 %), whereas more moderate reductions are recorded in the Eastern US (20-25 %) and Central Africa (25-35 %). On the other hand, the biogenic source is found to strongly increase in the arid and semi-arid regions of Central Asia (up to a factor of 5) and Western US (factor of 2), probably due to a source of methanol specific to these ecosystems which is unaccounted for in the MEGANv2.1 inventory. The most significant error reductions achieved by the optimization concern the derived biogenic emissions over the Amazon and over the Former Soviet Union. The robustness of the derived fluxes to changes in convective updraft fluxes, in methanol removal processes, and in the choice of the biogenic a priori inventory is assessed through sensitivity inversions. Detailed comparisons of the model with a number of aircraft and surface observations of methanol, as well as new methanol measurements in Europe and in the Reunion Island show that the satellite-derived methanol emissions improve significantly the agreement with the independent data, giving thus credence to the IASI dataset. © 2011 Author(s).
BibTeX: @article{Stavrakou2011, author = {Stavrakou, T. and Guenther, A. and Razavi, A. and Clarisse, L. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Karagulian, F. and De MaziÃ̈re, M. and Vigouroux, C. and Amelynck, C. and Schoon, N. and Laffineur, Q. and Heinesch, B. and Aubinet, M. and Rinsland, C. and Müller, J.-F.}, title = {First space-based derivation of the global atmospheric methanol emission fluxes}, journal = {Atmospheric Chemistry and Physics}, year = {2011}, volume = {11}, number = {10}, pages = {4873 – 4898}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-11-4873-2011} }
Stohl A, Prata A, Eckhardt S, Clarisse L, Durant A, Henne S, Kristiansen N, Minikin A, Schumann U, Seibert P, Stebel K, Thomas H, Thorsteinsson T, Tørseth K and Weinzierl B (2011), "Determination of time-and height-resolved volcanic ash emissions and their use for quantitative ash dispersion modeling: The 2010 Eyjafjallajökull eruption", Atmospheric Chemistry and Physics. Vol. 11(9), pp. 4333 – 4351. [Abstract] [BibTeX] [DOI]
Abstract: The Aprilg-May, 2010 volcanic eruptions of Eyjafjallajökull, Iceland caused significant economic and social disruption in Europe whilst state of the art measurements and ash dispersion forecasts were heavily criticized by the aviation industry. Here we demonstrate for the first time that large improvements can be made in quantitative predictions of the fate of volcanic ash emissions, by using an inversion scheme that couples a priori source information and the output of a Lagrangian dispersion model with satellite data to estimate the volcanic ash source strength as a function of altitude and time. From the inversion, we obtain a total fine ash emission of the eruption of 8.3 ± 4.2 Tg for particles in the size range of 2.8g-28 μm diameter. We evaluate the results of our model results with a posteriori ash emissions using independent ground-based, airborne and space-borne measurements both in case studies and statistically. Subsequently, we estimate the area over Europe affected by volcanic ash above certain concentration thresholds relevant for the aviation industry. We find that during three episodes in April and May, volcanic ash concentrations at some altitude in the atmosphere exceeded the limits for the "Normal" flying zone in up to 14 % (6g-16 %), 2 % (1g-3 %) and 7 % (4g-11 %), respectively, of the European area. For a limit of 2 mg mĝ̂'3 only two episodes with fractions of 1.5 % (0.2g-2.8 %) and 0.9 % (0.1g-1.6 %) occurred, while the current "No-Fly" zone criterion of 4 mg mg-3 was rarely exceeded. Our results have important ramifications for determining air space closures and for real-time quantitative estimations of ash concentrations. Furthermore, the general nature of our method yields better constraints on the distribution and fate of volcanic ash in the Earth system. © 2011 Author(s).
BibTeX: @article{Stohl2011, author = {Stohl, A. and Prata, A.J. and Eckhardt, S. and Clarisse, L. and Durant, A. and Henne, S. and Kristiansen, N.I. and Minikin, A. and Schumann, U. and Seibert, P. and Stebel, K. and Thomas, H.E. and Thorsteinsson, T. and Tørseth, K. and Weinzierl, B.}, title = {Determination of time-and height-resolved volcanic ash emissions and their use for quantitative ash dispersion modeling: The 2010 Eyjafjallajökull eruption}, journal = {Atmospheric Chemistry and Physics}, year = {2011}, volume = {11}, number = {9}, pages = {4333 – 4351}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-11-4333-2011} }
Sutcliffe BT (2011), "An analysis of the role of the Born--Oppenheimer approximation in calculating rotational--vibrational interactions in molecules", Theoretical Chemistry Accounts. Vol. 130(2-3), pp. 187 – 195. [Abstract] [BibTeX] [DOI]
Abstract: It is argued that whether the use of the Born--Oppenheimer approximation is thought to require consideration of the potential energy surface in the context of a full Coulomb Schrödinger Hamiltonian in which translational and rotational motions are explicitly considered, and then it is inconsistent to treat that surface without allowing for the rotational motion of the molecule. Some of the implications of this upon the calculation of partition functions are considered. © 2011 Springer-Verlag.
BibTeX: @article{Sutcliffe2011, author = {Sutcliffe, Brian T.}, title = {An analysis of the role of the Born--Oppenheimer approximation in calculating rotational--vibrational interactions in molecules}, journal = {Theoretical Chemistry Accounts}, year = {2011}, volume = {130}, number = {2-3}, pages = {187 – 195}, doi = {10.1007/s00214-011-0953-5} }
Sutcliffe BT and Woolley G (2011), "A comment on "Editorial 37"", Foundations of Chemistry. Vol. 13(2), pp. 93 – 95. [BibTeX] [DOI]
BibTeX: @article{Sutcliffe2011b, author = {Sutcliffe, Brian T. and Woolley, Guy}, title = {A comment on "Editorial 37"}, journal = {Foundations of Chemistry}, year = {2011}, volume = {13}, number = {2}, pages = {93 – 95}, doi = {10.1007/s10698-011-9110-4} }
Sutcliffe BT and Woolley RG (2011), "Atoms and Molecules in Classical Chemistry and Quantum Mechanics", Philosophy of Chemistry. , pp. 387 – 426. [Abstract] [BibTeX] [DOI]
Abstract: This chapter starts by giving a brief account of the development of the atomic–molecular conception of chemistry. An essential backdrop to the whole discussion is the importance throughout human history of the practical chemical arts that have informed the production of the whole range of useful materials and stimulated enquiry into the theoretical aspects of chemical processes. Chemistry is concerned with the composition and properties of matter, and with the transformations of matter that can occur spontaneously or under the action of heat, radiation or other sources of energy. From the results of chemical experiments the chemist singles out a particular class of materials that have characteristic and invariant properties. Such materials are called pure substances and may be of two kinds, viz: compounds and elements. Elements may be defined as substances which have not been converted either by the action of heat, radiation, or chemical reaction with other substances, or small electrical voltages, into any simpler substance. Compounds are formed from the chemical combination of the elements, and have properties that are invariably different from the properties of the constituent elements; they are also homogeneous. This characteristic chemical notion of a pure substance is based on an ideal conception of the chemical and physical properties of matter and their changes under specified experimental conditions. © 2012 Elsevier B.V. All rights reserved.
BibTeX: @book{Sutcliffe2011a, author = {Sutcliffe, Brian T. and Woolley, R. Guy}, title = {Atoms and Molecules in Classical Chemistry and Quantum Mechanics}, journal = {Philosophy of Chemistry}, year = {2011}, pages = {387 – 426}, doi = {10.1016/B978-0-444-51675-6.50028-1} }
Tandy J, Wang J-G, Liévin J and Bernath P (2011), "Investigating the electronic states of BaOH by V-type double resonance spectroscopy and ab initio calculations: Further evidence of perturbation from the Ã′2Δ state", Journal of Molecular Spectroscopy. Vol. 270(1), pp. 44 – 50. [Abstract] [BibTeX] [DOI]
Abstract: A single band belonging to the Ã′2Δ- X̃2Σ+ band system has been rotationally analyzed for each of the two isotopologues, BaOH and BaOD, using high-resolution V-type optical-optical double resonance spectroscopy. BaOH and BaOD molecules were synthesized in a Broida-type oven. High-resolution spectra were recorded by monitoring the dip in fluorescence of the B2Σ+- X2Σ+ transition excited by a single-mode ring dye laser (pump laser), whilst a single-mode Ti:Sapphire laser scanned the corresponding Ã′2Δ-X̃2 Σ+ transition. The observed spectra resemble a typical 2Π-2Σ transition, believed to emanate from single or triple quanta of the bending vibration in the Ã ′2Δ state. Measured rotational lines have been assigned and rotational and fine structure parameters determined through a combined least-squares fit with the millimeter-wave pure rotational data of the X 2Σ+ state. Previous analyses of the Ã2Π-X̃2Σ+ transitions of BaOH and BaOD yielded significantly different spin-orbit coupling constants, which were attributed to possible global and local perturbations arising from vibrationally-excited bands of the A′2Δ state. Although the newly observed A′2Δ state bands have not been conclusively assigned a specific spin state, the derived Ω-doubling constants show significant 2Π1/2 character, further indicating strong interactions between the A2Π and A ′2Δ states of BaOH. To validate these conclusions, ab initio calculations have been carried out to further understand the nature of the BaOH excited states. The D̃′2Σ+, D̃2Σ+, C̃2Π, B̃2Σ+, Ã2Π, Ã′2Δ and X̃2Σ+ states have been characterized by means of multireference configuration interaction calculations using the MOLPRO software. Calculated vertical term energies show relatively good agreement with existing optical data. © 2011 Elsevier Inc. All rights reserved.
BibTeX: @article{Tandy2011, author = {Tandy, J.D. and Wang, J.-G. and Liévin, J. and Bernath, P.F.}, title = {Investigating the electronic states of BaOH by V-type double resonance spectroscopy and ab initio calculations: Further evidence of perturbation from the Ã′2Δ state}, journal = {Journal of Molecular Spectroscopy}, year = {2011}, volume = {270}, number = {1}, pages = {44 – 50}, doi = {10.1016/j.jms.2011.08.009} }
Tereszchuk K, González Abad G, Clerbaux C, Hurtmans D, Coheur P-F and Bernath P (2011), "ACE-FTS measurements of trace species in the characterization of biomass burning plumes", Atmospheric Chemistry and Physics. Vol. 11(23), pp. 12169 – 12179. [Abstract] [BibTeX] [DOI]
Abstract: To further our understanding of the effects of biomass burning emissions on atmospheric composition, we report measurements of trace species in biomass burning plumes made by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) instrument on the SCISAT-1 satellite. An extensive set of 15 molecules, C 2H 2, C 2H 6, CH 3OH, CH 4, CO, H 2CO, HCN, HCOOH, HNO 3, NO, NO 2, N 2O 5, O 3, OCS and SF6 are used in our analysis. Even though most biomass burning smoke is typically confined to the boundary layer, some of these emissions are injected directly into the free troposphere via fire-related convective processes and transported away from the emission source. Further knowledge of the aging of biomass burning emissions in the free troposphere is needed. Tracer-tracer correlations are made between known pyrogenic species in these plumes in an effort to characterize them and follow their chemical evolution. Criteria such as age and type of biomass material burned are considered. © 2011 Author(s).
BibTeX: @article{Tereszchuk2011, author = {Tereszchuk, K.A. and González Abad, G. and Clerbaux, C. and Hurtmans, D. and Coheur, P.-F. and Bernath, P.F.}, title = {ACE-FTS measurements of trace species in the characterization of biomass burning plumes}, journal = {Atmospheric Chemistry and Physics}, year = {2011}, volume = {11}, number = {23}, pages = {12169 – 12179}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-11-12169-2011} }
Vaernewijck XGD, Didriche K, Lauzin C, Rizopoulos A, Herman M and Kassi S (2011), "Cavity enhanced FTIR spectroscopy using a femto OPO absorption source", Molecular Physics. Vol. 109(17-18), pp. 2173 – 2179. [Abstract] [BibTeX] [DOI]
Abstract: The v 1+v 3 band of 12Cv 2Hv 2 was recorded using a high resolution continuous scan Fourier transform interferometer fitted with a femto OPO absorption source. Various experimental schemes were successfully implemented, including multipass absorption in a cell and also in a supersonic expansion, and cavity enhanced absorption. An optimal rms noise equivalent absorption of 2.2×10 -9cm -1Hz 1/2 per spectral element was reached in the latter case, corresponding to α min=1.5×10 -7cm -1. Performances are illustrated and discussed. Copyright © 2011 Taylor and Francis Group, LLC.
BibTeX: @article{Vaernewijck2011, author = {Vaernewijck, X.De Ghellinck D'Elseghem and Didriche, K. and Lauzin, C. and Rizopoulos, A. and Herman, M. and Kassi, S.}, title = {Cavity enhanced FTIR spectroscopy using a femto OPO absorption source}, journal = {Molecular Physics}, year = {2011}, volume = {109}, number = {17-18}, pages = {2173 – 2179}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268976.2011.602990} }
Vandenbussche S, Reisse J, Bartik K and Lievin J (2011), "The search for a deterministic origin for the presence of nonracemic amino-acids in meteorites: A computational approach", Chirality. Vol. 23(5), pp. 367 – 373. [Abstract] [BibTeX] [DOI]
Abstract: Amino-acid enantiomeric excesses (ee's) have been detected in different types of carbonaceous chondrites, all in favor of the L enantiomer. In this article, we discuss possible deterministic causes to the presence of these amino-acid ee's in meteorites and evaluate in particular enantioselective photolysis by circularly polarized light (CPL). The electronic circular dichroism spectra of a set of amino- and hydroxy-acids, all detected in chondritic matter but some with ee's and others without ee's, were calculated and compared. The spectra were calculated for the most stable conformation(s) of the considered molecules using quantum mechanical methods (density functional theory). Our results suggest that CPL photolysis in the gas phase was perhaps not at the origin of the presence of ee's in meteorites and that the search for another, but still unknown, deterministic cause must be seriously undertaken. © 2011 Wiley-Liss, Inc.
BibTeX: @article{Vandenbussche2011, author = {Vandenbussche, Sophie and Reisse, Jacques and Bartik, Kristin and Lievin, Jacques}, title = {The search for a deterministic origin for the presence of nonracemic amino-acids in meteorites: A computational approach}, journal = {Chirality}, year = {2011}, volume = {23}, number = {5}, pages = {367 – 373}, doi = {10.1002/chir.20933} }
Amyay B, Herman M, Fayt A, Fusina L and Predoi-Cross A (2010), "High resolution FTIR investigation of 12C2H2 in the FIR spectral range using synchrotron radiation", Chemical Physics Letters. Vol. 491(1-3), pp. 17 – 19. [Abstract] [BibTeX] [DOI]
Abstract: FIR spectra of C2H2 have been recorded at 0.00096 cm-1 spectral resolution using the Canadian Light Source synchrotron facility. The analysis allowed us to assign 731 new vibration-rotation lines from 48 bands in 12C2H2, 38 of which are reported for the first time. Two additional bands are assigned to 13CH12CH. The measured line positions and calculated spectra can be made available to help in the remote sensing of acetylene in the terahertz spectral range. © 2010 Elsevier B.V. All rights reserved.
BibTeX: @article{Amyay2010, author = {Amyay, B. and Herman, M. and Fayt, A. and Fusina, L. and Predoi-Cross, A.}, title = {High resolution FTIR investigation of 12C2H2 in the FIR spectral range using synchrotron radiation}, journal = {Chemical Physics Letters}, year = {2010}, volume = {491}, number = {1-3}, pages = {17 – 19}, doi = {10.1016/j.cplett.2010.03.053} }
Borgoo A, Scharf O, Gaigalas G and Godefroid M (2010), "Multiconfiguration electron density function for the ATSP2K-package", Computer Physics Communications. Vol. 181(2), pp. 426 – 439. [Abstract] [BibTeX] [DOI]
Abstract: A new atsp2K module is presented for evaluating the electron density function of any multiconfiguration Hartree-Fock or configuration interaction wave function in the non-relativistic or relativistic Breit-Pauli approximation. It is first stressed that the density function is not a priori spherically symmetric in the general open shell case. Ways of building it as a spherical symmetric function are discussed, from which the radial electron density function emerges. This function is written in second quantized coupled tensorial form for exploring the atomic spherical symmetry. The calculation of its expectation value is performed using the angular momentum theory in orbital, spin, and quasispin spaces, adopting a generalized graphical technique. The natural orbitals are evaluated from the diagonalization of the density matrix. Program summary: Program title: DENSITY. Catalogue identifier: AEFR_v1_0. Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEFR_v1_0.html. Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland. Licensing provisions: Standard CPC license, http://cpc.cs.qub.ac.uk/licence/licence.html. No. of lines in distributed program, including test data, etc.: 6603. No. of bytes in distributed program, including test data, etc.: 169 881. Distribution format: tar.gz. Programming language: FORTRAN 90. Computer: HP XC Cluster Platform 4000. Operating system: HP XC System Software 3.2.1, which is a Linux distribution compatible with Red Hat Enterprise Advanced Server. Word size: 32 bits. Classification: 2.1, 2.9, 4.1. Subprograms used:A table is presented. Nature of problem: This program determines the atomic electronic density in the MCHF (LS) or Breit-Pauli (LS J) approximation. It also evaluates the natural orbitals by diagonalizing the density matrix. Solution method: Building the density operator using second quantization - spherical symmetry averaging - evaluating the matrix elements of the one-body excitation operators in the configuration state function (CSF) space using the angular momentum theory in orbital, spin, and quasispin spaces. Restrictions: Original restrictions from ATSP2K package, i.e. all orbitals within a wave function expansion are assumed to be orthonormal. Configuration states are restricted to at most eight subshells in addition to the closed shells common to all configuration states. The maximum size of the working arrays, related to the number of CSFs and active orbitals, is limited by the available memory and disk space. Unusual features: The programming style is essentially F77 with extensions for the POINTER data type and associated memory allocation. These have been available on workstations for more than a decade, but their implementations are compiler dependent. The present code has been installed and tested extensively using the Portland Group, pgf90, compiler. Running time: The calculation of the electron density for an n = 9 complete active space (CAS) MCHF wave function (271 733 CSFs - 45 orbitals) takes around 9 minutes on one AMD Opteron dual-core at 2.4 GHz CPU. References: [1]C. Froese Fischer, G. Tachiev, G. Gaigalas, M.R. Godefroid, An MCHF atomic-structure package for large-scale calculation, Comput. Phys. Commun. 176 (2007) 559-579. © 2009 Elsevier B.V. All rights reserved.
BibTeX: @article{Borgoo2010, author = {Borgoo, A. and Scharf, O. and Gaigalas, G. and Godefroid, M.}, title = {Multiconfiguration electron density function for the ATSP2K-package}, journal = {Computer Physics Communications}, year = {2010}, volume = {181}, number = {2}, pages = {426 – 439}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.cpc.2009.10.014} }
Boudon V, Pirali O, Roy P, Brubach J-B, Manceron L and Vander Auwera J (2010), "The high-resolution far-infrared spectrum of methane at the SOLEIL synchrotron", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 111(9), pp. 1117 – 1129. [Abstract] [BibTeX] [DOI]
Abstract: As a tetrahedral molecule, methane has no permanent dipole moment. Its spectrum, however, displays faint absorption lines in the THz region, due to centrifugal distorsion effects. This is important for planetary applications since this region is used to measure methane concentration in some planetary atmospheres, in particular on Titan. Up to now, all measurements relied either on some old low resolution infrared absorption spectra, or on high resolution Stark measurements for low J values only. Even if these results have been reexamined recently [Wishnow EH, Orton GS, Ozier I, Gush HP. The distorsion dipole rotational spectrum of CH4: a low temperature far-infrared study. J Quant Spectrosc Radiat Transfer 2007;103:102-17], it seemed highly desirable to obtain much more precise laboratory data.The high-intensity synchrotron radiation, combined with a 151.75±0.1m optical path in a White cell and a Bruker IFS 125 HR FTIR spectrometer at the AILES beamline of SOLEIL, enabled us to record this very weak spectrum at high resolution for the first time. Spectra were obtained in the 50-500cm-1 wavenumber range at 296K and 9.91, 20, 50 and 100mbar with a resolution of 0.00074, 0.00134, 0.0034 and 0.0067cm-1 (FWHM of the sinc function), respectively. The rotational clusters are fully resolved and the good signal-to-noise ratio has enabled precise measurements of transition intensities (92 cold band lines and 96 Dyad-Dyad hot band lines, with normal abundance intensities in the range 2×10-26-1×10-24cm-1/(molcm-2)), yielding an accurate determination of the dipole moment derivatives. Such results should allow a better determination of CH4 concentration in planetary objects. © 2010 Elsevier Ltd.
BibTeX: @article{Boudon2010, author = {Boudon, V. and Pirali, O. and Roy, P. and Brubach, J.-B. and Manceron, L. and Vander Auwera, J.}, title = {The high-resolution far-infrared spectrum of methane at the SOLEIL synchrotron}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2010}, volume = {111}, number = {9}, pages = {1117 – 1129}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2010.02.006} }
Campion R, Salerno GG, Coheur P-F, Hurtmans D, Clarisse L, Kazahaya K, Burton M, Caltabiano T, Clerbaux C and Bernard A (2010), "Measuring volcanic degassing of SO2 in the lower troposphere with ASTER band ratios", Journal of Volcanology and Geothermal Research. Vol. 194(1-3), pp. 42 – 54. [Abstract] [BibTeX] [DOI]
Abstract: We present a new method for measuring SO2 with the data from the ASTER (Advanced Spaceborne Thermal Emission and Reflectance radiometer) orbital sensor. The method consists of adjusting the SO2 column amount until the ratios of radiance simulated on several ASTER bands match the observations. We present a sensitivity analysis for this method, and two case studies. The sensitivity analysis shows that the selected band ratios depend much less on atmospheric humidity, sulfate aerosols, surface altitude and emissivity than the raw radiances. Measurements with <25% relative precision are achieved, but only when the thermal contrast between the plume and the underlying surface is higher than 10K. For the case studies we focused on Miyakejima and Etna, two volcanoes where SO2 is measured regularly by COSPEC or scanning DOAS. The SO2 fluxes computed from a series of ten images of Miyakejima over the period 2000-2002 is in agreement with the long term trend of measurement for this volcano. On Etna, we compared SO2 column amounts measured by ASTER with those acquired simultaneously by ground-based automated scanning DOAS. The column amounts compare quite well, providing a more rigorous validation of the method. The SO2 maps retrieved with ASTER can provide quantitative insights into the 2D structure of non-eruptive volcanic plumes, their dispersion and their progressive depletion in SO2. © 2010 .
BibTeX: @article{Campion2010, author = {Campion, Robin and Salerno, Giuseppe Giovanni and Coheur, Pierre-François and Hurtmans, Daniel and Clarisse, Lieven and Kazahaya, Kohei and Burton, Michael and Caltabiano, Tommaso and Clerbaux, Cathy and Bernard, Alain}, title = {Measuring volcanic degassing of SO2 in the lower troposphere with ASTER band ratios}, journal = {Journal of Volcanology and Geothermal Research}, year = {2010}, volume = {194}, number = {1-3}, pages = {42 – 54}, doi = {10.1016/j.jvolgeores.2010.04.010} }
Carette T, Drag C, Scharf O, Blondel C, Delsart C, Froese Fischer C and Godefroid M (2010), "Isotope shift in the sulfur electron affinity: Observation and theory", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 81(4) [Abstract] [BibTeX] [DOI]
Abstract: The sulfur electron affinities eA(S) are measured by photodetachment microscopy for the two isotopes S32 and S34 (16752.9753(41) and 16752.9776(85) cm-1, respectively). The isotope shift in the electron affinity is found to be more probably positive, eA(S34)-eA(S32) =+0.0023(70) cm -1, but the uncertainty allows for the possibility that it may be either "normal" [eA(S34) eA(S32)] or "anomalous" [eA(S34)
BibTeX: @article{Carette2010, author = {Carette, Thomas and Drag, Cyril and Scharf, Oliver and Blondel, Christophe and Delsart, Christian and Froese Fischer, Charlotte and Godefroid, Michel}, title = {Isotope shift in the sulfur electron affinity: Observation and theory}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2010}, volume = {81}, number = {4}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.81.042522} }
Carette T, Nemouchi M, Jönsson P and Godefroid M (2010), "Saturation spectra of low lying states of Nitrogen: Reconciling experiment with theory", European Physical Journal D. Vol. 60(2), pp. 231 – 242. [Abstract] [BibTeX] [DOI]
Abstract: The hyperfine constants of the levels 2p 2 (3P)3s 4P J, 2p 2 (3P)3p 4P oJ and 2p 2 (3P)3p 4D oJ, deduced by Jennerich et al. [Eur. Phys. J. D 40, 81 (2006)] from the observed hyperfine structures of the transitions 2p 2 (3P)3s 4P J→ 2p2 (3P)3p 4P oJ and 2p 2 (3P)3s 4P J→ 2p 2 ( 3P)3p 4D oJ recorded by saturation spectroscopy in the near-infrared, strongly disagree with the ab initio values of Jönsson et al. [J. Phys. B: At. Mol. Opt. Phys. 43, 115006 (2010)]. We propose a new interpretation of the recorded weak spectral lines. If the latter are indeed reinterpreted as crossover signals, a new set of experimental hyperfine constants is deduced, in very good agreement with the ab initio predictions. © 2010 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
BibTeX: @article{Carette2010a, author = {Carette, T. and Nemouchi, M. and Jönsson, P. and Godefroid, M.}, title = {Saturation spectra of low lying states of Nitrogen: Reconciling experiment with theory}, journal = {European Physical Journal D}, year = {2010}, volume = {60}, number = {2}, pages = {231 – 242}, doi = {10.1140/epjd/e2010-00241-2} }
Cauët E, Bogatko S, Mugeniwabagara E, Fusaro L, Kirsch-De Mesmaeker A, Luhmer M and Vaeck N (2010), "Density functional theory interpretation of the 1H photo-chemically induced dynamic nuclear polarization enhancements characterizing photoreduced polyazaaromatic Ru(II) coordination complexes", Inorganic Chemistry. Vol. 49(17), pp. 7826 – 7831. [Abstract] [BibTeX] [DOI]
Abstract: The unprotonated and protonated monoreduced forms of the polyazaaromatic Ru(II) coordination complexes [Ru(tap)3]2+ and [Ru(tap)2(phen)]2+ (tap = 1,4,5,8-tetraazaphenanthrene; phen = 1,10-phenanthroline), that is, [Ru(tap)3]•+, [Ru(tap)2(phen)]•+, [Ru(tap)2(tap-H)] •2+, and [Ru(tap)(tap-H)(phen)]•2+, were studied by Density Functional Theory (DFT). The electron spin density of these radical cations, the isotropic Fermi-contact, and the anisotropic dipolar contributions to the hyperfine coupling constants of the H nuclei were calculated in vacuo and using a continuum model for water solvation. For [Ru(tap)2(phen)] •+, as well as for its protonated form, the DFT results show that the unpaired electron is not localized on the phen ligand. For both [Ru(tap)3]•+ and [Ru(tap)2(phen)] •+, they reveal high electron spin density in the vicinity of tap H-2 and tap H-7 (the H atoms in the ortho position of the tap non-chelating N atoms). These results are in full agreement with recent steady-state 1H photo-Chemically Induced Dynamic Nuclear Polarization (photo-CIDNP) measurements. The DFT calculations performed for the protonated species also predict major 1H photo-CIDNP enhancements at these positions. Interestingly, they indicate significantly different polarization for tap H-9,10, suggesting that the occurrence of a photoinduced electron transfer with protonation of the reduced species might be detected by high-precision photo-CIDNP experiments. © 2010 American Chemical Society.
BibTeX: @article{Cauet2010, author = {Cauët, Emilie and Bogatko, Stuart and Mugeniwabagara, Epiphanie and Fusaro, Luca and Kirsch-De Mesmaeker, Andrée and Luhmer, Michel and Vaeck, Nathalie}, title = {Density functional theory interpretation of the 1H photo-chemically induced dynamic nuclear polarization enhancements characterizing photoreduced polyazaaromatic Ru(II) coordination complexes}, journal = {Inorganic Chemistry}, year = {2010}, volume = {49}, number = {17}, pages = {7826 – 7831}, doi = {10.1021/ic100636j} }
Cauët E, Bogatko S, Weare JH, Fulton JL, Schenter GK and Bylaska EJ (2010), "Structure and dynamics of the hydration shells of the Zn2+ ion from ab initio molecular dynamics and combined ab initio and classical molecular dynamics simulations", Journal of Chemical Physics. Vol. 132(19) [Abstract] [BibTeX] [DOI]
Abstract: Results of ab initio molecular dynamics (AIMD) simulations (density functional theory+PBE96) of the dynamics of waters in the hydration shells surrounding the Zn2+ ion (T≈300 K, ρ ≈1 gm/ cm3) are compared to simulations using a combined quantum and classical molecular dynamics [AIMD/molecular mechanical (MM)] approach. Both classes of simulations were performed with 64 solvating water molecules (∼15 ps) and used the same methods in the electronic structure calculation (plane-wave basis set, time steps, effective mass, etc.). In the AIMD/MM calculation, only six waters of hydration were included in the quantum mechanical (QM) region. The remaining 58 waters were treated with a published flexible water-water interaction potential. No reparametrization of the water-water potential was attempted. Additional AIMD/MM simulations were performed with 256 water molecules. The hydration structures predicted from the AIMD and AIMD/MM simulations are found to agree in detail with each other and with the structural results from x-ray data despite the very limited QM region in the AIMD/MM simulation. To further evaluate the agreement of these parameter-free simulations, predicted extended x-ray absorption fine structure (EXAFS) spectra were compared directly to the recently obtained EXAFS data and they agree in remarkable detail with the experimental observations. The first hydration shell contains six water molecules in a highly symmetric octahedral structure is (maximally located at 2.13-2.15 Å versus 2.072 Å EXAFS experiment). The widths of the peak of the simulated EXAFS spectra agree well with the data (8.4 Å2 versus 8.9 Å2 in experiment). Analysis of the H-bond structure of the hydration region shows that the second hydration shell is trigonally bound to the first shell water with a high degree of agreement between the AIMD and AIMD/MM calculations. Beyond the second shell, the bonding pattern returns to the tetrahedral structure of bulk water. The AIMD/MM results emphasize the importance of a quantum description of the first hydration shell to correctly describe the hydration region. In these calculations the full d10 electronic structure of the valence shell of the Zn2+ ion is retained. The simulations show substantial and complex charge relocation on both the Zn 2+ ion and the first hydration shell. The dipole moment of the waters in the first hydration shell is 3.4 D (3.3 D AIMD/MM) versus 2.73 D bulk. Little polarization is found for the waters in the second hydration shell (2.8 D). No exchanges were seen between the first and the second hydrations shells; however, many water transfers between the second hydration shell and the bulk were observed. For 64 waters, the AIMD and AIMD/MM simulations give nearly identical results for exchange dynamics. However, in the larger particle simulations (256 waters) there is a significant reduction in the second shell to bulk exchanges. © 2010 American Institute of Physics.
BibTeX: @article{Cauet2010a, author = {Cauët, Emilie and Bogatko, Stuart and Weare, John H. and Fulton, John L. and Schenter, Gregory K. and Bylaska, Eric J.}, title = {Structure and dynamics of the hydration shells of the Zn2+ ion from ab initio molecular dynamics and combined ab initio and classical molecular dynamics simulations}, journal = {Journal of Chemical Physics}, year = {2010}, volume = {132}, number = {19}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.3421542} }
Cauët E, Valiev M and Weare JH (2010), "Vertical ionization potentials of nucleobases in a fully solvated DNA environment", Journal of Physical Chemistry B. Vol. 114(17), pp. 5886 – 5894. [Abstract] [BibTeX] [DOI]
Abstract: Vertical ionization potentials (IPs) of nucleobases embedded in a fully solvated DNA fragment (12-mer B-DNA fragment + 22 sodium counterions + 5760 water molecules equilibrated to 298 K) have been calculated using a combined quantum mechanical molecular mechanics (QM/MM) approach. Calculations of the vertical IP of the anion Cl- are reported that support the accuracy of the application of a QM/MM method to this problem. It is shown that the π nucleotide HOMO origin for the emitted electron is localized on the base by the hydration structure surrounding the DNA in a way similar to that recently observed for pyrimidine nucleotides in aqueous solutions (Slavícě k, P.; et al. J. Am. Chem. Soc. 2009, 131, 6460). In a first step, a high level of theory, CCSD(T)/aug-cc-pVDZ, was used to calculate the vertical IP of each of the four single bases isolated in the QM region while the remaining DNA fragment, counterions, and water solvent molecules were included in the MM region. The calculated vertical IPs show a large positive shift of 3.2-3.3 eV compared to the corresponding gas-phase values. This shift is similar for all four DNA bases. The origin of the large increase in vertical IPs of nucleobases is found to be the long-range electrostatic interactions with the solvation structure outside the DNA helix. Thermal fluctuations in the fluid can result in IP changes of roughly 1 eV on a picosecond time scale. IPs of π-stacked and H-bonded clusters of DNA bases were also calculated using the same QM/MM model but with a lower level of theory, B3LYP/6-31G(d=0.2). An IP shift of 4.02 eV relative to the gas phase is found for a four-base-pair B-DNA duplex configuration. The primary goal of this work was to estimate the influence of long-range solvation interactions on the ionization properties of DNA bases rather than provide highly precise IP evaluations. The QM/MM model presented in this work provides an attractive method to treat the difficult problem of incorporating a detailed long-range structural model of physiological conditions into investigations of the electronic processes in DNA. © 2010 American Chemical Society.
BibTeX: @article{Cauet2010b, author = {Cauët, Emilie and Valiev, Marat and Weare, John H.}, title = {Vertical ionization potentials of nucleobases in a fully solvated DNA environment}, journal = {Journal of Physical Chemistry B}, year = {2010}, volume = {114}, number = {17}, pages = {5886 – 5894}, doi = {10.1021/jp9120723} }
Clarisse L, Hurtmans D, Prata AJ, Karagulian F, Clerbaux C, De Mazière M and Coheur P-F (2010), "Retrieving radius, concentration, optical depth, and mass of different types of aerosols from high-resolution infrared nadir spectra", Applied Optics. Vol. 49(19), pp. 3713 – 3722. [Abstract] [BibTeX] [DOI]
Abstract: We present a sophisticated radiative transfer code for modeling outgoing IR radiation from planetary atmospheres and, conversely, for retrieving atmospheric properties from high-resolution nadir-observed spectra. The forward model is built around a doubling-adding routine and calculates, in a spherical refractive geometry, the outgoing radiation emitted by the Earth and the atmosphere containing one layer of aerosol. The inverse model uses an optimal estimation approach and can simultaneously retrieve atmospheric trace gases, aerosol effective radius, and concentration. It is different from existing codes, as most forward codes dealing with multiple scattering assume a plane-parallel atmosphere, and as for the retrieval, it does not rely on precalculated spectra, the use of microwindows, or two-step retrievals. The simultaneous retrieval on a broad spectral range exploits the full potential of current state-of-the-art hyperspectral IR sounders, such as AIRS and IASI, and should be particularly useful in studying major pollution events. We present five example retrievals of IASI spectra observed in the range from 800 to 1200 cm-1 above dust, volcanic ash, sulfuric acid, ice particles, and biomass burning aerosols. © 2010 Optical Society of America.
BibTeX: @article{Clarisse2010b, author = {Clarisse, Lieven and Hurtmans, Daniel and Prata, Alfred J. and Karagulian, Federico and Clerbaux, Cathy and De Mazière, Martine and Coheur, Pierre-François}, title = {Retrieving radius, concentration, optical depth, and mass of different types of aerosols from high-resolution infrared nadir spectra}, journal = {Applied Optics}, year = {2010}, volume = {49}, number = {19}, pages = {3713 – 3722}, doi = {10.1364/AO.49.003713} }
Clarisse L, Prata F, Lacour J-L, Hurtmans D, Clerbaux C and Coheur P-F (2010), "A correlation method for volcanic ash detection using hyperspectral infrared measurements", Geophysical Research Letters. Vol. 37(19) [Abstract] [BibTeX] [DOI]
Abstract: Remote satellite detection of airborne volcanic ash is important for mitigating hazards to aviation and for calculating plume altitudes. Infrared sounders are essential for detecting ash, as they can distinguishing aerosol type and can be used day and night. While broadband sensors are mainly used for this purpose, they have inherent limitations. Typically, water and ice can mask volcanic ash, while wind blown dust can yield false detection. High spectral resolution sounders should be able to overcome some of these limitations. However, existing detection methods are not easily applicable to hyperspectral sounders and there is therefore a pressing need for novel techniques. In response, we propose a sensitive and robust volcanic ash detection method for hyperspectral sounders based on correlation coefficients and demonstrate it on IASI observations. We show that the method differentiates ash from clouds and dust. Easy to implement, it could contribute to operational volcanic hazard mitigation. © 2010 by the American Geophysical Union.
BibTeX: @article{Clarisse2010, author = {Clarisse, Lieven and Prata, Fred and Lacour, Jean-Lionel and Hurtmans, Daniel and Clerbaux, Cathy and Coheur, Pierre-François}, title = {A correlation method for volcanic ash detection using hyperspectral infrared measurements}, journal = {Geophysical Research Letters}, year = {2010}, volume = {37}, number = {19}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2010GL044828} }
Clarisse L, Shephard MW, Dentener F, Hurtmans D, Cady-Pereira K, Karagulian F, Van Damme M, Clerbaux C and Coheur P-F (2010), "Satellite monitoring of ammonia: A case study of the San Joaquin Valley", Journal of Geophysical Research Atmospheres. Vol. 115(13) [Abstract] [BibTeX] [DOI]
Abstract: [1] Atmospheric ammonia (NH3) has recently been observed with infrared sounders from space. Here we present 1 year of detailed bidaily satellite retrievals with the Infrared Atmospheric Sounding Interferometer and some retrievals of the Tropospheric Emission Spectrometer over the San Joaquin Valley, California, a highly polluted agricultural production region. Several sensitivity issues are discussed related to the sounding of ammonia, in terms of degrees of freedom, averaging kernels, and altitude of maximum sensitivity and in relation to thermal contrast and concentration. We also discuss their seasonal dependence and sources of errors. We demonstrate boundary layer sensitivity of infrared sounders when there is a large thermal contrast between the surface and the bottom of the atmosphere. For the San Joaquin Valley, large thermal contrast is the case for daytime measurements in spring, summer, and autumn and for nighttime measurements in autumn and winter when a large negative thermal contrast is amplified by temperature inversion. © 2010 by the American Geophysical Union.
BibTeX: @article{Clarisse2010a, author = {Clarisse, Lieven and Shephard, Mark W. and Dentener, Frank and Hurtmans, Daniel and Cady-Pereira, Karen and Karagulian, Federico and Van Damme, Martin and Clerbaux, Cathy and Coheur, Pierre-François}, title = {Satellite monitoring of ammonia: A case study of the San Joaquin Valley}, journal = {Journal of Geophysical Research Atmospheres}, year = {2010}, volume = {115}, number = {13}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1029/2009JD013291} }
Clerbaux C, Turquety S and Coheur P (2010), "Infrared remote sensing of atmospheric composition and air quality: Towards operational applications", Comptes Rendus - Geoscience. Vol. 342(4-5), pp. 349 – 356. [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric remote sensing from satellites is an essential component of the observational strategy deployed to monitor atmospheric pollution and changing composition. During this decade, remote sensors using the thermal infrared (TIR) spectral range have demonstrated their ability to sound the troposphere and provide global distribution for some of the key atmospheric species. This article illustrates three operational applications made possible with the IASI instrument onboard the European satellite MetOp, which opens new perspectives for routine observation of the evolution of atmospheric composition from space. © 2009 Académie des sciences.
BibTeX: @article{Clerbaux2010, author = {Clerbaux, Cathy and Turquety, Solène and Coheur, Pierre}, title = {Infrared remote sensing of atmospheric composition and air quality: Towards operational applications}, journal = {Comptes Rendus - Geoscience}, year = {2010}, volume = {342}, number = {4-5}, pages = {349 – 356}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.crte.2009.09.010} }
Colin R and Bernath PF (2010), "Revised molecular constants and term values for the X2Π state of CH", Journal of Molecular Spectroscopy. Vol. 263(1), pp. 120 – 122. [Abstract] [BibTeX] [DOI]
Abstract: An improved set of molecular constants and term values are given for the X2Π (v = 0-5) state of the CH radical. They are derived from a fit of previously published data and additional lines taken from infrared solar spectra recorded on orbit and from new laboratory IR emission data. © 2010 Elsevier Inc. All rights reserved.
BibTeX: @article{Colin2010, author = {Colin, Reginald and Bernath, Peter F.}, title = {Revised molecular constants and term values for the X2Π state of CH}, journal = {Journal of Molecular Spectroscopy}, year = {2010}, volume = {263}, number = {1}, pages = {120 – 122}, doi = {10.1016/j.jms.2010.06.013} }
De Natale P, Di Lonardo G, Herman M, Quack M and Softley T (2010), "Foreword: Twenty-first colloquium on high-resolution molecular spectroscopy", Molecular Physics. Vol. 108(6), pp. 675 – 676. [BibTeX] [DOI]
BibTeX: @article{DeNatale2010, author = {De Natale, Paolo and Di Lonardo, Gianfranco and Herman, Michel and Quack, Martin and Softley, Tim}, title = {Foreword: Twenty-first colloquium on high-resolution molecular spectroscopy}, journal = {Molecular Physics}, year = {2010}, volume = {108}, number = {6}, pages = {675 – 676}, doi = {10.1080/00268971003798187} }
Didriche K and Herman M (2010), "A four-atom molecule at the forefront of spectroscopy, intramolecular dynamics and astrochemistry: Acetylene", Chemical Physics Letters. Vol. 496(1-3), pp. 1 – 7. [Abstract] [BibTeX] [DOI]
Abstract: The prototype role of this simple four-atom molecule is highlighted in high-resolution vibration-rotation spectroscopy, intramolecular dynamics, and astrochemistry. © 2010 Elsevier B.V. All rights reserved.
BibTeX: @article{Didriche2010a, author = {Didriche, Keevin and Herman, Michel}, title = {A four-atom molecule at the forefront of spectroscopy, intramolecular dynamics and astrochemistry: Acetylene}, journal = {Chemical Physics Letters}, year = {2010}, volume = {496}, number = {1-3}, pages = {1 – 7}, doi = {10.1016/j.cplett.2010.07.031} }
Didriche K, Lauzin C, Foldes T, De Ghellinck XDV and Herman M (2010), "The FANTASIO+ set-up to investigate jet-cooled molecules: Focus on overtone bands of the acetylene dimer", Molecular Physics. Vol. 108(17), pp. 2155 – 2163. [Abstract] [BibTeX] [DOI]
Abstract: The experimental set-up FANTASIO, for 'Fourier trANsform, Tunable diode and quadrupole mAss spectrometers interfaced to a Supersonic expansIOn' (M. Herman, K. Didriche, D. Hurtmans, B. Kizil, P. Macko, A. Rizopoulos and P. Van Poucke, Mol. Phys. 105, 815 (2007)) built in Brussels has been updated. The turbomolecular pumping system of the supersonic expansion has been doubled and new mirrors, with reflectivity 99.999% instead of 99.99%, have been set in the CW-cavity ring down spectrometer probing jet-cooled molecules. The changes all together result in a signal to noise increased by up to a factor 10, around 1.5 μm. These improvements are demonstrated with various acetylene data in the 2CH excitation range, including the assignment of a new sub-band of acetylene-Ar, with K'-K'' = 2-3. The focus is set on the acetylene dimer. Overtone sub-bands, with b- and a-type structures, are identified for the first time in the literature. They are assigned to vibrational excitation in the hat and body units of the T shaped dimer, respectively. The relevance of the overtone data on acetylene dimers for space remote sensing is highlighted. © 2010 Taylor & Francis.
BibTeX: @article{Didriche2010, author = {Didriche, K. and Lauzin, C. and Foldes, T. and De Ghellinck, X. D'Elseghem Vaernewijck and Herman, M.}, title = {The FANTASIO+ set-up to investigate jet-cooled molecules: Focus on overtone bands of the acetylene dimer}, journal = {Molecular Physics}, year = {2010}, volume = {108}, number = {17}, pages = {2155 – 2163}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268976.2010.489525} }
Gangale G, Prata A and Clarisse L (2010), "The infrared spectral signature of volcanic ash determined from high-spectral resolution satellite measurements", Remote Sensing of Environment. Vol. 114(2), pp. 414 – 425. [Abstract] [BibTeX] [DOI]
Abstract: High-spectral resolution infrared spectra of the earth's atmosphere and surface are routinely available from satellite sensors, such as the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI). We exploit the spectral content of AIRS data to demonstrate that airborne volcanic ash has a unique signature in the infrared (8-12 μm) that can be used to infer particle size, infrared opacity and composition. The spectral signature is interpreted with the aid of a radiative transfer model utilizing the optical properties of andesite, rhyolite and quartz. Based on the infrared spectral signature, a new volcanic ash detection algorithm is proposed that can discriminate volcanic ash from other airborne substances and we show that the algorithm depends on particle size, optical depth and composition. The new algorithm has an improved sensitivity to optically thin ash clouds, and hence can detect them for longer ( 4 days) and at greater distances from the source( 5000 km). © 2009 Elsevier Inc. All rights reserved.
BibTeX: @article{Gangale2010, author = {Gangale, G. and Prata, A.J. and Clarisse, L.}, title = {The infrared spectral signature of volcanic ash determined from high-spectral resolution satellite measurements}, journal = {Remote Sensing of Environment}, year = {2010}, volume = {114}, number = {2}, pages = {414 – 425}, doi = {10.1016/j.rse.2009.09.007} }
Haywood JM, Jones A, Clarisse L, Bourassa A, Barnes J, Telford P, Bellouin N, Boucher O, Agnew P, Clerbaux C, Coheur P, Degenstein D and Braesicke P (2010), "Observations of the eruption of the Sarychev volcano and simulations using the HadGEM2 climate model", Journal of Geophysical Research Atmospheres. Vol. 115(21) [Abstract] [BibTeX] [DOI]
Abstract: In June 2009 the Sarychev volcano located in the Kuril Islands to the northeast of Japan erupted explosively, injecting ash and an estimated 1.2 0.2 Tg of sulfur dioxide into the upper troposphere and lower stratosphere, making it arguably one of the 10 largest stratospheric injections in the last 50 years. During the period immediately after the eruption, we show that the sulfur dioxide (SO2) cloud was clearly detected by retrievals developed for the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument and that the resultant stratospheric sulfate aerosol was detected by the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb sounder and CALIPSO lidar. Additional surface-based instrumentation allows assessment of the impact of the eruption on the stratospheric aerosol optical depth. We use a nudged version of the HadGEM2 climate model to investigate how well this state-of-the-science climate model can replicate the distributions of SO 2 and sulfate aerosol. The model simulations and OSIRIS measurements suggest that in the Northern Hemisphere the stratospheric aerosol optical depth was enhanced by around a factor of 3 (0.01 at 550 nm), with resultant impacts upon the radiation budget. The simulations indicate that, in the Northern Hemisphere for July 2009, the magnitude of the mean radiative impact from the volcanic aerosols is more than 60% of the direct radiative forcing of all anthropogenic aerosols put together. While the cooling induced by the eruption will likely not be detectable in the observational record, the combination of modeling and measurements would provide an ideal framework for simulating future larger volcanic eruptions. Copyright 2010 by the American Geophysical Union.
BibTeX: @article{Haywood2010, author = {Haywood, James M. and Jones, Andy and Clarisse, Lieven and Bourassa, Adam and Barnes, John and Telford, Paul and Bellouin, Nicolas and Boucher, Olivier and Agnew, Paul and Clerbaux, Cathy and Coheur, Pierre and Degenstein, Doug and Braesicke, Peter}, title = {Observations of the eruption of the Sarychev volcano and simulations using the HadGEM2 climate model}, journal = {Journal of Geophysical Research Atmospheres}, year = {2010}, volume = {115}, number = {21}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1029/2010JD014447} }
Herman M and Saykally R (2010), "Special issue devoted to molecular complexes in our atmosphere and beyond", Molecular Physics. Vol. 108(17), pp. 2153. [BibTeX] [DOI]
BibTeX: @article{Herman2010, author = {Herman, M. and Saykally, R.J.}, title = {Special issue devoted to molecular complexes in our atmosphere and beyond}, journal = {Molecular Physics}, year = {2010}, volume = {108}, number = {17}, pages = {2153}, note = {All Open Access, Bronze Open Access}, doi = {10.1080/00268976.2010.506048} }
Jönsson P, Carette T, Nemouchi M and Godefroid M (2010), "Ab initio calculations of 14N and 15N hyperfine structures", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 43(11) [Abstract] [BibTeX] [DOI]
Abstract: Hyperfine structure parameters are calculated for the 2p2( 3P)3s 4PJ, 2p2(3P)3p 4PoJ and 2p2(3P)3p 4DoJ levels, using the ab initio multiconfiguration Hartree-Fock method. The theoretical hyperfine coupling constants are in complete disagreement with the experimental values of Jennerich et al deduced from the analysis of the near-infrared Doppler-free saturated absorption spectra. © 2010 IOP Publishing Ltd.
BibTeX: @article{Joensson2010, author = {Jönsson, P. and Carette, T. and Nemouchi, M. and Godefroid, M.}, title = {Ab initio calculations of 14N and 15N hyperfine structures}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2010}, volume = {43}, number = {11}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/43/11/115006} }
Karagulian F, Clarisse L, Clerbaux C, Prata A, Hurtmans D and Coheur P (2010), "Detection of volcanic SO2, ash, and H2SO4 using the infrared atmospheric sounding interferometer (IASI)", Journal of Geophysical Research Atmospheres. Vol. 115(4) [Abstract] [BibTeX] [DOI]
Abstract: In this work we use infrared spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI) to characterize the emissions from the Mount Kasatochi volcanic eruption on 7 and 8 August 2008. We first derive the total atmospheric load of sulfur dioxide (SO2) and its evolution over time. For the initial plume, we found values over 1.7 Tg Of SO2, making it the largest eruption since the 1991 eruptions of Pinatubo and Hudson. Vertical profiles were retrieved using a line-by-line radiative transfer model and an inversion procedure based on the optimal estimation method (OEM). For the Kasatochi eruption, we found a plume altitude of 12.5 ± 4 km. Taking advantage of IASI's broad spectral coverage, we used the v3 band (∼ 1362 cm-1) and, for the first time, the v1 + v 3 band (∼2500 cm-1) of SO2 for the retrievals. While the v3 band saturates easily for high SO 2 concentrations, preventing accurate retrieval, the v1 + v3 band has a much higher saturation threshold. We also analyzed the broadband signature observed in the radiance spectra in the 1072-1215 cm -1 range associated with the presence of aerosols. In the initial volcanic plume the signature matches closely that of mineral ash, while by 10 August most mineral ash is undetectable, and the extinction is shown to match closely the absorption spectrum of liquid H2SO4 drops. The extinction by sulphuric acid particles was confirmed by comparing spectra before and a month after the eruption, providing the first spectral detection of such aerosols from nadir view radiance data. Copyright 2010 by the American Geophysical Union.
BibTeX: @article{Karagulian2010, author = {Karagulian, F. and Clarisse, L. and Clerbaux, C. and Prata, A.J. and Hurtmans, D. and Coheur, P.F.}, title = {Detection of volcanic SO2, ash, and H2SO4 using the infrared atmospheric sounding interferometer (IASI)}, journal = {Journal of Geophysical Research Atmospheres}, year = {2010}, volume = {115}, number = {4}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2009JD012786} }
Kassi S, Didriche K, Lauzin C, de Ghellinck d'Elseghem Vaernewijckb X, Rizopoulos A and Herman M (2010), "Demonstration of cavity enhanced FTIR spectroscopy using a femtosecond laser absorption source", Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy. Vol. 75(1), pp. 142 – 145. [Abstract] [BibTeX] [DOI]
Abstract: A proof of principle experiment was performed by recording the cavity enhanced absorption spectrum of the weak b-X transition of molecular oxygen in the atmosphere using a Ti:Sa femtosecond laser as an absorption source and a high resolution continuous scan Fourier transform interferometer. The cavity was mode matched and either continuously scanned or stabilized at the so-called magic point. An optimal rms noise equivalent absorption of 3 × 10-7 cm-1 Hz-1/2 was reached in the latter case, corresponding to αmin = 3 × 10-7 cm-1. © 2009 Elsevier B.V. All rights reserved.
BibTeX: @article{Kassi2010, author = {Kassi, S. and Didriche, K. and Lauzin, C. and de Ghellinck d'Elseghem Vaernewijckb, X. and Rizopoulos, A. and Herman, M.}, title = {Demonstration of cavity enhanced FTIR spectroscopy using a femtosecond laser absorption source}, journal = {Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy}, year = {2010}, volume = {75}, number = {1}, pages = {142 – 145}, doi = {10.1016/j.saa.2009.09.058} }
Keim C, Eremenko M, Orphal J, Dufour G, Flaud J-M, Höpfner M, Boynard A, Clerbaux C, Payan S, Coheur P-F, Hurtmans D, Claude H, De Backer H, Dier H, Johnson B, Kelder H, Kivi R, Koide T, López Bartolomé M, Lambkin K, Moore D, Schmidlin F and Stübi R (2010), "Erratum: Tropospheric ozone from IASI: Comparison of different inversion algorithms and validation with ozone sondes in the northern middle latitudes (Atmospheric Chemistry and Physics (2009) 9 (9329-9347) DOI: 10.5194/acp-9-9329-2009)", Atmospheric Chemistry and Physics. Vol. 10(13), pp. 6345. [BibTeX] [DOI]
BibTeX: @article{Keim2010, author = {Keim, C. and Eremenko, M. and Orphal, J. and Dufour, G. and Flaud, J.-M. and Höpfner, M. and Boynard, A. and Clerbaux, C. and Payan, S. and Coheur, P.-F. and Hurtmans, D. and Claude, H. and De Backer, H. and Dier, H. and Johnson, B. and Kelder, H. and Kivi, R. and Koide, T. and López Bartolomé, M. and Lambkin, K. and Moore, D. and Schmidlin, F.J. and Stübi, R.}, title = {Erratum: Tropospheric ozone from IASI: Comparison of different inversion algorithms and validation with ozone sondes in the northern middle latitudes (Atmospheric Chemistry and Physics (2009) 9 (9329-9347) DOI: 10.5194/acp-9-9329-2009)}, journal = {Atmospheric Chemistry and Physics}, year = {2010}, volume = {10}, number = {13}, pages = {6345}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-10-6345-2010} }
Loreau J, Liévin J, Palmeri P, Quinet P and Vaeck N (2010), "Ab initio calculation of the 66 low-lying electronic states of HeH +: Adiabatic and diabatic representations", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 43(6) [Abstract] [BibTeX] [DOI]
Abstract: Using the quantum chemistry package MOLPRO and an adapted basis set, we have calculated the adiabatic potential energy curves of the first 20 1Σ+, 19 3Σ+, 12 1Π, 9 3Π, 4 1Δ and 2 3Δ electronic states of the HeH+ molecular ion in CASSCF and CI approaches. The results are compared with previous works. The radial and rotational non-adiabatic coupling matrix elements as well as the dipole moments are also calculated. The asymptotic behaviour of the potential energy curves and of the various couplings between the states is also studied. Using the radial couplings, the diabatic representation is defined and we present an example of our diabatization procedure on the 1Σ + states. © 2010 IOP Publishing Ltd.
BibTeX: @article{Loreau2010b, author = {Loreau, Jérme and Liévin, Jacques and Palmeri, Patrick and Quinet, Pascal and Vaeck, Nathalie}, title = {Ab initio calculation of the 66 low-lying electronic states of HeH +: Adiabatic and diabatic representations}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2010}, volume = {43}, number = {6}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/43/6/065101} }
Loreau J, Lívin J and Vaeck N (2010), "Radiative lifetime of the a 3∑+ + state of HeH+ from ab initio calculations", Journal of Chemical Physics. Vol. 133(11) [Abstract] [BibTeX] [DOI]
Abstract: The first metastable triplet state of HeH+ was found to be present in ion beam experiments, with its lifetime estimated to be between hundreds of milliseconds and thousand of seconds. In this work, we use ab initio methods to evaluate the radiative lifetimes of the six vibrational levels of the a 3∑+ of HeH+. The transition a 3∑+ → X1∑+ is spin-forbidden, but acquires intensity through spin-orbit interaction with the singlet and triplet Π states. Large scale CASSCF/MRCI calculations using an adapted basis set were performed to determine the potential energy curves of the relevant states of HeH+ as well as the matrix elements of the dipole and spin-orbit operators. The wave functions and energies of the vibrational levels of the a3∑+ and X1∑+ states are obtained using a B-spline method and compared to previous works. We find that the radiative lifetime of the vibrational levels increases strongly with v, the lifetime of the v=0 state being 150 s. We also analyze the contributions from discrete and continuum parts of the spectrum. With such a long lifetime, the a3∑+ state could have astrophysical implications. © 2010 American Institute of Physics.
BibTeX: @article{Loreau2010a, author = {Loreau, J. and Lívin, J. and Vaeck, N.}, title = {Radiative lifetime of the a 3∑+ + state of HeH+ from ab initio calculations}, journal = {Journal of Chemical Physics}, year = {2010}, volume = {133}, number = {11}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.3481782} }
Loreau J, Sodoga K, Lauvergnat D, Desouter-Lecomte M and Vaeck N (2010), "Ab initio calculation of H+He+ charge-transfer cross sections for plasma physics", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 82(1) [Abstract] [BibTeX] [DOI]
Abstract: The charge-transfer in low-energy (0.25 to 150eV/amu) H(nl)+He +(1s) collisions is investigated using a quasimolecular approach for the n=2,3 as well as the first two n=4 singlet states. The diabatic potential energy curves of the HeH+ molecular ion are obtained from the adiabatic potential energy curves and the nonadiabatic radial coupling matrix elements using a two-by-two diabatization method, and a time-dependent wave-packet approach is used to calculate the state-to-state cross sections. We find a strong dependence of the charge-transfer cross section on the principal and orbital quantum numbers n and l of the initial or final state. We estimate the effect of the nonadiabatic rotational couplings, which is found to be important even at energies below 1eV/amu. However, the effect is small on the total cross sections at energies below 10eV/amu. We observe that to calculate charge-transfer cross sections in an n manifold, it is only necessary to include states with n′≤n, and we discuss the limitations of our approach as the number of states increases. © 2010 The American Physical Society.
BibTeX: @article{Loreau2010, author = {Loreau, J. and Sodoga, K. and Lauvergnat, D. and Desouter-Lecomte, M. and Vaeck, N.}, title = {Ab initio calculation of H+He+ charge-transfer cross sections for plasma physics}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2010}, volume = {82}, number = {1}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.82.012708} }
Loroño Gonzalez M, Boudon V, Loëte M, Rotger M, Bourgeois M-T, Didriche K, Herman M, Kapitanov V, Ponomarev Y, Solodov A, Solodov A and Petrova T (2010), "High-resolution spectroscopy and preliminary global analysis of C-H stretching vibrations of C2H4 in the 3000 and 6000cm-1 regions", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 111(15), pp. 2265 – 2278. [Abstract] [BibTeX] [DOI]
Abstract: Ethylene (ethene, H2C=CH2) is a naturally occurring compound in ambient air that affects atmospheric chemistry and global climate. The C2H4 spectrum is available in databases only for the 1000 and 3000cm-1 ranges. In this work, the ethylene absorption spectrum was measured in the 6030-6250cm-1 range with the use of a high resolution Bruker IFS 125HR Fourier-spectrometer and a two-channel opto-acoustic spectrometer with a diode laser. As a secondary standard of wavelengths, the methane absorption spectrum was used in both cases.A preliminary analysis was realized thanks to the tensorial formalism developed by the Dijon group that is implemented in the XTDS software package [39]. We considered the two combination bands ν5+ν9 and ν5+ν11 as an interacting dyad. Parameters for the ν9/ν11 dyad were fitted simultaneously from a re-analysis of previously recorded supersonic expansion jet FTIR data, while parameters for the v5=1 Raman level were taken from literature. More than 600 lines could be assigned in the 6030-6250cm-1 region (and also 682 in the 2950-3150cm-1 region) and effective Hamiltonian parameters were fitted, including Coriolis interaction parameters. The dyad features are globally quite well reproduced, even if there are still problems at high J values. © 2010 Elsevier Ltd.
BibTeX: @article{LoronoGonzalez2010, author = {Loroño Gonzalez, M.A. and Boudon, V. and Loëte, M. and Rotger, M. and Bourgeois, M.-T. and Didriche, K. and Herman, M. and Kapitanov, V.A. and Ponomarev, Yu.N. and Solodov, A.A. and Solodov, A.M. and Petrova, T.M.}, title = {High-resolution spectroscopy and preliminary global analysis of C-H stretching vibrations of C2H4 in the 3000 and 6000cm-1 regions}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2010}, volume = {111}, number = {15}, pages = {2265 – 2278}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2010.04.010} }
Mathonet P, Krins S, Godefroid M, Lamata L, Solano E and Bastin T (2010), "Entanglement equivalence of N-qubit symmetric states", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 81(5) [Abstract] [BibTeX] [DOI]
Abstract: We study the interconversion of multipartite symmetric N-qubit states under stochastic local operations and classical communication (SLOCC). We demonstrate that if two symmetric states can be connected with a nonsymmetric invertible local operation (ILO), then they belong necessarily to the separable, W, or Greenberger-Horne-Zeilinger (GHZ) entanglement class, establishing a practical method of discriminating subsets of entanglement classes. Furthermore, we prove that there always exists a symmetric ILO connecting any pair of symmetric N-qubit states equivalent under SLOCC, simplifying the requirements for experimental implementations of local interconversion of those states. © 2010 The American Physical Society.
BibTeX: @article{Mathonet2010, author = {Mathonet, P. and Krins, S. and Godefroid, M. and Lamata, L. and Solano, E. and Bastin, T.}, title = {Entanglement equivalence of N-qubit symmetric states}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2010}, volume = {81}, number = {5}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.81.052315} }
Mikhailenko S, Tashkun S, Daumont L, Jenouvrier A, Carleer M, Fally S and Vandaele A (2010), "Line positions and energy levels of the 18O substitutions from the HDO/D2O spectra between 5600 and 8800cm-1", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 111(15), pp. 2185 – 2196. [Abstract] [BibTeX] [DOI]
Abstract: Absorption spectra of HDO/D2O mixtures recorded in the 5600-8800cm-1 region with a total pressure of water from 13 up to 18hPa and an absorption path length of 600m have been analyzed in order to obtain new spectroscopic data for HD18O and D218O. In spite of the low natural 18O concentration (about 2×10-3 with respect to the 16O one), about 1100 transitions belonging to HD18O and more than 280 transitions belonging to D218O have been assigned. Most of the D218O transitions belong to the v1+v2+v3 and 2v1+v3 bands. Sets of energy levels for seven vibrational states of D218O and four states of HD18O are reported for the first time. The comparison of the experimental data with the calculated values based on Partridge-Schwenke global variational calculations is discussed. © 2010 Elsevier Ltd.
BibTeX: @article{Mikhailenko2010, author = {Mikhailenko, S.N. and Tashkun, S.A. and Daumont, L. and Jenouvrier, A. and Carleer, M. and Fally, S. and Vandaele, A.C.}, title = {Line positions and energy levels of the 18O substitutions from the HDO/D2O spectra between 5600 and 8800cm-1}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2010}, volume = {111}, number = {15}, pages = {2185 – 2196}, doi = {10.1016/j.jqsrt.2010.01.028} }
Perry DS, Miller A, Amyay B, Fayt A and Herman M (2010), "Vibration-rotation alchemy in acetylene (12C2H 2), X̃1Σ+g at low vibrational excitation: From high resolution spectroscopy to fast intramolecular dynamics", Molecular Physics. Vol. 108(7-9), pp. 1115 – 1132. [Abstract] [BibTeX] [DOI]
Abstract: The link between energy-resolved spectra and time-resolved dynamics is explored quantitatively for acetylene (12C2H2), X̃1Σ+g with up to 8600 cm -1 of vibrational energy. This comparison is based on the extensive and reliable knowledge of the vibration-rotation energy levels and on the model Hamiltonian used to fit them to high precision [B. Amyay, S. Robert, M. Herman, A. Fayt, B. Raghavendra, A. Moudens, J. Thiévin, B. Rowe, and R. Georges, J. Chem. Phys. 131, 114301 (2009)]. Simulated intensity borrowing features in high resolution absorption spectra and predicted survival probabilities in intramolecular vibrational redistribution (IVR) are first investigated for the v4 + v5 and v3 bright states, for J = 2, 30 and 100. The dependence of the results on the rotational quantum number and on the choice of vibrational bright state reflects the interplay of three kinds of off-diagonal resonances: anharmonic, rotational l-type, and Coriolis. The dynamical quantities used to characterize the calculated time-dependent dynamics are the dilution factor φd, the IVR lifetime τIVR, and the recurrence time τrec. For the two bright states v3 + 2v4 and 7v4, the collisionless dynamics for thermally averaged rotational distributions at T = 27, 270 and 500 K were calculated from the available spectroscopic data. For the 7v4 bright state, an apparent irreversible decay of is found. In all cases, the model Hamiltonian allows a detailed calculation of the energy flow among all of the coupled zeroth-order vibration-rotation states. © 2010 Taylor & Francis.
BibTeX: @article{Perry2010, author = {Perry, David S. and Miller, Anthony and Amyay, Badr and Fayt, André and Herman, Michel}, title = {Vibration-rotation alchemy in acetylene (12C2H 2), X̃1Σ+g at low vibrational excitation: From high resolution spectroscopy to fast intramolecular dynamics}, journal = {Molecular Physics}, year = {2010}, volume = {108}, number = {7-9}, pages = {1115 – 1132}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268971003660874} }
Pommier M, Law K, Clerbaux C, Turquety S, Hurtmans D, Hadji-Lazaro J, Coheur P-F, Schlager H, Ancellet G, Paris J-D, Néd́lec P, Diskin G, Podolske J, Holloway J and Bernath P (2010), "IASI carbon monoxide validation over the Arctic during POLARCAT spring and summer campaigns", Atmospheric Chemistry and Physics. Vol. 10(21), pp. 10655 – 10678. [Abstract] [BibTeX] [DOI]
Abstract: In this paper, we provide a detailed comparison between carbon monoxide (CO) data measured by the Infrared Atmospheric Sounding Interferometer (IASI)/MetOp and aircraft observations over the Arctic. The CO measurements were obtained during North American (NASA ARCTAS and NOAA ARCPAC) and European campaigns (POLARCAT-France, POLARCAT-GRACE and YAK-AEROSIB) as part of the International Polar Year (IPY) POLARCAT activity in spring and summer 2008. During the campaigns different air masses were sampled including clean air, polluted plumes originating from anthropogenic sources in Europe, Asia and North America, and forest fire plumes originating from Siberia and Canada. The paper illustrates that CO-rich plumes following different transport pathways were well captured by the IASI instrument, in particular due to the high spatial coverage of IASI. The comparison between IASI CO total columns, 0ĝ€"5 km partial columns and profiles with collocated aircraft data was achieved by taking into account the different sensitivity and geometry of the sounding instruments. A detailed analysis is provided and the agreement is discussed in terms of information content and surface properties at the location of the observations. For profiles, the data were found to be in good agreement in spring with differences lower than 17%, whereas in summer the difference can reach 20% for IASI profiles below 8 km for polluted cases. For total columns the correlation coefficients ranged from 0.15 to 0.74 (from 0.47 to 0.77 for partial columns) in spring and from 0.26 to 0.84 (from 0.66 to 0.88 for partial columns) in summer. A better agreement is seen over the sea in spring (0.73 for total column and 0.78 for partial column) and over the land in summer (0.69 for total columns and 0.81 for partial columns). The IASI vertical sensitivity was better over land than over sea, and better over land than over sea ice and snow allowing a higher potential to detect CO vertical distribution during summer. © 2010 Author(s).
BibTeX: @article{Pommier2010, author = {Pommier, M. and Law, K.S. and Clerbaux, C. and Turquety, S. and Hurtmans, D. and Hadji-Lazaro, J. and Coheur, P.-F. and Schlager, H. and Ancellet, G. and Paris, J.-D. and Néd́lec, P. and Diskin, G.S. and Podolske, J.R. and Holloway, J.S. and Bernath, P.}, title = {IASI carbon monoxide validation over the Arctic during POLARCAT spring and summer campaigns}, journal = {Atmospheric Chemistry and Physics}, year = {2010}, volume = {10}, number = {21}, pages = {10655 – 10678}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-10-10655-2010} }
Prata A, Gangale G, Clarisse L and Karagulian F (2010), "Ash and sulfur dioxide in the 2008 eruptions of Okmok and Kasatochi: Insights from high spectral resolution satellite measurements", Journal of Geophysical Research Atmospheres. Vol. 115(22) [Abstract] [BibTeX] [DOI]
Abstract: Ash particles and sulfur dioxide gas are two significant components of volcanic clouds that are important because of their effects on the atmosphere. Several different satellite instruments are capable of delivering quantitative measurements of ash and SO2, but few can provide simultaneous assessments. High-spectral resolution (ν/Δν ∼ 1200) infrared satellite data from the Atmospheric Infrared Sounder (AIRS) are utilized to detect volcanic ash within the 8-12 μm window region, and at the same time exploit the 4.0 μm and 7.3 μm bands of SO2 to detect SO 2 at two different heights. The purpose is to study the interaction between gas and particles in dispersing volcanic clouds, and investigate the circumstances when the gas-rich and ash-rich parts of the plume are collocated and when they separate. Simultaneous retrievals of ash and SO2 in the eruption clouds from Okmok and Kasatochi suggest that the two components were transported together for at least the first 3 days after the initial injection. Later (several days) transport is difficult to infer because of the lack of sensitivity of the ash algorithm to thin, dispersing ash clouds. For Kasatochi and Okmok, AIRS measured maximum masses of approximately 1.21 ± 0.01 Tg and 0.29 ± 0.01 Tg of SO2, and 0.31 ± 0.03 Tg and 0.07 ±0.03 Tg of fine ash (1 μm < radii < 10 μm), respectively. The retrieval schemes described here are capable of detecting the distribution of SO2 simultaneously with estimates of ash concentrations from the same satellite instrument and represent an important improvement for observations of multispecies dispersing volcanic clouds. Analyses of other volcanic eruptions show that SO2 and ash do not always travel together. Consequently, it is concluded that for dispersing volcanic clouds it is vital to be able to detect both SO2-rich and ash-rich clouds simultaneously in order to diagnose their effect on the atmosphere and the aviation hazard. © 2010 by the American Geophysical Union.
BibTeX: @article{Prata2010, author = {Prata, A.J. and Gangale, G. and Clarisse, L. and Karagulian, F.}, title = {Ash and sulfur dioxide in the 2008 eruptions of Okmok and Kasatochi: Insights from high spectral resolution satellite measurements}, journal = {Journal of Geophysical Research Atmospheres}, year = {2010}, volume = {115}, number = {22}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2009JD013556} }
Predoi-Cross A, Ibrahim A, Herman M, Fusina L, Nivellini G and Di Lonardo G (2010), "The high resolution infrared spectrum of the v4 band of 1,1,1-trifluoroethane", Molecular Physics. Vol. 108(18), pp. 2303 – 2307. [Abstract] [BibTeX] [DOI]
Abstract: The v4 band of 1,1,1-trifluoroethane (CH3CF3) has been studied using synchrotron radiation at the far-infrared beamline, Canadian Light Source. The spectra were recorded at a resolution of 0.00096 cm-1 in the spectral range 800 to 860 cm-1 using a Bruker IFS125 FT spectrometer. Altogether 2785 lines were assigned to qPK(J) and qRK(J) transitions with J″ up to 71 and K up to 45. The qQK(J) sub-branches are too congested and overlapped to other hot-band Q branches to be analysed. A Watson-type Hamiltonian containing the usual terms up to the 6th power in the angular momentum operators was used in the analysis. The spectroscopic parameters obtained from the fit reproduce 2636 transitions with a standard deviation of about 0.00016 cm-1. © 2010 Taylor & Francis.
BibTeX: @article{PredoiCross2010a, author = {Predoi-Cross, A. and Ibrahim, A. and Herman, M. and Fusina, L. and Nivellini, G. and Di Lonardo, G.}, title = {The high resolution infrared spectrum of the v4 band of 1,1,1-trifluoroethane}, journal = {Molecular Physics}, year = {2010}, volume = {108}, number = {18}, pages = {2303 – 2307}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268971003720322} }
Predoi-Cross A, Liu W, Murphy R, Povey C, Gamache R, Laraia A, McKellar A, Hurtmans D and Malathy Devi V (2010), "Measurement and computations for temperature dependences of self-broadened carbon dioxide transitions in the 30012←00001 and 30013←00001 bands", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 111(9), pp. 1065 – 1079. [Abstract] [BibTeX] [DOI]
Abstract: Using a Fourier transform spectrometer setup we have measured the self-broadened half width, pressure shift, and line asymmetry coefficients for transitions in the 30012←00001 and 30013←00001 vibrational bands of carbon dioxide for four different temperatures. A total of 46 pure CO2 spectra were recorded at 0.008 and 0.009cm-1 resolution and at pressures varying from a few Torr to nearly an atmosphere. The individual spectral line profiles have been fitted by a Voigt profile and a speed-dependent Voigt profile, to which we have added dispersion profiles to account for weak line mixing. A comparison of the sets of results obtained for each band showed no vibrational dependence of the broadening coefficients. The self-broadening and self-shift coefficients are compared to semiclassical calculations based on the Robert-Bonamy formalism and were found to be in good agreement. The line asymmetry results are compared to line mixing calculations based on the Energy Corrected Sudden (ECS) and Exponential Power Gap models. © 2010 Elsevier Ltd.
BibTeX: @article{PredoiCross2010, author = {Predoi-Cross, A. and Liu, W. and Murphy, R. and Povey, C. and Gamache, R.R. and Laraia, A.L. and McKellar, A.R.W. and Hurtmans, D.R. and Malathy Devi, V.}, title = {Measurement and computations for temperature dependences of self-broadened carbon dioxide transitions in the 30012←00001 and 30013←00001 bands}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2010}, volume = {111}, number = {9}, pages = {1065 – 1079}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2010.01.003} }
Sutcliffe B (2010), "To what question is the clamped-nuclei electronic potential the answer?", Theoretical Chemistry Accounts. Vol. 127(3), pp. 121 – 131. [Abstract] [BibTeX] [DOI]
Abstract: An examination is made of how the nuclear motion Hamiltonian arises from a consideration of solutions to the eigenvalue problem for the full Coulomb Hamiltonian and the role played by the usual clamped-nuclei electronic Hamiltonian in the construction of such solutions. © 2009 Springer-Verlag.
BibTeX: @article{Sutcliffe2010, author = {Sutcliffe, Brian}, title = {To what question is the clamped-nuclei electronic potential the answer?}, journal = {Theoretical Chemistry Accounts}, year = {2010}, volume = {127}, number = {3}, pages = {121 – 131}, doi = {10.1007/s00214-009-0594-0} }
Verdebout S, Jönsson P, Gaigalas G, Godefroid M and Fischer CF (2010), "Exploring biorthonormal transformations of pair-correlation functions in atomic structure variational calculations", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 43(7) [Abstract] [BibTeX] [DOI]
Abstract: Multiconfiguration expansions frequently target valence correlation and correlation between valence electrons and the outermost core electrons. Correlation within the core is often neglected. A large orbital basis is needed to saturate both the valence and core-valence correlation effects. This in turn leads to huge numbers of configuration state functions (CSFs), many of which are unimportant. To avoid the problems inherent to the use of a single common orthonormal orbital basis for all correlation effects in the multiconfiguration Hartree-Fock (MCHF) method, we propose to optimize independent MCHF pair-correlation functions (PCFs), bringing their own orthonormal one-electron basis. Each PCF is generated by allowing single- and double-excitations from a multireference (MR) function. This computational scheme has the advantage of using targeted and optimally localized orbital sets for each PCF. These pair-correlation functions are coupled together and with each component of the MR space through a low dimension generalized eigenvalue problem. Nonorthogonal orbital sets being involved, the interaction and overlap matrices are built using biorthonormal transformation of the coupled basis sets followed by a counter-transformation of the PCF expansions. Applied to the ground state of beryllium, the new method gives total energies that are lower than the ones from traditional complete active space (CAS)-MCHF calculations using large orbital active sets. It is fair to say that we now have the possibility to account for, in a balanced way, correlation deep down in the atomic core in variational calculations. © 2010 IOP Publishing Ltd.
BibTeX: @article{Verdebout2010, author = {Verdebout, S. and Jönsson, P. and Gaigalas, G. and Godefroid, M. and Fischer, C Froese}, title = {Exploring biorthonormal transformations of pair-correlation functions in atomic structure variational calculations}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2010}, volume = {43}, number = {7}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/43/7/074017} }
Zander R, Duchatelet P, Mahieu E, Demoulin P, Roland G, Servais C, Auwera J, Perrin A, Rinsland C and Crutzen P (2010), "Formic acid above the Jungfraujoch during 1985-2007: Observed variability, seasonality, but no long-term background evolution", Atmospheric Chemistry and Physics. Vol. 10(20), pp. 10047 – 10065. [Abstract] [BibTeX] [DOI]
Abstract: This paper reports on daytime total vertical column abundances of formic acid (HCOOH) above the Northern mid-latitude, high altitude Jungfraujoch station (Switzerland; 46.5° N, 8.0° E, 3580 m alt.). The columns were derived from the analysis of infrared solar observations regularly performed with high spectral resolution Fourier transform spectrometers during over 1500 days between September 1985 and September 2007. The investigation was based on the spectrometric fitting of five spectral intervals, one encompassing the HCOOH ν6 band Q branch at 1105 cm-1, and four additional ones allowing to optimally account for critical temperature-sensitive or time-evolving interferences by other atmospheric gases, in particular HDO, CCl2F2 and CHClF2. The main results derived from the 22 years long database indicate that the free tropospheric burden of HCOOH above the Jungfraujoch undergoes important short-term daytime variability, diurnal and seasonal modulations, inter-annual anomalies, but no significant long-term background change. A major progress in the remote determination of the atmospheric HCOOH columns reported here has resulted from the adoption of new, improved absolute spectral line intensities for the infrared ν6 band of trans-formic acid, resulting in retrieved free tropospheric loadings being about a factor two smaller than if derived with previous spectroscopic parameters. Implications of this significant change with regard to earlier remote measurements of atmospheric formic acid and comparison with relevant Northern mid-latitude findings, both in situ and remote, will be assessed critically. Sparse HCOOH model predictions will also be evoked and assessed with respect to findings reported here. © 2010 Author(s).
BibTeX: @article{Zander2010, author = {Zander, R. and Duchatelet, P. and Mahieu, E. and Demoulin, P. and Roland, G. and Servais, C. and Auwera, J.V. and Perrin, A. and Rinsland, C.P. and Crutzen, P.J.}, title = {Formic acid above the Jungfraujoch during 1985-2007: Observed variability, seasonality, but no long-term background evolution}, journal = {Atmospheric Chemistry and Physics}, year = {2010}, volume = {10}, number = {20}, pages = {10047 – 10065}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-10-10047-2010} }
Amyay B, Robert Ś, Herman M, Fayt A, Raghavendra B, Moudens A, Thívin J, Rowe B and Georges R (2009), "Vibration-rotation pattern in acetylene. II. Introduction of Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 μm", Journal of Chemical Physics. Vol. 131(11) [Abstract] [BibTeX] [DOI]
Abstract: A high temperature source has been developed and coupled to a high resolution Fourier transform spectrometer to record emission spectra of acetylene around 3 μm up to 1455 K under Doppler limited resolution (0.015 cm-1). The ν3-ground state (GS) and ν2+ν4+ν5(∑u + and Δu)-GS bands and 76 related hot bands, counting e and f parities separately, are assigned using semiautomatic methods based on a global model to reproduce all related vibration-rotation states. Significantly higher J -values than previously reported are observed for 40 known substates while 37 new e or f vibrational substates, up to about 6000 cm-1, are identified and characterized by vibration-rotation parameters. The 3 811 new or improved data resulting from the analysis are merged into the database presented by Robert [Mol. Phys. 106, 2581 (2008)], now including 15 562 lines accessing vibrational states up to 8600 cm-1. A global model, updated as compared to the one in the previous paper, allows all lines in the database to be simultaneously fitted, successfully. The updates are discussed taking into account, in particular, the systematic inclusion of Coriolis interaction. © 2009 American Institute of Physics.
BibTeX: @article{Amyay2009, author = {Amyay, Badr and Robert, Śverine and Herman, Michel and Fayt, Andŕ and Raghavendra, Balakrishna and Moudens, Audrey and Thívin, Jonathan and Rowe, Bertrand and Georges, Robert}, title = {Vibration-rotation pattern in acetylene. II. Introduction of Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 μm}, journal = {Journal of Chemical Physics}, year = {2009}, volume = {131}, number = {11}, doi = {10.1063/1.3200928} }
Astoreca R, Rousseau V and Lancelot C (2009), "Coloured dissolved organic matter (CDOM) in Southern North Sea waters: Optical characterization and possible origin", Estuarine, Coastal and Shelf Science. Vol. 85(4), pp. 633 – 640. [Abstract] [BibTeX] [DOI]
Abstract: The variability and origin of the Coloured Dissolved Organic Matter (CDOM) were studied in the Belgian coastal and adjacent areas including offshore waters and the Scheldt estuary, through the parameters: absorption at 375 nm, aCDOM(375), and the slope of the absorption curve, S. aCDOM(375) varied between 0.20 and 1.31 m-1 and between 0.97 and 4.30 m-1 in the marine area and Scheldt estuary, respectively. S fluctuated between 0.0101 and 0.0203 nm-1 in the marine area and between 0.0167 and 0.0191 nm-1 in the Scheldt estuary. The comparative analysis of aCDOM(375) and S variations evidenced different origins of CDOM in the BCZ. The Scheldt estuarine waters showed decreasing aCDOM(375) values with increasing salinity but constant S value of ∼0.018 nm-1 suggesting a dominant terrestrial origin of CDOM. On the contrary, samples collected in the marine domain showed a narrow range of aCDOM(375) but highly variable S suggesting the additional presence of autochthonous sources of CDOM. This source was evidenced based on the sorting of the marine offshore data according to the stage of the phytoplankton bloom when they were collected. A clear distinction was made between CDOM released during the growth stage characterized by high S (∼0.017 nm-1) and low aCDOM(375) and the decay phase characterized by low S (∼0.013 nm-1) and high aCDOM(375). This observation was supported by CDOM measurements performed on pure phytoplankton cultures which showed increased CDOM release along the wax and wane of the bloom but decreasing S. We concluded that the high variability of the CDOM signature in offshore waters is explained by the local biological production and processing of CDOM. © 2009 Elsevier Ltd. All rights reserved.
BibTeX: @article{Astoreca2009, author = {Astoreca, Rosa and Rousseau, Véronique and Lancelot, Christiane}, title = {Coloured dissolved organic matter (CDOM) in Southern North Sea waters: Optical characterization and possible origin}, journal = {Estuarine, Coastal and Shelf Science}, year = {2009}, volume = {85}, number = {4}, pages = {633 – 640}, doi = {10.1016/j.ecss.2009.10.010} }
Astoreca R, Rousseau V, Ruddick K, Knechciak C, Van Mol B, Parent J-Y and Lancelot C (2009), "Development and application of an algorithm for detecting Phaeocystis globosa blooms in the Case 2 Southern North Sea waters", Journal of Plankton Research. Vol. 31(3), pp. 287 – 300. [Abstract] [BibTeX] [DOI]
Abstract: While mapping algal blooms from space is now well-established, mapping undesirable algal blooms in eutrophicated coastal waters raises further challenge in detecting individual phytoplankton species. In this paper, an algorithm is developed and tested for detecting Phaeocystis globosa blooms in the Southern North Sea. For this purpose, we first measured the light absorption properties of two phytoplankton groups, P. globosa and diatoms, in laboratory-controlled experiments. The main spectral difference between both groups was observed at 467 nm due to the absorption of the pigment chlorophyll c3 only present in P. globosa, suggesting that the absorption at 467 nm can be used to detect this alga in the field. A Phaeocystis-detection algorithm is proposed to retrieve chlorophyll c3 using either total absorption or water-leaving reflectance field data. Application of this algorithm to absorption and reflectance data from Phaeocystis-dominated natural communities shows positive results. Comparison with pigment concentrations and cell counts suggests that the algorithm can flag the presence of P. globosa and provide quantitative information above a chlorophyll c3 threshold of 0.3 mg m -3 equivalent to a P. globosa cell density of 3 × 10 6 cells L-1. Finally, the possibility of extrapolating this information to remote sensing reflectance data in these turbid waters is evaluated. © 2008 The Author(s).
BibTeX: @article{Astoreca2009a, author = {Astoreca, Rosa and Rousseau, Véronique and Ruddick, Kevin and Knechciak, Cécile and Van Mol, Barbara and Parent, Jean-Yves and Lancelot, Christiane}, title = {Development and application of an algorithm for detecting Phaeocystis globosa blooms in the Case 2 Southern North Sea waters}, journal = {Journal of Plankton Research}, year = {2009}, volume = {31}, number = {3}, pages = {287 – 300}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1093/plankt/fbn116} }
Bastin T, Krins S, Mathonet P, Godefroid M, Lamata L and Solano E (2009), "Operational families of entanglement classes for symmetric N-qubit states", Physical Review Letters. Vol. 103(7) [Abstract] [BibTeX] [DOI]
Abstract: We solve the entanglement classification under stochastic local operations and classical communication (SLOCC) for all multipartite symmetric states in the general N-qubit case. For this purpose, we introduce 2 parameters playing a crucial role, namely, the diversity degree and the degeneracy configuration of a symmetric state. Those parameters give rise to a simple method of identifying operational families of SLOCC entanglement classes of all symmetric N-qubit states, where the number of families grows as the partition function of the number of qubits. © 2009 The American Physical Society.
BibTeX: @article{Bastin2009, author = {Bastin, T. and Krins, S. and Mathonet, P. and Godefroid, M. and Lamata, L. and Solano, E.}, title = {Operational families of entanglement classes for symmetric N-qubit states}, journal = {Physical Review Letters}, year = {2009}, volume = {103}, number = {7}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevLett.103.070503} }
Bernath PF and Colin R (2009), "Revised molecular constants and term values for the X2Π and B2Σ+ states of OH", Journal of Molecular Spectroscopy. Vol. 257(1), pp. 20 – 23. [Abstract] [BibTeX] [DOI]
Abstract: An improved set of molecular constants and term values are given for the X2Π (v = 0-13) and B2Σ+ (v = 0 and 1) states of the OH radical. They are derived from a fit of previously published laboratory data and additional lines taken from infrared solar spectra recorded on orbit. © 2009 Elsevier Inc. All rights reserved.
BibTeX: @article{Bernath2009, author = {Bernath, Peter F. and Colin, Reginald}, title = {Revised molecular constants and term values for the X2Π and B2Σ+ states of OH}, journal = {Journal of Molecular Spectroscopy}, year = {2009}, volume = {257}, number = {1}, pages = {20 – 23}, doi = {10.1016/j.jms.2009.06.003} }
Blanquet G, Auwera JV and Lepère M (2009), "N2-broadening coefficients of ethane", Journal of Molecular Spectroscopy. Vol. 255(1), pp. 72 – 74. [Abstract] [BibTeX] [DOI]
Abstract: The N2-broadening coefficients of ethane for 15 lines in the ν9 band at five pressures of nitrogen were measured. The measurements were carried out with a 1-m base White-type cell adjusted for four transits, yielding an optical path of 4.17 m. The average values of the N2-broadening coefficients obtained at 296 K from the Voigt and Rautian line shapes are respectively equal to 0.0822 and 0.0864 cm-1 atm-1. The results derived from the Voigt profile are 2 10% lower than those derived from the Rautian model. No rotational dependence is observed over the limited range of rotational quantum numbers investigated. The results also show that the adjustment of the Rautian profile provides an additional parameter, the collisional narrowing coefficient β0.
BibTeX: @article{Blanquet2009, author = {Blanquet, Ghislain and Auwera, Jean Vander and Lepère, Muriel}, title = {N2-broadening coefficients of ethane}, journal = {Journal of Molecular Spectroscopy}, year = {2009}, volume = {255}, number = {1}, pages = {72 – 74}, doi = {10.1016/j.jms.2009.02.020} }
Boynard A, Clerbaux C, Coheur P-F, Hurtmans D, Turquety S, George M, Hadji-Lazaro J, Keim C and Meyer-Arnek J (2009), "Measurements of total and tropospheric ozone from IASI: Comparison with correlative satellite, ground-based and ozonesonde observations", Atmospheric Chemistry and Physics. Vol. 9(16), pp. 6255 – 6271. [Abstract] [BibTeX] [DOI]
Abstract: In this paper, we present measurements of total and tropospheric ozone, retrieved from infrared radiance spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI), which was launched on board the MetOp-A European satellite in October 2006. We compare IASI total ozone columns to Global Ozone Monitoring Experiment-2 (GOME-2) observations and groundbased measurements from the Dobson and Brewer network for one full year of observations (2008). The IASI total ozone columns are shown to be in good agreement with both GOME-2 and ground-based data, with correlation coefficients of about 0.9 and 0.85, respectively. On average, IASI ozone retrievals exhibit a positive bias of about 9DU (3.3%) compared to both GOME-2 and ground-based measurements. In addition to total ozone columns, the good spectral resolution of IASI enables the retrieval of tropospheric ozone concentrations. Comparisons of IASI tropospheric columns to 490 collocated ozone soundings available from several stations around the globe have been performed for the period of June 2007-August 2008. IASI tropospheric ozone columns compare well with sonde observations, with correlation coefficients of 0.95 and 0.77 for the [surface-6 km] and [surface-12 km] partial columns, respectively. IASI retrievals tend to overestimate the tropospheric ozone columns in comparison with ozonesonde measurements. Positive average biases of 0.15DU (1.2%) and 3DU (11%) are found for the [surface-6 km] and for the [surface-12 km] partial columns respectively. © 2009 Author(s).
BibTeX: @article{Boynard2009, author = {Boynard, A. and Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Turquety, S. and George, M. and Hadji-Lazaro, J. and Keim, C. and Meyer-Arnek, J.}, title = {Measurements of total and tropospheric ozone from IASI: Comparison with correlative satellite, ground-based and ozonesonde observations}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {16}, pages = {6255 – 6271}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-9-6255-2009} }
Cauëet E and Liévin J (2009), "Ab initio study of the electron transfer in an ionized stacked complex of guanines", Journal of Physical Chemistry A. Vol. 113(36), pp. 9881 – 9890. [Abstract] [BibTeX] [DOI]
Abstract: The charge transfer process in an ionized stacking of two consecutive guanines (G5'G3')+ has been studied by means of state-averaged CASSCF/MRCI and RASSCF/RASPT2 calculations. The ground and two first excited states of the radical cation have been characterized, and the topology of the corresponding potential energy surfaces (PESs) has been studied as a function of all intermolecular geometrical parameters. The results demonstrate that the charge transfer process in (G5'G 3')- is governed by the avoiding crossing between the ground and first excited states of the complex. Relative translation motions of both guanines in their molecular planes are shown to lead to the charge migration between G5' and G3'. Five stationary points (three minima and two saddle points) have been characterized along the reaction path describing the passage of the positive charge from G5' to G 3'. The global minimum on the PES is found to correspond to the charge configuration G5'+G3'. The existence of an intermediate minimum along the reaction path has been established, characterizing a structure where the positive charge is equally distributed between the two guanines. The calculated energy profile allowed us to determine the height of the potential energy barrier (7.33 kcal/mol) and to evaluate the electronic coupling at a geometry close to the avoiding crossing (3.6 kcal/mol). Test calculations showed that the topology of the ground state PES of the complex GG+ is qualitatively conserved upon optimization of the intramolecular geometrical parameters of the stationary points. © 2009 American Chemical Society.
BibTeX: @article{Caueet2009, author = {Cauëet, Emilie and Liévin, Jacques}, title = {Ab initio study of the electron transfer in an ionized stacked complex of guanines}, journal = {Journal of Physical Chemistry A}, year = {2009}, volume = {113}, number = {36}, pages = {9881 – 9890}, doi = {10.1021/jp902426p} }
Clarisse L, Clerbaux C, Dentener F, Hurtmans D and Coheur P-F (2009), "Global ammonia distribution derived from infrared satellite observations", Nature Geoscience. Vol. 2(7), pp. 479 – 483. [Abstract] [BibTeX] [DOI]
Abstract: Global ammonia emissions have more than doubled since pre-industrial times, largely owing to agricultural intensification and widespread fertilizer use1. In the atmosphere, ammonia accelerates particulate matter formation, thereby reducing air quality. When deposited in nitrogen-limited ecosystems, ammonia can act as a fertilizer. This can lead to biodiversity reductions in terrestrial ecosystems, and algal blooms in aqueous environments2-8. Despite its ecological significance, there are large uncertainties in the magnitude of ammonia emissions, mainly owing to a paucity of ground-based observations and a virtual absence of atmospheric measurements3,8-11. Here we use infrared spectra, obtained by the IASI/MetOp satellite, to map global ammonia concentrations from space over the course of 2008. We identify several ammonia hotspots in middle-low latitudes across the globe. In general, we find a good qualitative agreement between our satellite measurements and simulations made using a global atmospheric chemistry transport model. However, the satellite data reveal substantially higher concentrations of ammonia north of 30° N, compared with model projections. We conclude that ammonia emissions could have been significantly underestimated in the Northern Hemisphere, and suggest that satellite monitoring of ammonia from space will improve our understanding of the global nitrogen cycle. © 2009 Macmillan Publishers Limited. All rights reserved.
BibTeX: @article{Clarisse2009, author = {Clarisse, Lieven and Clerbaux, Cathy and Dentener, Frank and Hurtmans, Daniel and Coheur, Pierre-François}, title = {Global ammonia distribution derived from infrared satellite observations}, journal = {Nature Geoscience}, year = {2009}, volume = {2}, number = {7}, pages = {479 – 483}, doi = {10.1038/ngeo551} }
Clerbaux C, Boynard A, Clarisse L, George M, Hadji-Lazaro J, Herbin H, Hurtmans D, Pommier M, Razavi A, Turquety S, Wespes C and Coheur P-F (2009), "Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder", Atmospheric Chemistry and Physics. Vol. 9(16), pp. 6041 – 6054. [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric remote sounding from satellites is an essential component of the observational strategy deployed to monitor atmospheric pollution and changing composition. The IASI nadir looking thermal infrared sounder onboard MetOp will provide 15 years of global scale observations for a series of key atmospheric species, with unprecedented spatial sampling and coverage. This paper gives an overview of the instrument's capability for measuring atmospheric composition in the perspective of chemistry and air quality. The assessment is made in terms of species, accuracy and vertical information. Global distributions are presented for CO, CH4, O3 (total and tropospheric), HNO3, NH3, and volcanic SO2. Local distributions of organic species measured during fire events, such as C2H4, CH3OH, HCOOH, and PAN are also shown. For each species or process, the link is made to specialized papers in this issue. © 2009 Author(s).
BibTeX: @article{Clerbaux2009, author = {Clerbaux, C. and Boynard, A. and Clarisse, L. and George, M. and Hadji-Lazaro, J. and Herbin, H. and Hurtmans, D. and Pommier, M. and Razavi, A. and Turquety, S. and Wespes, C. and Coheur, P.-F.}, title = {Monitoring of atmospheric composition using the thermal infrared IASI/MetOp sounder}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {16}, pages = {6041 – 6054}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-9-6041-2009} }
Coheur P-F, Clarisse L, Turquety S, Hurtmans D and Clerbaux C (2009), "IASI measurements of reactive trace species in biomass burning plumes", Atmospheric Chemistry and Physics. Vol. 9(15), pp. 5655 – 5667. [Abstract] [BibTeX] [DOI]
Abstract: This work presents observations of a series of short-lived species in biomass burning plumes from the Infrared Atmospheric Sounding Interferometer (IASI), launched onboard the MetOp-A platform in October 2006. The strong fires that have occurred in the Mediterranean Basin - and particularly Greece - in August 2007, and those in Southern Siberia and Eastern Mongolia in the early spring of 2008 are selected to support the analyses. We show that the IASI infrared spectra in these fire plumes contain distinctive signatures of ammonia (NH3), ethene (C2H4), methanol (CH 3OH) and formic acid (HCOOH) in the atmospheric window between 800 and 1200 cm-1, with some noticeable differences between the plumes. Peroxyacetyl nitrate (CH3COOONO2, abbreviated as PAN) was also observed with good confidence in some plumes and a tentative assignment of a broadband absorption spectral feature to acetic acid (CH3COOH) is made. For several of these species these are the first reported measurements made from space in nadir geometry. The IASI measurements are analyzed for plume height and concentration distributions of NH3, C2H 4 and CH3OH. The Greek fires are studied in greater detail for the days associated with the largest emissions. In addition to providing information on the spatial extent of the plume, the IASI retrievals allow an estimate of the total mass emissions for NH3, C2H 4 and CH3OH. Enhancement ratios are calculated for the latter relative to carbon monoxide (CO), giving insight in the chemical processes occurring during the transport, the first day after the emission.
BibTeX: @article{Coheur20095655, author = {Coheur, P.-F. and Clarisse, L. and Turquety, S. and Hurtmans, D. and Clerbaux, C.}, title = {IASI measurements of reactive trace species in biomass burning plumes}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {15}, pages = {5655 – 5667}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-9-5655-2009} }
Didriche K, Lauzin C, Macko P, Herman M and Lafferty W (2009), "Observation of the C2H2-N2O van der Waals complex in the overtone range using CW-CRDS", Chemical Physics Letters. Vol. 469(1-3), pp. 35 – 37. [Abstract] [BibTeX] [DOI]
Abstract: A slit nozzle supersonic expansion containing C2H2 (246 sccm) and N2O (355 sccm) seeded into Ar (1260 sccm) is investigated using CW cavity ring-down spectroscopy, in the 1.5 μm range. The C2H2-N2O van der Waals complex is observed around the 2CH acetylenic band. Despite strong perturbations, 117 b-type lines are assigned. Their combined fit with published microwave data leads to new upper state and improved lower state rotational constants. The Lorentzian width of the assigned line profiles sets the mean lifetime to 1.6 ns. The rotational temperature is estimated to be 15 K from the comparison between observed and simulated spectra. © 2008 Elsevier B.V. All rights reserved.
BibTeX: @article{Didriche2009, author = {Didriche, K. and Lauzin, C. and Macko, P. and Herman, M. and Lafferty, W.J.}, title = {Observation of the C2H2-N2O van der Waals complex in the overtone range using CW-CRDS}, journal = {Chemical Physics Letters}, year = {2009}, volume = {469}, number = {1-3}, pages = {35 – 37}, doi = {10.1016/j.cplett.2008.12.037} }
Fally S, Carleer M and Vandaele AC (2009), "UV Fourier transform absorption cross sections of benzene, toluene, meta-, ortho-, and para-xylene", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 110(9-10), pp. 766 – 782. [Abstract] [BibTeX] [DOI]
Abstract: New measurements of the absorption cross sections of gaseous benzene, toluene, meta-, ortho-, and para-xylene have been performed with a Fourier transform spectrometer Bruker IFS120 M at the resolution of 1 cm-1 over the 30 000-42 000 cm-1 spectral range. The recordings were carried out under different pressure and temperature conditions with pure samples. The effect of the temperature on the absorption cross sections is investigated. Comparison with the literature shows large differences, largely attributed to the experimental difficulties encountered during these previous measurements and to a resolution effect. To our knowledge, it is the first time that such a dataset of UV absorption cross sections with temperature dependence is reported in the literature. Such data should be useful for upcoming remote sensing applications, such as atmospheric studies both on Earth and on other planets. © 2008 Elsevier Ltd. All rights reserved.
BibTeX: @article{Fally2009, author = {Fally, Sophie and Carleer, Michel and Vandaele, Ann C.}, title = {UV Fourier transform absorption cross sections of benzene, toluene, meta-, ortho-, and para-xylene}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2009}, volume = {110}, number = {9-10}, pages = {766 – 782}, doi = {10.1016/j.jqsrt.2008.11.014} }
Fortems-Cheiney A, Chevallier F, Pison I, Bousquet P, Carouge C, Clerbaux C, Coheur P-F, George M, Hurtmans D and Szopa S (2009), "On the capability of IASI measurements to inform about CO surface emissions", Atmospheric Chemistry and Physics. Vol. 9(22), pp. 8735 – 8743. [Abstract] [BibTeX] [DOI]
Abstract: Between July and November 2008, simultaneous observations were conducted by several orbiting instruments that monitor carbon monoxide in the atmosphere, among them the Infrared Atmospheric Sounding Instrument (IASI) and Measurements Of Pollution In The Troposphere (MOPITT). In this paper, the concentration retrievals at about 700 hPa from these two instruments are successively used in a variational Bayesian system to infer the global distribution of CO emissions. Starting from a global emission budget of 479 Tg for the considered period, the posterior estimate of CO emissions using IASI retrievals gives a total of 643 Tg, which is in close agreement with the budget calculated with version 3 of the MOPITT data (649 Tg). The regional totals are also broadly consistent between the two inversions. Even though our theoretical error budget indicates that IASI constrains the emissions slightly less than MOPITT, because of lesser sensitivity in the lower troposphere, these first results indicate that IASI may play a major role in the quantification of the emissions of CO.
BibTeX: @article{Fortems-Cheiney20098735, author = {Fortems-Cheiney, A. and Chevallier, F. and Pison, I. and Bousquet, P. and Carouge, C. and Clerbaux, C. and Coheur, P.-F. and George, M. and Hurtmans, D. and Szopa, S.}, title = {On the capability of IASI measurements to inform about CO surface emissions}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {22}, pages = {8735 – 8743}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-9-8735-2009} }
George M, Clerbaux C, Hurtmans D, Turquety S, Coheur P-F, Pommier M, Hadji-Lazaro J, Edwards D, Worden H, Luo M, Rinsland C and McMillan W (2009), "Carbon monoxide distributions from the IASI/METOP mission: Evaluation with other space-borne remote sensors", Atmospheric Chemistry and Physics. Vol. 9(21), pp. 8317 – 8330. [Abstract] [BibTeX] [DOI]
Abstract: The Infrared Atmospheric Sounding Interferometer (IASI) onboard the MetOp satellite measures carbon monoxide (CO) on a global scale, twice a day. CO total columns and vertical profiles are retrieved in near real time from the nadir radiance spectra measured by the instrument in the thermal infrared (TIR) spectral range. This paper describes the measurement vertical sensitivity and provides a first assessment of the capabilities of IASI to measure CO distributions. On the global scale, 0.8 to 2.4 independent pieces of information are available for the retrieval. At mid latitudes, the information ranges between 1.5 and 2, which enables the lower and upper troposphere to be distinguished, especially when thermal contrast is significant. Global distributions of column CO are evaluated with correlative observations available from other nadir looking TIR missions currently in operation: the Measurements of Pollution in the Troposphere (MOPITT) onboard TERRA, the Atmospheric Infrared Sounder (AIRS) onboard AQUA and the Tropospheric Emission Spectrometer (TES) onboard AURA. The IASI CO columns are compared with MOPITT, AIRS and TES CO columns, adjusted with the a priori, for three different months: August 2008, November 2008 and February 2009. On average, total column discrepancies of about 7% are found between IASI and the three other sounders in the Northern Hemisphere and in the equatorial region. However when strong CO concentrations are present, such as during fire events, these discrepancies can climb as high as 17%. Instrument specifications of IASI versus other missions are also discussed.
BibTeX: @article{George20098317, author = {George, M. and Clerbaux, C. and Hurtmans, D. and Turquety, S. and Coheur, P.-F. and Pommier, M. and Hadji-Lazaro, J. and Edwards, D.P. and Worden, H. and Luo, M. and Rinsland, C. and McMillan, W.}, title = {Carbon monoxide distributions from the IASI/METOP mission: Evaluation with other space-borne remote sensors}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {21}, pages = {8317 – 8330}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-9-8317-2009} }
Herbin H, Hurtmans D, Clarisse L, Turquety S, Clerbaux C, Rinsland C, Boone C, Bernath P and Coheur P-F (2009), "Distributions and seasonal variations of tropospheric ethene (C 2H4) from Atmospheric Chemistry Experiment (ACE-FTS) solar occupation spectra", Geophysical Research Letters. Vol. 36(4) [Abstract] [BibTeX] [DOI]
Abstract: This work reports the first measurements of ethene (C2H 4) distributions in the upper troposphere. These are obtained by retrieving vertical profiles from 5 to 20 km infrared solar occultation spectra recorded in 2005 and 2006 by the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS). Background volume mixing ratios (vmrs) ranging from a few to about 50 pptv (10-12) are measured at the different altitudes, while for certain occultations, vmrs as high as 200 pptv are observed. Zonal distributions and vertically resolved latitudinal distributions are derived for the two year period analyzed, highlighting spatial -including a North-South gradient- as well as seasonal variations. We show the latter to be more pronounced at the highest latitudes, presumably as a result less active photochemistry during winter. The observation of C2H4 enhancements in remote Arctic regions at high latitudes is consistent with the occurrence fast transport processes of gaseous pollution from the continents leading to Arctic haze. © 2009.
BibTeX: @article{Herbin2009, author = {Herbin, H. and Hurtmans, D. and Clarisse, L. and Turquety, S. and Clerbaux, C. and Rinsland, C.P. and Boone, C. and Bernath, P.F. and Coheur, P.-F.}, title = {Distributions and seasonal variations of tropospheric ethene (C 2H4) from Atmospheric Chemistry Experiment (ACE-FTS) solar occupation spectra}, journal = {Geophysical Research Letters}, year = {2009}, volume = {36}, number = {4}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1029/2008GL036338} }
Herbin H, Hurtmans D, Clerbaux C, Clarisse L and Coheur P-F (2009), "H216O and HDO measurements with IASI/MetOp", Atmospheric Chemistry and Physics. Vol. 9(24), pp. 9433 – 9447. [Abstract] [BibTeX] [DOI]
Abstract: In this paper we analyze distributions of water vapour isotopologues in the troposphere using infrared spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI), which operates onboard the Metop satellite in nadir geometry. The simultaneous uncorrelated retrievals of H2 16O and HDO are performed on radiance measurements using a line-by-line radiative transfer model and an inversion procedure based on the Optimal Estimation Method (OEM). The characterizations of the retrieved products in terms of vertical sensitivity and error budgets show that IASI measurements contain up to 6 independent pieces of information on the vertical distribution of H216O and up to 3.5 for HDO from the surface up to the upper troposphere (0-20 km). Although the purpose of the paper is not validation, a restricted comparison with sonde measurements shows that the retrieved H216O profiles capture the seasonal/latitudinal variations of the water content, with good accuracy in the lowest layer but with larger uncertainties higher in the free and upper troposphere. Our results then demonstrate the ability of the IASI instrument to monitor atmospheric isotopologic water vapour distributions and to provide information on the partitioning of HDO as compared to H216O. The derivation of the δD is challenging and associated with large errors in the uncorrelated retrieval approach chosen here. As a result averaging on the vertical to produce a column-averaged δD is required to produce meaningful results for geophysical interpretation. As a case study, we analyse concentration distributions and spatio-temporal variations of H2 16O and δD during the October 2007 Krosa super-typhoon over South-East Asia. We show that individual δD have uncertainties of 37&permil; for the vertically averaged values. Using the latter, we suggest that the typhoon produces a so-called amount-effect, where the δD is negatively correlated to the water amounts as a result of intense depletion of the deuterated species.
BibTeX: @article{Herbin2009a, author = {Herbin, H. and Hurtmans, D. and Clerbaux, C. and Clarisse, L. and Coheur, P.-F.}, title = {H216O and HDO measurements with IASI/MetOp}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {24}, pages = {9433 – 9447}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-9-9433-2009} }
Hurtmans D, Henry A, Valentin A and Boulet C (2009), "Narrowing broadening and shifting parameters for R(2) and P(14) lines in the HCl fundamental band perturbed by N2 and rare gases from tunable diode laser spectroscopy", Journal of Molecular Spectroscopy. Vol. 254(2), pp. 126 – 136. [Abstract] [BibTeX] [DOI]
Abstract: High resolution measurements of room temperature absorption with a controlled tunable diode laser (TDL) spectrometer have been made for R(2) and P(14) lines in the HCl fundamental band perturbed by N2, Xe, Ar and He at pressures lower than one atmosphere. Pressure broadening, shift and collisional narrowing parameters have been extracted by least-squares fitting of several collisional profiles to the spectra. Asymmetries are observed for P(14) broadened by Xe at the lowest pressures and attributed to correlations between velocity- and phase-changing collisions. © 2009 Elsevier Inc. All rights reserved.
BibTeX: @article{Hurtmans2009, author = {Hurtmans, D. and Henry, A. and Valentin, A. and Boulet, C.}, title = {Narrowing broadening and shifting parameters for R(2) and P(14) lines in the HCl fundamental band perturbed by N2 and rare gases from tunable diode laser spectroscopy}, journal = {Journal of Molecular Spectroscopy}, year = {2009}, volume = {254}, number = {2}, pages = {126 – 136}, doi = {10.1016/j.jms.2009.01.015} }
Iluz D, Dishon G, Capuzzo E, Meeder E, Astoreca R, Montecino V, Znachor P, Ediger D and Marra J (2009), "Short-term variability in primary productivity during a wind-driven diatom bloom in the Gulf of Eilat (Aqaba)", Aquatic Microbial Ecology. Vol. 56(2-3), pp. 205 – 215. [Abstract] [BibTeX] [DOI]
Abstract: In the northern Gulf of Eilat (Aqaba), sharp increases in the biomass of diatoms and rates of primary production occurred in April 2008. Within 24 h, diatom abundance rose from 8 Ã- 103 to 228 Ã- 10 3 cells l-1, and photosynthetic rates concomitantly doubled from 15 to 35 μg C l-1 d-1. Water transparency declined, as indicated by the vertical diffusion attenuation coefficient K d for photosynthetically active radiation (PAR), which increased from 0.076 to 0.090 m-1 and decreased the euphotic depth from 60 to 45 m. During this time, a significant increase in silica deposition by the diatoms was also detected. We attribute the mentioned changes in environmental characteristics to wind-generated surface currents. Strong winds (up to 10 m s-1) during the measurements enriched the surface layers with unusually high nutrient concentrations within.
BibTeX: @article{Iluz2009, author = {Iluz, David and Dishon, Gal and Capuzzo, Elisa and Meeder, Efrat and Astoreca, Rosa and Montecino, Vivian and Znachor, Petr and Ediger, Dilek and Marra, John}, title = {Short-term variability in primary productivity during a wind-driven diatom bloom in the Gulf of Eilat (Aqaba)}, journal = {Aquatic Microbial Ecology}, year = {2009}, volume = {56}, number = {2-3}, pages = {205 – 215}, note = {All Open Access, Bronze Open Access}, doi = {10.3354/ame01321} }
Keim C, Eremenko M, Orphal J, Dufour G, Flaud J-M, Höpfner M, Boynard A, Clerbaux C, Payan S, Coheur P-F, Hurtmans D, Claude H, Dier H, Johnson B, Kelder H, Kivi R, Koide T, Bartolomé ML, Lambkin K, Moore D, Schmidlin F and Stübi R (2009), "Tropospheric ozone from IASI: Comparison of different inversion algorithms and validation with ozone sondes in the northern middle latitudes", Atmospheric Chemistry and Physics. Vol. 9(24), pp. 9329 – 9347. [Abstract] [BibTeX] [DOI]
Abstract: This paper presents a first statistical validation of tropospheric ozone products derived from measurements of the IASI satellite instrument. Since the end of 2006, IASI (Infrared Atmospheric Sounding Interferometer) aboard the polar orbiter Metop-A measures infrared spectra of the Earth's atmosphere in nadir geometry. This validation covers the northern mid-latitudes and the period from July 2007 to August 2008. Retrieval results from four different sources are presented: three are from scientific products (LATMOS, LISA, LPMAA) and the fourth one is the pre-operational product distributed by EUMETSAT (version 4.2). The different products are derived from different algorithms with different approaches. The difference and their implications for the retrieved products are discussed. In order to evaluate the quality and the performance of each product, comparisons with the vertical ozone concentration profiles measured by balloon sondes are performed and lead to estimates of the systematic and random errors in the IASI ozone products (profiles and partial columns). A first comparison is performed on the given profiles; a second comparison takes into account the altitude dependent sensitivity of the retrievals. Tropospheric columnar amounts are compared to the sonde for a lower tropospheric column (surface to about 6 km) and a total tropospheric column (surface to about 11 km). On average both tropospheric columns have small biases for the scientific products, less than 2 Dobson Units (DU) for the lower troposphere and less than 1 DU for the total troposphere. The comparison of the still pre-operational EUMETSAT columns shows higher mean differences of about 5 DU.
BibTeX: @article{Keim2009, author = {Keim, C. and Eremenko, M. and Orphal, J. and Dufour, G. and Flaud, J.-M. and Höpfner, M. and Boynard, A. and Clerbaux, C. and Payan, S. and Coheur, P.-F. and Hurtmans, D. and Claude, H. and Dier, H. and Johnson, B. and Kelder, H. and Kivi, R. and Koide, T. and Bartolomé, M. López and Lambkin, K. and Moore, D. and Schmidlin, F.J. and Stübi, R.}, title = {Tropospheric ozone from IASI: Comparison of different inversion algorithms and validation with ozone sondes in the northern middle latitudes}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {24}, pages = {9329 – 9347}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-9-9329-2009} }
Laj P, Klausen J, Bilde M, Plaß-Duelmer C, Pappalardo G, Clerbaux C, Baltensperger U, Hjorth J, Simpson D, Reimann S, Coheur P-F, Richter A, De Mazière M, Rudich Y, McFiggans G, Torseth K, Wiedensohler A, Morin S, Schulz M, Allan J, Attié J-L, Barnes I, Birmili W, Cammas J, Dommen J, Dorn H-P, Fowler D, Fuzzi S, Glasius M, Granier C, Hermann M, Isaksen I, Kinne S, Koren I, Madonna F, Maione M, Massling A, Moehler O, Mona L, Monks P, Müller D, Müller T, Orphal J, Peuch V-H, Stratmann F, Tanré D, Tyndall G, Abo Riziq A, Van Roozendael M, Villani P, Wehner B, Wex H and Zardini A (2009), "Measuring atmospheric composition change", Atmospheric Environment. Vol. 43(33), pp. 5351 – 5414. [Abstract] [BibTeX] [DOI]
Abstract: Scientific findings from the last decades have clearly highlighted the need for a more comprehensive approach to atmospheric change processes. In fact, observation of atmospheric composition variables has been an important activity of atmospheric research that has developed instrumental tools (advanced analytical techniques) and platforms (instrumented passenger aircrafts, ground-based in situ and remote sensing stations, earth observation satellite instruments) providing essential information on the composition of the atmosphere. The variability of the atmospheric system and the extreme complexity of the atmospheric cycles for short-lived gaseous and aerosol species have led to the development of complex models to interpret observations, test our theoretical understanding of atmospheric chemistry and predict future atmospheric composition. The validation of numerical models requires accurate information concerning the variability of atmospheric composition for targeted species via comparison with observations and measurements. In this paper, we provide an overview of recent advances in instrumentation and methodologies for measuring atmospheric composition changes from space, aircraft and the surface as well as recent improvements in laboratory techniques that permitted scientific advance in the field of atmospheric chemistry. Emphasis is given to the most promising and innovative technologies that will become operational in the near future to improve knowledge of atmospheric composition. Our current observation capacity, however, is not satisfactory to understand and predict future atmospheric composition changes, in relation to predicted climate warming. Based on the limitation of the current European observing system, we address the major gaps in a second part of the paper to explain why further developments in current observation strategies are still needed to strengthen and optimise an observing system not only capable of responding to the requirements of atmospheric services but also to newly open scientific questions. © 2009 Elsevier Ltd. All rights reserved.
BibTeX: @article{Laj20095351, author = {Laj, P. and Klausen, J. and Bilde, M. and Plaß-Duelmer, C. and Pappalardo, G. and Clerbaux, C. and Baltensperger, U. and Hjorth, J. and Simpson, D. and Reimann, S. and Coheur, P.-F. and Richter, A. and De Mazière, M. and Rudich, Y. and McFiggans, G. and Torseth, K. and Wiedensohler, A. and Morin, S. and Schulz, M. and Allan, J.D. and Attié, J.-L. and Barnes, I. and Birmili, W. and Cammas, J.P. and Dommen, J. and Dorn, H.-P. and Fowler, D. and Fuzzi, S. and Glasius, M. and Granier, C. and Hermann, M. and Isaksen, I.S.A. and Kinne, S. and Koren, I. and Madonna, F. and Maione, M. and Massling, A. and Moehler, O. and Mona, L. and Monks, P.S. and Müller, D. and Müller, T. and Orphal, J. and Peuch, V.-H. and Stratmann, F. and Tanré, D. and Tyndall, G. and Abo Riziq, A. and Van Roozendael, M. and Villani, P. and Wehner, B. and Wex, H. and Zardini, A.A.}, title = {Measuring atmospheric composition change}, journal = {Atmospheric Environment}, year = {2009}, volume = {43}, number = {33}, pages = {5351 – 5414}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.atmosenv.2009.08.020} }
Laruelle F, Boyé-Péronne S, Gauyacq D and Liévin J (2009), "Revisiting mulliken's concepts about rydberg states and rydberg-valence interactions from large-scale ab initio calculations on the acetylene molecule", Journal of Physical Chemistry A. Vol. 113(47), pp. 13210 – 13220. [Abstract] [BibTeX] [DOI]
Abstract: A quantitative characterization of the Rydberg and valence singlet electronic states of acetylene lying in the 5-10.7 eV region is performed by using large-scale ab initio calculations. A special attention is paid on the comparison between the present calculations and Mulliken's concepts for Rydberg states, based on singleelectron and single-configuration description. Most of the properties of the Rydberg states have been qualitatively understood via this comparison, mainly shown by the shape and size of the outer Rydberg molecular orbital. More quantitatively, Rydberg-valence mixing has been evaluated in several excited energy regions, as for instance, the interaction between the C̃ ' (1πg)2 1Ag doubly excited valence state and the manifold of electronic components of the np series, or the interaction between the Ẽ 1πg 1Bu valence state and the F̃ 3dπg 1σu+ Rydberg state. The rapid predissociation of the lowest C̃ 3só 1.u Rydberg state has been interpreted as a case of Rydbergization, earlier predicted by Mulliken. © 2009 American Chemical Society.
BibTeX: @article{Laruelle2009, author = {Laruelle, Fabrice and Boyé-Péronne, Séverine and Gauyacq, Dolores and Liévin, Jacques}, title = {Revisiting mulliken's concepts about rydberg states and rydberg-valence interactions from large-scale ab initio calculations on the acetylene molecule}, journal = {Journal of Physical Chemistry A}, year = {2009}, volume = {113}, number = {47}, pages = {13210 – 13220}, doi = {10.1021/jp903948k} }
Lauzin C, Didriche K, Lívin J, Herman M and Perrin A (2009), "Investigation of the C2 H2 - CO2 van der Waals complex in the overtone range using cw cavity ring-down spectroscopy", Journal of Chemical Physics. Vol. 130(20) [Abstract] [BibTeX] [DOI]
Abstract: A slit nozzle supersonic expansion containing acetylene [492 SCCM (SCCM denotes cubic centimeter per minute at STP)] and carbon dioxide (740 SCCM) seeded into Ar (837 SCCM) is investigated using cw-cavity ring-down spectroscopy, in the 1.5 μm range. The C2 H2 - CO 2 van der Waals complex is observed around the v1 + v 3 acetylenic band. The rotational temperature is estimated to be close to 60 K from the comparison between observed and simulated spectra. The analysis of the main, perturbed B -type band centered near 6 549.280 cm -1, is performed. It is attributed to a dimer with the known planar, C2v geometry. The present overtone data, involving ground state levels with higher J/K states (J≤35 and Ka≤ 20) than previously reported, are combined to 3 μm data [D. G. Prichard, R. N. Nandi, J. S. Muenter, and B. J. Howard, J. Chem. Phys. 89, 1245 (1988); Z. S. Huang and R. E. Miller, Chem. Phys. 132, 185 (1989)] to determine improved ground state parameters. The major perturbations affecting the upper state are accounted for through C -type Coriolis resonances involving one dark state, whose symmetry must therefore be A1. Upper state constants are obtained for the bright and dark states. The dependence upon vibrational excitation is demonstrated to arise from excitation in the acetylene unit, only, for the former, but cannot be unravelled for the latter. © 2009 American Institute of Physics.
BibTeX: @article{Lauzin2009, author = {Lauzin, C. and Didriche, K. and Lívin, J. and Herman, M. and Perrin, A.}, title = {Investigation of the C2 H2 - CO2 van der Waals complex in the overtone range using cw cavity ring-down spectroscopy}, journal = {Journal of Chemical Physics}, year = {2009}, volume = {130}, number = {20}, doi = {10.1063/1.3137069} }
Lauzin C, Didriche K, Macko P, Demaison J, Lievin J and Herman M (2009), "12C2H2-Ar van der Waals complex", Journal of Physical Chemistry A. Vol. 113(11), pp. 2359 – 2365. [Abstract] [BibTeX] [DOI]
Abstract: New theoretical and experimental results on the acetylene-Ar van der Waals complex are presented and the literature is reviewed. New ab initio calculations at the MP2 level were performed using large basis sets with diffuse functions and taking into account the basis set superposition error. It was found that the structure of acetylene is not significantly altered by the complexation and that its vibrational frequencies are only slightly lowered. Finally, it was observed that the calculated properties of the complex (structure, vibrational spectrum, bond dissociation energy) are not sensitive to the structure imposed on acetylene. Experimentally, acetylene-Ar was produced in a supersonic expansion under experimental conditions corresponding to 9 K rotational temperature. Thanks to the performances of CW-CRDS detection, the Ka = 0 ← 1, 1 ← 0, and 2 ← 1 sub- bands of the v1 + v3 band could be recorded and resolved and most of their lines assigned. Upper-state rotational constants were fitted, however not including the upper Ka = 2 state, which shows K-doubling the opposite of the expected. The Lorentzian width of most line profiles sets the mean lifetime to some 7.5 ns. Local perturbations affecting line positions and/or line widths are demonstrated. Additional series of lines tentatively attributed to acetylene-Ar are discussed.© 2009 American Chemical Society.
BibTeX: @article{Lauzin2009a, author = {Lauzin, C. and Didriche, K. and Macko, P. and Demaison, J. and Lievin, J. and Herman, M.}, title = {12C2H2-Ar van der Waals complex}, journal = {Journal of Physical Chemistry A}, year = {2009}, volume = {113}, number = {11}, pages = {2359 – 2365}, doi = {10.1021/jp8077908} }
Massart S, Clerbaux C, Cariolle D, Piacentini A, Turquety S and Hadji-Lazaro J (2009), "First steps towards the assimilation of IASI ozone data into the MOCAGE-PALM system", Atmospheric Chemistry and Physics. Vol. 9(14), pp. 5073 – 5091. [Abstract] [BibTeX] [DOI]
Abstract: With the use of data assimilation, we study the quality of the Infrared Atmospheric Sounding Interferometer (IASI) total ozone column measurements. The IASI data are provided by the inversion of IASI radiances performed at the Laboratoire ATmosphères, Milieux, Observations Spatiales (LATMOS). This data set is initially compared on a five-month period to a three-dimensional time varying ozone field that we take as a reference. This reference field results from the combined assimilation of ozone profiles from the Microwave Limb Sounder (MLS) instrument and of total ozone columns from the SCanning Imaging Absorption spectrometer for Atmospheric CHartographY (SCIAMACHY) instrument. It has low systematic and random errors when compared to ozonesondes and Ozone Monitoring Instrument (OMI) data. The comparison shows that on average, the LATMOS-IASI data tends to overestimate the total ozone columns by 2% to 8%. The random observation error of the LATMOS-IASI data is estimated to about 7%, except over polar regions and deserts where it is higher. The daytime data have generally lower biases but higher random error than the nighttime data. Using this information, the LATMOS-IASI data are then assimilated, combined with the MLS data. This first LATMOS-IASI data assimilation experiment shows that the resulting analysis is quite similar to the one obtained from the combined MLS and SCIAMACHY data assimilation. The differences are mainly due to the lack of SCIAMACHY measurements during polar night, and to the higher LATMOS-IASI random errors especially over the southern polar region. © 2009 Author(s).
BibTeX: @article{Massart2009, author = {Massart, S. and Clerbaux, C. and Cariolle, D. and Piacentini, A. and Turquety, S. and Hadji-Lazaro, J.}, title = {First steps towards the assimilation of IASI ozone data into the MOCAGE-PALM system}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {14}, pages = {5073 – 5091}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-9-5073-2009} }
Mikhailenko S, Tashkun S, Putilova T, Starikova E, Daumont L, Jenouvrier A, Fally S, Carleer M, Hermans C and Vandaele A (2009), "Critical evaluation of measured rotation-vibration transitions and an experimental dataset of energy levels of HD18O", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 110(9-10), pp. 597 – 608. [Abstract] [BibTeX] [DOI]
Abstract: All available transitions from microwave to visible region (0.2-12 105 cm-1) of the HD18O molecule were collected and tested using the RITZ computer code. Literature data were completed by transitions assigned to HD18O in long path Fourier transform absorption spectra of the H2O, HDO and D2O gas mixtures with natural abundance of oxygen-18. In addition about 40 unassigned lines between 4200 and 6600 cm-1 of our previous water study associated with the HD18O molecule have been found and assigned. The new long path absorption spectra of the HDO and D2O mixtures allow us to observe about 1000 transitions of HD18O in the 6125-10 720 cm-1 spectral region. These data have been critically analyzed and used to obtain the most complete and precise set of the experimental energy levels of this molecule. © 2009 Elsevier Ltd. All rights reserved.
BibTeX: @article{Mikhailenko2009597, author = {Mikhailenko, S.N. and Tashkun, S.A. and Putilova, T.A. and Starikova, E.N. and Daumont, L. and Jenouvrier, A. and Fally, S. and Carleer, M. and Hermans, C. and Vandaele, A.C.}, title = {Critical evaluation of measured rotation-vibration transitions and an experimental dataset of energy levels of HD18O}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2009}, volume = {110}, number = {9-10}, pages = {597 – 608}, doi = {10.1016/j.jqsrt.2009.01.012} }
Nemouchi M and Godefroid M (2009), "Irreducible tensor form of the relativistic corrections to the M1 transition operator", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 42(17) [Abstract] [BibTeX] [DOI]
Abstract: The relativistic corrections to the magnetic dipole moment operator in the Pauli approximation were derived originally by Drake (1971 Phys. Rev. A 3 908). In the present paper, we derive their irreducible tensor-operator form to be used in atomic structure codes adopting the Fano-Racah-Wigner algebra for calculating its matrix elements. © 2009 IOP Publishing Ltd.
BibTeX: @article{Nemouchi2009, author = {Nemouchi, M. and Godefroid, M.R.}, title = {Irreducible tensor form of the relativistic corrections to the M1 transition operator}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2009}, volume = {42}, number = {17}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/42/17/175002} }
Perrin A, Vander Auwera J and Zelinger Z (2009), "High-resolution Fourier transform study of the ν3 fundamental band of trans-formic acid", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 110(9-10), pp. 743 – 755. [Abstract] [BibTeX] [DOI]
Abstract: Using high-resolution Fourier transform spectra of trans-HCOOH recorded at 5.6 μm, we carried out an extensive analysis of the strong ν3 fundamental band (carbonyl stretching mode) at 1776.83 cm-1, starting from results of a previous analysis [Weber WH, Maker PD, Johns JWC, Weinberger E. J Mol Spectrosc 1987; 121: 243-60]. As pointed out in the literature, the ν3 band is significantly perturbed by resonances due to numerous dark bands. We were able to assign series belonging to the ν5+ν7, ν5+ν9, ν6+ν7 and ν6+ν9 dark bands, located at 1843.48, 1792.63, 1737.96 and 1726.40 cm-1, respectively. The model used to calculate energy levels accounts partly for the observed resonances, and enabled us to reproduce most of the observed line positions, within their experimental uncertainties. We also determined absolute line intensities with an accuracy estimated to 15%. Finally, we generated, for the first time, a list of line parameters for the 5.6 μm region of trans-formic acid. © 2008 Elsevier Ltd. All rights reserved.
BibTeX: @article{Perrin2009743, author = {Perrin, A. and Vander Auwera, J. and Zelinger, Z.}, title = {High-resolution Fourier transform study of the ν3 fundamental band of trans-formic acid}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2009}, volume = {110}, number = {9-10}, pages = {743 – 755}, doi = {10.1016/j.jqsrt.2008.09.006} }
Predoi-Cross A, Rohart F, Bouanich J-P and Hurtmans DR (2009), "Xenon-broadened CO line shapes in the fundamental band at 349 K", Canadian Journal of Physics. Vol. 87(5), pp. 485 – 498. [Abstract] [BibTeX] [DOI]
Abstract: We present a line shape analysis of the P(2) and P(7) transitions of CO broadened by Xe in the fundamental band. The spectra were recorded at 349 K using a difference frequency laser spectrometer. To obtain information on the influence of Dicke narrowing, relaxation speed dependence, and line mixing effects, several models for implementation of Dicke narrowing and (or) speed-dependent effects are discussed. From experimental data analysis, we conclude that line shape models taking into account the Dicke effect only fail in the high pressure regime and lead to optical diffusion parameters that are much larger than the kinetic diffusion ones. On the contrary, a fair interpretation of data is obtained from speed-dependent models, so that it is possible to derive a quantitative estimate of optical diffusion effects that appear much smaller than the kinetic diffusion ones. Xe-broadening coefficients of CO lines in the fundamental band at 297 and 349 K are calculated from a semiclassical formalism involving successively two intermolecular potentials, the atom-atom Lennard-Jones model, and a three-term expansion of Legendre polynomials with four adjustable parameters.
BibTeX: @article{PredoiCross2009, author = {Predoi-Cross, Adriana and Rohart, François and Bouanich, Jean-Pierre and Hurtmans, Daniel R.}, title = {Xenon-broadened CO line shapes in the fundamental band at 349 K}, journal = {Canadian Journal of Physics}, year = {2009}, volume = {87}, number = {5}, pages = {485 – 498}, doi = {10.1139/P08-123} }
Ram RS, Liévin J and Bernath PF (2009), "Fourier transform emission spectroscopy and ab initio calculations on WO", Journal of Molecular Spectroscopy. Vol. 256(2), pp. 216 – 227. [Abstract] [BibTeX] [DOI]
Abstract: Emission spectra of WO have been observed in the 4000-35 000 cm-1 region using a Fourier transform spectrometer. Molecules were produced by exciting a mixture of WCl6 vapor and He in a microwave discharge lamp. A 3Σ- state has been assigned as the ground state of WO based on a rotational analysis of the observed bands and ab initio calculations. After rotational analysis, a majority of strong bands have been classified into three groups. Most of the transitions belonging to the first group have an Ω = 0+ state as the lower state while the bands in the second group have an Ω′′ = 1 state as the lower state. These two lower states have been assigned as X0+ and X1 spin components of the X3Σ- ground state of WO. The third group consists of additional bands interconnected by common vibrational levels involving some very low-lying states. The spectroscopic properties of the low-lying electronic states have been predicted from ab initio calculations. The details of the rotational analysis are presented and an attempt has been made to explain the experimental observations in the light of the ab initio results. © 2009 Elsevier Inc. All rights reserved.
BibTeX: @article{Ram2009, author = {Ram, Ram S. and Liévin, J. and Bernath, Peter F.}, title = {Fourier transform emission spectroscopy and ab initio calculations on WO}, journal = {Journal of Molecular Spectroscopy}, year = {2009}, volume = {256}, number = {2}, pages = {216 – 227}, doi = {10.1016/j.jms.2009.04.010} }
Razavi A, Clerbaux C, Wespes C, Clarisse L, Hurtmans D, Payan S, Camy-Peyret C and Coheur P (2009), "Characterization of methane retrievals from the IASI space-borne sounder", Atmospheric Chemistry and Physics. Vol. 9(20), pp. 7889 – 7899. [Abstract] [BibTeX] [DOI]
Abstract: Although the global methane (CH4) concentration has more than doubled since pre-industrial times, local emission sources are still poorly identified and quantified. Instruments onboard satellites can improve our knowledge about the methane global distribution owing to their very good spatial coverage. The IASI (Infrared Atmospheric Sounding Interferometer) instrument launched on the European MetOp-A platform is a Fourier transform spectrometer which measures the thermal infrared radiation emitted by the Earth and its atmosphere. In this paper, we present the first global distribution of methane total columns (mostly sensitive to the middle troposphere) from the IASI spectra using the methane ν4 absorption band. The retrieval spectral range was set in order to minimize possible spectroscopic issues. Results are discussed in terms of error budget and vertical sensitivity. In addition, we study the gain of information on surface methane concentrations provided by using the ν3 band, which is partly covered by IASI on the short-wave end of the spectra (extending to 2760 cm−1), where solar reflection contributes significantly.
BibTeX: @article{Razavi2009, author = {Razavi, A. and Clerbaux, C. and Wespes, C. and Clarisse, L. and Hurtmans, D. and Payan, S. and Camy-Peyret, C. and Coheur, P.F.}, title = {Characterization of methane retrievals from the IASI space-borne sounder}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {20}, pages = {7889 – 7899}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-9-7889-2009} }
Rix M, Valks P, Hao N, Loyola DGR, Zimmer W, Emmadi S, van Geffen J, Clerbaux C, Clarisse L, Coheur P-F and Erbertseder T (2009), "Satellite Monitoring of Volcanic Sulfur Dioxide Emissions for Early Warning of Volcanic Hazards", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 2(3), pp. 196 – 206. [Abstract] [BibTeX] [DOI]
Abstract: Satellite-based remote sensing measurements of volcanic sulfur dioxide (SO2) provide critical information for reducing volcanic hazards. This paper describes the use of SO2 measurements from the thermal infrared sounder IASI and the UV-VIS instrument GOME-2 in services related to aviation hazard and early warning of volcanic unrest. The high sensitivity of both instruments to SO2 allows the detection and global tracking of volcanic eruption plumes and makes them a valuable tool for volcanic aviation hazard mitigation. The GOME-2 and IASI SO2 data are produced in near-real time and distributed to the Volcanic Ash Advisory Centers (VAACS) to assist them in issuing alerts to airlines and air traffic control organizations. Examples of recent eruptions affecting air traffic are presented including Jebel al Tair (Yemen, September 2007), Mount Okmok (Alaska, July 2008), and Mount Kasatochi (Alaska, August 2008). In addition, GOME-2 can detect changes in the SO2 emissions from passively degassing volcanoes and, therefore, provide critical information for hazard assessment. The monitoring of pre-emptive degassing by GOME-2 is used in early warning of volcanic activity by a mobile volcano fast response system in combination with numerous other parameters, such as seismicity, deformation, and thermal anomalies. © 2009, The Institute of Electrical and Electronics Engineers, Inc.
BibTeX: @article{Rix2009, author = {Rix, Meike and Valks, Pieter and Hao, Nan and Loyola, Diego G. R. and Zimmer, Walter and Emmadi, Sunil and van Geffen, Jos and Clerbaux, Catherine and Clarisse, Lieven and Coheur, Pierre-François and Erbertseder, Thilo}, title = {Satellite Monitoring of Volcanic Sulfur Dioxide Emissions for Early Warning of Volcanic Hazards}, journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing}, year = {2009}, volume = {2}, number = {3}, pages = {196 – 206}, doi = {10.1109/JSTARS.2009.2031120} }
Robert S, Amyay B, Fayt A, Di Lonardo G, Fusina L, Tamassia F and Herman M (2009), "Vibration-rotation energy pattern in acetylene: 13CH 12CH up to 10 120 cm-1", Journal of Physical Chemistry A. Vol. 113(47), pp. 13251 – 13259. [Abstract] [BibTeX] [DOI]
Abstract: All 18 219 vibration-rotation absorption lines of 13CH 12CH published in the literature, accessing substates up to 9400 cm-1 and including some newly assigned, were simultaneously fitted to J-dependent Hamiltonian matrices exploiting the well-known vibrational polyad or cluster block-diagonalization, in terms of the pseudo quantum numbers Ns = V1 + V2 + V3 and Nr = 5V1 + 3V2 + 5V3 + V4 + V5, also accounting for k = l4 + l5 parity and e/f symmetry properties. Some 1761 of these lines were excluded from the fit, corresponding either to blended lines, for about 30% of them, or probably to lines perturbed by Coriolis for the remaining ones. The dimensionless standard deviation of the fit is 1.10, and 317 vibration-rotation parameters are determined. These results significantly extend those of a previous report considering levels below only 6750 cm-1 [Fayt, A.; et al. J. Chem. Phys. 2007, 126, 114303]. Unexpected problems are reported when inserting in the global fit the information available on higher-energy polyads, extending from 9300 to 10 120 cm-1. They are tentatively interpreted as resulting from a combination of the relative evolution of the two effective bending frequencies and long-range interpolyad low-order anharmonic resonances. The complete database, made of 18 865 vibration-rotation lines accessing levels up to 10 120 cm-1, is made available as Supporting Information. © 2009 American Chemical Society.
BibTeX: @article{Robert2009, author = {Robert, S. and Amyay, B. and Fayt, A. and Di Lonardo, G. and Fusina, L. and Tamassia, F. and Herman, M.}, title = {Vibration-rotation energy pattern in acetylene: 13CH 12CH up to 10 120 cm-1}, journal = {Journal of Physical Chemistry A}, year = {2009}, volume = {113}, number = {47}, pages = {13251 – 13259}, doi = {10.1021/jp904000q} }
Rothman L, Gordon I, Barbe A, Benner D, Bernath P, Birk M, Boudon V, Brown L, Campargue A, Champion J-P, Chance K, Coudert L, Dana V, Devi V, Fally S, Flaud J-M, Gamache R, Goldman A, Jacquemart D, Kleiner I, Lacome N, Lafferty W, Mandin J-Y, Massie S, Mikhailenko S, Miller C, Moazzen-Ahmadi N, Naumenko O, Nikitin A, Orphal J, Perevalov V, Perrin A, Predoi-Cross A, Rinsland C, Rotger M, Šimečková M, Smith M, Sung K, Tashkun S, Tennyson J, Toth R, Vandaele A and Vander Auwera J (2009), "The HITRAN 2008 molecular spectroscopic database", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 110(9-10), pp. 533 – 572. [Abstract] [BibTeX] [DOI]
Abstract: This paper describes the status of the 2008 edition of the HITRAN molecular spectroscopic database. The new edition is the first official public release since the 2004 edition, although a number of crucial updates had been made available online since 2004. The HITRAN compilation consists of several components that serve as input for radiative-transfer calculation codes: individual line parameters for the microwave through visible spectra of molecules in the gas phase; absorption cross-sections for molecules having dense spectral features, i.e. spectra in which the individual lines are not resolved; individual line parameters and absorption cross-sections for bands in the ultraviolet; refractive indices of aerosols, tables and files of general properties associated with the database; and database management software. The line-by-line portion of the database contains spectroscopic parameters for 42 molecules including many of their isotopologues. © 2009 Elsevier Ltd.
BibTeX: @article{Rothman2009a, author = {Rothman, L.S. and Gordon, I.E. and Barbe, A. and Benner, D.Chris and Bernath, P.F. and Birk, M. and Boudon, V. and Brown, L.R. and Campargue, A. and Champion, J.-P. and Chance, K. and Coudert, L.H. and Dana, V. and Devi, V.M. and Fally, S. and Flaud, J.-M. and Gamache, R.R. and Goldman, A. and Jacquemart, D. and Kleiner, I. and Lacome, N. and Lafferty, W.J. and Mandin, J.-Y. and Massie, S.T. and Mikhailenko, S.N. and Miller, C.E. and Moazzen-Ahmadi, N. and Naumenko, O.V. and Nikitin, A.V. and Orphal, J. and Perevalov, V.I. and Perrin, A. and Predoi-Cross, A. and Rinsland, C.P. and Rotger, M. and Šimečková, M. and Smith, M.A.H. and Sung, K. and Tashkun, S.A. and Tennyson, J. and Toth, R.A. and Vandaele, A.C. and Vander Auwera, J.}, title = {The HITRAN 2008 molecular spectroscopic database}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2009}, volume = {110}, number = {9-10}, pages = {533 – 572}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jqsrt.2009.02.013} }
Rothman LS, Brown LR and Vander Auwera J (2009), "Preface", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 110(9-10), pp. 531 – 532. [BibTeX] [DOI]
BibTeX: @article{Rothman2009, author = {Rothman, Laurence S. and Brown, Linda R. and Vander Auwera, Jean}, title = {Preface}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2009}, volume = {110}, number = {9-10}, pages = {531 – 532}, doi = {10.1016/j.jqsrt.2009.02.025} }
Sodoga K, Loreau J, Lauvergnat D, Justum Y, Vaeck N and Desouter-Lecomte M (2009), "Photodissociation of the HeH+ ion into excited fragments (n=2,3) by time-dependent methods", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 80(3) [Abstract] [BibTeX] [DOI]
Abstract: The total and partial photodissociation cross sections of the molecular ion HeH+ are computed by time-dependent methods for fragmentation into the excited shells n=1,2,3 up to a photon energy of 40 eV. Σ1 + and Π1 states are considered for parallel and perpendicular transitions for different initial rotational or vibrational excitations. Nonadiabatic radial and rotational couplings are taken into account. The results from coupled-channel equations are compared with the Born-Oppenheimer approximation. A time-dependent calculation with a femtosecond laser pulse is carried out to simulate a recent crossed beam photodissociation imaging experiment with vacuum ultraviolet free-electron laser. The dominance of photodissociation perpendicular to the photon polarization is confirmed. © 2009 The American Physical Society.
BibTeX: @article{Sodoga2009, author = {Sodoga, K. and Loreau, J. and Lauvergnat, D. and Justum, Y. and Vaeck, N. and Desouter-Lecomte, M.}, title = {Photodissociation of the HeH+ ion into excited fragments (n=2,3) by time-dependent methods}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2009}, volume = {80}, number = {3}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.80.033417} }
Tennyson J, Bernath PF, Brown LR, Campargue A, Carleer MR, Császár AG, Gamache RR, Hodges JT, Jenouvrier A, Naumenko OV, Polyansky OL, Rothman LS, Toth RA, Vandaele AC, Zobov NF, Daumont L, Fazliev AZ, Furtenbacher T, Gordon IE, Mikhailenko SN and Shirin SV (2009), "IUPAC critical evaluation of the rotational-vibrational spectra of water vapor. Part I-Energy levels and transition wavenumbers for H2 17O and H2 18O", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 110(9-10), pp. 573 – 596. [Abstract] [BibTeX] [DOI]
Abstract: This is the first part of a series of articles reporting critically evaluated rotational-vibrational line positions, transition intensities, pressure dependence and energy levels, with associated critically reviewed assignments and uncertainties, for all the main isotopologues of water. The present article contains energy levels and data for line positions of the singly substituted isotopologues H2 17O and H2 18O. The procedure and code MARVEL, standing for measured active rotational-vibrational energy levels, is used extensively in all stages of determining the validated levels and lines and their self-consistent uncertainties. The spectral regions covered for both isotopologues H2 17O and H2 18O are 0 - 17 125 cm- 1. The energy levels are checked against ones determined from accurate variational calculations. The number of critically evaluated and recommended levels and lines are, respectively, 2687 and 8614 for H2 17O, and 4839 and 29 364 for H2 18O. The extensive lists of MARVEL lines and levels obtained are deposited in the Supplementary Material, as well as in a distributed information system applied to water, W@DIS, where they can easily be retrieved. A distinguishing feature of the present evaluation of water spectroscopic data is the systematic use of all available experimental data and validation by first-principles theoretical calculations. © 2009 Elsevier Ltd.
BibTeX: @article{Tennyson2009573, author = {Tennyson, Jonathan and Bernath, Peter F. and Brown, Linda R. and Campargue, Alain and Carleer, Michel R. and Császár, Attila G. and Gamache, Robert R. and Hodges, Joseph T. and Jenouvrier, Alain and Naumenko, Olga V. and Polyansky, Oleg L. and Rothman, Laurence S. and Toth, Robert A. and Vandaele, Ann Carine and Zobov, Nikolai F. and Daumont, Ludovic and Fazliev, Alexander Z. and Furtenbacher, Tibor and Gordon, Iouli E. and Mikhailenko, Semen N. and Shirin, Sergei V.}, title = {IUPAC critical evaluation of the rotational-vibrational spectra of water vapor. Part I-Energy levels and transition wavenumbers for H2 17O and H2 18O}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2009}, volume = {110}, number = {9-10}, pages = {573 – 596}, doi = {10.1016/j.jqsrt.2009.02.014} }
Turquety S, Hurtmans D, Hadji-Lazaro J, Coheur P-F, Clerbaux C, Josset D and Tsamalis C (2009), "Tracking the emission and transport of pollution from wildfires using the IASI CO retrievals: Analysis of the summer 2007 Greek fires", Atmospheric Chemistry and Physics. Vol. 9(14), pp. 4897 – 4913. [Abstract] [BibTeX] [DOI]
Abstract: In this paper, we analyze the performance of the Infrared Atmospheric Sounding Interferometer (IASI), launched in October 2006 on board METOP-A, for the monitoring of carbon monoxide (CO) during extreme fire events, focusing on the record-breaking fires which devastated thousands of square kilometers of forest in Greece during the last week (23-30) of August 2007. After an assessment of the quality of the profiles retrieved using the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, the information provided on fire emissions and subsequent pollution outflow is discussed. Large CO plumes were observed above the Mediterranean Basin and North Africa, with total CO columns exceeding 24×1018 molecules/cm2 and absolute volume mixing ratios up to 4 ppmv on the 25 August. Up to 30×1018 molecules/cm2 and 22 ppmv in the lower troposphere are retrieved close to the fires above the Peloponnese, but with larger uncertainty. The average root-mean-square (RMS) difference between simulated and observed spectrais close to the estimated radiometric noise level, slightly increasing (by ∼14%) in the fresh fire plumes. CO profiles are retrieved with a vertical resolution of about 8 km, with ∼1.7 pieces of independent information on the vertical in the region considered and a maximum sensitivity in the free troposphere (∼4-5 km). Using the integrated total amount, the increase in CO burden due to these fires is estimated to 0.321 Tg, ∼40% of the total annual anthropogenic emissions in Greece. The patterns of these CO enhance- ments are in good agreement with the aerosol optical depth (AOD) retrieved from the MODIS measurements, highlighting a rapid transport of trace gases and aerosols across the Mediterranean Basin (less than one day). While the coarse vertical resolution will not allow the location of the exact plume height, the large CO enhancements observed in the lower troposphere are consistent with the maximum aerosol backscatter coefficient at ∼2 km detected by the CALIPSO lidar in space (CALIOP). © Author(s) 2009.
BibTeX: @article{Turquety20094897, author = {Turquety, S. and Hurtmans, D. and Hadji-Lazaro, J. and Coheur, P.-F. and Clerbaux, C. and Josset, D. and Tsamalis, C.}, title = {Tracking the emission and transport of pollution from wildfires using the IASI CO retrievals: Analysis of the summer 2007 Greek fires}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {14}, pages = {4897 – 4913}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-9-4897-2009} }
Vigouroux C, Hendrick F, Stavrakou T, Dils B, De Smedt I, Hermans C, Merlaud A, Scolas F, Senten C, Vanhaelewyn G, Fally S, Carleer M, Metzger J-M, Müller J-F, Van Roozendael M and De Maziére M (2009), "Ground-based FTIR and MAX-DOAS observations of formaldehyde at Réunion Island and comparisons with satellite and model data", Atmospheric Chemistry and Physics. Vol. 9(24), pp. 9523 – 9544. [Abstract] [BibTeX] [DOI]
Abstract: Formaldehyde (HCHO) columns have been retrieved from ground-based Fourier transform infrared (FTIR) campaign measurements in 2004 and 2007 and from UV-Visible MAX-DOAS measurements in 2004-2005 at the NDACC site of Réunion Island (21° S, 55° E). The FTIR and MAX-DOAS daily mean formaldehyde total columns are intercompared in their common measurement period, from August to October 2004. The ground-based data are also compared to correlative SCIAMACHY data. The comparisons account for the vertical sensitivity differences of the data sets, by including their respective averaging kernels. Complete error budgets are also presented. The FTIR and MAX-DOAS daily mean total columns agree very well: no significant bias is observed and the standard deviation of the comparisons is only 8%. Both FTIR and MAX-DOAS HCHO total columns are in good agreement with SCIAMACHY values in the 2004-2005 period, with standard deviations of 21% and 31%, respectively. The same seasonal cycle is observed by the different instruments, with a minimum in austral winter and a maximum in February-March. The FTIR and MAX-DOAS data are confronted with HCHO columns calculated by a global CTM, the IMAGES model. The model underestimates the HCHO columns by 23-29% in comparison with FTIR, and by 15% in comparison with DOAS. This bias might have multiple causes, including an underestimation of OH concentrations in the model (as indicated by a sensitivity study using prescribed OH fields) and/or an underestimated contribution of large-scale transport of HCHO precursors from Madagascar. The latter hypothesis is comforted by the large observed day-to-day variability of HCHO columns, and by the observation that the peak values of FTIR columns can often be associated with free tropospheric transport patterns from source regions over Madagascar to Réunion Island, according to simulations performed with the Lagrangian particle dispersion model FLEXPART.
BibTeX: @article{Vigouroux2009, author = {Vigouroux, C. and Hendrick, F. and Stavrakou, T. and Dils, B. and De Smedt, I. and Hermans, C. and Merlaud, A. and Scolas, F. and Senten, C. and Vanhaelewyn, G. and Fally, S. and Carleer, M. and Metzger, J.-M. and Müller, J.-F. and Van Roozendael, M. and De Maziére, M.}, title = {Ground-based FTIR and MAX-DOAS observations of formaldehyde at Réunion Island and comparisons with satellite and model data}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {24}, pages = {9523 – 9544}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-9-9523-2009} }
Wespes C, Hurtmans D, Clerbaux C, Santee M, Martin R and Coheur P (2009), "Global distributions of nitric acid from IASI/MetOP measurements", Atmospheric Chemistry and Physics. Vol. 9(20), pp. 7949 – 7962. [Abstract] [BibTeX] [DOI]
Abstract: This paper presents the first global distributions of HNO3 total columns acquired by the Infrared Atmospheric Sounding Interferometer (IASI) instrument, launched onboard the MetOp platform in October 2006. IASI is an infrared nadir-looking Fourier transform spectrometer providing atmospheric radiance spectra at 0.5 cm?1 spectral resolution, from which temperature and infrared absorbing gas concentration profiles are retrieved with global Earth coverage twice a day. A first analysis of the IASI measurements in terms of information content demonstrates the possibility of retrieving a total column for HNO3 at all latitudes with a maximal sensitivity in the middle stratosphere. The retrievals are performed from IASI spectra in the atmospheric window using a fast radiative transfer model and inversion software (FORLI) relying on the Optimal Estimation Method. The operational processing of HNO3 total columns is achieved since March 2008. We show that FORLI-HNO3 performs well at all latitudes (RMS of the spectral residuals around 2.3×10?6 W/m2 srm?1) and provides HNO3 total columns with on average statistical errors of about 12%, reaching the threshold value of 32% at the equatorial belt. The global distributions of the retrieved total columns for one year (from March 2008 to February 2009) are presented and discussed with emphasis given to seasonal and interhemispheric variations. Local seasonal variations at 6 specific locations are also described and discussed in comparison with MLS volume mixing ratios at 46.5 hPa. The seasonal cycle observedin Polar regions is highlighted, with maxima observed in fallwinter and minima during spring-summer. The denitrification inside the Antarctic polar vortex during winter is clearly revealed with unprecedented horizontal resolution: HNO 3 columns decreasing down to about 1×cm?2 are observed, which is consistent with the lower values of temperature observed between 50 and 15 hPa (∼20-25 km) and the resulting formation and sedimentation of polar stratospheric clouds. During the same period, the collar region of high quantities of HNO3 at the vortex edge is also observed around 65-60° S latitude. Preliminary correlations between IASI derived HNO3 and O3 columns inside the polar vortex are presented and discussed. © 2009 Author(s).
BibTeX: @article{Wespes2009, author = {Wespes, C. and Hurtmans, D. and Clerbaux, C. and Santee, M.L. and Martin, R.V. and Coheur, P.F.}, title = {Global distributions of nitric acid from IASI/MetOP measurements}, journal = {Atmospheric Chemistry and Physics}, year = {2009}, volume = {9}, number = {20}, pages = {7949 – 7962}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-9-7949-2009} }
Cassam-Chenaï P, Scribano Y and Liévin J (2008), "Influence of kinetic coupling in rectilinear coordinates on the vibrational spectrum of fluoroform", Chemical Physics Letters. Vol. 466(1-3), pp. 16 – 20. [Abstract] [BibTeX] [DOI]
Abstract: The vibrational energy levels of fluoroform have been computed with and without the kinetic coupling terms of the Eckart-Watson Hamiltonian by using the vibrational mean field configuration interaction method. The results are well-converged as demonstrated by a comparison with those obtained with other variational methods when kinetic coupling is omitted. It is found that kinetic coupling is not negligible for this system. The wave number difference with and without kinetic coupling is 37 cm-1 for the ν1 (CH-stretching) fundamental transition and can be larger than 60 cm-1 in the ν1 s(-) ν4 (HCF bending) overtones. © 2008 Elsevier B.V. All rights reserved.
BibTeX: @article{Cassam-Chenaï200816, author = {Cassam-Chenaï, Patrick and Scribano, Yohann and Liévin, Jacques}, title = {Influence of kinetic coupling in rectilinear coordinates on the vibrational spectrum of fluoroform}, journal = {Chemical Physics Letters}, year = {2008}, volume = {466}, number = {1-3}, pages = {16 – 20}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.cplett.2008.10.025} }
Clarisse L, Coheur P, Prata A, Hurtmans D, Razavi A, Phulpin T, Hadji-Lazaro J and Clerbaux C (2008), "Tracking and quantifying volcanic SO2 with IASI, the September 2007 eruption at Jebel at Tair", Atmospheric Chemistry and Physics. Vol. 8(24), pp. 7723 – 7734. [Abstract] [BibTeX] [DOI]
Abstract: In this paper we demonstrate the potential of the infrared Fourier transform spectrometer IASI in analysing volcanic eruptions, using the September 2007 eruption at Jebel at Tair as an illustrative example. Detailed radiative transfer calculations are presented, simulating IASI-like transmittance spectra for a variety of volcanic plumes. We analyse the sensitivity of IASI to SO 2 at different altitudes and demonstrate that IASI is in principle capable of sensing SO2 down to the surface. Using the brightness temperature difference of well chosen SO2 channels as a filter, we are able to track the plume of the Jebel at Tair eruption for 12 days, on a par with state of the art UV sounders. A method is presented for quickly estimating the altitude of a volcanic plume based on the relative intensities of the SO2 absorption lines. Despite recent advances, it is still very challenging to retrieve vertical profiles of SO2 from nadir viewing satellites. Currently the most accurate profiles in nadir are retrieved using backtracking of the plume with atmospheric transport models. Via full inverse retrievals using the optimal estimation method, we show the possibility of extracting medium coarse vertical profiles from IASI data. The retrieval allows us to present an evolution of the total mass of SO2 in the plume for the Jebel at Tair eruption. An analytical relation is derived between brightness temperature differences and concentrations, which fits the experimental data very well. The spectral range of IASI also allows retrieval of volcanic aerosols. In the initial plume of the Jebel at Tair eruption, volcanic aerosols were found in the form of ice particles, for which we derived particle sizes. © Author(s) 2008.
BibTeX: @article{Clarisse20087723, author = {Clarisse, L. and Coheur, P.F. and Prata, A.J. and Hurtmans, D. and Razavi, A. and Phulpin, T. and Hadji-Lazaro, J. and Clerbaux, C.}, title = {Tracking and quantifying volcanic SO2 with IASI, the September 2007 eruption at Jebel at Tair}, journal = {Atmospheric Chemistry and Physics}, year = {2008}, volume = {8}, number = {24}, pages = {7723 – 7734}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-8-7723-2008} }
Clerbaux C, Coheur P-F, Clarisse L, Hadji-Lazaro J, Hurtmans D, Turquety S, Bowman K, Worden H and Carn S (2008), "Measurements of so2 profiles in volcanic plumes from the NASA Tropospheric Emission Spectrometer (TES)", Geophysical Research Letters. Vol. 35(22) [Abstract] [BibTeX] [DOI]
Abstract: Satellite measurements are now recognized as a key element for the early detection and characterization of volcanic eruptions, in particular in the context of aircraft routing. A common tracer of volcanic plumes is sulfur dioxide (SO2), which so far has been measured by ultraviolet-visible (UV-vis) instruments and multispectral infrared (IR) sounders. Here we report the first SO2 vertical profile retrieved from high spectral resolution thermal infrared nadir radiance spectra and we provide information on both the quantity of gas emitted and its altitude. From the radiance spectra provided by the Tropospheric Emission Spectrometer (TES) aboard the NASA AURA satellite, and owing to the ∼0.1 cm-1 (apodized) spectral resolution, elevated levels of SO2 were measured following volcanic eruptions occurring in 2005 (Manam, Sierra Negra) and 2006 (Rabaul, Nyamuragira). Column values are found to be in good agreement with the data provided by Ozone Mapping Instrument (OMI), a UV-vis instrument also onboard the AURA satellite. Copyright 2008 by the American Geophysical Union.
BibTeX: @article{Clerbaux2008, author = {Clerbaux, C. and Coheur, P.-F. and Clarisse, L. and Hadji-Lazaro, J. and Hurtmans, D. and Turquety, S. and Bowman, K. and Worden, H. and Carn, S.A.}, title = {Measurements of so2 profiles in volcanic plumes from the NASA Tropospheric Emission Spectrometer (TES)}, journal = {Geophysical Research Letters}, year = {2008}, volume = {35}, number = {22}, note = {All Open Access, Green Open Access}, doi = {10.1029/2008GL035566} }
Clerbaux C, Edwards DP, Deeter M, Emmons L, Lamarque J-F, Tie XX, Massie ST and Gille J (2008), "Carbon monoxide pollution from cities and urban areas observed by the Terra/MOPITT mission", Geophysical Research Letters. Vol. 35(3) [Abstract] [BibTeX] [DOI]
Abstract: Carbon monoxide (CO) is a key species for tracking pollution plumes. The Measurement Of Pollution in The Troposphere (MOPITT) mission onboard the Terra satellite has already provided 7.5 years of CO atmospheric concentration measurements around the globe. Limited sensitivity to the boundary layer is well known to be a weakness of nadir looking thermal infrared sounders. This paper investigates the possibility of using the MOPITT surface measurements to detect CO emitted by cities and urban centers. By selecting the data and averaging them over long time periods, we demonstrate that the CO pollution arising from the large cities and urban areas can be distinguished from the background transported pollution. The more favorable observations are obtained during daytime and at locations where the thermal contrast (temperature gradient) between the surface and lower atmosphere is significant. Copyright 2008 by the American Geophysical Union.
BibTeX: @article{Clerbaux2008, author = {Clerbaux, Cathy and Edwards, David P. and Deeter, Merritt and Emmons, Louisa and Lamarque, Jean-François and Tie, Xue Xi and Massie, Steve T. and Gille, John}, title = {Carbon monoxide pollution from cities and urban areas observed by the Terra/MOPITT mission}, journal = {Geophysical Research Letters}, year = {2008}, volume = {35}, number = {3}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1029/2007GL032300} }
Clerbaux C, George M, Turquety S, Walker K, Barret B, Bernath P, Boone C, Borsdorff T, Cammas J, Catoire V, Coffey M, Coheur P-F, Deeter M, De Mazière M, Drummond J, Duchatelet P, Dupuy E, De Zafra R, Eddounia F, Edwards D, Emmons L, Funke B, Gille J, Griffith D, Hannigan J, Hase F, Höpfner M, Jones N, Kagawa A, Kasai Y, Kramer I, Le Flochmoën E, Livesey N, López-Puertas M, Luo M, Mahieu E, Murtagh D, Nédélec P, Pazmino A, Pumphrey H, Ricaud P, Rinsland C, Robert C, Schneider M, Senten C, Stiller G, Strandberg A, Strong K, Sussmann R, Thouret V, Urban J and Wiacek A (2008), "CO measurements from the ACE-FTS satellite instrument: Data analysis and validation using ground-based, airborne and spaceborne observations", Atmospheric Chemistry and Physics. Vol. 8(9), pp. 2569 – 2594. [Abstract] [BibTeX] [DOI]
Abstract: The Atmospheric Chemistry Experiment (ACE) mission was launched in August 2003 to sound the atmosphere by solar occultation. Carbon monoxide (CO), a good tracer of pollution plumes and atmospheric dynamics, is one of the key species provided by the primary instrument, the ACE-Fourier Transform Spectrometer (ACE-FTS). This instrument performs measurements in both the CO 1-0 and 2-0 ro-vibrational bands, from which vertically resolved CO concentration profiles are retrieved, from the mid-troposphere to the thermosphere. This paper presents an updated description of the ACE-FTS version 2.2 CO data product, along with a comprehensive validation of these profiles using available observations (February 2004 to December 2006). We have compared the CO partial columns with ground-based measurements using Fourier transform infrared spectroscopy and millimeter wave radiometry, and the volume mixing ratio profiles with airborne (both high-altitude balloon flight and airplane) observations. CO satellite observations provided by nadir-looking instruments (MOPITT and TES) as well as limb-viewing remote sensors (MIPAS, SMR and MLS) were also compared with the ACE-FTS CO products. We show that the ACE-FTS measurements provide CO profiles with small retrieval errors (better than 5% from the upper troposphere to 40 km, and better than 10% above). These observations agree well with the correlative measurements, considering the rather loose coincidence criteria in some cases. Based on the validation exercise we assess the following uncertainties to the ACE-FTS measurement data: better than 15% in the upper troposphere (8-12 km), than 30% in the lower stratosphere (12-30 km), and than 25% from 30 to 100 km. © Author(s) 2008.
BibTeX: @article{Clerbaux20082569, author = {Clerbaux, C. and George, M. and Turquety, S. and Walker, K.A. and Barret, B. and Bernath, P. and Boone, C. and Borsdorff, T. and Cammas, J.P. and Catoire, V. and Coffey, M. and Coheur, P.-F. and Deeter, M. and De Mazière, M. and Drummond, J. and Duchatelet, P. and Dupuy, E. and De Zafra, R. and Eddounia, F. and Edwards, D.P. and Emmons, L. and Funke, B. and Gille, J. and Griffith, D.W.T. and Hannigan, J. and Hase, F. and Höpfner, M. and Jones, N. and Kagawa, A. and Kasai, Y. and Kramer, I. and Le Flochmoën, E. and Livesey, N.J. and López-Puertas, M. and Luo, M. and Mahieu, E. and Murtagh, D. and Nédélec, P. and Pazmino, A. and Pumphrey, H. and Ricaud, P. and Rinsland, C.P. and Robert, C. and Schneider, M. and Senten, C. and Stiller, G. and Strandberg, A. and Strong, K. and Sussmann, R. and Thouret, V. and Urban, J. and Wiacek, A.}, title = {CO measurements from the ACE-FTS satellite instrument: Data analysis and validation using ground-based, airborne and spaceborne observations}, journal = {Atmospheric Chemistry and Physics}, year = {2008}, volume = {8}, number = {9}, pages = {2569 – 2594}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-8-2569-2008} }
Demaison J and Lievin J (2008), "Equilibrium structure of the hydrogen bonded dimer H2O ⋯ HF", Molecular Physics. Vol. 106(9-10), pp. 1249 – 1256. [Abstract] [BibTeX] [DOI]
Abstract: The equilibrium structure of the hydrogen bonded complex H2O HF has been calculated ab initio using the CCSD(T) method with basis sets up to sextuple- quality with diffuse functions and taking into account the basis set superposition error correction. The calculations carried out confirm the importance of diffuse functions and of counterpoise correction to obtain an accurate geometry. The most important point is that the basis set convergence is extremely slow and, for this reason an accurate ab initio structure requires a very large basis set. Nevertheless, the ab initio structure is significantly different from the experimental r0 and rm structures. Analysis of the basis set convergence and of the approximations used for the determination of the experimental structures indicates that the ab initio structure is expected to be more reliable.
BibTeX: @article{Demaison20081249, author = {Demaison, J. and Lievin, J.}, title = {Equilibrium structure of the hydrogen bonded dimer H2O ⋯ HF}, journal = {Molecular Physics}, year = {2008}, volume = {106}, number = {9-10}, pages = {1249 – 1256}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268970802139908} }
Demaison J, Liévin J, Császár AG and Gutle C (2008), "Equilibrium structure and torsional barrier of BH3NH3", Journal of Physical Chemistry A. Vol. 112(19), pp. 4477 – 4482. [Abstract] [BibTeX] [DOI]
Abstract: Born-Oppenheimer equilibrium structures, reBO, of the electronic ground state of the borazane (BH3NH3) molecule of C3v., point-group symmetry are computed ab initio using the CCSD(T) method with basis sets up to quintuple-ζ quality. Inclusion of the counterpoise correction and extrapolation of the structural parameters to the complete basis set limit yield a best estimate of reBO of BH3NH3. The anharmonic force field of BH 3NH3, computed at the CCSD(T) level of theory with a basis set of triple-ζ quality, allows the determination of semi-experimental equilibrium rotational constants, which in turn result in a semi-experimental equilibrium structure, reSE. The re BO and reSE structures are in excellent agreement, indicating the validity of the methods used for their determination. The empirical mass-dependent structure, rm(1), of BH 3NH3 is also determined. Although it is inferior in quality to the previous two structures, it is much more accurate than the standard empirical r0 and rs structures reported earlier for BH3NH3. The semi-experimental re SE as well as the empirical rm(1) structures determined are based on experimental ground-state rotational constants available from the literature for nine isotopologues of borazane. The effective barrier to the internal rotation of BH3NH3, a molecule isoelectronic with CH3CH3, has been computed ab initio, employing the focal-point analysis (FPA) approach, to be 699 ±11 cm -1. This compares favorably with an empirical redetermination of the effective barrier based on the above reSE structure, V3 = 718(17) cm-1. © 2008 American Chemical Society.
BibTeX: @article{Demaison20084477, author = {Demaison, Jean and Liévin, Jacques and Császár, Attila G. and Gutle, Claudine}, title = {Equilibrium structure and torsional barrier of BH3NH3}, journal = {Journal of Physical Chemistry A}, year = {2008}, volume = {112}, number = {19}, pages = {4477 – 4482}, doi = {10.1021/jp710630j} }
Di Lonardo G, Fusina L, Tamassia F, Fayt A, Robert S, Auwera JV and Herman M (2008), "The FT absorption spectrum of 13CH12CH (III): Vibrational states in the range 6750 to 9500 cm-1", Molecular Physics. Vol. 106(9-10), pp. 1161 – 1169. [Abstract] [BibTeX] [DOI]
Abstract: Forty cold bands and 29 hot bands are reported from the high resolution Fourier transform (FT) absorption spectrum of 13CH12CH, all leading to vibrational states located between 6750 and 9500 cm-1. Each of these bands has been vibrationally assigned and rotationally analysed. The band centres (νc), vibrational term values (Gv) and rotational constants are listed.
BibTeX: @article{DiLonardo2008, author = {Di Lonardo, G. and Fusina, L. and Tamassia, F. and Fayt, A. and Robert, S. and Auwera, J. Vander and Herman, M.}, title = {The FT absorption spectrum of 13CH12CH (III): Vibrational states in the range 6750 to 9500 cm-1}, journal = {Molecular Physics}, year = {2008}, volume = {106}, number = {9-10}, pages = {1161 – 1169}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268970802020348} }
Didriche K, Lauzin C, Macko P, Lafferty W, Saykally R and Herman M (2008), "On the role of molecular clustering on infrared absorption line shapes of acetylene in a supersonic expansion", Chemical Physics Letters. Vol. 463(4-6), pp. 345 – 348. [Abstract] [BibTeX] [DOI]
Abstract: A supersonic expansion containing acetylene seeded into Ar and produced from a circular nozzle is investigated using CW/cavity ring down spectroscopy, in the 1.5 μm range. The results, also involving experiments with pure acetylene and acetylene-He expansions, as well as slit nozzles, demonstrate that the denser central section in the expansion is slightly heated by the formation of acetylene aggregates, resulting into a dip in the monomer absorption line profiles. Acetylene-Ar aggregates are also formed at the edge of the circular nozzle expansion cone. © 2008 Elsevier B.V. All rights reserved.
BibTeX: @article{Didriche2008345, author = {Didriche, K. and Lauzin, C. and Macko, P. and Lafferty, W.J. and Saykally, R.J. and Herman, M.}, title = {On the role of molecular clustering on infrared absorption line shapes of acetylene in a supersonic expansion}, journal = {Chemical Physics Letters}, year = {2008}, volume = {463}, number = {4-6}, pages = {345 – 348}, doi = {10.1016/j.cplett.2008.08.086} }
Jacquinet-Husson N, Scott N, Chédin A, Crépeau L, Armante R, Capelle V, Orphal J, Coustenis A, Boonne C, Poulet-Crovisier N, Barbe A, Birk M, Brown L, Camy-Peyret C, Claveau C, Chance K, Christidis N, Clerbaux C, Coheur P, Dana V, Daumont L, De Backer-Barilly M, Di Lonardo G, Flaud J, Goldman A, Hamdouni A, Hess M, Hurley M, Jacquemart D, Kleiner I, Köpke P, Mandin J, Massie S, Mikhailenko S, Nemtchinov V, Nikitin A, Newnham D, Perrin A, Perevalov V, Pinnock S, Régalia-Jarlot L, Rinsland C, Rublev A, Schreier F, Schult L, Smith K, Tashkun S, Teffo J, Toth R, Tyuterev V, Vander Auwera J, Varanasi P and Wagner G (2008), "The GEISA spectroscopic database: Current and future archive for Earth and planetary atmosphere studies", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 109(6), pp. 1043 – 1059. [Abstract] [BibTeX] [DOI]
Abstract: The development of Gestion et Etude des Informations Spectroscopiques Atmosphériques (GEISA: Management and Study of Spectroscopic Information) was started over three decades at Laboratoire de Météorologie Dynamique (LMD) in France. GEISA is a computer accessible spectroscopic database, designed to facilitate accurate forward radiative transfer calculations using a line-by-line and layer-by-layer approach. More than 350 users have been registered for on-line use of the GEISA facilities. The current 2003 edition of GEISA (GEISA-03) is a system comprising three independent sub-databases devoted respectively to: line transition parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols. Currently, GEISA is involved in activities related to the assessment of the capabilities of IASI (Infrared Atmospheric Sounding Interferometer on board of the METOP European satellite) through the GEISA/IASI database derived from GEISA. The GEISA-03 content is presented, placing emphasis on molecular species of interest for Earth and planetary atmosphere studies, with details on the updated 2008 archive underway. A critical assessment on the needs, in terms of molecular parameters archive, related with recent satellite astrophysical missions is made. Detailed information on free on-line GEISA and GEISA/IASI access is given at http://ara.lmd.polytechnique.fr and http://ether.ipsl.jussieu.fr. © 2008 Elsevier Ltd. All rights reserved.
BibTeX: @article{Jacquinet-Husson20081043, author = {Jacquinet-Husson, N. and Scott, N.A. and Chédin, A. and Crépeau, L. and Armante, R. and Capelle, V. and Orphal, J. and Coustenis, A. and Boonne, C. and Poulet-Crovisier, N. and Barbe, A. and Birk, M. and Brown, L.R. and Camy-Peyret, C. and Claveau, C. and Chance, K. and Christidis, N. and Clerbaux, C. and Coheur, P.F. and Dana, V. and Daumont, L. and De Backer-Barilly, M.R. and Di Lonardo, G. and Flaud, J.M. and Goldman, A. and Hamdouni, A. and Hess, M. and Hurley, M.D. and Jacquemart, D. and Kleiner, I. and Köpke, P. and Mandin, J.Y. and Massie, S. and Mikhailenko, S. and Nemtchinov, V. and Nikitin, A. and Newnham, D. and Perrin, A. and Perevalov, V.I. and Pinnock, S. and Régalia-Jarlot, L. and Rinsland, C.P. and Rublev, A. and Schreier, F. and Schult, L. and Smith, K.M. and Tashkun, S.A. and Teffo, J.L. and Toth, R.A. and Tyuterev, Vl.G. and Vander Auwera, J. and Varanasi, P. and Wagner, G.}, title = {The GEISA spectroscopic database: Current and future archive for Earth and planetary atmosphere studies}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2008}, volume = {109}, number = {6}, pages = {1043 – 1059}, doi = {10.1016/j.jqsrt.2007.12.015} }
Jolly A, Benilan Y, Cané E, Fusina L, Tamassia F, Fayt A, Robert S and Herman M (2008), "Measured integrated band intensities and simulated line-by-line spectra for 12C2HD between 25 and 2.5 μm, and new global vibration-rotation parameters for the bending vibrations", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 109(17-18), pp. 2846 – 2856. [Abstract] [BibTeX] [DOI]
Abstract: The global analysis of published high-resolution vibration-rotation spectra of 12C2HD in the bending spectral range is presented, resulting in an extension of the known vibration-rotation assignments, including a new band 2v4+v5←2v4 (IΠ←Δ). Experimental integrated band intensities are reported in the range from 25 to 2.5 μm, and both v4 and v5 bending fundamentals are simulated line by line. An extensive line list is produced in the bending energy range, to supply previously missing information in databases. © 2008 Elsevier Ltd. All rights reserved.
BibTeX: @article{Jolly20082846, author = {Jolly, A. and Benilan, Y. and Cané, E. and Fusina, L. and Tamassia, F. and Fayt, A. and Robert, S. and Herman, M.}, title = {Measured integrated band intensities and simulated line-by-line spectra for 12C2HD between 25 and 2.5 μm, and new global vibration-rotation parameters for the bending vibrations}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2008}, volume = {109}, number = {17-18}, pages = {2846 – 2856}, doi = {10.1016/j.jqsrt.2008.08.004} }
Lattanzi F, Lauro Cd and Vander Auwera J (2008), "Vibration-rotation-torsion analysis of the high resolution infrared spectrum of C2H6 between 1330 and 1610 cm-1: The ν6, ν8, ν4 + ν12, 2ν4 + ν9 interacting system and hot transitions from ν4 to ν4 + ν8", Journal of Molecular Spectroscopy. Vol. 248(2), pp. 134 – 145. [Abstract] [BibTeX] [DOI]
Abstract: The room temperature spectrum of ethane in the region of the ν6 and ν8 fundamentals, between 1330 and 1610 cm-1, has been re-investigated at a resolution of 0.002 cm-1. It is shown that the complex spectral structure with numerous strong local perturbations, which had hindered a global analysis of this region until now, is caused by a network of l-type resonances acting within the Fermi (or torsional-Coriolis) coupled system ν8, ν4 + ν12. The x,y-Coriolis interaction between ν6 and ν8 and vibration-rotation interactions between ν6 and 2ν4 + ν9 also generate relevant effects on the spectrum. With an appropriate Hamiltonian model accounting for all these effects, we could fit 1814 upper state level energies belonging to ν6, ν8 and ν4 + ν12 with an overall RMS deviation better than 3.8 × 10-3 cm-1. The determined values of the intrinsic torsional splittings in the different vibrational states are in agreement with the theoretical expectations. The intrinsic torsional splitting almost vanishes in ν8, as in digermane and disilane; it is slightly larger in ν4 + ν12 than in ν4, due to the decrease of the torsional barrier height with the excitation of ν12. For the 2ν4 + ν9 state, the determined values of the vibrational origin and torsional splittings are in good agreement with the large increase of the torsional barrier height expected with the excitation of the ν9 mode. Several hot transitions originating from the v4 = 1 torsional state have been observed. An analysis of 294 line positions belonging to the (ν4 + ν8) - ν4 hot band has been performed, leading to a fit with a RMS deviation of 5.1 × 10-3 cm-1. It is shown that a complex network of l-type resonances is also active in the ν4 + ν8,2ν4 + ν12 system. © 2007 Elsevier Inc. All rights reserved.
BibTeX: @article{Lattanzi2008134, author = {Lattanzi, F. and Lauro, C. di and Vander Auwera, J.}, title = {Vibration-rotation-torsion analysis of the high resolution infrared spectrum of C2H6 between 1330 and 1610 cm-1: The ν6, ν8, ν4 + ν12, 2ν4 + ν9 interacting system and hot transitions from ν4 to ν4 + ν8}, journal = {Journal of Molecular Spectroscopy}, year = {2008}, volume = {248}, number = {2}, pages = {134 – 145}, doi = {10.1016/j.jms.2007.12.006} }
Le Padellec A, Liévin J, Staicu-Casagrande E, Nzeyimana T, Naji E and Urbain X (2008), "Competitive processes in the associative ionization of C- with C+, N+, and O+", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 78(6) [Abstract] [BibTeX] [DOI]
Abstract: Absolute integral cross sections have been measured for associative ionization reactions involving the C- and C+, N+, and O+ reactants. These measurements, obtained using a merged-beam setup in the keV range, provide us with useful experimental information on the efficiency and mechanisms of molecular ion formation from ionic reactants. The relative magnitudes of the different cross sections are rationalized by considering the spin multiplicities of initial and final states, and the exothermicities of the detachment and transfer ionization channels. The very different production efficiencies of C O+ ions via the O- + C+ and C- + O+ channels are explained by statistical and energetic considerations. The potential energy curves of CO and C O+ have been calculated by quantum ab initio methods in order to characterize the reactive pathways leading to autoionization. Thermal rate coefficients are derived to serve the plasma physics community. © 2008 The American Physical Society.
BibTeX: @article{LePadellec2008, author = {Le Padellec, A. and Liévin, J. and Staicu-Casagrande, E.M. and Nzeyimana, T. and Naji, E.A. and Urbain, X.}, title = {Competitive processes in the associative ionization of C- with C+, N+, and O+}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2008}, volume = {78}, number = {6}, doi = {10.1103/PhysRevA.78.062705} }
Lubac B, Loisel H, Guiselin N, Astoreca R, Artigas LF and Mériaux X (2008), "Hyperspectral and multispectral ocean color inversions to detect Phaeocystis globosa blooms in coastal waters", Journal of Geophysical Research: Oceans. Vol. 113(6) [Abstract] [BibTeX] [DOI]
Abstract: Identification of phytoplankton groups from space is essential to map and monitor algal blooms in coastal waters, but remains a challenge due to the presence of suspended sediments and dissolved organic matter which interfere with phytoplankton signal. On the basis of field measurements of remote sensing reflectance (Rrs(λ)), bio-optical parameters, and phytoplankton cells enumerations, we assess the feasibility of using multispectral and hyperspectral approaches for detecting spring blooms of Phaeocystis globosa (P. globosa). The two reflectance ratios (Rrs(490) /Rrs(510) and Rrs(442.5) /Rrs(490)), used in the multispectral inversion, suggest that detection of P. globosa blooms are possible from current ocean color sensors. The effects of chlorophyll concentration, colored dissolved organic matter (CDOM), and particulate matter composition on the performance of this multispectral approach are investigated via sensitivity analysis. This analysis indicates that the development of a remote sensing algorithm, based on the values of these two ratios, should include information about CDOM concentration. The hyperspectral inversion is based on the analysis of the second derivative of Rrs(λ) (dλ2 Rrs). Two criteria, based on the position of the maxima and minima of dλ2Rrs, are established to discriminate the P. globosa blooms from diatoms blooms. We show that the position of these extremes is related to the specific absorption spectrum of P. globosa and is significantly correlated with the relative biomass of P. globosa. This result confirms the advantage of a hyperspectral over multispectral inversion for species identification and enumeration from satellite observations of ocean color. Copyright 2008 by the American Geophysical Union.
BibTeX: @article{Lubac2008, author = {Lubac, Bertrand and Loisel, Hubert and Guiselin, Natacha and Astoreca, Rosa and Artigas, L. Felipe and Mériaux, Xavier}, title = {Hyperspectral and multispectral ocean color inversions to detect Phaeocystis globosa blooms in coastal waters}, journal = {Journal of Geophysical Research: Oceans}, year = {2008}, volume = {113}, number = {6}, doi = {10.1029/2007JC004451} }
Neyns B, Aerts M, Van Nieuwenhove Y, Fontaine C, De Coster L, Schallier D, Vanderauwera J, De Munck F, Vandenbroucke F, Everaert H, Meert V, De Mey J, De Ridder M, Delvaux G and De Grève J (2008), "Cetuximab with hepatic arterial infusion of chemotherapy for the treatment of colorectal cancer liver metastases", Anticancer Research. Vol. 28(4 C), pp. 2459 – 2467. [Abstract] [BibTeX]
Abstract: Background: Both hepatic arterial infusion (HAI) of chemotherapy and cetuximab (CET) have interesting activity for the treatment of colorectal cancer liver metastases (CRC-LM). Patients and Methods: Intravenous CET with HAI oxaliplatin (OXA) or i.v. Irinotecan (IRI) followed by HAI of infusion of folic acid modulated 5-fluorouracil 5-FU/l-FA was administered to patients (pts) with CRC-LM who had failed at least one line of prior chemotherapy. Results: Eight pts received i.v. CET with HAI-OXA (5 pts) and i.v.-IRI (3 pts) and HAI-S-FU/I-FA. Adverse events: repeated grade 3 skin toxicity (1 pt), abdominal pain with elevated liver enzymes and asthenia (2 pts), duodenal ulcer (2 pts) with catheter migration and intestinal bleeding (1 pt), reversible interstitial pneumonitis (1 pt), and cystic bile duct dilatation (2 pts) with arteriobiliary fistulisation (1 pt). A partial response was documented in 5 pts (62%). The median time to progression was 8.7 months (95% confidence interval 8-14 months). Conclusion: Intravenous administration of CET with HAI of chemotherapy is feasible and has promising activity but is associated with specific toxicity.
BibTeX: @article{Neyns2008, author = {Neyns, Bart and Aerts, Maridi and Van Nieuwenhove, Yves and Fontaine, Christel and De Coster, Lore and Schallier, Dennis and Vanderauwera, Jacques and De Munck, Floris and Vandenbroucke, Frederik and Everaert, Hendrik and Meert, Vanessa and De Mey, Johan and De Ridder, Mark and Delvaux, Georges and De Grève, Jacques}, title = {Cetuximab with hepatic arterial infusion of chemotherapy for the treatment of colorectal cancer liver metastases}, journal = {Anticancer Research}, year = {2008}, volume = {28}, number = {4 C}, pages = {2459 – 2467} }
Nguyen L, Blanquet G, Vander Auwera J and Lepère M (2008), "Temperature dependence of the self-broadening coefficients of ethane", Journal of Molecular Spectroscopy. Vol. 249(1), pp. 1 – 5. [Abstract] [BibTeX] [DOI]
Abstract: Using a diode-laser spectrometer, self-broadening coefficients have been measured at three temperatures (246.2, 226.2 and 150.2 K) for 11 spectral lines in the ν9 fundamental band of 12C2H6. The collisional widths have been obtained by fitting each experimental absorption profile with a Rautian model. The temperature dependence exponent n was also determined for each line, and found to be constant within experimental uncertainties. The mean value is equal to n = 0.676. © 2008.
BibTeX: @article{Nguyen20081, author = {Nguyen, Linh and Blanquet, Ghislain and Vander Auwera, Jean and Lepère, Muriel}, title = {Temperature dependence of the self-broadening coefficients of ethane}, journal = {Journal of Molecular Spectroscopy}, year = {2008}, volume = {249}, number = {1}, pages = {1 – 5}, doi = {10.1016/j.jms.2008.01.003} }
Perevalov B, Deleporte T, Liu A, Kassi S, Campargue A, Vander Auwera J, Tashkun S and Perevalov V (2008), "Global modeling of 13C16O2 absolute line intensities from CW-CRDS and FTS measurements in the 1.6 and 2.0 μm regions", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 109(11), pp. 2009 – 2026. [Abstract] [BibTeX] [DOI]
Abstract: Line intensities of 13C16O2 have been measured between 5851 and 6580 cm-1 using CW-cavity ring down spectroscopy (CRDS) and in the 4700-5050 and 6050-6850 cm-1 regions using Fourier transform spectroscopy. As a result of the high sensitivity (noise equivalent absorption αmin∼3×10-10 cm-1) and high dynamics allowed by CW-CRDS, accurate line intensities of 2039 transitions ranging between 1.1×10-28 and 1.3×10-23 cm-1/(molecule cm-2) were measured with an average accuracy of 4%. These transitions belong to a total of 48 bands corresponding to the ΔP=9 series of transitions. Additionally, unapodized absorption spectra of 13C-enriched samples have been recorded using a high-resolution Bruker IFS125HR Fourier transform spectrometer. Spectral resolutions of 0.004 cm-1 (maximum optical path difference (MOPD)=225 cm) and 0.007 cm-1 (MOPD=128.6 cm), and pressure×path length products in the ranges 5.2-12 and 69-450 hPa×m have been used for the lower and higher energy spectral regions, respectively. Absolute line intensities have been measured in the 2001i-00001, 3001i-00001 (i=1, 2, 3) and 00031-00001 bands. An excellent agreement was achieved for the line intensities of the 3001i-00001 (i=1, 2, 3) bands measured by both FTS and CW-CRDS. The CW-CRDS and FTS experimental intensity data together with selected intensity information from the literature have been fitted simultaneously using the effective operators approach. Two sets of effective dipole moment parameters have thus been obtained, which reproduce the observed line intensities in the 2.0 and 1.6 μm regions within experimental uncertainties. © 2008 Elsevier Ltd. All rights reserved.
BibTeX: @article{Perevalov2008, author = {Perevalov, B.V. and Deleporte, T. and Liu, A.W. and Kassi, S. and Campargue, A. and Vander Auwera, J. and Tashkun, S.A. and Perevalov, V.I.}, title = {Global modeling of 13C16O2 absolute line intensities from CW-CRDS and FTS measurements in the 1.6 and 2.0 μm regions}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2008}, volume = {109}, number = {11}, pages = {2009 – 2026}, doi = {10.1016/j.jqsrt.2008.02.008} }
Predoi-Cross A, Hambrook K, Keller R, Povey C, Schofield I, Hurtmans D, Over H and Mellau GC (2008), "Spectroscopic lineshape study of the self-perturbed oxygen A-band", Journal of Molecular Spectroscopy. Vol. 248(2), pp. 85 – 110. [Abstract] [BibTeX] [DOI]
Abstract: This paper reports accurate line positions, intensities, self-broadening, -shift and -line mixing coefficients for 56 rotational transitions from multispectrum fits of low noise, high-resolution Fourier-transform spectra. The measured line intensities are within the statistical spread of the previous measurements available in the literature-thus contributing to the efforts to measure the oxygen A-band intensities with an accuracy better than 1%. We determined the integrated band strength and Einstein A coefficient. Using our spectrum calibration method we could clearly show for the first time that there is a meaningful statistical discrepancy in the frequency standards used in spectroscopic studies for the oxygen A-band. We were able to explain how this discrepancy leads to two different sets of shifts reported in the literature and demonstrate the need for precise frequency-type transition wavenumber measurements of the oxygen A-band transitions. We observed deviations from the conventional Voigt profile due to speed-dependent broadening and line mixing effects. Dicke narrowing was observed on a selected group of spectra recorded at pressures between 98 and 337 Torr. The Dicke narrowed lineshapes were best modeled using a Galatry profile implemented using a fixed value for the velocity-changing collision rate. The weak line mixing coefficients were determined from fits using the speed-dependent models. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws were used to calculate the self-broadening and self-line mixing coefficients. © 2007 Elsevier Inc. All rights reserved.
BibTeX: @article{Predoi-Cross200885, author = {Predoi-Cross, Adriana and Hambrook, Kyle and Keller, Reimund and Povey, Chad and Schofield, Ian and Hurtmans, Daniel and Over, Herbert and Mellau, Georg Ch.}, title = {Spectroscopic lineshape study of the self-perturbed oxygen A-band}, journal = {Journal of Molecular Spectroscopy}, year = {2008}, volume = {248}, number = {2}, pages = {85 – 110}, doi = {10.1016/j.jms.2007.11.007} }
Predoi-Cross A, Holladay C, Heung H, Bouanich J-P, Mellau GC, Keller R and Hurtmans DR (2008), "Nitrogen-broadened lineshapes in the oxygen A-band: Experimental results and theoretical calculations", Journal of Molecular Spectroscopy. Vol. 251(1-2), pp. 159 – 175. [Abstract] [BibTeX] [DOI]
Abstract: We report measurements for N2-broadening, pressure-shift and line mixing coefficients for 55 oxygen transitions in the A-band retrieved using a multispectrum fitting technique. Nineteen laboratory absorption spectra were recorded at 0.02 cm-1 resolution using a multi-pass absorption cell with path length of 1636.9 cm and the IFS 120 Fourier transform spectrometer located at Justus-Liebig-University in Giessen, Germany. The total sample pressures ranged from 8.8 to 3004.5 Torr with oxygen volume mixing ratios in nitrogen ranging between 0.057 and 0.62. An Exponential Power Gap (EPG) scaling law was used to calculate the N2-broadening and N2-line mixing coefficients. The line broadening and shift coefficients for the A-band of oxygen self-perturbed and perturbed by N2 are modeled using semiclassical calculations based on the Robert-Bonamy formalism and two intermolecular potentials. These potentials involve electrostatic contributions including the hexadecapole moment of the molecules and (a) a simple dispersion contribution with one adjustable parameter to fit the broadening coefficients or (b) the atom-atom Lennard-Jones model without such adjustable parameters. The first potential leads to very weak broadening coefficients for high J transitions whereas the second potential gives much more improved results at medium and large J values, in reasonable agreement with the experimental data. For the line shifts which mainly arise in our calculation from the electronic state dependence of the isotropic potential, their general trends with increasing J values can be well predicted, especially from the first potential. From the theoretical results, we have derived air-broadening and air-induced shift coefficients with an agreement comparable to that obtained for O2-O2 and O2-N2. © 2008 Elsevier Inc. All rights reserved.
BibTeX: @article{PredoiCross2008, author = {Predoi-Cross, Adriana and Holladay, Christopher and Heung, Henry and Bouanich, Jean-Pierre and Mellau, Georg Ch. and Keller, Reimund and Hurtmans, Daniel R.}, title = {Nitrogen-broadened lineshapes in the oxygen A-band: Experimental results and theoretical calculations}, journal = {Journal of Molecular Spectroscopy}, year = {2008}, volume = {251}, number = {1-2}, pages = {159 – 175}, doi = {10.1016/j.jms.2008.02.010} }
Predoi-Cross A, McKellar A and Hurtmans D (2008), "High accuracy line profile study of transitions in the 30012 ← 00001 and 30013 ← 00001 bands of carbon dioxide", AIP Conference Proceedings. Vol. 1058, pp. 265 – 272. [Abstract] [BibTeX] [DOI]
Abstract: This work is a room temperature study of the 30012 ← 00001 and 30013 ← 00001 vibrational bands in self- and air-broadened carbon dioxide. The spectra were recorded at a resolution of 0.008 cm-1 or 0.009 cm -1 using a Fourier transform spectrometer and a temperature stabilized long path absorption cell. The analysis is performed using a multispectrum nonlinear least squares fitting technique where the spectra are fitted simultaneously in spectral intervals of about 3 cm-1. Voigt and Speed Dependent Voigt line shape models are used. Intensities, self- and air-broadening, shifts, and weak line mixing coefficients are determined and compared with other studies. Comparisons are also made to demonstrate the importance of considering the line shape effects for measurements in Earth's atmosphere using satellite remote sensing. Examples of multispectrum fits with and without the inclusion of line mixing are also given. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws are used to calculate the relaxation matrix elements and model the broadening and line mixing coefficients. © 2008 American Institute of Physics.
BibTeX: @conference{Predoi-Cross2008265, author = {Predoi-Cross, A. and McKellar, A.R.W. and Hurtmans, D.R.}, title = {High accuracy line profile study of transitions in the 30012 ← 00001 and 30013 ← 00001 bands of carbon dioxide}, journal = {AIP Conference Proceedings}, year = {2008}, volume = {1058}, pages = {265 – 272}, doi = {10.1063/1.3026459} }
Predoi-Cross A, Rohart F, Bouanich J-P and Hurtmans D (2008), "Xe-broadened CO line shapes in the fundamental band at 349 K", AIP Conference Proceedings. Vol. 1058, pp. 178 – 180. [Abstract] [BibTeX] [DOI]
Abstract: We present a line shape analysis on the P(2) and P(7) transitions of CO broadened by Xe in the fundamental band. The spectra were recorded at 349 K using a difference frequency laser spectrometer. For line shape analysis, line mixing effects were included and several models describing the Dicke effect were considered. It is shown that retrieved diffusion parameters are pressure dependent and larger than kinetic diffusion parameters. Finally, all these Dicke line shape models fail in the high pressure regime, that rules out the appropriateness of the Dicke effect for the CO-Xe system. © 2008 American Institute of Physics.
BibTeX: @conference{Predoi-Cross2008178, author = {Predoi-Cross, A. and Rohart, F. and Bouanich, J.-P. and Hurtmans, D.R.}, title = {Xe-broadened CO line shapes in the fundamental band at 349 K}, journal = {AIP Conference Proceedings}, year = {2008}, volume = {1058}, pages = {178 – 180}, doi = {10.1063/1.3026438} }
Predoi-Cross A, Unni A, Liu W, Schofield I, Holladay C, McKellar A and Hurtmans D (2008), "Corrigendum to "Line profile study of transitions in the 30012 ← 00001 and 30013 ← 00001 bands of carbon dioxide perturbed by air" [J. Mol. Spectrosc. 246 (2007) 98-112] (DOI:10.1016/j.jms.2007.08.008)", Journal of Molecular Spectroscopy. Vol. 249(2), pp. 121. [BibTeX] [DOI]
BibTeX: @article{PredoiCross2008a, author = {Predoi-Cross, A. and Unni, A.V. and Liu, W. and Schofield, I. and Holladay, C. and McKellar, A.R.W. and Hurtmans, D.}, title = {Corrigendum to "Line profile study of transitions in the 30012 ← 00001 and 30013 ← 00001 bands of carbon dioxide perturbed by air" [J. Mol. Spectrosc. 246 (2007) 98-112] (DOI:10.1016/j.jms.2007.08.008)}, journal = {Journal of Molecular Spectroscopy}, year = {2008}, volume = {249}, number = {2}, pages = {121}, doi = {10.1016/j.jms.2008.03.001} }
Predoi-Cross A, Unni A, Liu W, Schofield I, Holladay C, McKellar A and Hurtmans D (2008), "Corrigendum to "Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing and speed dependence" [J. Mol. Spectrosc. 245 (2007) 34-51] (DOI:10.1016/j.jms.2007.07.004)", Journal of Molecular Spectroscopy. Vol. 249(1), pp. 72. [BibTeX] [DOI]
BibTeX: @article{Predoi-Cross200872, author = {Predoi-Cross, A. and Unni, A.V. and Liu, W. and Schofield, I. and Holladay, C. and McKellar, A.R.W. and Hurtmans, D.}, title = {Corrigendum to "Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing and speed dependence" [J. Mol. Spectrosc. 245 (2007) 34-51] (DOI:10.1016/j.jms.2007.07.004)}, journal = {Journal of Molecular Spectroscopy}, year = {2008}, volume = {249}, number = {1}, pages = {72}, note = {All Open Access, Bronze Open Access}, doi = {10.1016/j.jms.2008.02.011} }
Rinsland CP, Luo M, Shephard MW, Clerbaux C, Boone CD, Bernath PF, Chiou L and Coheur P (2008), "Tropospheric emission spectrometer (TES) and atmospheric chemistry experiment (ACE) measurements of tropospheric chemistry in tropical southeast Asia during a moderate El Niño in 2006", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 109(10), pp. 1931 – 1942. [Abstract] [BibTeX] [DOI]
Abstract: High spectral resolution Fourier transform spectrometer (FTS) measurements of tropospheric carbon monoxide (CO) distributions show mixing ratios over Indonesia during October 2006 of ∼200 ppbv (10-9 per unit volume) in the middle troposphere. The elevated emissions were caused by intense and widespread Indonesian peat and forest fire emissions elevated compared to other years by the impact of a moderate El Niño/Soutern Oscillation (ENSO) event, which delayed that year's monsoon season and produced very dry conditions. Moderate resolution imaging spectrometer (MODIS) fire counts, atmospheric chemistry experiment (ACE) measurements of elevated mixing ratios of fire emission products and near infrared extinction, and back trajectory calculations for a sample measurement location near the time of maximum emissions provide additional evidence that the elevated 2006 emissions resulted primarily from the Indonesia fires. Lower CO mixing ratios measured by ACE and fewer MODIS fire counts in Indonesia during October 2005 indicate lower emissions than during 2006. Coincident profiles from the ACE agree within the uncertainties with those from the tropospheric emission spectrometer (TES) for pressure ranges and time periods with good TES sensitivity after accounting for its lower vertical sensitivity compared with the ACE FTS. © 2007 Elsevier Ltd. All rights reserved.
BibTeX: @article{Rinsland20081931, author = {Rinsland, Curtis P. and Luo, Ming and Shephard, Mark W. and Clerbaux, Cathy and Boone, Chris D. and Bernath, Peter F. and Chiou, Linda and Coheur, P.F.}, title = {Tropospheric emission spectrometer (TES) and atmospheric chemistry experiment (ACE) measurements of tropospheric chemistry in tropical southeast Asia during a moderate El Niño in 2006}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2008}, volume = {109}, number = {10}, pages = {1931 – 1942}, doi = {10.1016/j.jqsrt.2007.12.020} }
Robert S, Herman M, Fayt A, Campargue A, Kassi S, Liu A, Wang L, Di Lonardo G and Fusina L (2008), "Acetylene, 12C2H2: New CRDS data and global vibration-rotation analysis up to 8600 cm-1", Molecular Physics. Vol. 106(21-23), pp. 2581 – 2605. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of 12C2H2 has been recorded using cavity ringdown spectroscopy and analyzed in the ranges 6000 - 6356 cm-1 and 6667-7015 cm-1. Fourteen new bands have been identified and additional J-lines were assigned in 10 already known bands. These new data, together with the published vibration-rotation absorption lines of 12C2H2 accessing vibrational states up to 8600 cm-1 have been gathered in a database. The resulting set includes 12137 transitions involving 186 different k = l4 + l 5 sub-states, with li the angular momentum quantum number associated to the i degenerate bending vibration. These lines have been fitted simultaneously to spectroscopic parameters through J-dependent Hamiltonian matrices exploiting the vibrational polyad or cluster block-diagonalization, in terms of the pseudo-quantum numbers Nr = 5ν1 + 3ν2 + 5ν3+ν4+ν5 and Ns = ν1 + ν2 + ν3, also accounting for k and e/f parities and u/g symmetry. Modes 1 and 2 correspond to the symmetric CH and CC stretchings, mode 3 to the antisymmetric CH stretch, and modes 4 and 5 to the trans- and cis-degenerate bendings, respectively. The fit was successfully achieved, with a dimensionless standard deviation of 0.92, leading to the determination of 266 effective vibration-rotation parameters. © 2008 Taylor and Francis.
BibTeX: @article{Robert20082581, author = {Robert, S. and Herman, M. and Fayt, A. and Campargue, A. and Kassi, S. and Liu, A. and Wang, L. and Di Lonardo, G. and Fusina, L.}, title = {Acetylene, 12C2H2: New CRDS data and global vibration-rotation analysis up to 8600 cm-1}, journal = {Molecular Physics}, year = {2008}, volume = {106}, number = {21-23}, pages = {2581 – 2605}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268970802620709} }
Rotger M, Boudon V and Vander Auwera J (2008), "Line positions and intensities in the ν12 band of ethylene near 1450 cm- 1: An experimental and theoretical study", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 109(6), pp. 952 – 962. [Abstract] [BibTeX] [DOI]
Abstract: Recently, we built a tensorial formalism adapted to the spectroscopy of X2Y4 molecules. It is based on formalisms developed in Dijon for spherical-top molecules. This approach has the advantages to allow a systematic development of rovibrational interactions and to make global analyses easier to perform. We used this tool to carry out an analysis of the ν12 band of 12C2H4 near 1450 cm- 1, both in frequencies and intensities. 1240 line positions and 871 intensities, measured in a set of spectra recorded in Brussels, with global root mean square deviations of 1.6 × 10- 4 cm- 1 and 1.88 %, respectively. © 2007 Elsevier Ltd. All rights reserved.
BibTeX: @article{Rotger2008952, author = {Rotger, M. and Boudon, V. and Vander Auwera, J.}, title = {Line positions and intensities in the ν12 band of ethylene near 1450 cm- 1: An experimental and theoretical study}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2008}, volume = {109}, number = {6}, pages = {952 – 962}, doi = {10.1016/j.jqsrt.2007.12.005} }
Ruddick K, Park Y, Astoreca R, Borges A, Lacroix G, Lancelot C and Rousseau V (2008), "Applications of the MERIS algal pigment products in Belgian waters", European Space Agency, (Special Publication) ESA SP. (666 SP) [Abstract] [BibTeX]
Abstract: Following validation activities and corresponding improvements in processing algorithms over the first few years of the MERIS mission, the algal1 and algal2 products are now considered as sufficiently mature for use in applications in Belgian waters. The utility of this product has been enhanced by the development of a number of multitemporal products including single point time series, multitemporal composites (monthly/3-monthly means) and annual products such as the mean and 90 percentile concentrations and the timing of the spring bloom. Marine management applications include: support for the assessment of eutrophication status in the context of the Oslo and Paris Convention for the Prevention of Marine Pollution (OSPAR), optimisation of seaborne monitoring, detection of harmful algal blooms and support for aquaculture. More generally, the MERIS data is used in support of marine science including the validation of ecosystem models and may be used in the future for the estimation of air-sea carbon fluxes. The current status of these applications is described together with an assessment of the remaining scientific challenges as well as the future possibilities.
BibTeX: @conference{Ruddick2008a, author = {Ruddick, Kevin and Park, Youngje and Astoreca, Rosa and Borges, Alberto and Lacroix, Geneviève and Lancelot, Christiane and Rousseau, Véronique}, title = {Applications of the MERIS algal pigment products in Belgian waters}, journal = {European Space Agency, (Special Publication) ESA SP}, year = {2008}, number = {666 SP} }
Ruddick K, Park Y, Astoreca R, Neukermans G and Van Mol B (2008), "Validation of MERIS water products in the southern North Sea: 2002-2008", European Space Agency, (Special Publication) ESA SP. (666 SP) [Abstract] [BibTeX]
Abstract: This paper describes the validation of MERIS water products for the Southern North Sea for the period July 2002 to September 2008. During this period, 39 matchups were obtained for the parameters water-leaving reflectance spectra, chlorophyll a concentration and total suspended matter concentration, of which 12 are in optimal conditions. Previous validation results reported for 2002-5 are updated to 2008. Conclusions are largely reinforced since the MERIS processor has not changed. In particular it is recommended to improve estimation of the spectral slope of aerosol reflectance in turbid waters. Some image artifacts are noted including noisy low chlorophyll data. Inherent optical property data is analysed and compared to the assumptions used for derivation of the MERIS products. Turbidity has been added to the in situ parameter set, strengthening quality control of water sample analysis.
BibTeX: @conference{Ruddick2008, author = {Ruddick, Kevin and Park, Youngje and Astoreca, Rosa and Neukermans, Griet and Van Mol, Barbara}, title = {Validation of MERIS water products in the southern North Sea: 2002-2008}, journal = {European Space Agency, (Special Publication) ESA SP}, year = {2008}, number = {666 SP} }
Senten C, De Mazière M, Dils B, Hermans C, Kruglanski M, Neefs E, Scolas F, Vandaele A, Vanhaelewyn G, Vigouroux C, Carleer M, Coheur P, Fally S, Barret B, Baray J, Delmas R, Leveau J, Metzger J, Mahieu E, Boone C, Walker K, Bernath P and Strong K (2008), "Technical note: New ground-based FTIR measurements at Ile de la Réunion: Observations, error analysis, and comparisons with independent data", Atmospheric Chemistry and Physics. Vol. 8(13), pp. 3483 – 3508. [Abstract] [BibTeX] [DOI]
Abstract: Ground-based high spectral resolution Fourier-transform infrared (FTIR) solar absorption spectroscopy is a powerful remote sensing technique to obtain information on the total column abundances and on the vertical distribution of various constituents in the atmosphere. This work presents results from two FTIR measurement campaigns in 2002 and 2004, held at Ile de La Réunion (21° S, 55° E). These campaigns represent the first FTIR observations carried out at a southern (sub)tropical site. They serve the initiation of regular, long-term FTIR monitoring at this site in the near future. To demonstrate the capabilities of the FTIR measurements at this location for tropospheric and stratospheric monitoring, a detailed report is given on the retrieval strategy, information content and corresponding full error budget evaluation for ozone (O3), methane (CH4), nitrous oxide (N2O), carbon monoxide (CO), ethane (C 2H6), hydrogen chloride (HCl), hydrogen fluoride (HF) and nitric acid (HNO3) total and partial column retrievals. Moreover, we have made a thorough comparison of the capabilities at sea level altitude (St.-Denis) and at 2200 m a.s.l. (Maïdo). It is proved that the performances of the technique are such that the atmospheric variability can be observed, at both locations and in distinct altitude layers. Comparisons with literature and with correlative data from ozone sonde and satellite (i.e., ACE-FTS, HALOE and MOPITT) measurements are given to confirm the results. Despite the short time series available at present, we have been able to detect the seasonal variation of CO in the biomass burning season, as well as the impact of particular biomass burning events in Africa and Madagascar on the atmospheric composition above Ile de La Réunion. We also show that differential measurements between St.-Denis and Maïdo provide useful information about the concentrations in the boundary layer.
BibTeX: @article{Senten20083483, author = {Senten, C. and De Mazière, M. and Dils, B. and Hermans, C. and Kruglanski, M. and Neefs, E. and Scolas, F. and Vandaele, A.C. and Vanhaelewyn, G. and Vigouroux, C. and Carleer, M. and Coheur, P.F. and Fally, S. and Barret, B. and Baray, J.L. and Delmas, R. and Leveau, J. and Metzger, J.M. and Mahieu, E. and Boone, C. and Walker, K.A. and Bernath, P.F. and Strong, K.}, title = {Technical note: New ground-based FTIR measurements at Ile de la Réunion: Observations, error analysis, and comparisons with independent data}, journal = {Atmospheric Chemistry and Physics}, year = {2008}, volume = {8}, number = {13}, pages = {3483 – 3508}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-8-3483-2008} }
Sutcliffe B (2008), "Risk aversion", Chemistry World. Vol. 5(1), pp. 40. [BibTeX]
BibTeX: @article{Sutcliffe200840, author = {Sutcliffe, Brian}, title = {Risk aversion}, journal = {Chemistry World}, year = {2008}, volume = {5}, number = {1}, pages = {40} }
Sutcliffe BT (2008), "What mathematicians know about the solutions of Schrodinger Coulomb Hamiltonian. Should chemists care?", Journal of Mathematical Chemistry. Vol. 44(4), pp. 988 – 1008. [Abstract] [BibTeX] [DOI]
Abstract: An attempt is made to determine the relationship between the full Schrödinger Coulomb Hamiltonian and the clamped nuclei form that is usually the basis of electronic structure calculations, without treating identical nuclei as distinguishable. It is concluded that it is not at present possible to establish such a relationship in a mathematically secure way. © 2008 Springer Science+Business Media, LLC.
BibTeX: @article{Sutcliffe2008, author = {Sutcliffe, Brian T.}, title = {What mathematicians know about the solutions of Schrodinger Coulomb Hamiltonian. Should chemists care?}, journal = {Journal of Mathematical Chemistry}, year = {2008}, volume = {44}, number = {4}, pages = {988 – 1008}, doi = {10.1007/s10910-008-9358-7} }
Tumuhimbise AT, Hurtmans D, Mondelain D and Mantz AW (2008), "Nitrogen-pressure shifts in the ν3 band of methane measured at several temperatures between 300 and 90 K", Journal of Molecular Spectroscopy. Vol. 252(2), pp. 239 – 241. [Abstract] [BibTeX] [DOI]
Abstract: The results of nitrogen broadening measurements in the ν3 band of 12CH4 using the 5.37 m long absorption path length all-copper Herriott cell were presented. The experimental pressure shift data for 90 and for 140 K temperatures were plotted, where the pressure shift for each component was plotted versus pressure expressed in units of atmospheres. The comparison of values with the values given by HITRAN04 at 296 K show differences of -2.77×10-3cm-1atm-1 in absolute value compared to the database which is largely in the error bar. Absolute differences from 1.9 to 15.3×10-4cm-1atm-1 are observed for the room temperature pressure shift coefficient.
BibTeX: @article{Tumuhimbise2008239, author = {Tumuhimbise, Anthony T. and Hurtmans, Daniel and Mondelain, Didier and Mantz, Arlan W.}, title = {Nitrogen-pressure shifts in the ν3 band of methane measured at several temperatures between 300 and 90 K}, journal = {Journal of Molecular Spectroscopy}, year = {2008}, volume = {252}, number = {2}, pages = {239 – 241}, doi = {10.1016/j.jms.2008.09.001} }
Turquety S, Clerbaux C, Law K, Coheur P-F, Cozic A, Szopa S, Hauglustaine D, Hadji-Lazaro J, Gloudemans A, Schrijver H, Boone C, Bernath P and Edwards D (2008), "CO emission and export from Asia: An analysis combining complementary satellite measurements (MOPITT, SCIAMACHY and ACE-FTS) with global modeling", Atmospheric Chemistry and Physics. Vol. 8(17), pp. 5187 – 5204. [Abstract] [BibTeX] [DOI]
Abstract: This study presents the complementary picture of the pollution outflow provided by several satellite observations of carbon monoxide (CO), based on different observation techniques. This is illustrated by an analysis of the Asian outflow during the spring of 2005, through comparisons with simulations by the LMDz-INCA global chemistry transport model. The CO observations from the MOPITT and SCIAMACHY nadir sounders, which provide vertically integrated information with excellent horizontal sampling, and from the ACE-FTS solar occultation instrument, which has limited spatial coverage but allows the retrieval of vertical profiles, are used. Combining observations from MOPITT (mainly sensitive to the free troposphere) and SCIAMACHY (sensitive to the full column) allows a qualitative evaluation of the boundary layer CO. The model tends to underestimate this residual compared to the observations, suggesting underestimated emissions, especially in eastern Asia. However, a better understanding of the consistency and possible biases between the MOPITT and SCIAMACHY CO is necessary for a quantitative evaluation. Underestimated emissions, and possibly too low lofting and underestimated chemical production in the model, lead to an underestimate of the export to the free troposphere, as highlighted by comparisons with MOPITT and ACE-FTS. Both instruments observe large trans-Pacific transport extending from ∼20° N to ∼60° N, with high upper tropospheric CO observed by ACE-FTS above the eastern Pacific (with values of up to 300 ppbv around 50° N at 500 hPa and up to ∼200 ppbv around 30° N at 300 hPa). The low vertical and horizontal resolutions of the global model do not allow the simulation of the strong enhancements in the observed plumes. However, the transport patterns are well captured, and are mainly attributed to export from eastern Asia, with increasing contributions from South Asia and Indonesia towards the tropics. Additional measurements of C2H2, C2H 6 and HCN by ACE-FTS provide further information on the plume history. C2H2 and C2H6 enhancements are well correlated with the CO plumes, indicating common sources and rapid trans-Pacific transport. HCN observations show that the biomass burning contributes mainly at latitudes lower than ∼40° N. This study provides a first step towards a full combination of complementary observations, but also highlights the need for a better evaluation of consistency between the datasets in order to allow precise quantitative analyses.
BibTeX: @article{Turquety20085187, author = {Turquety, S. and Clerbaux, C. and Law, K. and Coheur, P.-F. and Cozic, A. and Szopa, S. and Hauglustaine, D.A. and Hadji-Lazaro, J. and Gloudemans, A.M.S. and Schrijver, H. and Boone, C.D. and Bernath, P.F. and Edwards, D.P.}, title = {CO emission and export from Asia: An analysis combining complementary satellite measurements (MOPITT, SCIAMACHY and ACE-FTS) with global modeling}, journal = {Atmospheric Chemistry and Physics}, year = {2008}, volume = {8}, number = {17}, pages = {5187 – 5204}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-8-5187-2008} }
Zobov NF, Shirin SV, Ovsyannikov RI, Polyansky OL, Barber RJ, Tennyson J, Bernath PF, Carleer M, Colin R and Coheur P-F (2008), "Spectrum of hot water in the 4750-13 000 cm-1 wavenumber range (0.769-2.1 μm)", Monthly Notices of the Royal Astronomical Society. Vol. 387(3), pp. 1093 – 1098. [Abstract] [BibTeX] [DOI]
Abstract: The high resolution laboratory spectrum of hot water vapour has been recorded in the 500-13 000 cm-1 wavenumber range and we report on the analysis of the 4750-13 000 cm-1 (0.769-2.1 μm) portion. The emission spectrum was recorded using an oxy-acetylene welding torch and a Fourier transform spectrometer. Line assignments in the laboratory spectrum as well as in an absorption spectrum of a sunspot umbra were made with the help of the BT2 line-list. Our torch spectrum is the first laboratory observation of the 9300 Å 'steam bands' seen in M-stars and brown dwarfs. © 2008 The Authors.
BibTeX: @article{Zobov20081093, author = {Zobov, Nikolai F. and Shirin, Sergei V. and Ovsyannikov, Roman I. and Polyansky, Oleg L. and Barber, Robert J. and Tennyson, Jonathan and Bernath, Peter F. and Carleer, Michel and Colin, Reginald and Coheur, Pierre-François}, title = {Spectrum of hot water in the 4750-13 000 cm-1 wavenumber range (0.769-2.1 μm)}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {2008}, volume = {387}, number = {3}, pages = {1093 – 1098}, note = {All Open Access, Bronze Open Access}, doi = {10.1111/j.1365-2966.2008.13234.x} }
Bégué D, Gohaud N, Pouchan C, Cassam-Chenai P and Liévin J (2007), "A comparison of two methods for selecting vibrational configuration interaction spaces on a heptatomic system: Ethylene oxide", Journal of Chemical Physics. Vol. 127(16) [Abstract] [BibTeX] [DOI]
Abstract: Two recently developed methods for solving the molecular vibrational Schrödinger equation, namely, the parallel vibrational multiple window configuration interaction and the vibrational mean field configuration interaction, are presented and compared on the same potential energy surface of ethylene oxide, c-C2H4O. It is demonstrated on this heptatomic system with strong resonances that both approaches converge towards the same fundamental frequencies. This confirms their ability to tackle the vibrational problem of large molecules for which full configuration interaction calculations are not tractable. © 2007 American Institute of Physics.
BibTeX: @article{Bégué2007, author = {Bégué, Didier and Gohaud, Neil and Pouchan, Claude and Cassam-Chenai, Patrick and Liévin, Jacques}, title = {A comparison of two methods for selecting vibrational configuration interaction spaces on a heptatomic system: Ethylene oxide}, journal = {Journal of Chemical Physics}, year = {2007}, volume = {127}, number = {16}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.2795711} }
Borgoo A, Godefroid M, Indelicato P, De Proft F and Geerlings P (2007), "Quantum similarity study of atomic density functions: Insights from information theory and the role of relativistic effects", Journal of Chemical Physics. Vol. 126(4) [Abstract] [BibTeX] [DOI]
Abstract: A novel quantum similarity measure (QSM) is constructed based on concepts from information theory. In an application of QSM to atoms, the new QSM and its corresponding quantum similarity index (QSI) are evaluated throughout the periodic table, using the atomic electron densities and shape functions calculated in the Hartree-Fock approximation. The periodicity of Mendeleev's table is regained for the first time through the evaluation of a QSM. Evaluation of the information theory based QSI demonstrates, however, that the patterns of periodicity are lost due to the renormalization of the QSM, yielding chemically less appealing results for the QSI. A comparison of the information content of a given atom on top of a group with the information content of the elements in the subsequent rows reveals another periodicity pattern. Relativistic effects on the electronic density functions of atoms are investigated. Their importance is quantified in a QSI study by comparing for each atom, the density functions evaluated in the Hartree-Fock and Dirac-Fock approximations. The smooth decreasing of the relevant QSI along the periodic table illustrates in a quantitative way the increase of relativistic corrections with the nuclear charge. © 2007 American Institute of Physics.
BibTeX: @article{Borgoo2007, author = {Borgoo, A. and Godefroid, M. and Indelicato, P. and De Proft, F. and Geerlings, P.}, title = {Quantum similarity study of atomic density functions: Insights from information theory and the role of relativistic effects}, journal = {Journal of Chemical Physics}, year = {2007}, volume = {126}, number = {4}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.2428295} }
Cauët E and Liévin J (2007), "Radical Cations of the Nucleic Bases and Radiation Damage to DNA: Ab Initio Study", Advances in Quantum Chemistry. Vol. 52, pp. 121 – 147. [Abstract] [BibTeX] [DOI]
Abstract: This review summarizes the contribution of high level quantum chemical calculations to the investigation of some elementary reactive processes related to the radiation damage to DNA. It is focused on the biomimetic species that govern these processes at the molecular level. These species are the DNA bases, isolated or embedded in base clusters. Their cations, formed by ionization in their ground and first excited electronic states, are at the center of the present work. We present a synthetic and critical overview of the computational methods used to predict accurate ionization potentials, to correctly describe the non-bonding interactions (stacking, H-bonding and cation-π) stabilizing the studied biomimetic clusters, to characterize their excited states and to investigate the topology of the corresponding potential energy surfaces (minima, transition states, avoided crossings, conical intersections, reaction paths). All these aspects are illustrated by the recent literature and by our own research work, namely on the electron transfer occurring within a stacked dimer of guanines. © 2007 Elsevier Inc. All rights reserved.
BibTeX: @article{Cauët2007121, author = {Cauët, Emilie and Liévin, Jacques}, title = {Radical Cations of the Nucleic Bases and Radiation Damage to DNA: Ab Initio Study}, journal = {Advances in Quantum Chemistry}, year = {2007}, volume = {52}, pages = {121 – 147}, doi = {10.1016/S0065-3276(06)52006-4} }
Clarisse L, Ghosh S, Severini S and Sudbery A (2007), "The disentangling power of unitaries", Physics Letters, Section A: General, Atomic and Solid State Physics. Vol. 365(5-6), pp. 400 – 402. [Abstract] [BibTeX] [DOI]
Abstract: We define the disentangling power of a unitary operator in a similar way as the entangling power defined by Zanardi et al. [P. Zanardi, C. Zalka, L. Faoro, Phys. Rev. A 62 (2000) 030301(R), quant-ph/0005031]. A general formula is derived and it is shown that both quantities are directly proportional. All results concerning the entangling power can simply be translated into similar statements for the disentangling power. In particular, the disentangling power is maximal for certain permutations derived from orthogonal Latin squares. These permutations can therefore be interpreted as those that distort entanglement in a maximal way. © 2007 Elsevier B.V. All rights reserved.
BibTeX: @article{Clarisse2007400, author = {Clarisse, Lieven and Ghosh, Sibasish and Severini, Simone and Sudbery, Anthony}, title = {The disentangling power of unitaries}, journal = {Physics Letters, Section A: General, Atomic and Solid State Physics}, year = {2007}, volume = {365}, number = {5-6}, pages = {400 – 402}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.physleta.2007.02.001} }
Clerbaux C, Hadji-Lazaro J, Turquety S, George M, Coheur P-F, Hurtmans D, Wespes C, Herbin H, Blumstein D, Tourniers B and Phulpin T (2007), "The IASI/MetOp1Mission: First observations and highlights of its potential contribution to GMES2 ", Space Research Today. Vol. 168, pp. 19 – 24. [BibTeX] [DOI]
BibTeX: @article{Clerbaux200719, author = {Clerbaux, C. and Hadji-Lazaro, J. and Turquety, S. and George, M. and Coheur, P.-F. and Hurtmans, D. and Wespes, C. and Herbin, H. and Blumstein, D. and Tourniers, B. and Phulpin, T.}, title = {The IASI/MetOp1Mission: First observations and highlights of its potential contribution to GMES2 }, journal = {Space Research Today}, year = {2007}, volume = {168}, pages = {19 – 24}, doi = {10.1016/S0045-8732(07)80046-5} }
Coheur P-F, Herbin H, Clerbaux C, Hurtmans D, Wespes C, Carleer M, Turquety S, Rinsland C, Remedios J, Hauglustaine D, Boone C and Bernath P (2007), "ACE-FTS observation of a young biomass burning plume: First reported measurements of C2H4, C3H6O, H 2CO and PAN by infrared occultation from space", Atmospheric Chemistry and Physics. Vol. 7(20), pp. 5437 – 5446. [Abstract] [BibTeX] [DOI]
Abstract: In the course of our study of the upper tropospheric composition with the infrared Atmospheric Chemistry Experiment - Fourier Transform Spectrometer (ACEFTS), we found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere are performed for this period and they suggest that the emissions for this event likely originated from a nearby forest fire, after which the plume was transported from the source region to the upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE-FTS spectra over a wide wavenumber range (750-4400 cm-1), we present in-depth analyses of the chemical composition of this plume in the middle and upper troposphere, focusing on the measurements of weakly absorbing pollutants. For this specific biomass burning event, we report simultaneous observations of an unprecedented number of organic species. Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) and CH3COO2NO2 (peroxyacetylnitrate, abbreviated as PAN) are the first reported detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the emitted species, we discuss the photochemical age of the plume and also report, whenever possible, the enhancement ratios relative to CO.
BibTeX: @article{Coheur20075437, author = {Coheur, P.-F. and Herbin, H. and Clerbaux, C. and Hurtmans, D. and Wespes, C. and Carleer, M. and Turquety, S. and Rinsland, C.P. and Remedios, J. and Hauglustaine, D. and Boone, C.D. and Bernath, P.F.}, title = {ACE-FTS observation of a young biomass burning plume: First reported measurements of C2H4, C3H6O, H 2CO and PAN by infrared occultation from space}, journal = {Atmospheric Chemistry and Physics}, year = {2007}, volume = {7}, number = {20}, pages = {5437 – 5446}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-7-5437-2007} }
Czakó G, Császár AG, Szalay V and Sutcliffe BT (2007), "Adiabatic Jacobi corrections for H2+ -like systems", Journal of Chemical Physics. Vol. 126(2) [Abstract] [BibTeX] [DOI]
Abstract: The Coulomb three-body problem in Jacobi coordinates was solved by treating the distance of the particles having equal charge as a parameter. This method allows computation of electronic energies with finite nuclear masses while maintaining the notion of a potential energy curve. The rotationless ground-state electronic and the so-called adiabatic Jacobi correction (AJC) energies are presented for H2+, D2+, and H D+ at fixed internuclear separations. The AJCs are defined as the difference between the results obtained from calculations using proper finite and infinite nuclear masses. Except at the united atom limit, the AJCs are smaller than the traditional first-order diagonal Born-Oppenheimer corrections. Expectation values of proton-electron, p-e, and deuteron-electron, d-e, distances for H D+ have been computed as a function of internuclear separation. Similarly to the fully nonadiabatic approach, the present method is able to follow the symmetry breaking in H D+. Exact and approximate analytical and numerical results are given for counterfactual systems as well. In these cases changes are allowed for the values of the electron rest mass or the elementary charge, as well as for the mass or charge of the unique particle (electron). © 2007 American Institute of Physics.
BibTeX: @article{Czakó2007, author = {Czakó, Gábor and Császár, Attila G. and Szalay, Viktor and Sutcliffe, Brian T.}, title = {Adiabatic Jacobi corrections for H2+ -like systems}, journal = {Journal of Chemical Physics}, year = {2007}, volume = {126}, number = {2}, doi = {10.1063/1.2406068} }
Czakó G, Furtenbacher T, Barletta P, Császár AG, Szalay V and Sutcliffe BT (2007), "Use of a nondirect-product basis for treating singularities in triatomic rotational-vibrational calculations", Physical Chemistry Chemical Physics. Vol. 9(26), pp. 3407 – 3415. [Abstract] [BibTeX] [DOI]
Abstract: A technique has been developed which in principle allows the determination of the full rotational-vibrational eigenspectrum of triatomic molecules by treating the important singularities present in the triatomic rotational-vibrational kinetic energy operator given in Jacobi coordinates and the R1 embedding. The singular term related to the diatom-type coordinate, R1, deemed to be unimportant for spectroscopic applications, is given no special attention. The work extends a previous [J. Chem. Phys., 2005, 122, 024101] vibration-only approach and employs a generalized finite basis representation (GFBR) resulting in a nonsymmetric Hamiltonian matrix [J. Chem. Phys., 2006, 124, 014110]. The basis set to be used is obtained by taking the direct product of a 1-D DVR basis, related to R1, with a 5-D nondirect-product basis, the latter formed by coupling Bessel-DVR functions depending on the distance-type coordinate causing the singularity, associated Legendre polynomials depending on the Jacobi angle, and rotational functions depending on the three Euler angles. The robust implicitly restarted Arnoldi method within the ARPACK package is used for the determination of a number of eigenvalues of the nonsymmetric Hamiltonian matrix. The suitability of the proposed approach is shown by the determination of the rotational-vibrational energy levels of the ground electronic state of H3+ somewhat above its barrier to linearity. Convergence of the eigenenergies is checked by an alternative approach, employing a Hamiltonian expressed in Radau coordinates, a standard direct-product basis, and no treatment of the singularities. © the Owner Societies.
BibTeX: @article{Czako2007, author = {Czakó, Gábor and Furtenbacher, Tibor and Barletta, Paolo and Császár, Attila G. and Szalay, Viktor and Sutcliffe, Brian T.}, title = {Use of a nondirect-product basis for treating singularities in triatomic rotational-vibrational calculations}, journal = {Physical Chemistry Chemical Physics}, year = {2007}, volume = {9}, number = {26}, pages = {3407 – 3415}, doi = {10.1039/b701911d} }
Daumont L, Vander Auwera J, Teffo J-L, Perevalov VI and Tashkun SA (2007), "Line intensity measurements in 14N216O and their treatment using the effective dipole moment approach.II. The 5400-11 000 cm-1 region", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 104(3), pp. 342 – 356. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of N2O, at room temperature, was recorded in the 5400-11 000 cm-1 region at resolutions ranging from 0.008 cm-1 near 5400 to 0.023 cm-1 near 11 000 cm-1 using a Bruker IFS120HR Fourier transform spectrometer. Sample pressure/absorption path length products ranging from 200 to 4700 mbar×m were used. More than 6000 absolute line intensities have been measured in 64 different bands of 14N216O. Using wavefunctions previously determined from a global fit of an effective Hamiltonian to more than 18 000 line positions [Tashkun SA, Perevalov VI, and Teffo JL, to be published], the experimental intensities measured in this work and by Toth [J Mol Spectrosc 1999;197:158-87] were fit using 62 parameters of a corresponding effective dipole moment, with residuals very close to the experimental uncertainty. © 2006 Elsevier Ltd. All rights reserved.
BibTeX: @article{Daumont2007342, author = {Daumont, Ludovic and Vander Auwera, Jean and Teffo, Jean-Luc and Perevalov, Valery I. and Tashkun, Sergeï A.}, title = {Line intensity measurements in 14N216O and their treatment using the effective dipole moment approach.II. The 5400-11 000 cm-1 region}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2007}, volume = {104}, number = {3}, pages = {342 – 356}, doi = {10.1016/j.jqsrt.2006.09.004} }
Demaison J, Herman M and Lievin J (2007), "The equilibrium OH bond length", International Reviews in Physical Chemistry. Vol. 26(3), pp. 391 – 420. [Abstract] [BibTeX] [DOI]
Abstract: The equilibrium structure of 36 small molecules containing OH bonds, including molecules with an internal hydrogen bond, is reviewed from the literature. The structures are redetermined or determined, if necessary, using high level ab initio calculations at the CCSD(T) level of theory with basis sets of quintuple zeta quality and with a correction for the core correlation. The possibility of calculating accurate ab initio OH bond lengths at different levels of theory (MP2/VTZ, MP2/VQZ, CCSD(T)/VTZ, and CCSD(T)/AVTZ) is examined. All methods agree provided a small offset correction is taken into account. In most cases, the addition of diffuse functions does not improve the results. The MP2 method appears to be satisfactory whenever the non-dynamical electron correlation is small, which is the most typical situation. The various results are merged to demonstrate the following quantitative correlation between re(OH) and 'isolated' OH stretching frequencies, relevant for predictive use: re(OH) [Å] = 1.2261(76)-7.29(21) x 10-5 νis(OH) [cm-1]. © 2007 Taylor & Francis.
BibTeX: @article{Demaison2007391, author = {Demaison, J. and Herman, M. and Lievin, J.}, title = {The equilibrium OH bond length}, journal = {International Reviews in Physical Chemistry}, year = {2007}, volume = {26}, number = {3}, pages = {391 – 420}, doi = {10.1080/01442350701371919} }
Demaison J, Herman M, Liévin J, Margulès L and Møllendal H (2007), "Rotational spectrum and structure of asymmetric dinitrogen trioxide, N2O3", Journal of Molecular Spectroscopy. Vol. 244(2), pp. 160 – 169. [Abstract] [BibTeX] [DOI]
Abstract: The rotational spectra of the ground vibrational state and the ν9 = 1 torsional state have been reinvestigated and accurate spectroscopic constants have been determined. The torsional frequency, ν9 = 70(15) cm-1, has been determined by relative intensity measurements. The assignment of the infrared spectrum has been slightly revised and an accurate harmonic force field has been calculated. The equilibrium structure has been determined using different, complementary methods: experimental, semi-experimental and ab initio, leading to r(NN) = 1.870(2) Å, in particular. © 2007 Elsevier Inc. All rights reserved.
BibTeX: @article{Demaison2007160, author = {Demaison, J. and Herman, M. and Liévin, J. and Margulès, L. and Møllendal, H.}, title = {Rotational spectrum and structure of asymmetric dinitrogen trioxide, N2O3}, journal = {Journal of Molecular Spectroscopy}, year = {2007}, volume = {244}, number = {2}, pages = {160 – 169}, doi = {10.1016/j.jms.2007.06.003} }
Demaison J, Herman M, Liévin J and Rudolph H (2007), "Equilibrium structure of sulfuric acid", Journal of Physical Chemistry A. Vol. 111(13), pp. 2602 – 2609. [Abstract] [BibTeX] [DOI]
Abstract: The equilibrium structure of the more stable conformer of H 2SO4, of C2 symmetry, has been calculated ab initio using the CCSD(T) method and taking into account the core correlation correction. The accuracy of this structure has been checked by comparing it to that of similar molecules and by estimating the effects of basis set enlargement and of diffuse functions. Furthermore, the quadratic, cubic, and quartic force fields have been calculated at the MP2 level of theory using a basis set of triple-ζ quality. The spectroscopic constants derived from the force field are in satisfactory agreement with the experimental ones. The resulting band origins are compared to literature infrared values, including those for overtone and combination bands. Normal modes of vibration are pictured. Using this force field, semiexperimental equilibrium rotational constants are determined which allows us to check the accuracy of the ab initio structure and to refine it using a mixed regression method. © 2007 American Chemical Society.
BibTeX: @article{Demaison20072602, author = {Demaison, J. and Herman, M. and Liévin, J. and Rudolph, H.D.}, title = {Equilibrium structure of sulfuric acid}, journal = {Journal of Physical Chemistry A}, year = {2007}, volume = {111}, number = {13}, pages = {2602 – 2609}, doi = {10.1021/jp068808e} }
Demaison J, Herman M and Lívin J (2007), "Anharmonic force field of cis- and trans-formic acid from high-level ab initio calculations, and analysis of resonance polyads", Journal of Chemical Physics. Vol. 126(16) [Abstract] [BibTeX] [DOI]
Abstract: The quadratic, cubic, and semidiagonal quartic force fields of cis- and trans-formic acid have been calculated using three different levels of theory. They all give satisfactory results, including the one at the lowest level of theory which is the MP2 method employing a basis set of triple- quality. The results are used to theoretically analyze resonance polyads, including the one involving the 41, 51, 61, 81, 71 91, and 92 vibrational states. A semiexperimental equilibrium structure is derived from experimental ground state rotational constants and rovibrational interaction parameters calculated from the ab initio force field. The ab initio structure calculated at the CCSD(T) level of theory using a basis set of quintuple- quality is in excellent agreement with the semiexperimental structure. © 2007 American Institute of Physics.
BibTeX: @article{Demaison2007, author = {Demaison, J. and Herman, M. and Lívin, J.}, title = {Anharmonic force field of cis- and trans-formic acid from high-level ab initio calculations, and analysis of resonance polyads}, journal = {Journal of Chemical Physics}, year = {2007}, volume = {126}, number = {16}, doi = {10.1063/1.2722752} }
Didriche K, Macko P, Herman M, Thiévin J, Benidar A and Georges R (2007), "Investigation of the shape of the R(0) absorption line in ν3, N2O recorded from an axisymmetric supersonic free jet expansion", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 105(1), pp. 128 – 138. [Abstract] [BibTeX] [DOI]
Abstract: The hydrodynamic structure of an axisymmetric supersonic expansion can be regarded as a series of concentric divergent cones, with decreasing particle densities as the cone angle increases. Different groups of molecules therefore contribute to high-resolution absorption line shapes when optically probing the expansion in a direction perpendicular to the jet axis. These groups are distinguished by the cone angle, inducing a specific Doppler shift, and by the particle density, contributing a specific weight to the absorption intensity. As a result different broader line profiles are observed compared to room temperature spectra. This effect is investigated here selecting as the working example the R(0), ν3 absorption line in N2O recorded using a Fourier transform interferometer. Independent impact pressure and quadrupole mass spectrometric measurements are performed leading to two complementary maps of the expansion, allowing the recorded absorption line shape to be quantitatively modeled. © 2006 Elsevier Ltd. All rights reserved.
BibTeX: @article{Didriche2007128, author = {Didriche, Keevin and Macko, Peter and Herman, Michel and Thiévin, Jonathan and Benidar, Abdessamad and Georges, Robert}, title = {Investigation of the shape of the R(0) absorption line in ν3, N2O recorded from an axisymmetric supersonic free jet expansion}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2007}, volume = {105}, number = {1}, pages = {128 – 138}, doi = {10.1016/j.jqsrt.2006.10.002} }
Fayt A, Robert S, Di Lonardo G, Fusina L, Tamassia F and Herman M (2007), "Vibration-rotation energy pattern in acetylene:13CH 12CH up to 6750 cm-1", Journal of Chemical Physics. Vol. 126(11) [Abstract] [BibTeX] [DOI]
Abstract: All known vibration-rotation absorption lines of 13CH 12CH accessing levels up to 6750 cm-1 were gathered from the literature. They were fitted simultaneously to J-dependent Hamiltonian matrices exploiting the well known vibrational polyad or cluster block diagonalization, in terms of the pseudo-quantum-numbers Ns=v 1+v2+v3 and Nr=5v 1+3v2+5v3+v4+v5, and accounting also for I parity and elf symmetry properties. The anharmonic interaction coupling terms known to occur from a pure vibrational fit in this acetylene isotopologue [Robert et al., J. Chem. Phys. 123, 174302 (2005)] were included in the model. A total of 12 703 transitions accessing 158 different (v1v2V3V4v5, l 4l5) vibrational states was fitted with a dimensionless standard deviation of 0.99, leading to the determination of 216 vibration-rotation parameters. The experimental data included very weak vibration-rotation transitions accessing 18 previously unreported states, some of them forming Q branches with very irregular patterns. © 2007 American Institute of Physics.
BibTeX: @article{Fayt2007, author = {Fayt, A. and Robert, S. and Di Lonardo, G. and Fusina, L. and Tamassia, F. and Herman, M.}, title = {Vibration-rotation energy pattern in acetylene:13CH 12CH up to 6750 cm-1}, journal = {Journal of Chemical Physics}, year = {2007}, volume = {126}, number = {11}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.2464101} }
Froese Fischer C, Tachiev G, Gaigalas G and Godefroid MR (2007), "An MCHF atomic-structure package for large-scale calculations", Computer Physics Communications. Vol. 176(8), pp. 559 – 579. [Abstract] [BibTeX] [DOI]
Abstract: An MCHF atomic-structure package is presented based on dynamic memory allocation, sparse matrix methods, and a recently developed angular library. It is meant for large-scale calculations in a basis of orthogonal orbitals for groups of LS terms of arbitrary parity. For Breit-Pauli calculations, all operators-spin-orbit, spin-other orbit, spin-spin, and orbit-orbit-may be included. For transition probabilities the orbitals of the initial and final state need not be orthogonal. A bi-orthogonal transformation is used for the evaluation of matrix elements in such cases. In addition to transition rates of all types, isotope shifts and hyperfine constants can be computed as well as gJ factors. New version summary: Title of program: atsp2K. Version number: 1.00. Catalogue identifier: ADLY_v2_0. Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADLY_v2_0. Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland. Computer: Pentium III 500 MHz. Installations: Vanderbilt University, Nashville, TN 37235, USA. Operating systems under which the present version has been tested: Red Hat 8. Programming language used in the present version: FORTRAN 90. Memory required to execute with typical data: 256 Mbytes words. No. of bits in a word: 32. Supplementary material: User manuals for the program atsp2k and for the Spin-Angular library are available. No. of lines in distributed program, including test data, etc.:209 992. No. of bytes in distributed package, including test data, etc.: 1 740 883. Distribution format: tar.gz. CPC Program Library subprograms used: none. Does the new version supersede the previous version?: Yes. Nature of physical problem: This program determines energy levels and associated wave functions for states of atoms and ions in the MCHF (LS) or Breit-Pauli (LSJ) approximation. Given the wave function, various atomic properties can be computed such as electric (Ek) and magnetic (Mk) multipole radiative transition probabilities (kmax = 10) between LS or LSJ states, isotope shift constants, hyperfine parameters, and gJ factors. Method of solution: The new version of the program closely follows the design and structure of the previous one [C. Froese Fischer, Comput. Phys. Comm. 128 (2000) 635], except that a simultaneous optimization scheme has been introduced. This program uses the angular methodology of [G. Gaigalas, Lithuanian J. Phys. 41 (2000) 39] and has been extended to include partially filled f-subshells in wavefunction expansions but assumes all orbitals are orthonormal. The bi-orthogonal transformation method is used to deal with the non-orthogonality of orbitals between initial and final states of an electromagnetic radiative transition. Reasons for new version: The previous version of the MCHF atomic structure package [C. Froese Fischer, Comput. Phys. Comm. 128 (2000) 635] was intended for small calculations, ideal for someone not familiar with the code, producing extensive print-out of intermediate results. The codes for the calculation of spin-angular coefficients were often not the most efficient and could only treat configurations with open f-subshells containing at most two electrons or an almost filled shell with one hole. The present version is designed for large-scale computation using algorithms for angular integration that have been shown to be faster, and include the case of arbitrarily filled f-shells. In addition, the MCHF program has been modified to include optimization on an energy functional that is a weighted average of energy functionals for expansions of wavefunctions for different LS terms or parity, thus facilitating Breit-Pauli calculations for complex atomic systems and for computing targets in collision calculations. Summary of revisions: Programs have been modified to take advantage of the newly developed angular library [G. Gaigalas, Lithuanian J. Phys. 41 (2000) 39], extended to arbitrarily filled f-shells. New programs have been developed for simultaneous optimization and for the efficient calculation of atomic spectra and transition rates for an iso-electronic sequence. All applications now take advantage of dynamic memory allocation and sparse matrix methods. Restrictions on the complexity of the problem: All orbitals in a wave function expansion are assumed to be orthonormal. Configuration states are restricted to at most eight (8) subshells in addition to the closed shells common to all configuration states. The maximum size is limited by the available memory and disk space. Typical running time: Included with the code are scripts for calculating E2 and M1 transitions between levels of 3 s2 3 p2 for Si and P+. This calculation has two stages: LS and LSJ. The calculation of the former required 21 minutes for the LS calculation and 36.5 minutes for the Breit-Pauli configuration interaction calculation that determines the mixing of the terms. Unusual features of the program: The programming style is essentially F77 with extensions for the POINTER data type and associated memory allocation. These have been available on workstations for more than a decade but their implementations are compiler dependent. The present serial code has been installed and tested extensively using both the Portland Group, pgf90, compiler and the IBM SP2, xlf90, compiler. The former is compatible also with the Intel Fortran90 compiler. The MPI codes are included for completeness though testing has not been as extensive. Additional comments: Parallel versions (MPI) of the following programs are included in the distribution. Use of these is optional but can speed up the angular integration processing. A table is presented. © 2007 Elsevier B.V. All rights reserved.
BibTeX: @article{FroeseFischer2007559, author = {Froese Fischer, Charlotte and Tachiev, Georgio and Gaigalas, Gediminas and Godefroid, Michel R.}, title = {An MCHF atomic-structure package for large-scale calculations}, journal = {Computer Physics Communications}, year = {2007}, volume = {176}, number = {8}, pages = {559 – 579}, doi = {10.1016/j.cpc.2007.01.006} }
Herbin H, Hartmans D, Turquety S, Wespes C, Barret B, Hadji-Lazaro J, Clerbaux C and Coheur P-F (2007), "Global distributions of water vapour isotopologues retrieved from IMG/ADEOS data", Atmospheric Chemistry and Physics. Vol. 7(14), pp. 3957 – 3968. [Abstract] [BibTeX] [DOI]
Abstract: The isotopologic composition of water vapour in the atmosphere provides valuable information on many climate, chemical and dynamical processes. The accurate measurements of the water isotopologues by remote-sensing techniques remains a challenge, due to the large spatial and temporal variations. Simultaneous profile retrievals of the main water isotopologues (i.e. H 216O, H218O and HDO) and their ratios are presented here for the first time, along their retrieved global distributions. The results are obtained by exploiting the high resolution infrared spectra recorded by the Interferometric Monitor for Greenhouse gases (IMG) instrument, which has operated in the nadir geometry onboard the ADEOS satellite between 1996 and 1997. The retrievals are performed on cloud-free radiances, measured during ten days of April 1997, considering two atmospheric windows (1205-1228 cm-1; 2004-2032 cm-1) and using a line-by-line radiative transfer model and an inversion procedure based on the Optimal Estimation Method (OEM). Characterizations in terms of vertical sensitivity and error budget are provided. We show that a relatively high vertical resolution is achieved for H216O (∼4-5 km), and that the retrieved profiles are in fair agreement with local sonde measurements, at different latitudes. The retrieved global distributions of H216O, H218O, HDO and their ratios are presented and found to be consistent with previous experimental studies and models. The Ocean-Continent difference, the latitudinal and vertical dependence of the water vapour amount and the isotopologic depletion are notably well reproduced. Others trends, possibly related to small-scale variations in the vertical profiles are also discussed. Despite the difficulties encountered for computing accurately the isotopologic ratios, our results demonstrate the ability of infrared nadir sounding for monitoring atmospheric isotopologic water vapour distributions on a global scale.
BibTeX: @article{Herbin20073957, author = {Herbin, H. and Hartmans, D. and Turquety, S. and Wespes, C. and Barret, B. and Hadji-Lazaro, J. and Clerbaux, C. and Coheur, P.-F.}, title = {Global distributions of water vapour isotopologues retrieved from IMG/ADEOS data}, journal = {Atmospheric Chemistry and Physics}, year = {2007}, volume = {7}, number = {14}, pages = {3957 – 3968}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-7-3957-2007} }
Herman M (2007), "The acetylene ground state saga", Molecular Physics. Vol. 105(17-18), pp. 2217 – 2241. [Abstract] [BibTeX] [DOI]
Abstract: The evolution of high-resolution spectroscopic investigation of the vibration-rotation energy states of acetylene in its ground electronic state is presented, focusing on advances co-authored by the ULB group. The emergence of a global picture accounting for all available spectroscopic fingerprints, at their full accuracy, is highlighted. The contributions of this research to various topics is illustrated, including instrumental developments, local mode trends, quantum vs. classical correspondence, energy vs. time approaches and nucleation processes.
BibTeX: @article{Herman20072217, author = {Herman, M.}, title = {The acetylene ground state saga}, journal = {Molecular Physics}, year = {2007}, volume = {105}, number = {17-18}, pages = {2217 – 2241}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268970701518103} }
Herman M, Didriche K, Hurtmans D, Kizil B, MacKo P, Rizopoulos A and Van Poucke P (2007), "FANTASIO: A versatile experimental set-up to investigate jet-cooled molecules", Molecular Physics. Vol. 105(5-7), pp. 815 – 823. [Abstract] [BibTeX] [DOI]
Abstract: The design of a new apparatus, named FANTASIO, for studying jet-cooled molecules is described. It includes, around the same supersonic expansion cell, a high resolution Fourier transform spectrometer with single or multipass optics, a tunable diode laser spectrometer with optional cavity ring-down facilities, and a quadrupole mass spectrometer. Performance and operational procedures are illustrated.
BibTeX: @article{Herman2007815, author = {Herman, M. and Didriche, K. and Hurtmans, D. and Kizil, B. and MacKo, P. and Rizopoulos, A. and Van Poucke, P.}, title = {FANTASIO: A versatile experimental set-up to investigate jet-cooled molecules}, journal = {Molecular Physics}, year = {2007}, volume = {105}, number = {5-7}, pages = {815 – 823}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268970601063820} }
Jenouvrier A, Daumont L, Régalia-Jarlot L, Tyuterev VG, Carleer M, Vandaele AC, Mikhailenko S and Fally S (2007), "Fourier transform measurements of water vapor line parameters in the 4200-6600 cm-1 region", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 105(2), pp. 326 – 355. [Abstract] [BibTeX] [DOI]
Abstract: New high-resolution water vapor absorption spectra were obtained at room temperature in the 4200-6600 cm-1 spectral region by combining Fourier transform spectrometers (FTS) with single and multiple reflection cells. With absorption paths from 0.3 to 1800 m in pure and air diluted water vapor, accurate measurements of about 10400 lines in an intensity range from 10-29 to 10-19 cm/molecule have been performed. Positions, intensities, self- and air-broadening coefficients and air-induced shifts were determined for the H2 16O, H2 17O, H2 18O and HDO isotopologues. The rovibrational assignment of the observed lines was performed with the use of global variational predictions and allowed the identification of several new energy levels. One major contribution of this work consists of the identification of 3280 new weak lines. A very close agreement between the new measured parameters and those listed in the database is reported as well as between the observations and the most recent variational calculations for the positions and the intensities. The present parameters provide an extended and homogeneous data set for water vapor, which is shown to significantly improve the databases for atmospheric applications, especially in the transmission windows on both sides of the band centered at 5400 cm-1. © 2006 Elsevier Ltd. All rights reserved.
BibTeX: @article{Jenouvrier2007326, author = {Jenouvrier, Alain and Daumont, Ludovic and Régalia-Jarlot, Laurence and Tyuterev, Vladimir G. and Carleer, Michel and Vandaele, Ann Carine and Mikhailenko, Semen and Fally, Sophie}, title = {Fourier transform measurements of water vapor line parameters in the 4200-6600 cm-1 region}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2007}, volume = {105}, number = {2}, pages = {326 – 355}, doi = {10.1016/j.jqsrt.2006.11.007} }
Lattanzi F, Di Lauro C, Horneman V-M, Herman M and Auwera JV (2007), "Perturbation activated transitions in the high resolution infrared spectrum of C2H6: Rotational constants and torsional splitting in the ground state", Molecular Physics. Vol. 105(5-7), pp. 733 – 740. [Abstract] [BibTeX] [DOI]
Abstract: The l-type perturbation mechanisms that activate vibration-rotation transitions with k = 2, (l modulo 3) = 1 in the perpendicular bands of molecules with threefold axial symmetry have been investigated in the case of ethane-like molecules. It is shown that in this class of molecules such transitions, combined with the usual ones with k = (l modulo 3) = 1, give information not only on the values of the K-structure rotational parameters, but also on the torsional splitting of the lower combining state. Transitions of this type have been examined in two perturbed regions of the infrared spectrum of C2H6, in the 8 fundamental and in the 4 + 10 combination. Assuming that the four torsional components in the ground state of C2H6 follow the energy pattern generated when tunneling occurs from one minimum of the torsional potential barrier to the two adjacent minima only, a torsional splitting of 0.00566 0.00015 cm-1 in each rotational level has been evaluated. The values of the ground state rotational constants A' = 2.669693 0.000020 cm-1 and 105 [image omitted] = 0.885 0.050 cm-1 have also been determined.
BibTeX: @article{Lattanzi2007733, author = {Lattanzi, F. and Di Lauro, C. and Horneman, V.-M. and Herman, M. and Auwera, J. Vander}, title = {Perturbation activated transitions in the high resolution infrared spectrum of C2H6: Rotational constants and torsional splitting in the ground state}, journal = {Molecular Physics}, year = {2007}, volume = {105}, number = {5-7}, pages = {733 – 740}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268970601110324} }
Lee Y-C, Venkatesan V, Lee Y-P, Macko P, Didiriche K and Herman M (2007), "Infrared spectra of C2H2 under jet-cooled and para-H2 matrix conditions", Chemical Physics Letters. Vol. 435(4-6), pp. 247 – 251. [Abstract] [BibTeX] [DOI]
Abstract: In spectra of jet-cooled C2H2 recorded with an FTIR spectrometer, the ν5, ν4 + ν5, ν3 and ν2 + ν4 + ν5 bands all exhibit an intensity distribution corresponding to ∼6 K for rotation, with no evidence of nuclear spin conversion. Spectra of C2H2 isolated in solid p-H2 show no evidence of rotation of C2H2. The strong interaction between ν3 and ν2 + ν4 + ν5 in the gas phase is diminished in solid p-H2. Lines associated with dimer, trimer and tetramer of C2H2 are identified. Spectral features characteristic of solid state acetylene are observed under jet-cooled conditions. © 2007 Elsevier B.V. All rights reserved.
BibTeX: @article{Lee2007, author = {Lee, Ying-Chi and Venkatesan, V. and Lee, Yuan-Pern and Macko, P. and Didiriche, K. and Herman, M.}, title = {Infrared spectra of C2H2 under jet-cooled and para-H2 matrix conditions}, journal = {Chemical Physics Letters}, year = {2007}, volume = {435}, number = {4-6}, pages = {247 – 251}, doi = {10.1016/j.cplett.2007.01.014} }
Lepère M, Blanquet G, Walrand J, Bouanich J-P, Herman M and Auwera JV (2007), "Self-broadening coefficients and absolute line intensities in the ν4 + ν5 band of acetylene", Journal of Molecular Spectroscopy. Vol. 242(1), pp. 25 – 30. [Abstract] [BibTeX] [DOI]
Abstract: Self-broadening coefficients and line strengths have been measured at room temperature for 30 lines of C2H2 in the P and R branches of the ν4 + ν5 band, using a tunable diode laser spectrometer. These lines, ranging from P(22) to R(23), are located in the spectral range 1275-1390 cm-1. A semiclassical calculation of the line broadenings has been performed considering the main electrostatic interactions and an anisotropic dispersion contribution leading to results in satisfactory agreement with the experimental data. © 2007 Elsevier Inc. All rights reserved.
BibTeX: @article{Lepere2007, author = {Lepère, Muriel and Blanquet, Ghislain and Walrand, Jacques and Bouanich, Jean-Pierre and Herman, Michel and Auwera, Jean Vander}, title = {Self-broadening coefficients and absolute line intensities in the ν4 + ν5 band of acetylene}, journal = {Journal of Molecular Spectroscopy}, year = {2007}, volume = {242}, number = {1}, pages = {25 – 30}, doi = {10.1016/j.jms.2007.01.004} }
Macko P, Lauzin C and Herman M (2007), "High resolution spectroscopy of the 2CH band in the 12C2H2-Ar van der Waals complex", Chemical Physics Letters. Vol. 445(4-6), pp. 113 – 116. [Abstract] [BibTeX] [DOI]
Abstract: We have used CW cavity-ring-down-spectroscopy around 1.5 μm to probe a free supersonic expansion of mixed acetylene and Argon. The high resolution spectrum of the 2CH band in the 12C2H2-Ar van der Waals complex was recorded, at a rotational temperature of about 15 K. Upper state spectroscopic constants are provided from the fit of the 44 assigned vibration-rotation lines in the Ka = 0 ← 1 and 1 ← 0 sub-bands to a conventional Watsonian. © 2007 Elsevier B.V. All rights reserved.
BibTeX: @article{Macko2007113, author = {Macko, P. and Lauzin, C. and Herman, M.}, title = {High resolution spectroscopy of the 2CH band in the 12C2H2-Ar van der Waals complex}, journal = {Chemical Physics Letters}, year = {2007}, volume = {445}, number = {4-6}, pages = {113 – 116}, doi = {10.1016/j.cplett.2007.07.074} }
Mátyus E, Czakó G, Sutcliffe BT and Császár AG (2007), "Vibrational energy levels with arbitrary potentials using the Eckart-Watson Hamiltonians and the discrete variable representation", Journal of Chemical Physics. Vol. 127(8) [Abstract] [BibTeX] [DOI]
Abstract: An effective and general algorithm is suggested for variational vibrational calculations of N -atomic molecules using orthogonal, rectilinear internal coordinates. The protocol has three essential parts. First, it advocates the use of the Eckart-Watson Hamiltonians of nonlinear or linear reference configuration. Second, with the help of an exact expression of curvilinear internal coordinates (e.g., valence coordinates) in terms of orthogonal, rectilinear internal coordinates (e.g., normal coordinates), any high-accuracy potential or force field expressed in curvilinear internal coordinates can be used in the calculations. Third, the matrix representation of the appropriate Eckart-Watson Hamiltonian is constructed in a discrete variable representation, in which the matrix of the potential energy operator is always diagonal, whatever complicated form the potential function assumes, and the matrix of the kinetic energy operator is a sparse matrix of special structure. Details of the suggested algorithm as well as results obtained for linear and nonlinear test cases including H2 O, H3+, C O2, HCNHNC, and C H4 are presented. © 2007 American Institute of Physics.
BibTeX: @article{Mátyus2007, author = {Mátyus, Edit and Czakó, Gábor and Sutcliffe, Brian T. and Császár, Attila G.}, title = {Vibrational energy levels with arbitrary potentials using the Eckart-Watson Hamiltonians and the discrete variable representation}, journal = {Journal of Chemical Physics}, year = {2007}, volume = {127}, number = {8}, doi = {10.1063/1.2756518} }
Mondelain D, Payan S, Deng W, Camy-Peyret C, Hurtmans D and Mantz AW (2007), "Measurement of the temperature dependence of line mixing and pressure broadening parameters between 296 and 90 K in the ν3 band of 12CH4 and their influence on atmospheric methane retrievals", Journal of Molecular Spectroscopy. Vol. 244(2), pp. 130 – 137. [Abstract] [BibTeX] [DOI]
Abstract: We measured the temperature dependence of the nitrogen broadening, narrowing and line-mixing coefficients of four lines of the P9 manifold in the ν3 band of 12CH4 for atmospheric purposes. The data were collected using our tunable diode laser (TDL) spectrometer with active wavenumber control coupled to a newly developed cold Herriott cell with a path length of 5.37 m and a temperature uniformity of better than 0.01 K along the cell. We recorded and analyzed spectra recorded at sample temperatures between 90 K and room temperature. We have investigated the influence of our new results in the inversion model used to retrieve methane profiles from atmospheric spectra; our new results make it possible to retrieve significantly more precise methane profiles. The atmospheric spectra we utilized were obtained by several of us with a balloon-born Fourier Transform infrared experiment in a limb configuration. Differences up to 7% on the retrieved volume mixing ratio were found compared to an inversion model using only HITRAN04 spectroscopic parameters. © 2007 Elsevier Inc. All rights reserved.
BibTeX: @article{Mondelain2007130, author = {Mondelain, Didier and Payan, Sébastien and Deng, Wenping and Camy-Peyret, Claude and Hurtmans, Daniel and Mantz, Arlan W.}, title = {Measurement of the temperature dependence of line mixing and pressure broadening parameters between 296 and 90 K in the ν3 band of 12CH4 and their influence on atmospheric methane retrievals}, journal = {Journal of Molecular Spectroscopy}, year = {2007}, volume = {244}, number = {2}, pages = {130 – 137}, doi = {10.1016/j.jms.2007.05.005} }
Perrin A and Vander Auwera J (2007), "An improved database for the 9 μ m region of the formic acid spectrum", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 108(3), pp. 363 – 370. [Abstract] [BibTeX] [DOI]
Abstract: The 9 μ m region of the formic acid spectrum is associated with the strong ν6 band. Located in an atmospheric window, its sharp Q-branch structure near 1105 cm- 1 is commonly used to probe tropospheric formic acid by infrared remote sensing techniques. Retrieval of HCOOH concentrations usually rely on spectroscopic information available in atmospheric databases such as HITRAN and GEISA. The intensity information available therein is a factor of about 2 lower than laboratory measurements. Following our recent contribution [Vander Auwera J, Didriche K, Perrin A, Keller F. Absolute line intensities for formic acid and dissociation constant of the dimer. J Chem Phys 2007;126:124311], we generated a new set of line parameters and show that it provides a significantly improved modeling of the ν6 spectral region of formic acid. © 2007 Elsevier Ltd. All rights reserved.
BibTeX: @article{Perrin2007363, author = {Perrin, A. and Vander Auwera, J.}, title = {An improved database for the 9 μ m region of the formic acid spectrum}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2007}, volume = {108}, number = {3}, pages = {363 – 370}, doi = {10.1016/j.jqsrt.2007.05.002} }
Predoi-Cross A, Liu W, Holladay C, Unni A, Schofield I, McKellar A and Hurtmans D (2007), "Line profile study of transitions in the 30012 ← 00001 and 30013 ← 00001 bands of carbon dioxide perturbed by air", Journal of Molecular Spectroscopy. Vol. 246(1), pp. 98 – 112. [Abstract] [BibTeX] [DOI]
Abstract: In this work we present a line profile study for air-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 vibrational bands. The room temperature spectra were recorded at a resolution of 0.008 cm-1 using a Fourier Transform spectrometer. The air-broadening, air-shift, and air-line mixing coefficients were derived from a simultaneous fitting of spectra using the Voigt model and a Speed-Dependent Voigt lineshape model. The results obtained are consistent with other studies in addition to the theoretically calculated values. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws were used to calculate the relaxation matrix elements. © 2007 Elsevier Inc. All rights reserved.
BibTeX: @article{Predoi-Cross200798, author = {Predoi-Cross, A. and Liu, W. and Holladay, C. and Unni, A.V. and Schofield, I. and McKellar, A.R.W. and Hurtmans, D.}, title = {Line profile study of transitions in the 30012 ← 00001 and 30013 ← 00001 bands of carbon dioxide perturbed by air}, journal = {Journal of Molecular Spectroscopy}, year = {2007}, volume = {246}, number = {1}, pages = {98 – 112}, doi = {10.1016/j.jms.2007.08.008} }
Predoi-Cross A, Unni A, Liu W, Schofield I, Holladay C, McKellar A and Hurtmans D (2007), "Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing, and speed dependence", Journal of Molecular Spectroscopy. Vol. 245(1), pp. 34 – 51. [Abstract] [BibTeX] [DOI]
Abstract: Transitions of pure carbon dioxide have been measured using a Fourier transform spectrometer in the 30012 ← 00001 and 30013 ← 00001 vibrational bands. The room temperature spectra, recorded at a resolution of 0.008 cm-1, were analyzed using the Voigt model and a Speed Dependent Voigt line shape model that includes a pressure dependent narrowing parameter. Intensities, self-induced pressure broadening, shifts, and weak line mixing coefficients are determined. The results obtained are consistent with other studies in addition to the theoretically calculated values. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws were used to calculate the relaxation matrix elements. © 2007 Elsevier Inc. All rights reserved.
BibTeX: @article{Predoi-Cross200734, author = {Predoi-Cross, A. and Unni, A.V. and Liu, W. and Schofield, I. and Holladay, C. and McKellar, A.R.W. and Hurtmans, D.}, title = {Line shape parameters measurement and computations for self-broadened carbon dioxide transitions in the 30012 ← 00001 and 30013 ← 00001 bands, line mixing, and speed dependence}, journal = {Journal of Molecular Spectroscopy}, year = {2007}, volume = {245}, number = {1}, pages = {34 – 51}, doi = {10.1016/j.jms.2007.07.004} }
Pumphrey H, Filipiak M, Livesey NJ, Schwartz MJ, Boone C, Walker K, Bernath P, Ricaud P, Barret B, Clerbaux C, Jarnot R, Manney G and Waters JW (2007), "Validation of middle-atmosphere carbon monoxide retrievals from the Microwave Limb Sounder on Aura", Journal of Geophysical Research Atmospheres. Vol. 112(24) [Abstract] [BibTeX] [DOI]
Abstract: The Microwave Limb Sounder on Aura has produced an extensive set of measurement of CO in the middle atmosphere. The measurements are usable for scientific studies from the upper troposphere up to 90 km altitude. We describe these measurements and validate them by demonstrating their internal consistency and by comparing them to other remotely sounded measurements and to 2-D model simulations. Comparisons with other measurements suggest that MLS has a positive bias of 25-50% in the mesosphere and a negative bias of up to 70% in the (almost CO-free) lower stratosphere. The geophysical features observed in the MLS CO field show excellent qualitative agreement with other measurements. Copyright 2007 by the American Geophysical Union.
BibTeX: @article{Pumphrey2007, author = {Pumphrey, H.C. and Filipiak, M.J. and Livesey, Nathaniel J. and Schwartz, Michael J. and Boone, C. and Walker, K.A. and Bernath, P. and Ricaud, Philippe and Barret, B. and Clerbaux, C. and Jarnot, R.F. and Manney, G.L. and Waters, Joe W.}, title = {Validation of middle-atmosphere carbon monoxide retrievals from the Microwave Limb Sounder on Aura}, journal = {Journal of Geophysical Research Atmospheres}, year = {2007}, volume = {112}, number = {24}, note = {All Open Access, Green Open Access}, doi = {10.1029/2007JD008723} }
Rinsland C, Coheur P, Herbin H, Clerbaux C, Boone C, Bernath P and Chiou L (2007), "Detection of elevated tropospheric hydrogen peroxide (H2O2) mixing ratios in atmospheric chemistry experiment (ACE) subtropical infrared solar occultation spectra", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 107(2), pp. 340 – 348. [Abstract] [BibTeX] [DOI]
Abstract: We report measurements of hydrogen peroxide (H2O2) profiles from infrared solar occultation spectra recorded at 0.02 cm-1 resolution by the atmospheric chemistry experiment (ACE) during 2004 and 2005. Mixing ratios as high as 1.7 ppbv (1 ppbv=1×10-9 per unit volume) were measured in the subtropical troposphere. Back trajectories, fire count statistics, and simultaneous measurements of other species from the same occultation provide evidence that the elevated H2O2 mixing ratios originated from a young biomass-burning plume. The ACE time series show only a few cases with elevated H2O2 mixing ratios likely because of the short lifetime of H2O2 and the limited sampling during biomass-burning time periods. © 2007 Elsevier Ltd. All rights reserved.
BibTeX: @article{Rinsland2007340, author = {Rinsland, C.P. and Coheur, P.F. and Herbin, H. and Clerbaux, C. and Boone, C. and Bernath, P. and Chiou, L.S.}, title = {Detection of elevated tropospheric hydrogen peroxide (H2O2) mixing ratios in atmospheric chemistry experiment (ACE) subtropical infrared solar occultation spectra}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2007}, volume = {107}, number = {2}, pages = {340 – 348}, doi = {10.1016/j.jqsrt.2007.02.009} }
Rinsland CP, Bernath P, Boone C, Nassar R, Dufour G and Clerbaux C (2007), "Atmospheric Chemistry Experiment (ACE) measurements of the upper troposphere and stratosphere", European Space Agency, (Special Publication) ESA SP. (SP-636) [Abstract] [BibTeX]
Abstract: We highlight chemistry and trend measurements from the Atmospheric Chemistry Experiment (ACE) which is providing precise middle troposphere to the lower thermosphere measurements of the Earth's upper troposphere to lower mesosphere with the solar occultation technique. The primary instrument is a 0.02 cm -1 resolution Fourier transform spectrometer covering 750-4400 cm -1 simultaneously. ACE also known as SCISAT 1 is a Canadian lead mission launched into a 74° inclined orbit at 650 km altitude on August 12, 2003 by a U.S.-supplied Pegasus vehicle. Additional measurements are obtained with a UV-visible spectrometer and two imagers providing measurements at 0.525 and 1.02 microns.
BibTeX: @conference{Rinsland2007, author = {Rinsland, Curtis P. and Bernath, Peter and Boone, Chris and Nassar, Ray and Dufour, Gaëlle and Clerbaux, Catherine}, title = {Atmospheric Chemistry Experiment (ACE) measurements of the upper troposphere and stratosphere}, journal = {European Space Agency, (Special Publication) ESA SP}, year = {2007}, number = {SP-636} }
Rinsland CP, Dufour G, Boone CD, Bernath PF, Chiou L, Coheur P-F, Turquety S and Clerbaux C (2007), "Satellite boreal measurements over Alaska and Canada during June-July 2004: Simultaneous measurements of upper tropospheric CO, C2H6, HCN, CH3Cl, CH4, C2H2, CH3OH, HCOOH, OCS, and SF6 mixing ratios", Global Biogeochemical Cycles. Vol. 21(3) [Abstract] [BibTeX] [DOI]
Abstract: Simultaneous ACE (Atmospheric Chemistry Experiment) upper tropospheric CO, C2H6, HCN, CH3Cl, CH4, C2H2, CH3OH, HCOOH, and OCS measurements show plumes up to 185 ppbv (10-9 per unit volume) for CO, 1.36 ppbv for C2H6, 755 pptv (10-12 per unit volume) for HCN, 1.12 ppbv for CH3Cl, 1.82 ppmv (10-6 per unit volume) for CH4, 0.178 ppbv for C2H2, 3.89 ppbv for CH3OH, 0.843 ppbv for HCOOH, and 0.48 ppbv for OCS in western Canada and Alaska at 50°N-68°N latitude between 29 June and 23 July 2004. Enhancement ratios and emission factors for HCOOH, CH3OH, HCN, C2H6, and OCS relative to CO at 250-350 hPa are inferred from measurements of young plumes compared with lower mixing ratios assumed to represent background conditions based on a CO emission factor derived from boreal measurements. Results are generally consistent with the limited data reported for various vegetative types and emission phases measured in extratropical forests including boreal forests. The low correlation between fire product emission mixing ratios and the SF6 mixing ratio is consistent with no significant SF6 emissions from the biomass fires. Copyright 2007 by the American Geophysical Union.
BibTeX: @article{Rinsland2007, author = {Rinsland, Curtis P. and Dufour, Gaëlle and Boone, Chris D. and Bernath, Peter F. and Chiou, Linda and Coheur, Pierre-François and Turquety, Solène and Clerbaux, Cathy}, title = {Satellite boreal measurements over Alaska and Canada during June-July 2004: Simultaneous measurements of upper tropospheric CO, C2H6, HCN, CH3Cl, CH4, C2H2, CH3OH, HCOOH, OCS, and SF6 mixing ratios}, journal = {Global Biogeochemical Cycles}, year = {2007}, volume = {21}, number = {3}, note = {All Open Access, Green Open Access}, doi = {10.1029/2006GB002795} }
Robert S, Herman M, Auwera JV, Di Lonardo G, Fusina L, Blanquet G, Lepere M and Fayt A (2007), "The bending vibrations in 12C2H2: Global vibration-rotation analysis", Molecular Physics. Vol. 105(5-7), pp. 559 – 568. [Abstract] [BibTeX] [DOI]
Abstract: A total of 3155 vibration-rotation line positions providing accurate information on all known vibration-rotation states up to 3000 cm-1 in 12C2H2 were gathered from the literature. An additional 966 lines were assigned on new spectra. The full data set was simultaneously fitted using an appropriate Hamiltonian, with 85 refined parameters. A dimensionless standard deviation equal to 0.86, accounting for 92% of the lines, was achieved. The vibrational transition dipole moment of the 5 = 1 4 = 1 band observed in the far-infrared was estimated to be \|μ5←4\| = 0.55 D with 20% accuracy, from absolute intensity measurements for a few Q-branch lines.
BibTeX: @article{Robert2007559, author = {Robert, S. and Herman, M. and Auwera, J. Vander and Di Lonardo, G. and Fusina, L. and Blanquet, G. and Lepere, M. and Fayt, A.}, title = {The bending vibrations in 12C2H2: Global vibration-rotation analysis}, journal = {Molecular Physics}, year = {2007}, volume = {105}, number = {5-7}, pages = {559 – 568}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268970601099261} }
Robert S, Herman M, Auwera JV, Di Lonardo G, Fusina L, Blanquet G, Lepère M and Fayt A (2007), "Erratum: The bending vibrations in 12C2H2: Global vibration-rotation analysis (Molecular Physics (2007) 105:5 (559-568))", Molecular Physics. Vol. 105(13-14), pp. 2009. [BibTeX] [DOI]
BibTeX: @article{Robert20072009, author = {Robert, S. and Herman, M. and Auwera, J. Vander and Di Lonardo, G. and Fusina, L. and Blanquet, G. and Lepère, M. and Fayt, A.}, title = {Erratum: The bending vibrations in 12C2H2: Global vibration-rotation analysis (Molecular Physics (2007) 105:5 (559-568))}, journal = {Molecular Physics}, year = {2007}, volume = {105}, number = {13-14}, pages = {2009}, note = {All Open Access, Bronze Open Access}, doi = {10.1080/00268970701499478} }
Sutcliffe BT (2007), "Concluding remarks", Faraday Discussions. Vol. 135, pp. 503 – 506. [BibTeX] [DOI]
BibTeX: @article{Sutcliffe2007503, author = {Sutcliffe, Brian T.}, title = {Concluding remarks}, journal = {Faraday Discussions}, year = {2007}, volume = {135}, pages = {503 – 506}, doi = {10.1039/b613462a} }
Sutcliffe BT (2007), "The separation of electronic and nuclear motion in the diatomic molecule", Theoretical Chemistry Accounts. Vol. 118(3), pp. 563 – 571. [Abstract] [BibTeX] [DOI]
Abstract: The Schrödinger Coulomb Hamiltonian for electronic and nuclear motion in a diatomic molecule is presented and its effect upon functions which are products of functions of electronic and of nuclear variables is explicitly exhibited. Computational approaches to finding approximate solutions in such a basis are outlined. © 2007 Springer-Verlag.
BibTeX: @article{Sutcliffe2007, author = {Sutcliffe, Brian T}, title = {The separation of electronic and nuclear motion in the diatomic molecule}, journal = {Theoretical Chemistry Accounts}, year = {2007}, volume = {118}, number = {3}, pages = {563 – 571}, doi = {10.1007/s00214-007-0357-8} }
Thibault F, Mantz A, Claveau C, Henry A, Valentin A and Hurtmans D (2007), "Broadening of the R(0) and P(2) lines in the 13CO fundamental by helium atoms from 300 K down to 12 K: Measurements and comparison with close-coupling calculations", Journal of Molecular Spectroscopy. Vol. 246(1), pp. 118 – 125. [Abstract] [BibTeX] [DOI]
Abstract: We present measurements of He-broadening parameters for the R(0) and P(2) lines in the fundamental band of 13CO at different temperatures between 12 K and room temperature. The broadening parameters are determined, taking into account confinement narrowing, by simultaneous least-squares fitting of spectra recorded using a frequency stabilized diode laser spectrometer. The pressure broadening cross sections are deduced and compared to close-coupling calculations and earlier results obtained for rotational transitions of 12CO. © 2007 Elsevier Inc. All rights reserved.
BibTeX: @article{Thibault2007118, author = {Thibault, F. and Mantz, A.W. and Claveau, C. and Henry, A. and Valentin, A. and Hurtmans, D.}, title = {Broadening of the R(0) and P(2) lines in the 13CO fundamental by helium atoms from 300 K down to 12 K: Measurements and comparison with close-coupling calculations}, journal = {Journal of Molecular Spectroscopy}, year = {2007}, volume = {246}, number = {1}, pages = {118 – 125}, doi = {10.1016/j.jms.2007.09.001} }
Timmermans B, Reniers F, Weightman P and Vaeck N (2007), "Auger and photoelectron relaxation energy in aluminum compounds: A cluster model", Journal of Electron Spectroscopy and Related Phenomena. Vol. 159(1-3), pp. 1 – 7. [Abstract] [BibTeX] [DOI]
Abstract: The energies of the Al Auger KL2,3L2,3 transitions and the Al 2p photoelectron peak have been determined experimentally by AES, XPS and XAES for several Al compounds. The experimental results are compared with ab initio calculations based on a cluster model in which a central aluminum atom is surrounded by its first neighbours in the crystal. This model includes chemical, structural and relaxation effects and it allows the direct ab initio determination of the intra- and extra-atomic relaxation energies. These values are compared with the Wagner equation that relates the extra-atomic relaxation energy and the Auger parameter. The three approximations that support this equation are examined on the basis of the cluster results. © 2007 Elsevier B.V. All rights reserved.
BibTeX: @article{Timmermans20071, author = {Timmermans, B. and Reniers, F. and Weightman, P. and Vaeck, N.}, title = {Auger and photoelectron relaxation energy in aluminum compounds: A cluster model}, journal = {Journal of Electron Spectroscopy and Related Phenomena}, year = {2007}, volume = {159}, number = {1-3}, pages = {1 – 7}, doi = {10.1016/j.elspec.2007.01.004} }
Vander Auwera J, Didriche K, Perrin A and Keller F (2007), "Absolute line intensities for formic acid and dissociation constant of the dimer", Journal of Chemical Physics. Vol. 126(12) [Abstract] [BibTeX] [DOI]
Abstract: Absolute line intensities in the v6 and v8 interacting bands of trans-HCOOH, observed near 1105.4 and 1033.5 cm -1, respectively, and the dissociation constant of the formic acid dimer (HCOOH)2 have been measured using Fourier transform spectroscopy at a resolution of 0.002 cm-1. Eleven spectra of formic acid, at 296.0(5) K and pressures ranging from 14.28(25) to 314.0(24) Pa, have been recorded between 600 and 1900 cm-1 with an absorption path length of 19.7(2) cm. 437 integrated absorption coefficients have been measured for 72 lines in the v6 band. Analysis of the pressure dependence yielded the dissociation constant of the formic acid dimer, k p=361(45) Pa, and the absolute intensity of the 72 lines of HCOOH. The accuracy of these results was carefully estimated. The absolute intensities of four lines of the weak v8 band were also measured. Using an appropriate theory, the integrated intensity of the v6 and v 8 bands was determined to be 3.47 × 1017 and 4.68 × 10-19 cm-1/(molecule cm-1) respectively, at 296 K. Both the dissociation constant and integrated intensities were compared to earlier measurements. © 2007 American Institute of Physics.
BibTeX: @article{VanderAuwera2007, author = {Vander Auwera, J. and Didriche, K. and Perrin, A. and Keller, F.}, title = {Absolute line intensities for formic acid and dissociation constant of the dimer}, journal = {Journal of Chemical Physics}, year = {2007}, volume = {126}, number = {12}, doi = {10.1063/1.2712439} }
Vander Auwera J, Moazzen-Ahmadi N and Flaud J-M (2007), "Toward an accurate database for the 12 μm region of the ethane spectrum", Astrophysical Journal. Vol. 662(1 I), pp. 750 – 757. [Abstract] [BibTeX] [DOI]
Abstract: The ν9 fundamental band of ethane occurs in the 12 μm region. It is the strongest band of ethane in a terrestrial window in the thermal infrared and is commonly used to determine ethane's abundance in the atmospheres of the Jovian planets and comets and to determine their temperature. Precise and accurate absolute intensities of this band are crucial for correct interpretation of recent Cassini observations of ethane spectra in the atmospheres of Saturn and Titan, as well as of Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) observations in the terrestrial atmosphere. Using a spectrum of the ν9 band of ethane recorded at 278 K at the Pacific Northwest National Laboratory, we show that the line parameters available in the HITRAN and GEISA databases do not allow reproduction of the experimental data to within their accuracy. In fact, the integrated band intensity calculated at 296 K using both line lists are, respectively, a factor 1.57 larger and 1.44 smaller than the observed value. Using results from a recent global analysis of data involving the four lowest vibrational states of ethane and measurements of pressure-broadening parameters, we generate a new set of line parameters which we show to provide a much more accurate description of the experimental spectrum of C2H6 in the 12 μm region. © 2007. The American Astronomical Society. All rights reserved.
BibTeX: @article{VanderAuwera2007a, author = {Vander Auwera, J. and Moazzen-Ahmadi, N. and Flaud, J.-M.}, title = {Toward an accurate database for the 12 μm region of the ethane spectrum}, journal = {Astrophysical Journal}, year = {2007}, volume = {662}, number = {1 I}, pages = {750 – 757}, note = {All Open Access, Bronze Open Access}, doi = {10.1086/515567} }
Voronin B, Naumenko O, Carleer M, Coheur P-F, Fally S, Jenouvrier A, Tolchenov R, Vandaele A and Tennyson J (2007), "HDO absorption spectrum above 11 500 cm-1: Assignment and dynamics", Journal of Molecular Spectroscopy. Vol. 244(1), pp. 87 – 101. [Abstract] [BibTeX] [DOI]
Abstract: Assignment of an HDO line list extracted from a recently measured H2O/HDO/D2O Fourier transform absorption spectrum recorded in the 11 600-23 000 cm-1 region by Bach et al. (M. Bach, S. Fally, P.-F. Coheur, M. Carleer, A. Jenouvrier, A.C. Vandaele, J. Mol. Spectrosc. 232 (2005) 341-350.) is presented. More than 94% of the 3256 lines are given quantum number assignments and ascribed to line absorption by HDO; most of the remaining lines are actually due to D2O. High accuracy variational predictions of line positions and intensities are used for the spectral assignment process. Assignments to the ν1 + 5ν3, 2ν2 + 5ν3, ν1 + ν2 + 3ν3 and ν1 + 6ν3 bands are presented for the first time. Comparisons are made with published ICLAS spectra covering the same spectral region and suggestions made for its recalibration. The results are used to illustrate the dynamical behaviour of highly excited vibrational states of HDO and to discuss previous vibrational assignments to high lying rotation-vibration states of this system. © 2007 Elsevier Inc. All rights reserved.
BibTeX: @article{Voronin200787, author = {Voronin, B.A. and Naumenko, O.V. and Carleer, M. and Coheur, P.-F. and Fally, S. and Jenouvrier, A. and Tolchenov, R.N. and Vandaele, A.C. and Tennyson, J.}, title = {HDO absorption spectrum above 11 500 cm-1: Assignment and dynamics}, journal = {Journal of Molecular Spectroscopy}, year = {2007}, volume = {244}, number = {1}, pages = {87 – 101}, doi = {10.1016/j.jms.2007.03.008} }
Wespes C, Hurtmans D, Herbin H, Barret B, Turquety S, Hadji-Lazaro J, Clerbaux C and Coheur P-F (2007), "First global distributions of nitric acid in the troposphere and the stratosphere derived from infrared satellite measurements", Journal of Geophysical Research Atmospheres. Vol. 112(13) [Abstract] [BibTeX] [DOI]
Abstract: Global distributions of nitric acid (HNO3) partial columns in the troposphere and the stratosphere are shown for the first time. HNO3 vertical profiles are retrieved from a set of high-resolution infrared spectra, measured by the nadir-viewing Interferometric Monitor for Greenhouse Gases (IMG) instrument onboard the ADEOS satellite. Ten successive days of IMG operation in April 1997 are analyzed, yielding quasi-global distributions. We show that the IMG measurements contain between 0.7 and 1.8 independent pieces of information on the HNO3 vertical distribution; the extent of which depends on the observed scene. In the tropics and the midlatitudes, tropospheric and stratospheric columns can be separated, whereas, in the colder polar regions, the total column is the most relevant quantity. A detailed error budget reveals that the accuracy on the profile measurements ranges from 5-15% in the stratosphere to about 20-30% in the middle troposphere, and as much as 60% in the lowermost troposphere where the measurements are less sensitive. The global distributions of tropospheric and stratospheric partial columns are presented and discussed. In the stratosphere we measure higher columns at both poles than in the intertropical belt, as expected for the period in April analyzed here. In the troposphere, the zonal distributions show elevated values nearby NOx source regions, such as central Europe, the Eastern coast of the United States, and the North-West of India. Typical profiles with mixing ratios up to 2 ppbv in the boundary layer and 1 ppbv in the free troposphere are identified. These novel results indicate a possible role of HNO3 in the long-range transport of active nitrogen and open promising perspectives for future space missions dedicated to atmospheric chemistry. Copyright 2007 by the American Geophysical Union.
BibTeX: @article{Wespes2007, author = {Wespes, Catherine and Hurtmans, Daniel and Herbin, Hervé and Barret, Brice and Turquety, Solène and Hadji-Lazaro, Juliette and Clerbaux, Cathy and Coheur, Pierre-François}, title = {First global distributions of nitric acid in the troposphere and the stratosphere derived from infrared satellite measurements}, journal = {Journal of Geophysical Research Atmospheres}, year = {2007}, volume = {112}, number = {13}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2006JD008202} }
Astoreca R, Rousseau V and Lancelot C (2006), "Specific phytoplankton absorption variability and implication for chlorophyll a retrieval in Belgian waters (Southern North Sea)", European Space Agency, (Special Publication) ESA SP. (615) [Abstract] [BibTeX]
Abstract: Chlorophyll a retrieval from satellite is based on algorithms that convert the phytoplankton absorption into chlorophyll a by means of the specificphytoplankton absorption. This factor has been found to be highly variable, spatially and seasonally. The variability of the chlorophyll a-specific phytoplankton absorption in Belgian waters (Southern North Sea) was investigated to determine how it is affecting the chlorophyll a retrieval from satellite information. The Southern Bight of the North Sea is a very dynamic area influenced by river discharges and characterised by highly variable chlorophyll, suspended matter and coloured dissolved organic matter absorption. The impact of using a mean value of specificphytoplankton absorption as usually done instead of the real one in chlorophyll a retrieval was estimated and found to be significant (underestimation up to 70% at 665 nm).
BibTeX: @conference{Astoreca2006, author = {Astoreca, Rosa and Rousseau, Véronique and Lancelot, Christiane}, title = {Specific phytoplankton absorption variability and implication for chlorophyll a retrieval in Belgian waters (Southern North Sea)}, journal = {European Space Agency, (Special Publication) ESA SP}, year = {2006}, number = {615} }
Auwera JV, Claveau C, Teffo J-L, Tashkun S and Perevalov V (2006), "Absolute line intensities of 13C16O2 in the 3090-3920 cm-1 region", Journal of Molecular Spectroscopy. Vol. 235(1), pp. 77 – 83. [Abstract] [BibTeX] [DOI]
Abstract: Absolute line intensities of 13C16O2 were retrieved from high-resolution Fourier transform spectra recorded in the region 3090-3920 cm-1. The uncertainty of the line intensity determination is estimated to be between 3 and 5% for the strong lines. The global fittings of the observed line intensities within the framework of the effective operators approach have been performed, reaching the experimental accuracy. A comparison of newly measured line intensities with those found in the HITRAN database is presented. © 2005 Elsevier Inc. All rights reserved.
BibTeX: @article{Auwera200677, author = {Auwera, J. Vander and Claveau, C. and Teffo, J.-L. and Tashkun, S.A. and Perevalov, V.I.}, title = {Absolute line intensities of 13C16O2 in the 3090-3920 cm-1 region}, journal = {Journal of Molecular Spectroscopy}, year = {2006}, volume = {235}, number = {1}, pages = {77 – 83}, doi = {10.1016/j.jms.2005.10.005} }
Baray J-L, Leveau J, Baldy S, Jouzel J, Keckhut P, Bergametti G, Ancellet G, Bencherif H, Cadet B, Carleer M, David C, De Mazière M, Faduilhe D, Godin Beekmann S, Goloub P, Goutail F, Metzger J, Morel B, Pommereau J, Porteneuve J, Portafaix T, Posny F, Robert L and Van Roozendael M (2006), "An instrumented station for the survey of ozone and climate change in the southern tropics", Journal of Environmental Monitoring. Vol. 8(10), pp. 1020 – 1028. [Abstract] [BibTeX] [DOI]
Abstract: The assessment of changes induced by human activities on Earth atmospheric composition and thus on global climate requires a long-term and regular survey of the stratospheric and tropospheric atmospheric layers. The objective of this paper is to describe the atmospheric observations performed continuously at Reunion Island (55.5°east, 20.8°south) for 15 years. The various instruments contributing to the systematic observations are described as well as the measured parameters, the accuracy and the database. The LiDAR systems give profiles of temperature, aerosols and ozone in the troposphere and stratosphere, probes give profiles of temperature, ozone and relative humidity, radiometers and spectrometers give stratospheric and tropospheric integrated columns of a variety of atmospheric trace gases. Data are included in international networks, and used for satellite validation. Moreover, some scientific activities for which this station offers exceptional opportunities are highlighted, especially air mass exchanges nearby dynamical barriers: (1) On the vertical scale through the tropical tropopause layer (stratosphere-troposphere exchange). (2) On the quasi-horizontal scale across the southern subtropical barrier separating the tropical stratospheric reservoir from mid- and high latitudes. © The Royal Society of Chemistry 2006.
BibTeX: @article{Baray20061020, author = {Baray, J.-L. and Leveau, J. and Baldy, S. and Jouzel, J. and Keckhut, P. and Bergametti, G. and Ancellet, G. and Bencherif, H. and Cadet, B. and Carleer, M. and David, C. and De Mazière, M. and Faduilhe, D. and Godin Beekmann, S. and Goloub, P. and Goutail, F. and Metzger, J.M. and Morel, B. and Pommereau, J.P. and Porteneuve, J. and Portafaix, T. and Posny, F. and Robert, L. and Van Roozendael, M.}, title = {An instrumented station for the survey of ozone and climate change in the southern tropics}, journal = {Journal of Environmental Monitoring}, year = {2006}, volume = {8}, number = {10}, pages = {1020 – 1028}, note = {All Open Access, Green Open Access}, doi = {10.1039/b607762e} }
Boyé-Péronne S, Gauyacq D and Liévin J (2006), "Vinylidene-acetylene cation isomerization investigated by large scale ab initio calculations", Journal of Chemical Physics. Vol. 124(21) [Abstract] [BibTeX] [DOI]
Abstract: The planar isomerization routes of the vinylidene/acetylene cation in the lowest electronic states are accurately examined for the first time, by using large scale MRCI and CCSD(T) calculations in a complementary way. They are compared with the similar calculations performed for the neutral ground state isomerization. An accurate value of the adiabatic ionization potential of vinylidene (11.26 eV) is predicted. The vinylidene cation lowest state, 1 A12, follows an almost flat pathway with a shallow secondary minimum on the 1 A′2 potential energy surface, before suddenly dropping to the stable acetylene cation ground state, X̃ Πu2. It is therefore confirmed to be completely unstable with respect to isomerization. The first excited state of the vinylidene cation, 1 B12, which also correlates with the Πu2 ground state of acetylene cation along a A′2 isomerization route, has been studied at the same level of calculation. This 1 B12 state is lying only 0.15 eV above the 1 A12 state, and exhibits a potential energy barrier of 0.55 eV which explains the earlier assignment of this symmetry to the ground state of vinylidene cation. In addition to large scale calculations, a comprehensive description of the important steps of isomerization drawn from a very simple model involving monoconfigurational states is presented. In particular, the behavior of one unique orbital, namely, the 5 a1 outer molecular orbital, is shown to completely govern the molecular geometry and energy evolution along the isomerization route of the ground state cation C2 H2+. © 2006 American Institute of Physics.
BibTeX: @article{Boyé-Péronne2006, author = {Boyé-Péronne, Séverine and Gauyacq, Dolores and Liévin, Jacques}, title = {Vinylidene-acetylene cation isomerization investigated by large scale ab initio calculations}, journal = {Journal of Chemical Physics}, year = {2006}, volume = {124}, number = {21}, doi = {10.1063/1.2187002} }
Cané E, Fusina L, Tamassia F, Fayt A, Herman M, Robert S and Auwera JV (2006), "The FT absorption spectrum of 13CH 12 CH: Rotational analysis of the vibrational states from 3800 to 6750cm -1", Molecular Physics. Vol. 104(4), pp. 515 – 526. [Abstract] [BibTeX] [DOI]
Abstract: Thirty four cold bands and 37 hot bands are reported from the high resolution FT absorption spectrum of 13 CH 12 CH, all leading to vibrational states located between 3800 and 6750cm -1 . Each band has been vibrationally assigned and rotationally analysed. The band centres and rotational constants are listed.
BibTeX: @article{Cané2006515, author = {Cané, E. and Fusina, L. and Tamassia, F. and Fayt, A. and Herman, M. and Robert, S. and Auwera, J. Vander}, title = {The FT absorption spectrum of 13CH 12 CH: Rotational analysis of the vibrational states from 3800 to 6750cm -1}, journal = {Molecular Physics}, year = {2006}, volume = {104}, number = {4}, pages = {515 – 526}, doi = {10.1080/00268970500428991} }
Cassam-Chenaï P and Liévin J (2006), "The VMFCI method: A flexible tool for solving the molecular vibration problem", Journal of Computational Chemistry. Vol. 27(5), pp. 627 – 640. [Abstract] [BibTeX] [DOI]
Abstract: The present article introduces a general variational scheme to find approximate solutions of the spectral problem for the molecular vibration Hamiltonian. It is called the "vibrational mean field configuration interaction" (VMFCI) method, and consists in performing vibrational configuration interactions (VCI) for selected modes in the mean field of the others. The same partition of modes can be iterated until self-consistency, generalizing the vibrational self-consistent field (VSCF) method. As in contracted-mode methods, a hierarchy of partitions can be built to ultimately contract all the modes together. So, the VMFCI method extends the traditional variational approaches and can be included in existing vibrational codes based on the latter approaches. The flexibility and efficiency of this new method are demonstrated on several molecules of atmospheric interest. © 2006 Wiley Periodicals, Inc.
BibTeX: @article{Cassam-Chenaï2006627, author = {Cassam-Chenaï, P. and Liévin, J.}, title = {The VMFCI method: A flexible tool for solving the molecular vibration problem}, journal = {Journal of Computational Chemistry}, year = {2006}, volume = {27}, number = {5}, pages = {627 – 640}, doi = {10.1002/jcc.20374} }
Cauët E, Dehareng D and Liévin J (2006), "Ab initio study of the lonization of the DNA bases: Ionization potentials and excited states of the cations", Journal of Physical Chemistry A. Vol. 110(29), pp. 9200 – 9211. [Abstract] [BibTeX] [DOI]
Abstract: The ionization of the four DNA bases is investigated by means of ab initio calculations. Accurate values of the gas-phase vertical and adiabatic ionization potentials (IP) are obtained at the MP2/6-31G(2d(0.8,αd),p) level of theory. The need of introducing extra polarization to the standard 6-31G(d,p) basis set is demonstrated by test calculations and an optimal value of αd = 0.1 is obtained. Ionization to electronically excited radical cations is also considered. The low-lying excited states of the cations are characterized for the first time. The topology of the corresponding potential energy surfaces is qualitatively described in terms of the stationary points (minima and saddle points) located on these surfaces. A conical intersection is characterized for the first time on the ground-state potential energy surface of all cations. It arises from the crossing of the adiabatic surfaces of the ground and first excited state at planar geometries. A nonplanar minimum is observed for the cytosine cation only. The geometry and electronic changes occurring along these surfaces are analyzed, leading to a comparison between the different nucleobase cations. The study of larger ionized systems related to DNA is rendered possible thanks to the optimized medium size basis set proposed in this work, as exemplified by the calculation of the IP of a stacked dimer of guanines. © 2006 American Chemical Society.
BibTeX: @article{Cauët20069200, author = {Cauët, Emilie and Dehareng, Dominique and Liévin, Jacques}, title = {Ab initio study of the lonization of the DNA bases: Ionization potentials and excited states of the cations}, journal = {Journal of Physical Chemistry A}, year = {2006}, volume = {110}, number = {29}, pages = {9200 – 9211}, doi = {10.1021/jp0617625} }
Clarisse L (2006), "Construction of bound entangled edge states with special ranks", Physics Letters, Section A: General, Atomic and Solid State Physics. Vol. 359(6), pp. 603 – 607. [Abstract] [BibTeX] [DOI]
Abstract: Relating to a conjecture on the decomposability of positive maps in 3 ⊗ 3, we solve the open problem of the existence of (5, 5) and (6, 6) PPT edge states. © 2006 Elsevier B.V. All rights reserved.
BibTeX: @article{Clarisse2006603, author = {Clarisse, Lieven}, title = {Construction of bound entangled edge states with special ranks}, journal = {Physics Letters, Section A: General, Atomic and Solid State Physics}, year = {2006}, volume = {359}, number = {6}, pages = {603 – 607}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.physleta.2006.07.045} }
Clarisse L (2006), "On the Schmidt robustness of pure states", Journal of Physics A: Mathematical and General. Vol. 39(16), pp. 4239 – 4249. [Abstract] [BibTeX] [DOI]
Abstract: Robustness measures as introduced by Vidal and Tarrach (1999 Robustness of entanglement Phys. Rev. A 59 141-55) quantify the extent to which entangled states remain entangled under mixing. Analogously, we introduce here the Schmidt robustness and the random Schmidt robustness. The latter notion is closely related to the construction of Schmidt balls around the identity. We analyse the situation for pure states and provide nontrivial upper and lower bounds. Upper bounds to the random Schmidt-2 robustness allow us to construct a particularly simple distillability criterion. We present two conjectures, the first one is related to the radius of inner balls around the identity in the convex set of Schmidt number n-states. We also conjecture a class of optimal Schmidt witnesses for pure states. © 2006 IOP Publishing Ltd.
BibTeX: @article{Clarisse2006, author = {Clarisse, Lieven}, title = {On the Schmidt robustness of pure states}, journal = {Journal of Physics A: Mathematical and General}, year = {2006}, volume = {39}, number = {16}, pages = {4239 – 4249}, doi = {10.1088/0305-4470/39/16/010} }
Clarisse L (2006), "The distillability problem revisited", Quantum Information and Computation. Vol. 6(6), pp. 539 – 560. [Abstract] [BibTeX]
Abstract: An important open problem in quantum information theory is the question of the existence of NPT bound entanglement. In the past years, little progress has been made, mainly because of the lack of mathematical tools to address the problem, (i) In an attempt to overcome this, we show how the distillability problem can be reformulated as a special instance of the separability problem, for which a large number of tools and techniques are available. (ii) Building up to this we also show how the problem can be formulated as a Schmidt number problem. (iii) A numerical method for detecting distillability is presented and strong evidence is given that all 1-copy undistillable Werner states are also 4-copy undistillable. (iv) The same method is used to estimate the volume of distillable states, and the results suggest that bound entanglement is primarily a phenomenon found in low dimensional quantum systems. (v) Finally, a set of one parameter states is presented which we conjecture to exhibit all forms of distillability. © Rinton Press.
BibTeX: @article{Clarisse2006539, author = {Clarisse, Lieven}, title = {The distillability problem revisited}, journal = {Quantum Information and Computation}, year = {2006}, volume = {6}, number = {6}, pages = {539 – 560} }
Clarisse L and Wocjan P (2006), "On independent permutation separability criteria", Quantum Information and Computation. Vol. 6(3), pp. 277 – 288. [Abstract] [BibTeX]
Abstract: Recently, P. Wocjan and M. Horodecki [Open Syst. Inf. Dyn. 12, 331 (2005)] gave a characterization of combinatorially independent permutation separability criteria. Combinatorial independence is a necessary condition for permutations to yield truly independent criteria meaning that no criterion is strictly stronger that any other. In this paper we observe that some of these criteria are still dependent and analyze why these dependencies occur. To remove them we introduce an improved necessary condition and give a complete classification of the remaining permutations. We conjecture that the remaining class of criteria only contains truly independent permutation separability criteria. Our conjecture is based on the proof that for two, three and four parties all these criteria are truly independent and on numerical verification of their independence for up to 8 parties. It was commonly believed that for three parties there were 9 independent criteria, here we prove that there are exactly 6 independent criteria for three parties and 22 for four parties. © Rinton Press.
BibTeX: @article{Clarisse2006277, author = {Clarisse, Lieven and Wocjan, Pawel}, title = {On independent permutation separability criteria}, journal = {Quantum Information and Computation}, year = {2006}, volume = {6}, number = {3}, pages = {277 – 288} }
Clerbaux C, Turquety S, Hadji-Lazaro J, Granier C, Hauglustaine D, Laval SS, Beekmann M, Orphal J, Bergametti G, Camy-Peyret C, Payan S, Coheur P, De Mazière M, Müller J-F, Prunet P and Klonecki A (2006), "French/belgian scientific contribution to tropospheric studies using the metop sensors", European Space Agency, (Special Publication) ESA SP. (618) [Abstract] [BibTeX]
Abstract: We propose to combine the tropospheric measurements provided by the IASI and GOME2 instruments aboard METOP, together with data from ground-based stations, airborne and spaceborne remote sensors, along with atmospheric chemistry models (CTMs) in order to improve our knowledge of processes constraining the chemical composition of the troposphere and to study the regional and global scale air quality. The measurements of ozone (O 3), carbon monoxide (CO), nitrogen dioxide (NO2), formaldehyde (CH2O), and methane (CH4) will be used in conjunction with the 3D tropospheric LMDz-INCA, MOZART, IMAGES and CHIMERE CTM models, using data assimilation and inversion modeling techniques, to study the global distribution of these species and to derive improved emissions estimates. Before the METOP launch, all the tools developed in the framework of this project will be used to analyse the AURA TES and OMI tropospheric products. After the launch of METOP, the data provided by both satellites will then be analyzed with the CTMs. The resulting global distributions will be used to perform detailed studies of the role of biomass burning in the budget of tropospheric species, the emissions of ozone precursors, the role of convective transport of pollutants, and its consequences in terms of air quality.
BibTeX: @conference{Clerbaux2006, author = {Clerbaux, Cathy and Turquety, Solène and Hadji-Lazaro, Juliette and Granier, Claire and Hauglustaine, Didier and Laval, Sophie Szopa and Beekmann, Matthias and Orphal, Johannes and Bergametti, Gilles and Camy-Peyret, Claude and Payan, Sébastien and Coheur, Pierre and De Mazière, Martine and Müller, Jean-François and Prunet, Pascal and Klonecki, Andrzej}, title = {French/belgian scientific contribution to tropospheric studies using the metop sensors}, journal = {European Space Agency, (Special Publication) ESA SP}, year = {2006}, number = {618} }
Di Lonardo G, Fusina L, Tamassia F, Fayt A, Robert S, Vander Auwera J and Herman M (2006), "The FT absorption spectrum of 13CH12CH (II): Rotational analysis of the range 9500 to 10000 cm−1", Molecular Physics. Vol. 104(16-17), pp. 2617 – 2625. [Abstract] [BibTeX] [DOI]
Abstract: The infrared spectrum of 13CH12CH has been recorded in the 9500–10000 cm−1 wavenumber region by Fourier transform spectroscopy. Twelve Σ+–Σ+ and one ‘perturbation allowed’ Δ–Σ+ cold bands, and four Π–Π hot bands have been identified. All these bands have been rotationally analysed and vibrationally assigned. They mainly involve triple excitations of the CH stretching modes. The relative intensities have been measured. Local interaction patterns are identified and discussed. Line wavenumbers from the two strongest bands observed in the range are listed. © 2006 Taylor & Francis Group, LLC.
BibTeX: @article{DiLonardo20062617, author = {Di Lonardo, G. and Fusina, L. and Tamassia, F. and Fayt, A. and Robert, S. and Vander Auwera, J. and Herman, M.}, title = {The FT absorption spectrum of 13CH12CH (II): Rotational analysis of the range 9500 to 10000 cm−1}, journal = {Molecular Physics}, year = {2006}, volume = {104}, number = {16-17}, pages = {2617 – 2625}, doi = {10.1080/00268970600688536} }
Furtenbacher T, Czakó G, Sutcliffe BT, Császár AG and Szalay V (2006), "The methylene saga continues: Stretching fundamentals and zero-point energy of X̃3 B1 CH2", Journal of Molecular Structure. Vol. 780-781(SPEC. ISS.), pp. 283 – 294. [Abstract] [BibTeX] [DOI]
Abstract: The vibrational fundamentals and the rotational levels up to J=7 of the X̃3B1 and ã1A1 electronic states of CH2 have been computed completely ab initio. The calculations were based on converged, variational nuclear motion calculations employing high-quality ab initio quartic force field approximations of the related potential energy surfaces (PES). The vibrational fundamentals obtained are compared to other computational results, namely those obtained from second-order vibrational perturbation theory (VPT2) and the nonrigid-rotation- large-amplitude-internal-motion Hamiltonian (NRLH) approach. The variationally computed rotational transitions are compared both to experimentally available results and to results obtained using empirical, fitted PESs. The comparisons suggest that while the fitted PESs of X̃3B1 CH 2 reproduce excellently the available rovibrational transition wavenumbers, the corresponding stretching fundamental term values, which have not been determined experimentally, are less accurate than the ab initio values obtained in the present study. This means that the zero-point energy (ZPE) computed ab initio in the present work is an improvement over that computed from the fitted PES of X̃3B1 CH2. No similar problems are observed for the semirigid ã1A1 state of CH2, where the computed, the fitted, and the experimental results all agree with each other. The symmetric and antisymmetric stretching fundamentals of X̃3B1 CH2 obtained in this study are 3035±7 and 3249±7 cm-1, respectively. The corresponding ZPE of X̃3B1 is 3733±10 cm -1, while that of ã1A1 CH2 is 3605±15 cm-1. © 2005 Elsevier B.V. All rights reserved.
BibTeX: @article{Furtenbacher2006283, author = {Furtenbacher, Tibor and Czakó, Gábor and Sutcliffe, Brian T. and Császár, Attila G. and Szalay, Viktor}, title = {The methylene saga continues: Stretching fundamentals and zero-point energy of X̃3 B1 CH2}, journal = {Journal of Molecular Structure}, year = {2006}, volume = {780-781}, number = {SPEC. ISS.}, pages = {283 – 294}, doi = {10.1016/j.molstruc.2005.06.052} }
Kruglanski M, De Mazière M, Vandaele A and Hurtmans D (2006), "Boundary layer aerosol retrieval from thermal infrared nadir sounding - Preliminary results", Advances in Space Research. Vol. 37(12), pp. 2160 – 2165. [Abstract] [BibTeX] [DOI]
Abstract: A non-empirical algorithm is presented to retrieve the optical depth in the 750-1250 cm -1 spectral range, of aerosol located in the boundary layer over the ocean, from nadir high-resolution radiance spectra in the thermal infrared. The algorithm is based on a line-by-line radiative transfer forward model and used the Optimal Estimation Method for the retrieval. Its performance strongly depends on the quality of the a priori temperature and H 2 O atmospheric profiles. To demonstrate the relevance of the algorithm, distributions of maritime aerosol parameters have been retrieved from IMG/ADEOS data for December 1996, using the algorithm with the LBLRTM radiative transfer code, and ERA40 (ECMWF) a priori atmospheric profiles and surface conditions. © 2005 COSPAR.
BibTeX: @article{Kruglanski20062160, author = {Kruglanski, M. and De Mazière, M. and Vandaele, A.C. and Hurtmans, D.}, title = {Boundary layer aerosol retrieval from thermal infrared nadir sounding - Preliminary results}, journal = {Advances in Space Research}, year = {2006}, volume = {37}, number = {12}, pages = {2160 – 2165}, doi = {10.1016/j.asr.2005.08.032} }
Lafferty W, Flaud J-M and Herman M (2006), "Resolved torsional splitting in the ν18 and ν19- bands of propene", Journal of Molecular Structure. Vol. 780-781(SPEC. ISS.), pp. 65 – 69. [Abstract] [BibTeX] [DOI]
Abstract: FT-jet spectra of propene were recorded at 0.005 cm-1 instrumental resolution around 950 cm-1. Thanks to the jet conditions, probably corresponding to Trot close to 80 K, the torsion degrees of freedom are efficiently cooled down and the fine structure of the ν18 and ν19 vibrational bands could be investigated. The bands are perturbed and approximate variation of the principal rotational constants are obtained, as well as band origins. The A/E torsional splitting appears totally unpredictable over the range of vibrational-torsional energy investigated. © 2005 Elsevier B.V. All rights reserved.
BibTeX: @article{Lafferty200665, author = {Lafferty, W.J. and Flaud, J.-M. and Herman, M.}, title = {Resolved torsional splitting in the ν18 and ν19- bands of propene}, journal = {Journal of Molecular Structure}, year = {2006}, volume = {780-781}, number = {SPEC. ISS.}, pages = {65 – 69}, doi = {10.1016/j.molstruc.2005.03.051} }
Lasorne B, Bacchus-Montabonel M, Vaeck N and Desouter-Lecomte M (2006), "Quantum dynamics simulations of photodissociation reactions", International Journal of Quantum Chemistry. Vol. 106(3), pp. 670 – 675. [Abstract] [BibTeX] [DOI]
Abstract: Wave packet simulations using ab initio potential energy surfaces (PES) have been developed within the framework of the constrained Hamiltonian methodology. The approach is presented with the example of bromoacetyl chloride photodissociation. © 2005 Wiley Periodicals, Inc.
BibTeX: @article{Lasorne2006670, author = {Lasorne, B. and Bacchus-Montabonel, M.C. and Vaeck, N. and Desouter-Lecomte, M.}, title = {Quantum dynamics simulations of photodissociation reactions}, journal = {International Journal of Quantum Chemistry}, year = {2006}, volume = {106}, number = {3}, pages = {670 – 675}, doi = {10.1002/qua.20829} }
Le Roy RJ, Appadoo DR, Colin R and Bernath PF (2006), "On the X2Σ+, A2Π, and C2Σ+ states of BeH, BeD, and BeT", Journal of Molecular Spectroscopy. Vol. 236(2), pp. 178 – 188. [Abstract] [BibTeX] [DOI]
Abstract: New Fourier transform measurements for the A2Π - X2Σ+ system of BeH are combined with previously published A - X data for BeH, BeD, and BeT, with existing data for the C2Σ+ - X2Σ+ system, and with recent vibration-rotation data for BeH and BeD, and fitted using combined-isotopologue Dunham expansion and direct-potential-fit methods. This data set provides direct spectroscopic information spanning 95% of the ground X2Σ+ state potential well, and provides the most comprehensive spectroscopic description of this state reported to date. The analysis of this data set allows us to study the breakdown of the Born-Oppenheimer approximation for a metal hydride from the minimum of the potential well to near the dissociation limit. Improved molecular constants are also determined for the A2Π and C2Σ+ states. © 2006 Elsevier Inc. All rights reserved.
BibTeX: @article{LeRoy2006, author = {Le Roy, Robert J. and Appadoo, Dominique R.T. and Colin, Reginald and Bernath, Peter F.}, title = {On the X2Σ+, A2Π, and C2Σ+ states of BeH, BeD, and BeT}, journal = {Journal of Molecular Spectroscopy}, year = {2006}, volume = {236}, number = {2}, pages = {178 – 188}, doi = {10.1016/j.jms.2006.01.010} }
Liu C-P, Elliott NL, Western CM, Lee Y-P and Colin R (2006), "The B 3Σ- state of the SO radical", Journal of Molecular Spectroscopy. Vol. 238(2), pp. 213 – 223. [Abstract] [BibTeX] [DOI]
Abstract: Spectra of the B 3Σ-- X 3Σ- transition in SO above the first dissociation limit are recorded using degenerate four wave mixing. These spectra are combined with earlier work involving laser induced fluorescence, absorption spectra and Fourier transform emission spectra, to enable a rotational analysis and deperturbation of vibrational levels of the B state up to v′ = 16. Numerous perturbations were noted within the B 3Σ- state, and the origin of these is discussed. In a number of cases, these perturbations can be attributed to interactions with specific other electronic states of SO, such as A 3Π, C 3Π, d 1Π, and A″ 3Σ+. © 2006 Elsevier Inc. All rights reserved.
BibTeX: @article{Liu2006, author = {Liu, Ching-Ping and Elliott, Nicola L. and Western, Colin M. and Lee, Yuan-Pern and Colin, Reginald}, title = {The B 3Σ- state of the SO radical}, journal = {Journal of Molecular Spectroscopy}, year = {2006}, volume = {238}, number = {2}, pages = {213 – 223}, doi = {10.1016/j.jms.2006.05.005} }
Macko P and Herman M (2006), "Absolute line intensity with FT-ICLAS: 12C2H 2 near 12 800 cm-1", Chemical Physics Letters. Vol. 417(4-6), pp. 471 – 474. [Abstract] [BibTeX] [DOI]
Abstract: We have used a Fourier transform intracavity laser absorption spectrometer to measure the absolute intensity of lines in the ν1 + 3ν3 band of 12C2H2 at 12675 cm-1. Under optimal conditions the agreement is found to be within 5% of reference values measured by conventional Fourier transform spectroscopy [F. Herregodts et al., Mol. Phys., 101 (2003) 3427]. The absolute intensity of 21 weaker lines not experimentally investigated in the latter work, is listed. Various tests of the instrumental method are presented, also demonstrating its ability to determine pressure self-broadening coefficients. © 2005 Elsevier B.V. All rights reserved.
BibTeX: @article{Macko2006471, author = {Macko, P. and Herman, M.}, title = {Absolute line intensity with FT-ICLAS: 12C2H 2 near 12 800 cm-1}, journal = {Chemical Physics Letters}, year = {2006}, volume = {417}, number = {4-6}, pages = {471 – 474}, doi = {10.1016/j.cplett.2005.10.065} }
Merke I, Vaeck N, Petitprez D and Wlodarczak G (2006), "The rotational spectrum of bromoacetyl chloride", Journal of Molecular Structure. Vol. 780-781(SPEC. ISS.), pp. 306 – 309. [Abstract] [BibTeX] [DOI]
Abstract: The rotational spectrum of bromoacetyl chloride, BrCH2COCl, has been assigned using a pulsed molecular beam Fourier transform microwave spectrometer. It has been possible to determine the rotational and quartic centrifugal distortion constants of the energetically favoured conformer (anti-periplanar) as well as the complete bromine and chlorine quadrupole coupling tensors including their off diagonal elements for the following isotopomers: 79BrCH2CO35Cl, 81BrCH2CO35Cl, 79BrCH 2CO37Cl, and 81BrCH2CO 37Cl. Experimental results are supported by quantum chemical calculations. © 2005 Elsevier B.V. All rights reserved.
BibTeX: @article{Merke2006306, author = {Merke, I. and Vaeck, N. and Petitprez, D. and Wlodarczak, G.}, title = {The rotational spectrum of bromoacetyl chloride}, journal = {Journal of Molecular Structure}, year = {2006}, volume = {780-781}, number = {SPEC. ISS.}, pages = {306 – 309}, doi = {10.1016/j.molstruc.2005.06.040} }
Nassar R, Bernath P, Boone C, Clerbaux C, Coheur P, Dufour G, Froidevaux L, Mahieu E, McConnell J, McLeod S, Murtagh D, Rinsland C, Semeniuk K, Skelton R, Walker K and Zander R (2006), "A global inventory of stratospheric chlorine in 2004", Journal of Geophysical Research Atmospheres. Vol. 111(22) [Abstract] [BibTeX] [DOI]
Abstract: Total chlorine (CITOT) in the stratosphere has been determined using the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) measurements of HCl, ClONO2, CH3Cl, CCl4, CCl3F (CFC-11), CCl2F2 (CFC-12), CHClF2 (HCFC-22), CCl2FCClF2 (CFC-113), CH3CClF2 (HCFC-142b), COClF, and ClO supplemented by data from several other sources, including both measurements and models. Separate chlorine inventories were carried out in five latitude zones (60°-82°N, 30°-60°N, 30°S-30°N, 30°-60°S, and 60°-82°S), averaging the period of February 2004 to January 2005 inclusive, when possible, to deal with seasonal variations. The effect of diurnal variation was avoided by only using measurements taken at local sunset. Mean stratospheric ClTOT values of 3.65 ppbv were determined for both the northern and southern midlatitudes (with an estimated 1σ, accuracy of ±0.13 ppbv and a precision of ±.09 ppbv), accompanied by a slightly lower value in the tropics and slightly higher values at high latitudes. Stratospheric ClTOT profiles in all five latitude zones are nearly linear with a slight positive slope in ppbv /km. Both the observed slopes and pattern of latitudinal variation can be interpreted as evidence of the beginning of a decline in global stratospheric chlorine, which is qualitatively consistent with the mean stratospheric circulation pattern and time lag necessary for transport. Copyright 2006 by the American Geophysical Union.
BibTeX: @article{Nassar2006, author = {Nassar, Ray and Bernath, P.F. and Boone, C.D. and Clerbaux, C. and Coheur, P.F. and Dufour, G. and Froidevaux, L. and Mahieu, E. and McConnell, J.C. and McLeod, S.D. and Murtagh, D.P. and Rinsland, C.P. and Semeniuk, K. and Skelton, R. and Walker, K.A. and Zander, R.}, title = {A global inventory of stratospheric chlorine in 2004}, journal = {Journal of Geophysical Research Atmospheres}, year = {2006}, volume = {111}, number = {22}, note = {All Open Access, Green Open Access}, doi = {10.1029/2006JD007073} }
Rinsland C, Bernath P, Boone C, Clerbaux C and Turquety S (2006), "Upper tropospheric measurements of biomass burning emissions with the Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer", European Space Agency, (Special Publication) ESA SP. (628) [BibTeX]
BibTeX: @conference{Rinsland2006, author = {Rinsland, Curtis and Bernath, Peter and Boone, Chris and Clerbaux, Cathy and Turquety, Solène}, title = {Upper tropospheric measurements of biomass burning emissions with the Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer}, journal = {European Space Agency, (Special Publication) ESA SP}, year = {2006}, number = {628} }
Rinsland CP, Boone CD, Bernath PF, Mahieu E, Zander R, Dufour G, Clerbaux C, Turquety S, Chiou L, McConnell JC, Neary L and Kaminski JW (2006), "First space-based observations of formic acid (HCOOH): Atmospheric Chemistry Experiment austral spring 2004 and 2005 Southern Hemisphere tropical-mid-latitude upper tropospheric measurements", Geophysical Research Letters. Vol. 33(23) [Abstract] [BibTeX] [DOI]
Abstract: The first space-based measurements of upper tropospheric (110-300 hPa) formic acid (HCOOH) are reported from 0.02 cm-1 resolution Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer solar occultation measurements at 16°S-43°S latitude during late September to early October in 2004 and 2005. A maximum upper tropospheric HCOOH mixing ratio of 3.13 ± 0.02 ppbv (1 ppbv = 10-9 per unit volume), 1 sigma, at 10.5 km altitude was measured during 2004 at 29.97°S latitude and a lower maximum HCOOH mixing ratio of 2.03 ± 0.28 ppbv, at 9.5 km altitude was measured during 2005. Fire counts, back trajectories, and correlations of HCOOH mixing ratios with ACE simultaneous measurements of other fire products confirm the elevated HCOOH mixing ratios originated primarily from tropical fire emissions. A HCOOH emission factor relative to CO of 1.99 ± 1.34 g kg-1 during 2004 in upper tropospheric plumes is inferred from a comparison with lower mixing ratios measured during the same time period assuming HITRAN 2004 spectroscopic parameters. Copyright 2006 by the American Geophysical Union.
BibTeX: @article{Rinsland2006, author = {Rinsland, Curtis P. and Boone, Chris D. and Bernath, Peter F. and Mahieu, Emmanuel and Zander, Rodolphe and Dufour, Gaëlle and Clerbaux, Cathy and Turquety, Solène and Chiou, Linda and McConnell, John C. and Neary, Lori and Kaminski, Jacek W.}, title = {First space-based observations of formic acid (HCOOH): Atmospheric Chemistry Experiment austral spring 2004 and 2005 Southern Hemisphere tropical-mid-latitude upper tropospheric measurements}, journal = {Geophysical Research Letters}, year = {2006}, volume = {33}, number = {23}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2006GL027128} }
Sutcliffe B (2006), "The idea of a potential energy surface", Molecular Physics. Vol. 104(5-7), pp. 715 – 722. [Abstract] [BibTeX] [DOI]
Abstract: The development of the idea of a potential energy surface is examined in the context of solutions to the full quantum mechanical problem specified by the Schrödinger Coulomb Hamiltonian expressed in laboratory-fixed coordinates.
BibTeX: @article{Sutcliffe2006715, author = {Sutcliffe, B.T.}, title = {The idea of a potential energy surface}, journal = {Molecular Physics}, year = {2006}, volume = {104}, number = {5-7}, pages = {715 – 722}, doi = {10.1080/00268970500418059} }
Vander Auwera J and Fayt A (2006), "Absolute line intensities for carbonyl sulfide from 827 to 2939 cm -1", Journal of Molecular Structure. Vol. 780-781(SPEC. ISS.), pp. 134 – 141. [Abstract] [BibTeX] [DOI]
Abstract: Using a total of 18 unapodized high-resolution (MOPD=300 and 450 cm) Fourier transform absorption spectra of carbonyl sulfide (P×ℓ=14.3-60, 600 Pa×cm, T=296.0 K), we measured 1340 absolute line intensities in 8 bands (ν1+ν21-ν21,2ν20,2ν1,ν1+2ν20,4ν20,ν3, ν21+ν3-ν21,ν1+ν3) of the main isotopologue, located between 827 and 2939 cm-1. In addition, we measured 307 absolute line intensities in the ν3 fundamental band of 16O12C 34S and 16O13C32S, observed near 2061.45 and 2009.23 cm-1, respectively. The observed Herman-Wallis dependences are in most cases reproduced by the global model of OCS [E. Rbaihi, A. Belafhal, J. Vander Auwera, S. Naïm, and A. Fayt, J. Mol. Spectrosc., 191:32-44, 1998]. The pressure self-broadening parameter was also measured up to J=83. © 2005 Elsevier B.V. All rights reserved.
BibTeX: @article{VanderAuwera2006134, author = {Vander Auwera, J. and Fayt, A.}, title = {Absolute line intensities for carbonyl sulfide from 827 to 2939 cm -1}, journal = {Journal of Molecular Structure}, year = {2006}, volume = {780-781}, number = {SPEC. ISS.}, pages = {134 – 141}, doi = {10.1016/j.molstruc.2005.04.052} }
Zobov NF, Shirin SV, Polyansky OL, Barber RJ, Tennyson J, Coheur P-F, Bernath PF, Carleer M and Colin R (2006), "Spectrum of hot water in the 2000-4750 cm-1 frequency range", Journal of Molecular Spectroscopy. Vol. 237(1), pp. 115 – 122. [Abstract] [BibTeX] [DOI]
Abstract: An emission spectrum recorded in an oxyacetylene torch [P.-F. Coheur, P.F. Bernath, M. Carleer, R. Colin, O.L. Polyansky, N.F. Zobov, S.V. Shirin, R.J. Barber, J. Tennyson, J. Chem. Phys. 122 (2005) 074307] is analyzed for the region covering stretching fundamentals and associated hot bands of water. Many lines could be assigned on the basis of previously determined energy levels. New assignments made with a new variational linelist allow a further 800 energy levels covering 15 vibrational states and rotations up to J = 32 to be assigned. A simultaneous re-analysis of previously reported sunspot absorption spectra leads to the assignment of 581 further lines in the L-band spectrum and 67 in the N-band spectrum. © 2006 Elsevier Inc. All rights reserved.
BibTeX: @article{Zobov2006115, author = {Zobov, Nikolai F. and Shirin, Sergei V. and Polyansky, Oleg L. and Barber, Robert J. and Tennyson, Jonathan and Coheur, Pierre-François and Bernath, Peter F. and Carleer, Michel and Colin, Reginald}, title = {Spectrum of hot water in the 2000-4750 cm-1 frequency range}, journal = {Journal of Molecular Spectroscopy}, year = {2006}, volume = {237}, number = {1}, pages = {115 – 122}, doi = {10.1016/j.jms.2006.03.001} }
Astoreca R, Rousseau V, Ruddick K, Van Mol B, Parent J-Y and Lancelot C (2005), "Optical properties of algal blooms in an eutrophicated coastal area and its relevance to remote sensing", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 5885, pp. 1 – 11. [Abstract] [BibTeX] [DOI]
Abstract: The Southern Bight of the North Sea is characterised by a large influence of river inputs, which results in eutrophication of the area. High concentrations of plankton biomass and suspended matter have been reported for this area, in relation with blooms of different species and resuspension of bottom sediments. In spring the haptophyte Phaeocystis globosa blooms throughout the area reaching up to 30 mg Chlorophyll m-3 or more nearshore. This event is followed in June by red tides of the dinoflagellate Noctiluca scintillans. These blooms are concurrent with different species of diatoms. The strong optical signature of these blooms is clear to human observers making them potentially detectable in satellite imagery. As a first step in this direction, sampling has been carried out in the area, during Phaeocystis and Noctiluca blooms in 2003 and 2004. Phytoplankton pigments and inherent optical properties (particle, detrital and phytoplankton absorption) have been measured spectrophotometrically, and in situ using an ac-9 for total absorption and particle scattering. Field data were compared with optical properties of pure species obtained in laboratory. In parallel, water-leaving reflectance has been also measured. In this paper we characterise the optical signatures of diatoms, Phaeocystis and Noctiluca and their contribution to total absorption. The impact on water-leaving reflectance spectra is evaluated; in order to assess the conditions in which remote sensing can provide information for monitoring the timing, extent and magnitude of blooms in this coastal area.
BibTeX: @conference{Astoreca20051, author = {Astoreca, Rosa and Rousseau, Véronique and Ruddick, Kevin and Van Mol, Barbara and Parent, Jean-Yves and Lancelot, Christiane}, title = {Optical properties of algal blooms in an eutrophicated coastal area and its relevance to remote sensing}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2005}, volume = {5885}, pages = {1 – 11}, doi = {10.1117/12.615160} }
Bach M, Fally S, Coheur P-F, Carleer M, Jenouvrier A and Vandaele AC (2005), "Line parameters of HDO from high-resolution Fourier transform spectroscopy in the 11 500-23 000 cm-1 spectral region", Journal of Molecular Spectroscopy. Vol. 232(2), pp. 341 – 350. [Abstract] [BibTeX] [DOI]
Abstract: This work presents new measurements of HDO line parameters in the near-infrared and visible regions (11 500-23 000 cm-1). The measurements consist in high-resolution Fourier transform absorption spectra of H2O/HDO/D2O vapor mixtures, obtained using a long absorption path. Spectra with and without nitrogen as the buffer gas were recorded. Due to the simultaneous presence of the three isotopologues H 2O, D2O, and HDO, the H2O lines removal and the D2O lines identification were two necessary preliminary steps to derive the HDO line parameters. The D2O contribution was small and confined to the well-known 4ν1 + ν3 band. An extensive listing of HDO spectroscopic parameters was obtained, for the first time, by fitting some 3256 observed lines to Voigt line profiles. The list contains calibrated line positions, absorption cross-sections and, for many of the lines, N2-broadening coefficients, as well as N 2-induced frequency shifts. As a result of the low HDO vapor pressures, it was not possible to retrieve the self-broadening parameters. The list is available on the http://www.ulb.ac.be/cpm website. © 2005 Elsevier Inc. All rights reserved.
BibTeX: @article{Bach2005341, author = {Bach, Mohamed and Fally, Sophie and Coheur, Pierre-François and Carleer, Michel and Jenouvrier, Alain and Vandaele, Ann Carine}, title = {Line parameters of HDO from high-resolution Fourier transform spectroscopy in the 11 500-23 000 cm-1 spectral region}, journal = {Journal of Molecular Spectroscopy}, year = {2005}, volume = {232}, number = {2}, pages = {341 – 350}, doi = {10.1016/j.jms.2005.04.018} }
Barret B, Hurtmans D, Carleer M, De Mazière M, Mahieu E and Coheur P-F (2005), "Line narrowing effect on the retrieval of HF and HCl vertical profiles from ground-based FTIR measurements", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 95(4), pp. 499 – 519. [Abstract] [BibTeX] [DOI]
Abstract: Collision-induced line narrowing, which has been discovered in the 1950s and investigated thoroughly in the laboratory since then, has yet never been taken into account in the spectroscopic remote sensing of the atmosphere. This work investigates the effect of collision-induced line narrowing onto the retrieval of HCl and HF vertical profiles from ground-based solar absorption FTIR measurements made at the NDSC station of the Jungfraujoch (46.5°N, 8°E and 3580 m above see level). The retrievals are performed with the Atmosphit software, recently developed at the Université Libre de Bruxelles. It is presented in this paper for the first time and is validated against the widely used SFIT2 software. The impact of the line narrowing onto the retrieval of HCl and HF vertical profiles is examined relying on careful information content and error budget analyses. We report that the effect is relatively weak for HCl but significant for HF. Confirmation of the need to take the line narrowing into account for the retrieval of vertical profiles from ground-based FTIR spectra is given by comparison with data from the HALOE space borne instrument, rather insensitive to this spectroscopic effect. © 2005 Elsevier Ltd. All rights reserved.
BibTeX: @article{Barret2005499, author = {Barret, B. and Hurtmans, D. and Carleer, M.R. and De Mazière, M. and Mahieu, E. and Coheur, P.-F.}, title = {Line narrowing effect on the retrieval of HF and HCl vertical profiles from ground-based FTIR measurements}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2005}, volume = {95}, number = {4}, pages = {499 – 519}, doi = {10.1016/j.jqsrt.2004.12.005} }
Barret B, Turquety S, Hurtmans D, Clerbaux C, Hadji-Lazaro J, Bey I, Auvray M and Coheur P-F (2005), "Global carbon monoxide vertical distributions from spaceborne high-resolution FTIR nadir measurements", Atmospheric Chemistry and Physics. Vol. 5(11), pp. 2901 – 2914. [Abstract] [BibTeX] [DOI]
Abstract: This paper presents the first global distributions of CO vertical profiles retrieved from a thermal infrared FTS working in the nadir geometry. It is based on the exploitation of the high resolution and high quality spectra measured by the Interferometric Monitor of Greenhouse gases (IMG) which flew onboard the Japanese ADEOS platform in 1996-1997. The retrievals are performed with an algorithm based on the Optimal Estimation Method (OEM) and are characterized in terms of vertical sensitivity and error budget. It is found that most of the IMG measurements contain between 1.5 and 2.2 independent pieces of information about the vertical distribution of CO from the lower troposphere to the upper troposphere-lower stratosphere (UTLS). The retrievals are validated against coincident NOAA/CMDL in situ surface measurements and NDSC/FTIR total columns measurements. The retrieved global distributions of CO are also found to be in good agreement with the distributions modeled by the GEOS-CHEM 3D CTM, highlighting the ability of IMG to capture the horizontal as well as the vertical structure of the CO distribution. © 2005 Author(s). This work is licensed under a Creative Commons License.
BibTeX: @article{Barret20052901, author = {Barret, Brice and Turquety, S. and Hurtmans, D. and Clerbaux, C. and Hadji-Lazaro, J. and Bey, I. and Auvray, M. and Coheur, P.-F.}, title = {Global carbon monoxide vertical distributions from spaceborne high-resolution FTIR nadir measurements}, journal = {Atmospheric Chemistry and Physics}, year = {2005}, volume = {5}, number = {11}, pages = {2901 – 2914}, note = {All Open Access, Gold Open Access}, doi = {10.5194/acp-5-2901-2005} }
Bernath P, McElroy C, Abrams M, Boone C, Butler M, Camy-Peyret C, Carleer M, Clerbaux C, Coheur P-F, Colin R, DeCola P, DeMazière M, Drummond J, Dufour D, Evans W, Fast H, Fussen D, Gilbert K, Jennings D, Llewellyn E, Lowe R, Mahieu E, McConnell J, McHugh M, McLeod S, Michaud R, Midwinter C, Nassar R, Nichitiu F, Nowlan C, Rinsland C, Rochon Y, Rowlands N, Semeniuk K, Simon P, Skelton R, Sloan J, Soucy M-A, Strong K, Tremblay P, Turnbull D, Walker K, Walkty I, Wardle D, Wehrle V, Zander R and Zou J (2005), "Atmospheric chemistry experiment (ACE): Mission overview", Geophysical Research Letters. Vol. 32(15) [Abstract] [BibTeX] [DOI]
Abstract: SCISAT-1, also known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission for remote sensing of the Earth's atmosphere. It was launched into low Earth circular orbit (altitude 650 km, inclination 74°) on 12 Aug. 2003. The primary ACE instrument is a high spectral resolution (0.02 cm-1) Fourier Transform Spectrometer (FTS) operating from 2.2 to 13.3 μm (750-4400 cm-1). The satellite also features a dual spectrophotometer known as MAESTRO with wavelength coverage of 285-1030 nm and spectral resolution of 1-2 nm. A pair of filtered CMOS detector arrays records images of the Sun at 0.525 and 1.02 μm. Working primarily in solar occultation, the satellite provides altitude profile information (typically 10-100 km) for temperature, pressure, and the volume mixing ratios for several dozen molecules of atmospheric interest, as well as atmospheric extinction profiles over the latitudes 85°N to 85°S. This paper presents a mission overview and some of the first scientific results. Copyright 2005 by the American Geophysical Union.
BibTeX: @article{Bernath2005, author = {Bernath, P.F. and McElroy, C.T. and Abrams, M.C. and Boone, C.D. and Butler, M. and Camy-Peyret, C. and Carleer, M. and Clerbaux, C. and Coheur, P.-F. and Colin, R. and DeCola, P. and DeMazière, M. and Drummond, J.R. and Dufour, D. and Evans, W.F.J. and Fast, H. and Fussen, D. and Gilbert, K. and Jennings, D.E. and Llewellyn, E.J. and Lowe, R.P. and Mahieu, E. and McConnell, J.C. and McHugh, M. and McLeod, S.D. and Michaud, R. and Midwinter, C. and Nassar, R. and Nichitiu, F. and Nowlan, C. and Rinsland, C.P. and Rochon, Y.J. and Rowlands, N. and Semeniuk, K. and Simon, P. and Skelton, R. and Sloan, J.J. and Soucy, M.-A. and Strong, K. and Tremblay, P. and Turnbull, D. and Walker, K.A. and Walkty, I. and Wardle, D.A. and Wehrle, V. and Zander, R. and Zou, J.}, title = {Atmospheric chemistry experiment (ACE): Mission overview}, journal = {Geophysical Research Letters}, year = {2005}, volume = {32}, number = {15}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1029/2005GL022386} }
Cauët E, Rooman M, Wintjens R, Liévin J and Biot C (2005), "Histidine-aromatic interactions in proteins and protein-ligand complexes: Quantum chemical study of X-ray and model structures", Journal of Chemical Theory and Computation. Vol. 1(3), pp. 472 – 483. [Abstract] [BibTeX] [DOI]
Abstract: His-aromatic complexes, with the His located above the aromatic plane, are stabilized by π-π, δ+-π and/or cation-π interactions according to whether the His is neutral or protonated and the partners are in stacked or T-shape conformations. Here we attempt to probe the relative strength of these interactions as a function of the geometry and protonation state, in gas phase, in water and protein-like environments (acetone, THF and CCl4), by means of quantum chemistry calculations performed up to second order of the Møller-Plesset pertubation theory. Two sets of conformations are considered for that purpose. The first set contains 89 interactions between His and Phe, Tyr, Trp, or Ade, observed in X-ray structures of proteins and protein-ligand complexes. The second set contains model structures obtained by moving an imidazolium/imida-zole moiety above a benzene ring or an adenine moiety. We found that the protonated complexes are much more stable than the neutral ones in gas phase. This higher stability is due to the electrostatic contributions, the electron correlation contributions being equally important in the two forms. Thus, π-π and δ+-π interactions present essentially favorable electron correlation energy terms, whereas cation-π interactions feature in addition favorable electrostatic energies. The pro-tonated complexes remain more stable than the neutral ones in protein-like environments, but the difference is drastically reduced. Furthermore, the T-shape conformation is undoubtedly more favorable than the stacked one in gas phase. This advantage decreases in the solvents, and the stacked conformation becomes even slightly more favorable in water. The frequent occurrence of His-aromatic interactions in catalytic sites, at protein-DNA or protein-ligand interfaces and in 3D domain swapping proteins emphasize their importance in biological processes. © 2005 American Chemical Society.
BibTeX: @article{Cauët2005472, author = {Cauët, Emilie and Rooman, Marianne and Wintjens, René and Liévin, Jacques and Biot, Christophe}, title = {Histidine-aromatic interactions in proteins and protein-ligand complexes: Quantum chemical study of X-ray and model structures}, journal = {Journal of Chemical Theory and Computation}, year = {2005}, volume = {1}, number = {3}, pages = {472 – 483}, doi = {10.1021/ct049875k} }
Clarisse L (2005), "Characterization of distillability of entanglement in terms of positive maps", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 71(3) [Abstract] [BibTeX] [DOI]
Abstract: A necessary and sufficient condition for one-distillability is formulated in terms of decomposable positive maps. As an application we provide insight into why all states violating the reduction criterion map are distillable and demonstrate how to construct such maps in a systematic way. We establish a connection between a number of existing results, which leads to an elementary proof for the characterization of distillability in terms of two-positive maps. ©2005 The American Physical Society.
BibTeX: @article{Clarisse2005, author = {Clarisse, Lieven}, title = {Characterization of distillability of entanglement in terms of positive maps}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2005}, volume = {71}, number = {3}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.71.032332} }
Clarisse L, Ghosh S, Severini S and Sudbery A (2005), "Entangling power of permutations", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 72(1) [Abstract] [BibTeX] [DOI]
Abstract: The notion of entangling power of unitary matrices was introduced by Zanardi, [Phys. Rev. A 62, 030301 (2000)]. We study the entangling power of permutations, given in terms of a combinatorial formula. We show that the permutation matrices with zero entangling power are, up to local unitaries, the identity and the swap. We construct the permutations with the minimum nonzero entangling power for every dimension. With the use of orthogonal latin squares, we construct the permutations with the maximum entangling power for every dimension. Moreover, we show that the value obtained is maximum over all unitaries of the same dimension, with a possible exception for 36. Our result enables us to construct generic examples of 4-qudit maximally entangled states for all dimensions except for 2 and 6. We numerically classify, according to their entangling power, the permutation matrices of dimensions 4 and 9, and we give some estimates for higher dimensions. © 2005 The American Physical Society.
BibTeX: @article{Clarisse2005, author = {Clarisse, Lieven and Ghosh, Sibasish and Severini, Simone and Sudbery, Anthony}, title = {Entangling power of permutations}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2005}, volume = {72}, number = {1}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.72.012314} }
Clerbaux C, Coheur P-F, Hurtmans D, Barret B, Carleer M, Colin R, Semeniuk K, McConnell J, Boone C and Bernath P (2005), "Carbon monoxide distribution from the ACE-FTS solar occultation measurements", Geophysical Research Letters. Vol. 32(16), pp. 1 – 4. [Abstract] [BibTeX] [DOI]
Abstract: This paper presents a comprehensive analysis of the CO observations acquired during the first eight months (January to September 2004) of the ACE mission. We show that the ACE high-resolution Fourier transform spectrometer (ACE-FTS), which operates in the solar occultation geometry and covers a wide spectral interval in the infrared, provides useful measurements in both the CO 1-0 and 2-0 vibrational bands. Vertically-resolved CO concentration profiles are retrieved, extending from the mid-troposphere to the thermosphere (from about 5 to 110 km). We have analyzed the latitudinal variability of the measurements, from which various physical and chemical atmospheric processes are highlighted for further study. Copyright 2005 by the American Geophysical Union.
BibTeX: @article{Clerbaux20051, author = {Clerbaux, C. and Coheur, P.-F. and Hurtmans, D. and Barret, B. and Carleer, M. and Colin, R. and Semeniuk, K. and McConnell, J.C. and Boone, C. and Bernath, P.}, title = {Carbon monoxide distribution from the ACE-FTS solar occultation measurements}, journal = {Geophysical Research Letters}, year = {2005}, volume = {32}, number = {16}, pages = {1 – 4}, note = {All Open Access, Green Open Access}, doi = {10.1029/2005GL022394} }
Coheur P-F, Barret B, Turquety S, Hurtmans D, Hadji-Lazaro J and Clerbaux C (2005), "Retrieval and characterization of ozone vertical profiles from a thermal infrared nadir sounder", Journal of Geophysical Research Atmospheres. Vol. 110(24), pp. 1 – 12. [Abstract] [BibTeX] [DOI]
Abstract: This paper presents the first retrievals and validations of ozone vertical distributions from a set of high-resolution nadir thermal infrared measurements. These were obtained by the Interferometric Monitor for Greenhouse gases (IMG) instrument, which has operated on board the Japanese ADEOS platform between 1996 and 1997. The Optimal Estimation Method is used for the retrievals, along with a priori profile and covariance matrix built from model climatologies. We compare the retrieved IMG profiles with high-vertical-resolution ozone sonde measurements. Therefore we selected a set of IMG spectra collocated to within 3° of longitude and latitude with a representative distribution of ground-based stations. We demonstrate that thanks to the two to four independent pieces of vertical information contained in the spectroscopic measurements with a maximum sensitivity in the upper troposphere-middle stratosphere, the thermal infrared nadir sounders are able to capture most of the ozone spatial and temporal variations. In particular, the latitudinal variations of the stratospheric ozone maximum are well represented in the retrievals, as are the high ozone concentrations observed in the upper troposphere- lower stratosphere at northern midlatitudes during springtime. Ozone depletion events in the Arctic vortex are also well reproduced. The measurements provide an accurate view of the tropospheric ozone content, except when the latter is very low. A detailed error budget reveals that the major part of the error in the IMG retrieved ozone profile is due to the smoothing of the true profile by the averaging kernel matrix, with additional contributions associated with the measurement noise and the inaccurate knowledge of the temperature profile and of the Instrument Line Shape (ILS). Copyright 2005 by the American Geophysical Union.
BibTeX: @article{Coheur20051, author = {Coheur, Pierre-François and Barret, Brice and Turquety, Solène and Hurtmans, Daniel and Hadji-Lazaro, Juliette and Clerbaux, Cathy}, title = {Retrieval and characterization of ozone vertical profiles from a thermal infrared nadir sounder}, journal = {Journal of Geophysical Research Atmospheres}, year = {2005}, volume = {110}, number = {24}, pages = {1 – 12}, note = {All Open Access, Bronze Open Access, Green Open Access}, doi = {10.1029/2005JD005845} }
Coheur P-F, Bernath PF, Carleer M, Colin R, Polyansky OL, Zobov NF, Shirin SV, Barber RJ and Tennyson J (2005), "A 3000K laboratory emission spectrum of water", Journal of Chemical Physics. Vol. 122(7) [Abstract] [BibTeX] [DOI]
Abstract: An emission spectrum of hot water with a temperature of about 3000 K is obtained using an oxy-acetylene torch. This spectrum contains a very large number of transitions. The spectrum, along with previous cooler laboratory emission spectra and an absorption spectrum recorded from a sunspot, is analyzed in the 500-2000 cm -1 region. Use of a calculated variational linelist for water allows significant progress to be made on assigning transitions involving highly excited vibrational and rotational states. In particular emission from rotationally excited states up to J=42 and vibrational levels with up to eight quanta of bending motion are assigned.
BibTeX: @article{Coheur2005, author = {Coheur, Pierre-François and Bernath, Peter F. and Carleer, Michel and Colin, Reginald and Polyansky, Oleg L. and Zobov, Nikolai F. and Shirin, Sergei V. and Barber, Robert J. and Tennyson, Jonathan}, title = {A 3000K laboratory emission spectrum of water}, journal = {Journal of Chemical Physics}, year = {2005}, volume = {122}, number = {7}, note = {All Open Access, Green Open Access}, doi = {10.1063/1.1847571} }
Depiesse C, Di Lonardo G, Fayt A, Fusina L, Hurtmans D, Robert S, Tamassia F, Vander Auwera J, Baldan A and Herman M (2005), "New combination bands in12C13CH2 around 0.83 μm recorded using FT-ICLAS", Journal of Molecular Spectroscopy. Vol. 229(1), pp. 137 – 139. [Abstract] [BibTeX] [DOI]
Abstract: Fourier-transform intracavity laser absorption spectroscopy allowed five 12C13CH2Σ+- Σ+ bands, all from the ground state, to be identified in the 0.83 μm range. Their rotational analysis was performed and rotational constants are provided. Three of these bands, with origins at 11616.9684(18), 11737.2356(14), and 11761.0322(23) cm-1, have never been reported before. Their upper states are assigned to V1V2V 3v4l4v5l5 = 1302 020, 130113-1, and 22011 1-1, respectively. © 2004 Elsevier Inc. All rights reserved.
BibTeX: @article{Depiesse2005137, author = {Depiesse, C. and Di Lonardo, G. and Fayt, A. and Fusina, L. and Hurtmans, D. and Robert, S. and Tamassia, F. and Vander Auwera, J. and Baldan, A. and Herman, M.}, title = {New combination bands in12C13CH2 around 0.83 μm recorded using FT-ICLAS}, journal = {Journal of Molecular Spectroscopy}, year = {2005}, volume = {229}, number = {1}, pages = {137 – 139}, doi = {10.1016/j.jms.2004.08.006} }
Forster PM, Burkholder J, Clerbaux C, Coheur P, Dutta M, Gohar L, Hurley M, Myhre G, Portmann R, Shine K, Wallington T and Wuebbles D (2005), "Resolution of the uncertainties in the radiative forcing of HFC-134a", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 93(4), pp. 447 – 460. [Abstract] [BibTeX] [DOI]
Abstract: HFC-134a (CF3CH2F) is the most rapidly growing hydrofluorocarbon in terms of atmospheric abundance. It is currently used in a large number of household refrigerators and air-conditioning systems and its concentration in the atmosphere is forecast to increase substantially over the next 50-100 years. Previous estimates of its radiative forcing per unit concentration have differed significantly ∼25%. This paper uses a two-step approach to resolve this discrepancy. In the first step six independent absorption cross section datasets are analysed. We find that, for the integrated cross section in the spectral bands that contribute most to the radiative forcing, the differences between the various datasets are typically smaller than 5% and that the dependence on pressure and temperature is not significant. A "recommended" HFC-134a infrared absorption spectrum was obtained based on the average band intensities of the strongest bands. In the second step, the "recommended" HFC-134a spectrum was used in six different radiative transfer models to calculate the HFC-134a radiative forcing efficiency. The clear-sky instantaneous radiative forcing, using a single global and annual mean profile, differed by 8%, between the 6 models, and the latitudinally-resolved adjusted cloudy sky radiative forcing estimates differed by a similar amount. We calculate that the radiative forcing efficiency of HFC-134a is 0.16 ± 0.02 Wm-2 ppbv-1. © 2004 Elsevier Ltd. All rights reserved.
BibTeX: @article{Forster2005447, author = {Forster, Piers M.De.F. and Burkholder, J.B. and Clerbaux, C. and Coheur, P.F. and Dutta, M. and Gohar, L.K. and Hurley, M.D. and Myhre, G. and Portmann, R.W. and Shine, K.P. and Wallington, T.J. and Wuebbles, D.}, title = {Resolution of the uncertainties in the radiative forcing of HFC-134a}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2005}, volume = {93}, number = {4}, pages = {447 – 460}, doi = {10.1016/j.jqsrt.2004.08.038} }
Herman M, Didriche K, Rizopoulos A and Hurtmans D (2005), "FT-jet spectroscopy: Vibrational energy transfer in N2O", Chemical Physics Letters. Vol. 414(4-6), pp. 282 – 286. [Abstract] [BibTeX] [DOI]
Abstract: A set-up combining a high resolution Fourier transform interferometer and a quadrupole mass spectrometer with a supersonic jet expansion produced thanks to a large turbomolecular pumping unit is described. A rotational temperature close to 3 K is demonstrated. Vibration-vibration energy transfer in the expansion affecting the v2 = 1 state in N2O is monitored in the presence of various collision partners. The transfer from the v 2 = 1 state of N2O towards the quasi resonant, lower energy v2 = 1 state of OCS is demonstrated, in particular. © 2005 Elsevier B.V. All rights reserved.
BibTeX: @article{Herman2005282, author = {Herman, M. and Didriche, K. and Rizopoulos, A. and Hurtmans, D.}, title = {FT-jet spectroscopy: Vibrational energy transfer in N2O}, journal = {Chemical Physics Letters}, year = {2005}, volume = {414}, number = {4-6}, pages = {282 – 286}, doi = {10.1016/j.cplett.2005.08.087} }
Jacquinet-Husson N, Scott N, Chédin A, Garceran K, Armante R, Chursin A, Barbe A, Birk M, Brown L, Camy-Peyret C, Claveau C, Clerbaux C, Coheur P, Dana V, Daumont L, Debacker-Barilly M, Flaud J, Goldman A, Hamdouni A, Hess M, Jacquemart D, Köpke P, Mandin J, Massie S, Mikhailenko S, Nemtchinov V, Nikitin A, Newnham D, Perrin A, Perevalov V, Régalia-Jarlot L, Rublev A, Schreier F, Schult I, Smith K, Tashkun S, Teffo J, Toth R, Tyuterev V, Vander Auwera J, Varanasi P and Wagner G (2005), "The 2003 edition of the GEISA/IASI spectroscopic database", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 95(4), pp. 429 – 467. [Abstract] [BibTeX] [DOI]
Abstract: The content of the current (2003) version, GEISA/IASI-03, of the computer-accessible spectroscopic database, GEISA/IASI, is described. This "system" or database is comprised of three independent spectroscopic archives, which are (a) a database of individual spectral line parameters on 14 molecules, H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, HNO3, OCS, C2H2, N2, and the related 51 isotopomers and isotopologues, representing 702,550 entries, in the spectral range 599-3001 cm-1, (b) a database of spectral absorption cross-sections (6,572,329 entries related to six molecules, CFC-11, CFC-12, CFC-14, HCFC-22, N2O5, CCl4), and a catalogue of microphysical and optical properties (mainly, the refractive indices) of atmospheric aerosols. The modifications and improvements, which have been implemented since the earlier editions of this database, in terms of content and management, have been explained in detail. GEISA/IASI has been created with the specific purpose of assessing the capability of measurement by the IASI instrument within the designated goals of ISSWG in the frame of the CNES/EUMETSAT European Polar System preparation. All the archived data can be handled through a user-friendly associated management software, which is posted on the ARA/LMD group web site at http://ara.lmd.polyechnique.fr. © 2005 Elsevier Ltd. All rights reserved.
BibTeX: @article{Jacquinet-Husson2005429, author = {Jacquinet-Husson, Nicole and Scott, N.A. and Chédin, A. and Garceran, K. and Armante, R. and Chursin, A.A. and Barbe, A. and Birk, M. and Brown, L.R. and Camy-Peyret, C. and Claveau, C. and Clerbaux, C. and Coheur, P.F. and Dana, V. and Daumont, L. and Debacker-Barilly, M.R. and Flaud, J.M. and Goldman, A. and Hamdouni, A. and Hess, M. and Jacquemart, D. and Köpke, P. and Mandin, J.Y. and Massie, S. and Mikhailenko, S. and Nemtchinov, V. and Nikitin, A. and Newnham, D. and Perrin, A. and Perevalov, V.I. and Régalia-Jarlot, L. and Rublev, A. and Schreier, F. and Schult, I. and Smith, K.M. and Tashkun, S.A. and Teffo, J.L. and Toth, R.A. and Tyuterev, Vl.G. and Vander Auwera, J. and Varanasi, P. and Wagner, G.}, title = {The 2003 edition of the GEISA/IASI spectroscopic database}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2005}, volume = {95}, number = {4}, pages = {429 – 467}, doi = {10.1016/j.jqsrt.2004.12.004} }
Mondelain D, Chelin P, Valentin A, Hurtmans D and Camy-Peyret C (2005), "Line profile study by diode laser spectroscopy in the 12CH 4 ν2 + ν4 band", Journal of Molecular Spectroscopy. Vol. 233(1), pp. 23 – 31. [Abstract] [BibTeX] [DOI]
Abstract: We present a complete study on four methane lines for two atmospheric micro-windows (in the ν2 + ν4 absorption band) used for the determination of atmospheric methane concentrations with ground-based Fourier transform spectrometers. Thanks to our tunable diode laser (TDL) spectrometer with active wavenumber control and step-by-step recording mode we have improved the accuracy on intensity, broadening, narrowing, and pressure shift parameters. To make our results directly useable in atmospheric models which usually assume a Voigt line shape, we have parameterised an effective-broadening parameter γVoigt (P) for each line and each gas mixture (CH4-N2 and CH4-O 2). When this parameterisation is used to fit a "true" line profile, the same concentration as with more sophisticated models is retrieved using a consistent set of spectroscopic parameters in both approaches. © 2005 Elsevier Inc. All rights reserved.
BibTeX: @article{Mondelain200523, author = {Mondelain, D. and Chelin, P. and Valentin, A. and Hurtmans, D. and Camy-Peyret, C.}, title = {Line profile study by diode laser spectroscopy in the 12CH 4 ν2 + ν4 band}, journal = {Journal of Molecular Spectroscopy}, year = {2005}, volume = {233}, number = {1}, pages = {23 – 31}, doi = {10.1016/j.jms.2005.05.012} }
Montecino V, Astoreca R, Alarcón G, Retamal L and Pizarro G (2005), "Erratum: Bio-optical characteristics and primary productivity during upwelling and non-upwelling conditions in a highly productive coastal ecosystem off central Chile (∼361S) (Deep-Sea Research II (2004) 51 (2413-2426) DOI: 10.1016/j.dsr2.2004.08.012)", Deep-Sea Research Part II: Topical Studies in Oceanography. Vol. 52(1-2 SPEC. ISS.), pp. 373 – 374. [BibTeX] [DOI]
BibTeX: @article{Montecino2005373, author = {Montecino, Vivian and Astoreca, Rosa and Alarcón, Gadiel and Retamal, Leira and Pizarro, Gemita}, title = {Erratum: Bio-optical characteristics and primary productivity during upwelling and non-upwelling conditions in a highly productive coastal ecosystem off central Chile (∼361S) (Deep-Sea Research II (2004) 51 (2413-2426) DOI: 10.1016/j.dsr2.2004.08.012)}, journal = {Deep-Sea Research Part II: Topical Studies in Oceanography}, year = {2005}, volume = {52}, number = {1-2 SPEC. ISS.}, pages = {373 – 374}, doi = {10.1016/j.dsr2.2005.02.001} }
Palmeri P, Fischer CF, Wyart J-F and Godefroid M (2005), "Oscillator strength calculations in neutral technetium", Monthly Notices of the Royal Astronomical Society. Vol. 363(2), pp. 452 – 458. [Abstract] [BibTeX] [DOI]
Abstract: Ab initio multiconfiguration calculations are performed for the oscillator strengths of the λ = 4238, 4262 and 4297 Å Tc I resonance lines of astrophysical interest. Electron correlation is treated through multiconfiguration expansions built from elaborate correlation models, while relativistic effects are introduced in the perturbation Breit-Pauli approximation or in the multiconfiguration Dirac-Fock-Breit variational approach. The calculated gf-values are sensitively lower (≈30 per cent) than the values obtained with the pseudo-relativistic Hartree-Fock wavefunctions calculated from a parametric analysis of Tc I by Palmeri & Wyart. The inclusion of a core-polarization potential in the latter approach confirms the present ab initio results when different ionic cores are used for the different transition arrays. The strong lines of Tc I are revisited adopting this model, giving rise to a systematic reduction in the oscillator strength scale due to core polarization. The astrophysical implications are discussed. © 2005 RAS.
BibTeX: @article{Palmeri2005452, author = {Palmeri, P. and Fischer, C. Froese and Wyart, J.-F. and Godefroid, M.R.}, title = {Oscillator strength calculations in neutral technetium}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {2005}, volume = {363}, number = {2}, pages = {452 – 458}, note = {All Open Access, Hybrid Gold Open Access}, doi = {10.1111/j.1365-2966.2005.09410.x} }
Robert S, Fayt A, Di Lonardo G, Fusina L, Tamassia F and Herman M (2005), "The vibrational energy pattern in acetylene VII: 12C 13CH 2 ", Journal of Chemical Physics. Vol. 123(17) [Abstract] [BibTeX] [DOI]
Abstract: In C12 C13 H2 129 vibrational term values up to 10 000 cm-1 are merged, about 60% of which are newly reported. They are fitted using an effective Hamiltonian with a standard deviation of 0.22 cm-1. The vibrational assignments and vibrational constants are listed and discussed. The energy pattern is found to be very similar to the one in C212 H2 with additional anharmonic resonances arising from the lack of ug character in the asymmetric isotopolog. © 2005 American Institute of Physics.
BibTeX: @article{Robert2005, author = {Robert, S. and Fayt, A. and Di Lonardo, G. and Fusina, L. and Tamassia, F. and Herman, M.}, title = {The vibrational energy pattern in acetylene VII: 12C 13CH 2 }, journal = {Journal of Chemical Physics}, year = {2005}, volume = {123}, number = {17}, doi = {10.1063/1.2056538} }
Rothman L, Jacquemart D, Barbe A, Benner DC, Birk M, Brown L, Carleer M, Chackerian Jr. C, Chance K, Coudert L, Dana V, Devi V, Flaud J-M, Gamache R, Goldman A, Hartmann J-M, Jucks K, Maki A, Mandin J-Y, Massie S, Orphal J, Perrin A, Rinsland C, Smith M, Tennyson J, Tolchenov R, Toth R, Vander Auwera J, Varanasi P and Wagner G (2005), "The HITRAN 2004 molecular spectroscopic database", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 96(2 SPEC. ISS.), pp. 139 – 204. [Abstract] [BibTeX] [DOI]
Abstract: This paper describes the status of the 2004 edition of the HITRAN molecular spectroscopic database. The HITRAN compilation consists of several components that serve as input for radiative transfer calculation codes: individual line parameters for the microwave through visible spectra of molecules in the gas phase; absorption cross-sections for molecules having dense spectral features, i.e., spectra in which the individual lines are unresolvable; individual line parameters and absorption cross-sections for bands in the ultra-violet; refractive indices of aerosols; tables and files of general properties associated with the database; and database management software. The line-by-line portion of the database contains spectroscopic parameters for 39 molecules including many of their isotopologues. The format of the section of the database on individual line parameters of HITRAN has undergone the most extensive enhancement in almost two decades. It now lists the Einstein A-coefficients, statistical weights of the upper and lower levels of the transitions, a better system for the representation of quantum identifications, and enhanced referencing and uncertainty codes. In addition, there is a provision for making corrections to the broadening of line transitions due to line mixing. © 2005 Elsevier Ltd. All rights reserved.
BibTeX: @article{Rothman2005139, author = {Rothman, L.S. and Jacquemart, D. and Barbe, A. and Benner, D. Chris and Birk, M. and Brown, L.R. and Carleer, M.R. and Chackerian Jr., C. and Chance, K. and Coudert, L.H. and Dana, V. and Devi, V.M. and Flaud, J.-M. and Gamache, R.R. and Goldman, A. and Hartmann, J.-M. and Jucks, K.W. and Maki, A.G. and Mandin, J.-Y. and Massie, S.T. and Orphal, J. and Perrin, A. and Rinsland, C.P. and Smith, M.A.H. and Tennyson, J. and Tolchenov, R.N. and Toth, R.A. and Vander Auwera, J. and Varanasi, P. and Wagner, G.}, title = {The HITRAN 2004 molecular spectroscopic database}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2005}, volume = {96}, number = {2 SPEC. ISS.}, pages = {139 – 204}, doi = {10.1016/j.jqsrt.2004.10.008} }
Schäfer K, Comerón A, Slusser JR, Picard RH, Carleer MR and Sifakis N (2005), "Proceedings of SPIE - The International Society for Optical Engineering: Introduction", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 5979, pp. xv. [BibTeX]
BibTeX: @conference{Schäfer2005xv, author = {Schäfer, Klaus and Comerón, Adolfo and Slusser, James R. and Picard, Richard H. and Carleer, Michel R. and Sifakis, Nicolaos}, title = {Proceedings of SPIE - The International Society for Optical Engineering: Introduction}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2005}, volume = {5979}, pages = {xv} }
Sutcliffe B (2005), "Permutational symmetry and molecular structure calculations", Collection of Czechoslovak Chemical Communications. Vol. 70(5), pp. 657 – 676. [Abstract] [BibTeX] [DOI]
Abstract: In a paper published in 1985 (Katriel J., Paldus J., Pauncz R.: Int. J. Quantum Chem. 1985, 28, 181) Paldus and his colleagues considered explicit relations between the permutational symmetry and the spin operators for systems of identical particles. The principal concern of this paper was with particles for which σ = 1/2 but there is some consideration of the case of particles for which σ = 1. This latter consideration was developed by Katriel (Katriel J.: J. Mol. Struct. (THEOCHEM) 2001, 547, 1) in a paper honouring Prof. Paldus on the occasion of his 65th birthday. The present paper attempts a consideration of aspects of permutational symmetry, not explicitly considered in those two papers, as they affect the interpretation of the results of molecular structure calculations.
BibTeX: @article{Sutcliffe2005657, author = {Sutcliffe, Brian}, title = {Permutational symmetry and molecular structure calculations}, journal = {Collection of Czechoslovak Chemical Communications}, year = {2005}, volume = {70}, number = {5}, pages = {657 – 676}, doi = {10.1135/cccc20050657} }
Sutcliffe B, Nakai H, Hoshino M, Miyamoto K and Hyodo S-A (2005), "Comment on "elimination of translational and rotational motions in nuclear orbital plus molecular orbital theory" [J. Chem. Phys. 122, 164101 (2005)]", Journal of Chemical Physics. Vol. 123(23) [Abstract] [BibTeX] [DOI]
Abstract: In moving-nuclei calculations on some simple diatomics and on water, Nakai [J. Chem. Phys.122, 164101 (2005)] extend their earlier translation-free nuclear orbital plus molecular orbital (TF-NOMO) theory, in which the translational part of the Hamiltonian is subtracted from the full Hamiltonian, to a translation- and rotation-free approach, in which a rotational term is subtracted from the TF-NOMO Hamiltonian. It is suggested that the chosen rotational term is not unique and is not valid over all regions of space. © 2005 American Institute of Physics.
BibTeX: @article{Sutcliffe2005, author = {Sutcliffe, Brian and Nakai, Hiromi and Hoshino, Minoru and Miyamoto, Kaito and Hyodo, Shi-Aki}, title = {Comment on "elimination of translational and rotational motions in nuclear orbital plus molecular orbital theory" [J. Chem. Phys. 122, 164101 (2005)]}, journal = {Journal of Chemical Physics}, year = {2005}, volume = {123}, number = {23}, doi = {10.1063/1.2134699} }
Sutcliffe B and Woolley RG (2005), "Comment on 'Molecular structure in non-Born-Oppenheimer quantum mechanics'", Chemical Physics Letters. Vol. 408(4-6), pp. 445 – 447. [Abstract] [BibTeX] [DOI]
Abstract: A recent Letter has proposed a method for obtaining molecular structures of small polyatomic molecules without recourse to the Born-Oppenheimer approximation. In this Comment we highlight the difficulties in the proposed strategy when identifying molecular structures in general. © 2005 Elsevier B.V. All rights reserved.
BibTeX: @article{Sutcliffe2005445, author = {Sutcliffe, B.T. and Woolley, R. Guy}, title = {Comment on 'Molecular structure in non-Born-Oppenheimer quantum mechanics'}, journal = {Chemical Physics Letters}, year = {2005}, volume = {408}, number = {4-6}, pages = {445 – 447}, doi = {10.1016/j.cplett.2005.04.022} }
Sutcliffe BT (2005), "Victor Ronald Saunders: Upon his retirement from Daresbury Lab", Molecular Physics. Vol. 103(18), pp. 2461 – 2463. [BibTeX] [DOI]
BibTeX: @article{Sutcliffe20052461, author = {Sutcliffe, Brian T.}, title = {Victor Ronald Saunders: Upon his retirement from Daresbury Lab}, journal = {Molecular Physics}, year = {2005}, volume = {103}, number = {18}, pages = {2461 – 2463}, doi = {10.1080/00268970500178802} }
Sutcliffe BT and Woolley RG (2005), "Molecular structure calculations without clamping the nuclei", Physical Chemistry Chemical Physics. Vol. 7(21), pp. 3664 – 3676. [Abstract] [BibTeX] [DOI]
Abstract: A number of recent papers have considered ways in which molecular structure may be calculated when both the electrons and the nuclei are treated from the outset as quantum particles. This is in contrast to the conventional approach in which the nuclei initially have their positions fixed and so merely provide a potential for electronic motion. The usual approach is generally assumed to be justified by the 1927 work of Born and Oppenheimer. In this paper we discuss what precisely might be anticipated in the way of molecular structure from a mathematical consideration of the spectral properties of the full Coulomb Hamiltonian, to what extent the very idea of molecular structure might be dependent upon treating the nuclei simply as providing a potential and the extent to which the work of Born and Oppenheimer can be used to support this position. © The Owner Societies 2005.
BibTeX: @article{Sutcliffe20053664, author = {Sutcliffe, Brian T. and Woolley, R. Guy}, title = {Molecular structure calculations without clamping the nuclei}, journal = {Physical Chemistry Chemical Physics}, year = {2005}, volume = {7}, number = {21}, pages = {3664 – 3676}, doi = {10.1039/b509723c} }
Tolchenov RN, Naumenko O, Zobov NF, Shirin SV, Polyansky OL, Tennyson J, Carleer M, Coheur P-F, Fally S, Jenouvrier A and Vandaele AC (2005), "Water vapour line assignments in the 9250-26 000 cm-1 frequency range", Journal of Molecular Spectroscopy. Vol. 233(1), pp. 68 – 76. [Abstract] [BibTeX] [DOI]
Abstract: Line parameters for water vapour in natural abundance have recently been determined for the 9250-13 000 cm-1 region [M.-F. Mérienne, A. Jenouvrier, C. Hermans, A.C. Vandaele, M. Carleer, C. Clerbaux, P.-F. Coheur, R. Colin, S. Fally, M. Bach, J. Quant. Spectrosc. Radiat. Transfer 82 (2003) 99] and the 13 000-26 000 cm-1 region [P.-F. Coheur, S. Fally, M. Carleer, C. Clerbaux, R. Colin, A. Jenouvrier, M.-F. Mérienne, C. Hermans, A.C. Vandaele, J. Quant. Spectrosc. Radiat. Transfer 74 (2002) 493] using a high-resolution Fourier-transform spectrometer with a long-path absorption cell. These spectra are analysed using several techniques including variational line lists and assignments made. In total, over 15 000 lines were assigned to transitions involving more than 150 exited vibrational states of H216O. Twelve new vibrational band origins are determined and estimates for a further 16 are presented. © 2005 Elsevier Inc. All rights reserved.
BibTeX: @article{Tolchenov200568, author = {Tolchenov, Roman N. and Naumenko, Olga and Zobov, Nikolai F. and Shirin, Sergei V. and Polyansky, Oleg L. and Tennyson, Jonathan and Carleer, Michel and Coheur, Pierre-François and Fally, Sophie and Jenouvrier, Alain and Vandaele, Ann Carine}, title = {Water vapour line assignments in the 9250-26 000 cm-1 frequency range}, journal = {Journal of Molecular Spectroscopy}, year = {2005}, volume = {233}, number = {1}, pages = {68 – 76}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.jms.2005.05.015} }
Vander Auwera J (2005), "Quantitative laboratory spectroscopy of atmospheric trace gases", NATO Security through Science Series C: Environmental Security. , pp. 123 – 137. [Abstract] [BibTeX]
Abstract: The analysis of spectra of the terrestrial atmosphere recorded using remote sensing techniques requires reference spectroscopic information, measured in the laboratory. This article describes laboratory measurements of reference absolute absorption intensities for atmospheric trace species using Fourier transform spectroscopy in the infrared spectral range. Emphasis is put on measurements of quantitative information for chemically unstable species. © 2006 Springer.
BibTeX: @article{VanderAuwera2005123, author = {Vander Auwera, Jean}, title = {Quantitative laboratory spectroscopy of atmospheric trace gases}, journal = {NATO Security through Science Series C: Environmental Security}, year = {2005}, pages = {123 – 137} }
Zobov NF, Shirin SV, Polyansky OL, Tennyson J, Coheur P-F, Bernath PF, Carleer M and Colin R (2005), "Monodromy in the water molecule", Chemical Physics Letters. Vol. 414(1-3), pp. 193 – 197. [Abstract] [BibTeX] [DOI]
Abstract: The change in the energy level structure of a bent molecule as it starts to sample linear geometries has been discussed in terms of monodromy found in simple two-dimensional model problems. Infrared spectra of hot (T ∼ 3000 K) water are analysed for transitions involving states with high bending excitation which can sample linear HOH geometries. One hundred and thirty four new experimental energy levels are determined for bending states with 5 ≤ v 2≤9 including band origins for 7ν2, 8ν2 and 9ν2. Plots of those levels with J = K a show the characteristic rearrangement of energy levels predicted for a system displaying quantum monodromy. Quantum monodromy for water occurs about the ν2 = 7, J = 0 level. The barrier to linearity in H 216O is estimated to lie at 11 114 ± 5 cm -1. © 2005 Elsevier B.V. All rights reserved.
BibTeX: @article{Zobov2005193, author = {Zobov, Nikolai F. and Shirin, Sergei V. and Polyansky, Oleg L. and Tennyson, Jonathan and Coheur, Pierre-François and Bernath, Peter F. and Carleer, Michel and Colin, Reginald}, title = {Monodromy in the water molecule}, journal = {Chemical Physics Letters}, year = {2005}, volume = {414}, number = {1-3}, pages = {193 – 197}, note = {All Open Access, Green Open Access}, doi = {10.1016/j.cplett.2005.08.028} }
Borgoo A, Godefroid M, Sen K, De Proft F and Geerlings P (2004), "Quantum similarity of atoms: A numerical Hartree-Fock and Information Theory approach", Chemical Physics Letters. Vol. 399(4-6), pp. 363 – 367. [Abstract] [BibTeX] [DOI]
Abstract: In this Letter Quantum Similarity for Atoms (H-Xe) is investigated using electron densities and shape functions, looking for patterns of periodicity as in Mendeleev's Table. An LS-dependent restricted Hartree-Fock method is used to obtain the wave functions from which the electron densities are calculated. Utilizing the quantum similarity proposed by Carbó a nearest neighbour dominated similarity is retrieved, masking periodicity. Introduction of the information discrimination concept with reference to the noble gas atom of the previous row is found to reveal periodicity, with improved results when densities are replaced by shape functions throughout. This confirms recent literature on the fundamental role of the shape function as carrier of information. © 2004 Elsevier B.V. All rights reserved.
BibTeX: @article{Borgoo2004363, author = {Borgoo, A. and Godefroid, M. and Sen, K.D. and De Proft, F. and Geerlings, P.}, title = {Quantum similarity of atoms: A numerical Hartree-Fock and Information Theory approach}, journal = {Chemical Physics Letters}, year = {2004}, volume = {399}, number = {4-6}, pages = {363 – 367}, doi = {10.1016/j.cplett.2004.10.026} }
Clerbaux C, Gille J and Edwards D (2004), "New Directions: Infrared measurements of atmospheric pollution from space", Atmospheric Environment. Vol. 38(27), pp. 4599 – 4601. [BibTeX] [DOI]
BibTeX: @article{Clerbaux20044599, author = {Clerbaux, Cathy and Gille, John and Edwards, David}, title = {New Directions: Infrared measurements of atmospheric pollution from space}, journal = {Atmospheric Environment}, year = {2004}, volume = {38}, number = {27}, pages = {4599 – 4601}, doi = {10.1016/j.atmosenv.2004.05.005} }
Dufour G, Valentin A, Henry A, Hurtmans D and Camy-Peyret C (2004), "Concentration measurements of ozone in the 1200-300 ppbv range: An intercomparison between the BNM ultraviolet standard and infrared methods", Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy. Vol. 60(14), pp. 3345 – 3352. [Abstract] [BibTeX] [DOI]
Abstract: Simultaneous ultraviolet (UV) and infrared (IR) measurements of ozone concentration in air in the 1200-300 ppbv range have been performed using the ultraviolet absorption in the Hartley band at 0.2537 μm and the infrared absorption of a doublet at 9.507 μm in the ν3 vibration-rotation band. Infrared concentration measurements were achieved using the tunable diode laser spectrometer of LPMA in Paris with interferometric control of the emitted wavelength while the UV concentration measurements were performed with the 49PS Megatec ozone generator of the Bureau National de Métrologie (BNM). The simultaneous recording of spectra of a reference cell filled with pure distilled ozone and of a low concentration mixture inside a long absorbing path Herriott cell allows to carry out infrared concentration measurements with an accuracy of the same order as the ultraviolet ones and provides the instrumental parameters of the spectrometer corresponding to each concentration measurement, which reduces systematic errors. Within the respective absolute uncertainties proper to the two techniques, no systematic discrepancy was evidenced between the IR and the UV measurements. The ozone ultraviolet absorption coefficient value determined by Hearn (308.3±4 cm-1 atm-1) and used by the BNM and the National Institute of Standards and Technology (NIST) is confirmed by the present work. © 2004 Elsevier B.V. All rights reserved.
BibTeX: @article{Dufour20043345, author = {Dufour, Gaëlic and Valentin, Alain and Henry, Annie and Hurtmans, Daniel and Camy-Peyret, Claude}, title = {Concentration measurements of ozone in the 1200-300 ppbv range: An intercomparison between the BNM ultraviolet standard and infrared methods}, journal = {Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy}, year = {2004}, volume = {60}, number = {14}, pages = {3345 – 3352}, doi = {10.1016/j.saa.2003.12.056} }
Georges R, Freytes M, Hurtmans D, Kleiner I, Vander Auwera J and Herman M (2004), "Jet-cooled and room temperature FTIR spectra of the dimer of formic acid in the gas phase", Chemical Physics. Vol. 305(1-3), pp. 187 – 196. [Abstract] [BibTeX] [DOI]
Abstract: Room temperature absorption spectra of the gaseous (C2h) dimer of formic acid were recorded from the lowest energy fundamental, ν16, with origin at 69.2 cm-1, up to the CH overtone bands with Δv=4, with origin at 11,103 cm-1, using a high resolution Fourier transform interferometer. These spectra are complemented with liquid phase data in the NIR region. In addition, jet-cooled spectra were recorded over the range 1850-3750 cm-1. The origin of the many observed bands is listed, together with relative intensities for those recorded under jet-cooled conditions. Systematic problems encountered with vibrational assignments for bands other than fundamentals are highlighted and, as a rule, left unsolved except for the bands at 167.26 and 2586.34 cm-1 tentatively assigned to ν15+ν16-ν16 and ν5+ν22 or ν6+ν21, respectively. For the first, FIR band the assignment is supported by partly unravelling the hot band pattern around ν15 at 168.47 cm -1. The jet-cooled rotational contour of the second, MIR band was simulated, allowing the rotational temperature in the jet to be estimated to 35 K. © 2004 Elsevier B.V. All rights reserved.
BibTeX: @article{Georges2004187, author = {Georges, R. and Freytes, M. and Hurtmans, D. and Kleiner, I. and Vander Auwera, J. and Herman, M.}, title = {Jet-cooled and room temperature FTIR spectra of the dimer of formic acid in the gas phase}, journal = {Chemical Physics}, year = {2004}, volume = {305}, number = {1-3}, pages = {187 – 196}, doi = {10.1016/j.chemphys.2004.06.027} }
Herman M, Depiesse C, Di Lonardo G, Fayt A, Fusina L, Hurtmans D, Kassi S, Mollabashi M and Vander Auwera J (2004), "The vibration-rotation spectrum of 12C2HD: New overtone bands and global vibrational analysis", Journal of Molecular Spectroscopy. Vol. 228(2 SPEC. ISS.), pp. 499 – 510. [Abstract] [BibTeX] [DOI]
Abstract: Two new bands, 2ν1+ν2+ν 3+2ν5 and 5ν3 with origin at 12220.692 and 12496.158cm-1, respectively, were identified on new FT-ICLAS spectra of 12C2HD and rotationally analyzed. The rotational analysis of two known bands, with origin at 12038.538 and 12234.872cm-1 was extended. Another band, 2ν 1+2ν5 with origin at 7843.6622cm-1, was identified for the first time and rotationally analyzed, from a high pressure conventional FT spectrum. Some 115 known vibrational state energies in the molecule, extending up to the visible range, were used to produce updated vibrational constants. Both a straightforward Dunham model and a global model accounting for a single anharmonic resonance, K1/255, were used. The results are discussed. © 2004 Elsevier Inc. All rights reserved.
BibTeX: @article{Herman2004499, author = {Herman, M. and Depiesse, C. and Di Lonardo, G. and Fayt, A. and Fusina, L. and Hurtmans, D. and Kassi, S. and Mollabashi, M. and Vander Auwera, J.}, title = {The vibration-rotation spectrum of 12C2HD: New overtone bands and global vibrational analysis}, journal = {Journal of Molecular Spectroscopy}, year = {2004}, volume = {228}, number = {2 SPEC. ISS.}, pages = {499 – 510}, doi = {10.1016/j.jms.2004.05.005} }
Lasorne B, Bacchus-Montabonel M-C, Vaeck N and Desouter-Lecomte M (2004), "Nonadiabatic interactions in wave packet dynamics of the bromoacetyl chloride photodissociation", Journal of Chemical Physics. Vol. 120(3), pp. 1271 – 1278. [Abstract] [BibTeX] [DOI]
Abstract: Wave packet simulations have shown that the preferential breaking of the C-Cl bond versus the weaker C-Br one can be explained by nonadiabatic interactions at avoided crossings in both C-O/C-Br and C-O/C-Cl subspaces leading to a stronger trapping of the C-Br population. However, the branching ratio obtained by propagating wave packets in the two 2D subspaces was very satisfactory and permits not to discard this explanation. It was found that the results were in better agreement with the experimental branching ratio in 2D than in 1D.
BibTeX: @article{Lasorne20041271, author = {Lasorne, B. and Bacchus-Montabonel, M.-C. and Vaeck, N. and Desouter-Lecomte, M.}, title = {Nonadiabatic interactions in wave packet dynamics of the bromoacetyl chloride photodissociation}, journal = {Journal of Chemical Physics}, year = {2004}, volume = {120}, number = {3}, pages = {1271 – 1278}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.1633759} }
Montecino V, Astoreca R, Alarcón G, Retamal L and Pizarro G (2004), "Bio-optical characteristics and primary productivity during upwelling and non-upwelling conditions in a highly productive coastal ecosystem off central Chile (∼36°S)", Deep-Sea Research Part II: Topical Studies in Oceanography. Vol. 51(20-21), pp. 2413 – 2426. [Abstract] [BibTeX] [DOI]
Abstract: Variability of several bio-optical and photosynthetic properties of phytoplankton in the highly productive coast off Concepción, central Chile (∼36°S) was quantified during contrasting seasons at offshore, shelf, and nearshore sites. During October 1998 (upwelling) and July 1999 (non-upwelling), 21 stations were sampled for chlorophyll-a, pigment spectral light absorption, primary production, and attenuation coefficients (kλ) of downwelling irradiance (Ed(λ)); kλ was used to estimate the depth of the euphotic zone (Zeu). Primary production was measured through 14C-fixation experiments using simulated in situ and in situ incubations with water from six depths within the Zeu. The photosynthetic parameters (αB, PBmax) were obtained through photosynthesis-irradiance experiments with samples from two Zeu depths. Bio-optical properties showed large spatial variability during both seasons, including spectral in vivo phytoplankton absorption (aph(λ)), pigment specific phytoplankton absorption (a(λ)) within the upper 25 m, and water-column transmittance (T(λ)), calculated for the upper 10 m using Ed(λ) at four wavelengths. Under non-upwelling conditions, a(λ), T(λ), and αB presented higher values whereas a ph(λ) values decreased accordingly. Under upwelling conditions, primary productivity ranged from 0.7 to 7.5 g C m-2 d-1 at the coastal stations and was <0.6 g C m-2 d -1 at the oceanic stations; in the non-upwelling season, values over the entire area ranged from 0.2 to 1.9 g C m-2 d-1. The significant correlations found among bio-optical properties and physiological parameters highlight both the short- and long-term changes in the area's environmental conditions. The combination of three independent biological parameters - αB, PBmax, and a ph(442) - accounted for most of the horizontal and vertical variability among and within stations for each cruise. These results support a distinction of different functional zones for the two contrasting upwelling conditions. © 2004 Elsevier Ltd. All rights reserved.
BibTeX: @article{Montecino20042413, author = {Montecino, Vivian and Astoreca, Rosa and Alarcón, Gadiel and Retamal, Leira and Pizarro, Gemita}, title = {Bio-optical characteristics and primary productivity during upwelling and non-upwelling conditions in a highly productive coastal ecosystem off central Chile (∼36°S)}, journal = {Deep-Sea Research Part II: Topical Studies in Oceanography}, year = {2004}, volume = {51}, number = {20-21}, pages = {2413 – 2426}, doi = {10.1016/j.dsr2.2004.08.012} }
Nemouchi M, Taleb A and Godefroid M (2004), "Isotope shift in the electron affinity of beryllium", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 37(4), pp. 865 – 874. [Abstract] [BibTeX] [DOI]
Abstract: The study of the isotope shift in the electron affinity is interesting for probing correlation effects. Experiments that allow this property to be measured are rare, being difficult to realize, while accurate calculations remain a challenge for atomic theory. The present work focuses on the theoretical estimation of the isotope shift in the electron affinity of Be (2s2p 3Po), using correlated electronic wavefunctions obtained from multiconfiguration Hartree-Fock and configuration interaction variational calculations. The reliability of the correlation models is assessed from a comparison between the observed and theoretical electron affinities, and between theoretical isotope shift values for the 2s2p 3P o-2s2 1S transition of neutral beryllium. The sign and the magnitude of the difference between the mass polarization term expectation values obtained for the neutral atom and the negative ion are such that the resulting irsotope shift in the electron affinity is 'anomalous', corresponding to a smaller electron affinity for the heavier isotope.
BibTeX: @article{Nemouchi2004865, author = {Nemouchi, M. and Taleb, A. and Godefroid, M.}, title = {Isotope shift in the electron affinity of beryllium}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2004}, volume = {37}, number = {4}, pages = {865 – 874}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/37/4/013} }
Ram R, Rinskopf N, Liévin J and Bernath P (2004), "Fourier transform emission spectroscopy and ab initio calculations on NbCl", Journal of Molecular Spectroscopy. Vol. 228(2 SPEC. ISS.), pp. 544 – 553. [Abstract] [BibTeX] [DOI]
Abstract: The emission spectrum of NbCl has been recorded in the 3000-20000cm -1 region using a Fourier transform spectrometer. The bands were observed by microwave excitation of a mixture of NbCl5 vapor and He. Two groups of bands observed in the 6500-7000cm-1 and 9800-11000cm-1 regions have been assigned to two electronic transitions. Five bands observed in the 6500-7000cm-1 region consist of R, P, and Q branches with no combination defect or Λ-doubling. They have been assigned as five sub-bands of a ΔΛ=±1 transition with Λ1. Nine bands observed in the 9800-11000cm-1 regions consist of R and P branches, and they are also free from Λ-doubling. These bands have been classified into four sub-bands of a ΔΛ=0 transition (with Λ1), which has tentatively been assigned as 5Δ-5Δ. The two transitions have no electronic states in common. Ab initio calculations have been performed on NbCl and the spectroscopic properties of the low-lying electronic states have been calculated. The ground state of NbCl has been predicted to be a 5Π state arising from the 3σ1 1δ 2 2π1 configuration, with a low-lying 5Δ state at 1300cm-1 from the 3σ1 1δ1 2π2 configuration. The results of our experimental and theoretical studies will be presented. This work represents the first experimental investigation of the spectra of NbCl and the first ab initio prediction of the spectroscopic properties of the low-lying electronic states. © 2004 Elsevier Inc. All rights reserved.
BibTeX: @article{Ram2004544, author = {Ram, R.S. and Rinskopf, N. and Liévin, J. and Bernath, P.F.}, title = {Fourier transform emission spectroscopy and ab initio calculations on NbCl}, journal = {Journal of Molecular Spectroscopy}, year = {2004}, volume = {228}, number = {2 SPEC. ISS.}, pages = {544 – 553}, doi = {10.1016/j.jms.2004.02.001} }
Schäfer K, Comerón A, Picard RH, Carleer MR and Sifakis NI (2004), "Proceedings of SPIE - The International Society for Optical Engineering: Introduction", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 5571, pp. xi. [BibTeX]
BibTeX: @conference{Schäfer2004xi, author = {Schäfer, Klaus and Comerón, Adolfo and Picard, Richard H. and Carleer, Michel R. and Sifakis, Nicolaos I.}, title = {Proceedings of SPIE - The International Society for Optical Engineering: Introduction}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2004}, volume = {5571}, pages = {xi} }
Schäfer KP, Comerón A, Picard RH and Carleer MR (2004), "Proceeding of SPIE - The International Society for Optical Engineering: Introduction", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 5235, pp. xiii. [BibTeX]
BibTeX: @conference{Schäfer2004xiii, author = {Schäfer, Klaus P. and Comerón, Adolfo and Picard, Richard H. and Carleer, Michel R.}, title = {Proceeding of SPIE - The International Society for Optical Engineering: Introduction}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2004}, volume = {5235}, pages = {xiii} }
Timmermans B, Hubin A, Vaeck N and Reniers F (2004), "Experimental and theoretical study of CVV Auger peaks of selected aluminium and carbon compounds", Surface and Interface Analysis. Vol. 36(8), pp. 798 – 800. [Abstract] [BibTeX] [DOI]
Abstract: The Auger valence peak of Al2O3, Al and carbon compounds (graphite, fullerene, carbides) has been studied experimentally and theoretically. It is demonstrated, from a comparison of the experimental spectrum with the self-convolution of the valence band, that the Al CVV transition in Al2O3 is an intra-atomic transition. The behaviour of the C KVV Auger peak is shown to be intermediate between atomic and band-like transitions. The different experimental carbide peaks could be reconstructed by a self-convolution of the valence band and the introduction of a hole-hole repulsion term extracted from the Cini-Sawatzki equation. A non-expected behaviour of the satellite peak at 280 eV for tungsten and chromium carbide is shown and interpreted, with a comparison with the Ramaker approach. Copyright © 2004 John Wiley & Sons, Ltd.
BibTeX: @article{Timmermans2004798, author = {Timmermans, B. and Hubin, A. and Vaeck, N. and Reniers, F.}, title = {Experimental and theoretical study of CVV Auger peaks of selected aluminium and carbon compounds}, journal = {Surface and Interface Analysis}, year = {2004}, volume = {36}, number = {8}, pages = {798 – 800}, doi = {10.1002/sia.1767} }
Turquety S, Hadji-Lazaro J, Clerbaux C, Hauglustaine D, Clough S, Cassé V, Schlüssel P and Mégie G (2004), "Operational trace gas retrieval algorithm for the Infrared Atmospheric Sounding Interferometer", Journal of Geophysical Research D: Atmospheres. Vol. 109(21), pp. D21301 1–19. [Abstract] [BibTeX] [DOI]
Abstract: The Infrared Atmospheric Sounding Interferometer (IASI) is a nadir-viewing remote sensor due for launch on board the European Metop satellites (to be launched in 2005, 2010, and 2015). It is dedicated to the study of the troposphere and the lower stratosphere to support operational meteorology as well as atmospheric chemistry and climate studies. For this purpose, it will record high resolution atmospheric spectra in the thermal infrared, allowing the measurement of several infrared absorbing species. This paper describes the clear-sky retrieval scheme developed in the framework of the preparation of the IASI mission for the operational, near real time, retrieval Of O3, CH 4, and CO concentrations. It includes the inversion module, based on a neural network approach, as well as an error analysis module. The studies undertaken on test simulations have shown that a performance of the order of 1.5%, 2%, and 5% for the retrieval of total columns Of O3, CH4, and CO, respectively, can be achieved, and of the order of 28%, 15%, and 9% for the retrieval of partial columns Of O3 between the surface and 6, 12, and 16 km high, respectively. The efficiency of the algorithm is demonstrated on the atmospheric measurements provided by the Interferometric Monitor for Greenhouse Gases (IMG)/ADEOS, allowing to obtain the first remote-sensing simultaneous distributions of ozone and its two precursors, CO and CH4. Copyright 2004 by the American Geophysical Union.
BibTeX: @article{Turquety2004D213011, author = {Turquety, S. and Hadji-Lazaro, J. and Clerbaux, C. and Hauglustaine, D.A. and Clough, S.A. and Cassé, V. and Schlüssel, P. and Mégie, G.}, title = {Operational trace gas retrieval algorithm for the Infrared Atmospheric Sounding Interferometer}, journal = {Journal of Geophysical Research D: Atmospheres}, year = {2004}, volume = {109}, number = {21}, pages = {D21301 1–19}, note = {All Open Access, Green Open Access}, doi = {10.1029/2004JD004821} }
Vaeck N and Godefroid M (2004), "Physica Script T: Preface", Physica Scripta T. Vol. T112, pp. 5. [BibTeX] [DOI]
BibTeX: @conference{Vaeck20045, author = {Vaeck, Nathalie and Godefroid, Michel}, title = {Physica Script T: Preface}, journal = {Physica Scripta T}, year = {2004}, volume = {T112}, pages = {5}, doi = {10.1238/Physica.Topical.112a00005} }
Valentin A, Henry A, Claveau C, Camy-Peyret C, Hurtmans D and Mantz A (2004), "Development of a stabilized low temperature infrared absorption cell for use in low temperature and collisional cooling experiments", Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy. Vol. 60(14), pp. 3477 – 3482. [Abstract] [BibTeX] [DOI]
Abstract: We have constructed a stabilized low temperature infrared absorption cell cooled by an open cycle refrigerator, which can run with liquid nitrogen from 250 to 80 K or with liquid helium from 80 K to a few kelvin. Several CO infrared spectra were recorded at low temperature using a tunable diode laser spectrometer. These spectra were analyzed taking into account the detailed effects of collisions on the line profile when the pressure increases. We also recorded spectra at very low pressure to accurately model the diode laser emission. Spectra of the R(2) line in the fundamental band of 13CO cooled by collisions with helium buffer gas at 10.5 K and at pressures near 1 Torr have been recorded. The He-pressure broadening parameter (γ0 = 0.3 cm-1 atm-1) has been derived from the simultaneous analysis of four spectra at different pressures. © 2004 Elsevier B.V. All rights reserved.
BibTeX: @article{Valentin20043477, author = {Valentin, A. and Henry, A. and Claveau, C. and Camy-Peyret, C. and Hurtmans, D. and Mantz, A.W.}, title = {Development of a stabilized low temperature infrared absorption cell for use in low temperature and collisional cooling experiments}, journal = {Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy}, year = {2004}, volume = {60}, number = {14}, pages = {3477 – 3482}, doi = {10.1016/j.saa.2003.12.058} }
Valentin A, Henry A, Claveau C, Hurtmans D and Mantz A (2004), "Line profile study down to 80 K of R(7) in the13CO (1-0) band perturbed by Ar and13CO collisional cooling with he at 6.9 K", Molecular Physics. Vol. 102(16-17), pp. 1793 – 1802. [Abstract] [BibTeX] [DOI]
Abstract: We present a line profile study at 150, 110 and 80 K for the R(7) line in the fundamental band of 13CO perturbed by Ar in a new stabilized low-temperature cell cooled by liquid nitrogen. The broadening, shifting and narrowing parameters are determined taking into account the absorber speed dependence by simultaneous least-squares fitting of spectra over a 4-300 Torr pressure range recorded using a frequency-stabilized diode laser spectrometer. When the cell is cooled by liquid helium the (1-0) R(2) line of 13CO in collision with helium is observed at a temperature of 6.9 K.
BibTeX: @article{Valentin20041793, author = {Valentin, A. and Henry, A. and Claveau, C. and Hurtmans, D. and Mantz, A.W.}, title = {Line profile study down to 80 K of R(7) in the13CO (1-0) band perturbed by Ar and13CO collisional cooling with he at 6.9 K}, journal = {Molecular Physics}, year = {2004}, volume = {102}, number = {16-17}, pages = {1793 – 1802}, doi = {10.1080/00268970412331287007} }
Bacchus-Montabonel M-C, Vaeck N, Lasorne B and Desouter-Lecomte M (2003), "Non-adiabatic effects in the photodissociation of bromoacetyl chloride", Chemical Physics Letters. Vol. 374(3-4), pp. 307 – 313. [Abstract] [BibTeX] [DOI]
Abstract: The competitive photodissociation of bromoacetyl chloride has been investigated by means of ab initio methods. Quantum dynamics in full dimensionality is prohibitive for such a system and therefore a reduced dimensionality method based on constrained Hamiltonians has been used. A one-dimensional (1-D) non-adiabatic wave packet treatment in the CS optimized geometry (trans Cl and Br) on the first excited states leads to encouraging results when compared to experimental data. The slow relaxation of the torsion angle is assessed by a 2-D dynamics in the subspace including the C=O bond length. © 2003 Elsevier Science B.V. All rights reserved.
BibTeX: @article{Bacchus-Montabonel2003307, author = {Bacchus-Montabonel, Marie-Christine and Vaeck, Nathalie and Lasorne, Benjamin and Desouter-Lecomte, Michèle}, title = {Non-adiabatic effects in the photodissociation of bromoacetyl chloride}, journal = {Chemical Physics Letters}, year = {2003}, volume = {374}, number = {3-4}, pages = {307 – 313}, doi = {10.1016/S0009-2614(03)00606-7} }
Blanchet V, Boyé S, Zamith S, Campos A, Girard B, Liévin J and Gauyacq D (2003), "(3+1)-resonantly enhanced multiphoton ionization-photoelectron spectroscopy of the (3d-4s) supercomplex of acetylene: The geometry of the E state revisited through experiment and theory", Journal of Chemical Physics. Vol. 119(7), pp. 3751 – 3762. [Abstract] [BibTeX] [DOI]
Abstract: A study was performed on the (3 + 1)-resonantly enhanced multiphoton ionization-photoelectron spectroscopy of the (3d-4s) supercomplex of acetylene. The Renner-Teller coupling occurring in the ion ground state was considered during the photoelectron analysis. The results showed the tentative frequencies for the stretching mode as well as for the bending mode.
BibTeX: @article{Blanchet20033751, author = {Blanchet, Valérie and Boyé, Séverine and Zamith, Sébastien and Campos, Andréa and Girard, Bertrand and Liévin, Jacques and Gauyacq, Dolores}, title = {(3+1)-resonantly enhanced multiphoton ionization-photoelectron spectroscopy of the (3d-4s) supercomplex of acetylene: The geometry of the E state revisited through experiment and theory}, journal = {Journal of Chemical Physics}, year = {2003}, volume = {119}, number = {7}, pages = {3751 – 3762}, doi = {10.1063/1.1589480} }
Cassam-Chenaï P and Liévin J (2003), "Alternative perturbation method for the molecular vibration-rotation problem", International Journal of Quantum Chemistry. Vol. 93(3), pp. 245 – 264. [Abstract] [BibTeX] [DOI]
Abstract: This article introduces an alternative perturbation scheme to find approximate solutions of the spectral problem for the rotation-vibration molecular Hamiltonian. The method is implemented for the Watson Hamiltonian and applied to methane. The complete J = 0 spectrum of this penta-atomic molecule of atmospheric interest is calculated up to 9200 cm-1 in a purely ab initio fashion. Then, the rotational spectra of the vibrational ground state is obtained up to J = 18. The largest relative error is 2.10-5 (for the highest J = 18 level) after scaling of a single parameter. Without scaling the accuracy on the rotational levels is limited by that of the ab initio equilibrium bond distance. The convergence of our results is analyzed with respect to the different parameters involved in our approach. The important concept of vibrational mean-field configuration interaction is introduced.
BibTeX: @article{Cassam-Chenaï2003245, author = {Cassam-Chenaï, P. and Liévin, J.}, title = {Alternative perturbation method for the molecular vibration-rotation problem}, journal = {International Journal of Quantum Chemistry}, year = {2003}, volume = {93}, number = {3}, pages = {245 – 264}, doi = {10.1002/qua.10556} }
Chédin A, Saunders R, Hollingsworth A, Scott N, Matricardi M, Etcheto J, Clerbaux C, Armante R and Crevoisier C (2003), "The feasibility of monitoring CO2 from high-resoluion infrared sounders", Journal of Geophysical Research D: Atmospheres. Vol. 108(2), pp. ACH 6–1 ACH 6–19. [Abstract] [BibTeX]
Abstract: Satellite instruments specifically designed to monitor atmospheric carbon dioxide concentrations have not been flown to date but, high-resolution infrared sounders, being launched in the next few years, may offer the possibility of at least a basic carbon dioxide monitoring capability. This paper explores the sensitivity of this new generation of advanced infrared sounders to changing carbon dioxide concentrations and also compares this with uncertainties due to the atmospheric temperature, water vapor, and minor constituent concentrations using the current background errors in numerical weather prediction models as a baseline. The sensitivity results shown are computed for the Infrared Atmospheric Sounding Interferometer (IASI), which is due to fly on the European METOP platform from 2005. We show that although the carbon dioxide signal is below or at the instrument noise for IASI and that uncertainties in temperature and water vapor errors can dominate, a careful averaging of the retrieved carbon dioxide fields over areas of 500 × 500 km2 and 2 weeks should be able to extract changes at the level of 1% or less in the total column carbon dioxide amount. We also show results of an information content study for the Atmospheric InfraRed Sounder, AIRS, data, which suggests 50 channels are adequate for inferring the tropospheric carbon dioxide amounts but that they are not sensitive to CO2 changes in the boundary layer.
BibTeX: @article{Chédin2003ACH6, author = {Chédin, A. and Saunders, R. and Hollingsworth, A. and Scott, N. and Matricardi, M. and Etcheto, J. and Clerbaux, C. and Armante, R. and Crevoisier, C.}, title = {The feasibility of monitoring CO2 from high-resoluion infrared sounders}, journal = {Journal of Geophysical Research D: Atmospheres}, year = {2003}, volume = {108}, number = {2}, pages = {ACH 6–1 ACH 6–19} }
Clerbaux C, Hadji-Lazaro J, Turquety S, Mégie G and Coheur P-F (2003), "Trace gas measurements from infrared satellite for chemistry and climate applications", Atmospheric Chemistry and Physics. Vol. 3(5), pp. 1495 – 1508. [Abstract] [BibTeX] [DOI]
Abstract: Space-borne thermal infrared instruments working in the nadir geometry are providing spectroscopic measurements of species that impact on the chemical composition of the atmosphere and on the climate forcing: H2O, CO2, N2O, CH4, CFCs, O3, and CO. The atmospheric abundances obtained from the analysis of IMG/ADEOS measurements are discussed in order to demonstrate the potential scientific return to be expected from future missions using advanced infrared nadir sounders. Some strengths and limitations of passive infrared remote sensing from space are illustrated. © 2003 European Geosciences Union.
BibTeX: @article{Clerbaux20031495, author = {Clerbaux, C. and Hadji-Lazaro, J. and Turquety, S. and Mégie, G. and Coheur, P.-F.}, title = {Trace gas measurements from infrared satellite for chemistry and climate applications}, journal = {Atmospheric Chemistry and Physics}, year = {2003}, volume = {3}, number = {5}, pages = {1495 – 1508}, note = {All Open Access, Gold Open Access, Green Open Access}, doi = {10.5194/acp-3-1495-2003} }
Coheur P, Bach M, Carleer M, Clerbaux C, Colin R, Hurtmans D, Barret B, Hermans C, Neefs E, De Mazière M, Metzger J and Leveau J (2003), "Ground-based solar absorption FTIR Spectroscopy at the Reunion Island", Optics InfoBase Conference Papers. [Abstract] [BibTeX]
Abstract: This paper gives preliminary results of FTS atmospheric measurements at the Reunion Island. A special emphasis is given to the retrievals of CH4, CO, O3, N2O, HCl, HF and HNO3 © 2003 OSA/FTS.
BibTeX: @conference{Coheur2003, author = {Coheur, P. and Bach, M. and Carleer, M. and Clerbaux, C. and Colin, R. and Hurtmans, D. and Barret, B. and Hermans, C. and Neefs, E. and De Mazière, M. and Metzger, J. and Leveau, J.}, title = {Ground-based solar absorption FTIR Spectroscopy at the Reunion Island}, journal = {Optics InfoBase Conference Papers}, year = {2003} }
Coheur P, Clerbaux C and Colin R (2003), "Spectroscopic measurements of halocarbons and hydrohalocarbons by satellite-borne remote sensors", Journal of Geophysical Research: Atmospheres. Vol. 108(4), pp. 1–1 – 1–14. [Abstract] [BibTeX] [DOI]
Abstract: Infrared spectra recorded by the Atmospheric Trace Molecule Spectroscopy Experiment (ATMOS) and the Interferometric Monitor for Greenhouse Gases (IMG) remote sensors have been analyzed by means of line-by-line radiative transfer calculations in order to evaluate the possibilities offered by solar occultation and by nadir instruments to monitor the cholorofluorocarbons (CFCs) and their substitutes. The reliability of the existing spectroscopic parameters has been examined, and it was found that only laboratory parameters measured at high resolution reproduce the satellite observations well. It is shown that solar occultation spectra can give information regarding the atmospheric abundance of CFC-113, in addition to the usual retrievals of CFC-11, CFC-12 and HCFC-22. Also, relying on existing emission scenarios, it is foreseen that future solar occultation experiments, such as the Atmospheric Chemistry Experiment (ACE), will be able to detect HCFC-142b and HFC-134a, from the year 2005 onward and at low tangent heights. As for the nadir-looking missions, it is found that CFC-11, CFC-12 and HCFC-22 can be retrieved from IMG spectra, provided that numerous measurements are averaged over space or time, thereby mitigating the usefulness of such measurements for determining surface sources. The improved geometrical scanning performances of the future nadir-looking Infrared Atmospheric Sounding Interferometer (IASI) and the Tropospheric Emission Spectrometer (TES), however, are shown to be more promising in this respect.
BibTeX: @article{Coheur20031, author = {Coheur, P.F. and Clerbaux, C. and Colin, R.}, title = {Spectroscopic measurements of halocarbons and hydrohalocarbons by satellite-borne remote sensors}, journal = {Journal of Geophysical Research: Atmospheres}, year = {2003}, volume = {108}, number = {4}, pages = {1–1 – 1–14}, doi = {10.1029/2002jd002649} }
Coheur P, Liévin J, Colin R and Razbirin B (2003), "Electronic and photophysical properties of C60Cl24", Journal of Chemical Physics. Vol. 118(2), pp. 550 – 556. [Abstract] [BibTeX] [DOI]
Abstract: The geometry, ground-state, and optical properties of three isomers of C60Cl24, displaying Th or D2h symmetries were analyzed by means of semiempirical quantum-chemical calculations. Among these, the Th isomer was found to be the preferred thermodynamic product. The results bring some new information on the structure of halogenated fullerenes, which in turn were essential to determine the mechanism of halogen addition onto the carbon cages. Furthermore, the present analysis reinforces the usefulness of the semiempirical calculations of absorption spectra for the determination of the structural and the optical properties of fullerene derivatives.
BibTeX: @article{Coheur2003550, author = {Coheur, P.F. and Liévin, J. and Colin, R. and Razbirin, B.}, title = {Electronic and photophysical properties of C60Cl24}, journal = {Journal of Chemical Physics}, year = {2003}, volume = {118}, number = {2}, pages = {550 – 556}, doi = {10.1063/1.1525807} }
Coheur P-F, Clerbaux C, Carleer M, Fally S, Hurtmans D, Colin R, Hermans C, Vandaele AC, Barret B, De Mazière M and De Backer H (2003), "Retrieval of atmospheric water vapor columns from FT visible solar absorption spectra and evaluation of spectroscopic databases", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 82(1-4), pp. 133 – 150. [Abstract] [BibTeX] [DOI]
Abstract: The absorption of solar light by atmospheric water vapor in the visible spectral region is analyzed by means of ground-based absorption Fourier transform spectroscopy, performed at high resolution in Brussels during summer 2001. Several microwindows between 14,000 and 18,000 cm-1, in which water vapor lines are well isolated from solar lines and other atmospheric trace gases absorptions, are examined. They are demonstrated to be adequate for the retrieval of the total water vapor column. Based on the retrievals, a detailed analysis of the water vapor line parameters published in the HITRAN database and recently reinvestigated by different groups is performed. The analysis focuses on the one hand on the comparison of the retrieved water vapor columns with in situ measurements, performed at the same time as the spectroscopic measurements and at the same location, and on the other hand on the quality of the spectral fits. It is shown that the discrepancies between the line lists affect significantly the results. In particular it is shown that the weaker lines, not measured in earlier laboratory experiments, do contribute at large zenith angles and need to be taken into account in order to better simulate the atmospheric spectra. The importance of the pressure broadening parameters is also highlighted. © 2003 Elsevier Ltd. All rights reserved.
BibTeX: @article{Coheur2003133, author = {Coheur, Pierre-François and Clerbaux, Cathy and Carleer, Michel and Fally, Sophie and Hurtmans, Daniel and Colin, Réginald and Hermans, Christian and Vandaele, Ann Carine and Barret, Brice and De Mazière, Martine and De Backer, Hugo}, title = {Retrieval of atmospheric water vapor columns from FT visible solar absorption spectra and evaluation of spectroscopic databases}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2003}, volume = {82}, number = {1-4}, pages = {133 – 150}, note = {All Open Access, Green Open Access}, doi = {10.1016/S0022-4073(03)00150-X} }
Dufour G, Hurtmans D, Henry A, Valentin A and Lepère M (2003), "Line profile study from diode laser spectroscopy in the 12CH4 2v3 band perturbed by N2, O2, Ar, and He", Journal of Molecular Spectroscopy. Vol. 221(1), pp. 80 – 92. [Abstract] [BibTeX] [DOI]
Abstract: We present a line profile study for two lines in the 2v3 band of CH4 recorded with a frequency stabilized tunable diode laser spectrometer. The broadening and narrowing (Dicke effect) parameters of the R(0) line perturbed by N2, O2, and He are derived from a simultaneous fitting of spectra at pressures from 20 to 300 Torr by using the soft and hard collision models. These parameters are determined for the A and F components of the unresolved R(3) manifold perturbed by N2, Ar, and He from the line profile analysis of spectra at pressures between 50 and 500 Torr. The line mixing effect between the two F components is also taken into account and the absorber speed dependent effect on broadening is estimated for N2 and Ar.
BibTeX: @article{Dufour200380, author = {Dufour, G. and Hurtmans, D. and Henry, A. and Valentin, A. and Lepère, M.}, title = {Line profile study from diode laser spectroscopy in the 12CH4 2v3 band perturbed by N2, O2, Ar, and He}, journal = {Journal of Molecular Spectroscopy}, year = {2003}, volume = {221}, number = {1}, pages = {80 – 92}, doi = {10.1016/S0022-2852(03)00178-4} }
Fally S, Coheur P-F, Carleer M, Clerbaux C, Colin R, Jenouvrier A, Mérienne M-F, Hermans C and Vandaele AC (2003), "Water vapor line broadening and shifting by air in the 26,000-13,000 cm-1 region", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 82(1-4), pp. 119 – 131. [Abstract] [BibTeX] [DOI]
Abstract: Considering the unique role that water in its vapor phase plays in atmospheric physical and chemical processes, there is a need for accurate spectroscopic parameters for this molecule. Long-pathlength Fourier transform spectra of water vapor with synthetic air as the perturbing gas were recorded and analyzed in the 26,000-13,000 cm-1 spectral region. New measurements of air-broadening and air-shifting parameters, with associated uncertainties are presented for about 5000 lines. These data complement our existing database, providing a homogeneous and extensive dataset extending from 26,000 to 9250 cm-1. Comparisons with the two most frequently used HITRAN and ESA databases as well as with other literature data available are made. Agreements and discrepancies are underlined and briefly discussed. © 2003 Elsevier Ltd. All rights reserved.
BibTeX: @article{Fally2003119, author = {Fally, Sophie and Coheur, Pierre-François and Carleer, Michel and Clerbaux, Cathy and Colin, Réginald and Jenouvrier, Alain and Mérienne, Marie-France and Hermans, Christian and Vandaele, Ann Carine}, title = {Water vapor line broadening and shifting by air in the 26,000-13,000 cm-1 region}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2003}, volume = {82}, number = {1-4}, pages = {119 – 131}, doi = {10.1016/S0022-4073(03)00149-3} }
Herman M, Campargue A, El Idrissi M and Vander Auwera J (2003), "Vibrational spectroscopic database on acetylene, X̃ 1∑g+ (12C2H2, 12C2D2, and 13C2H2)", Journal of Physical and Chemical Reference Data. Vol. 32(3), pp. 921 – 929. [Abstract] [BibTeX] [DOI]
Abstract: Information on the vibrational energy states in acetylene (12C2H2, 12C2D2, and 13C2H2) is gathered: spectroscopic constants (vibrational frequencies and anharmonicities, vibration-rotation interaction parameters), observed vibrational energy states and complete sets of predicted vibrational energies and predicted principal rotational constants Bv for states of 12C2H2, 12C2D2, and 13C2H2 up to 15000, 10000, and 12000 cm-1, respectively. Statistical parameters (partition functions and integrated number of states) deduced from these predicted spectroscopic data are provided for the three isotopomers. The equilibrium geometrical structure is determined to be re(CH) =106.138(35) pm and re(CC)=120.292(13) pm from constants available for 12C2H2, 12C2D2, 13C2H2, and 12C2HD. © 2003 American Institute of Physics.
BibTeX: @article{Herman2003921, author = {Herman, M. and Campargue, A. and El Idrissi, M.I. and Vander Auwera, J.}, title = {Vibrational spectroscopic database on acetylene, X̃ 1∑g+ (12C2H2, 12C2D2, and 13C2H2)}, journal = {Journal of Physical and Chemical Reference Data}, year = {2003}, volume = {32}, number = {3}, pages = {921 – 929}, doi = {10.1063/1.1531651} }
Herregodts F, Kerrinckx E, Huet T and Auwera J (2003), "Absolute line intensities in the ν1 + 3ν3 band of 12C2H2 by laser photoacoustic spectroscopy and Fourier transform spectroscopy", Molecular Physics. Vol. 101(23-24), pp. 3427 – 3438. [Abstract] [BibTeX] [DOI]
Abstract: Line intensities and self-broadening coefficients in the ν1 + 3ν3 band of 12C2H2 near 0.8 μm at room temperature were measured by means of both laser photoacoustic and Fourier transform spectroscopy. An experimental protocol has been developed to obtain absolute intensities from the photoacoustic measurements. Namely, the spectrometer was calibrated using water vapour line intensities available in Hitran 1996 [L. S. Rothman et al. (1998) J. quant. Spectrosc. Radiat. Transfer, 60, 665–710]. These photoacoustic line intensities were found to be on average 5% higher than corresponding measurements performed using Fourier transform spectroscopy, the accuracy of the latter being estimated to better than 4%. The accuracy of the photoacoustic intensities is discussed. Previous results from the literature [F. Herregodts, D. Hurtmans, J. Vander Auwera, and M. Herman (1999) J. chem. Phys., 111, 7954—7960] are revised. © 2003 Taylor & Francis Group, LLC.
BibTeX: @article{Herregodts20033427, author = {Herregodts, F. and Kerrinckx, E. and Huet, T.R. and Auwera, J.V.}, title = {Absolute line intensities in the ν1 + 3ν3 band of 12C2H2 by laser photoacoustic spectroscopy and Fourier transform spectroscopy}, journal = {Molecular Physics}, year = {2003}, volume = {101}, number = {23-24}, pages = {3427 – 3438}, doi = {10.1080/00268970310001632426} }
Hurtmans D (2003), "Achieving kilometric absorption paths using intracavity laser absorption spectroscopy detected by FTS (FT-ICLAS); Development and applications", Optics InfoBase Conference Papers. [Abstract] [BibTeX]
Abstract: We have built an intracavity laser absorption spectrometer based on a pulsed Ti:Sa laser synchronized to a commercial continuous scan interferometer. A two generation times technique was used to improve the signal-to-noise ratio. Overtone absorption spectra will illustrate the technique. © 2003 OSA/FTS.
BibTeX: @conference{Hurtmans2003, author = {Hurtmans, D.}, title = {Achieving kilometric absorption paths using intracavity laser absorption spectroscopy detected by FTS (FT-ICLAS); Development and applications}, journal = {Optics InfoBase Conference Papers}, year = {2003} }
Idrissi M, Zhilinskii B, Gaspard P and Herman M (2003), "The integrated number of vibrational states in acetylene (12C2H2, 13C2H2, 12C2D2)", Molecular Physics. Vol. 101(4-5), pp. 595 – 601. [Abstract] [BibTeX] [DOI]
Abstract: A calculated exhaustive set of vibrational state energies in 12C2H2, 13C2H2 and 12C2D2 has been used to analyse the evolution of the integrated number of states with increasing vibrational energy N(E) up to 15000 cm−1, 12000cm−1 and 10000 cm−1 in each isotopomer, respectively. The regular contribution to N(E) was modelled analytically and numerical parameters were fitted. The other expected contribution to N(E), which is of oscillatory nature, was quantified and is discussed using energyand time-dependent theories. Related periods of oscillation and temporal recurrences are interpreted consistently in terms of the constant of the motion Nr = 5v2 + 3v2 + 5v3 + v4 + v5 and of an average vibrational quantum. More pragmatically, the vibrational dynamics appear to be dominated by the bending vibrations, i.e., by the slowest oscillators. © 2003 Taylor & Francis Group, LLC.
BibTeX: @article{Idrissi2003595, author = {Idrissi, M.I.E. and Zhilinskii, B. and Gaspard, P. and Herman, M.}, title = {The integrated number of vibrational states in acetylene (12C2H2, 13C2H2, 12C2D2)}, journal = {Molecular Physics}, year = {2003}, volume = {101}, number = {4-5}, pages = {595 – 601}, doi = {10.1080/0026897021000024324} }
Jacquemart D, Mandin J-Y, Dana V, Claveau C, Vander Auwera J, Herman M, Rothman L, Régalia-Jarlot L and Barbe A (2003), "The IR acetylene spectrum in HITRAN: Update and new results", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 82(1-4), pp. 363 – 382. [Abstract] [BibTeX] [DOI]
Abstract: The 2000 HITRAN edition, with the updates of 2001, contains improved and new data on the acetylene molecule. The main changes concern the 13.6- and 7.5-μm spectral regions (improved line intensities), and the 5-μm region (previously absent from the database). These changes are reviewed, and the key problem of the validation of line intensities is dealt with. The status of the currently available line parameters is critically examined, and recommendations for future improvements are given. © 2003 Elsevier Ltd. All rights reserved.
BibTeX: @article{Jacquemart2003363, author = {Jacquemart, D. and Mandin, J.-Y. and Dana, V. and Claveau, C. and Vander Auwera, J. and Herman, M. and Rothman, L.S. and Régalia-Jarlot, L. and Barbe, A.}, title = {The IR acetylene spectrum in HITRAN: Update and new results}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2003}, volume = {82}, number = {1-4}, pages = {363 – 382}, doi = {10.1016/S0022-4073(03)00163-8} }
Kassi S, Depiesse C, Herman M and Hurtmans D (2003), "Fourier transform-intracavity laser absorption spectroscopy: Sampling the overtone spectrum of 12C2HD", Molecular Physics. Vol. 101(8), pp. 1155 – 1163. [Abstract] [BibTeX] [DOI]
Abstract: A newly home-built Ti:sapphire laser resonator was used to record portions of the FT-ICLAS overtone absorption spectrum of 12C2HD between 12 800 and 14 200 cm-1. The experimental set-up is presented and the recording procedure is detailed. The spectral data are illustrated with the help of five selected bands, four of them previously not reported and none previously rotationally analysed in the literature. These bands, with ṽ0 = 13 360.003(3), 13 246.266(9), 13 234.135(7), 12 938.982(5) and 13 215.45 cm-1, are assigned to 3v1 + 2v2, 2v1 + 2v2 + v4 + 4v5, 4v1 + v4, 3v2 + 3v3 and, tentatively, 4v1 + 2v4 - v4, respectively. The results of the rotational analysis of the first four mentioned bands is presented.
BibTeX: @article{Kassi20031155, author = {Kassi, S. and Depiesse, C. and Herman, M. and Hurtmans, D.}, title = {Fourier transform-intracavity laser absorption spectroscopy: Sampling the overtone spectrum of 12C2HD}, journal = {Molecular Physics}, year = {2003}, volume = {101}, number = {8}, pages = {1155 – 1163}, doi = {10.1080/0026897031000114765} }
Mantz A, Thibault F, Cacheiro J, Fernandez B, Pedersen T, Koch H, Valentin A, Claveau C, Henry A and Hurtmans D (2003), "Argon broadening of the 13CO R(0) and R(7) transitions in the fundamental band at temperatures between 80 and 297 K: Comparison between experiment and theory", Journal of Molecular Spectroscopy. Vol. 222(2), pp. 131 – 141. [Abstract] [BibTeX] [DOI]
Abstract: We present measurements of Ar-broadening parameters for the R(0) and R(7) lines in the fundamental band of 13CO at eight temperatures from 80 to 297 K. The broadening parameters are determined by simultaneous least-squares fitting of spectra recorded using a frequency stabilized diode laser spectrometer. The comparison of the broadening parameter values for R(7) derived at room temperature and different pressures from different line profiles shows that an empirical line profile, which takes into account narrowing effects (Dicke narrowing and absorber speed dependence) but neglects any correlation between collisions, is able to describe the observed lines with constant values of the narrowing and broadening parameters over a 10-500 Torr pressure range. Starting from a recent ab initio potential energy surface, theoretical thermally averaged close coupling values of the Ar broadening parameter are calculated for the same temperatures. The comparison between experimental and calculated values shows an overall agreement of 1.5%. © 2003 Elsevier Inc. All rights reserved.
BibTeX: @article{Mantz2003131, author = {Mantz, A.W. and Thibault, F. and Cacheiro, J.L. and Fernandez, B. and Pedersen, T.B. and Koch, H. and Valentin, A. and Claveau, C. and Henry, A. and Hurtmans, D.}, title = {Argon broadening of the 13CO R(0) and R(7) transitions in the fundamental band at temperatures between 80 and 297 K: Comparison between experiment and theory}, journal = {Journal of Molecular Spectroscopy}, year = {2003}, volume = {222}, number = {2}, pages = {131 – 141}, doi = {10.1016/S0022-2852(03)00200-5} }
Mérienne M-F, Jenouvrier A, Hermans C, Vandaele AC, Carleer M, Clerbaux C, Coheur P-F, Colin R, Fally S and Bach M (2003), "Water vapor line parameters in the 13 000 9250 cm-1 region", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 82(1-4), pp. 99 – 117. [Abstract] [BibTeX] [DOI]
Abstract: Line parameters of water vapor have been obtained in the 13 000-9250 cm-1 spectral region. The measurements were performed with a high resolution Fourier transform spectrometer coupled to long-path multiple reflection cells. Emphasis was put on the determination of accurate parameters for the weak lines, most of which have not been previously reported in the literature. A total of 7061 lines have been studied. Their positions and intensities have been determined, and for many of analyzed lines, self- and air-broadening coefficients, as well as pressure-induced shifts were obtained. A preliminary analysis of the dependence of the broadenings and shifts, with vibrational and rotational quantum numbers is given. The discussion is focused on the comparison between our measured parameters and those listed in the HITRAN database. A very good agreement is reported for the positions and intensities. It is suggested that the construction of a comprehensive and complete dataset for water vapor in this spectral region requires the merging of independent measurements, and of calculated values of broadenings and shifts for weak and blended lines. © 2003 Elsevier Ltd. All rights reserved.
BibTeX: @article{Mérienne200399, author = {Mérienne, Marie-France and Jenouvrier, Alain and Hermans, Christian and Vandaele, Ann Carine and Carleer, Michel and Clerbaux, Cathy and Coheur, Pierre-François and Colin, Réginald and Fally, Sophie and Bach, Mohamed}, title = {Water vapor line parameters in the 13 000 9250 cm-1 region}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2003}, volume = {82}, number = {1-4}, pages = {99 – 117}, doi = {10.1016/S0022-4073(03)00148-1} }
Nemouchi M, Jönsson P, Pinard J and Godefroid M (2003), "Theoretical evaluation of the 7,9Be- 2s2p2 4P1/2,3/2,5/2 hyperfine structure parameters and Be 2s2p 3Po electron affinity", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 36(11), pp. 2189 – 2201. [Abstract] [BibTeX] [DOI]
Abstract: The hyperfine structures of 7,9Be- 2s2p2 4P1/2,3/2,5/2 are investigated theoretically using the multiconfiguration Hartree - Fock and configuration interaction methods. The effects of the hyperfine mixing between the fine-structure J-levels are discussed. The feasibility of some atomic spectroscopy experiments, allowing determination of the 7Be quadrupole moment from the observed hyperfine structure of the 7Be- negative ion and from the present electronic parameters, is investigated. The Be 2s2p 3Po electron affinity is monitored as a function of the orbital and configuration spaces to assess the reliability of the wavefunctions of the neutral atom and the negative ion. The theoretical value nicely converges towards the most recent theoretical and experimental results.
BibTeX: @article{Nemouchi20032189, author = {Nemouchi, M. and Jönsson, P. and Pinard, J. and Godefroid, M.}, title = {Theoretical evaluation of the 7,9Be- 2s2p2 4P1/2,3/2,5/2 hyperfine structure parameters and Be 2s2p 3Po electron affinity}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2003}, volume = {36}, number = {11}, pages = {2189 – 2201}, doi = {10.1088/0953-4075/36/11/305} }
Palmeri P, Quinet P, Zitane N and Vaeck N (2003), "Auger processes in hollow atoms", Revista Mexicana de Fisica. Vol. 49(SUPPL. 3), pp. 76 – 78. [Abstract] [BibTeX]
Abstract: Hollow atoms are characterized by a large number of vacant inner shells and electrons occupying the outer shells. These 'exotic' atomic species are formed in collision processes between highly-charged ions and several types of targets. The scope of the present contribution is to estimate, using a global approach, the Auger rates of the complex configurations belonging to these atoms.
BibTeX: @article{Palmeri200376, author = {Palmeri, P. and Quinet, P. and Zitane, N. and Vaeck, N.}, title = {Auger processes in hollow atoms}, journal = {Revista Mexicana de Fisica}, year = {2003}, volume = {49}, number = {SUPPL. 3}, pages = {76 – 78} }
Panchenko YN, Auwera JV, Moussaoui Y and De Maré GR (2003), "Predictive Abilities of Scaled Quantum Mechanical Molecular Force Fields: Application to 1,3-Butadiene", Structural Chemistry. Vol. 14(4), pp. 337 – 348. [Abstract] [BibTeX] [DOI]
Abstract: The positions of some IR bands of the s-trans-1,3-butadiene-h6 and -1,1,2-d3 isotopomers in the gas phase have been measured using a Brucker IFS 120 HR spectrometer with a resolution of 2 cm-1. The structural parameters of the s-trans- and s-gauche-1,3-butadiene conformers were optimized completely at the MP2/6-31G* theoretical level and their MP2/6-31G//MP2/6-31G quantum mechanical force fields (QMFFs) were calculated. Using only the experimental vibrational frequencies of s-trans-1,3-butadiene-h6, the QMFF of the s-trans conformer was corrected by Pulay's scaling method (eight scale factors were involved). The scaled QMFF was used to calculate the mean vibrational amplitudes and the Coriolis coupling constants of s-trans-1,3-butadiene-h6 and the vibrational frequencies of 12 of its deuterated isotopomers. The set of scale factors obtained for correction of the s-trans QMFF was transferred to the QMFF of the s-gauche conformer. Its theoretical vibrational spectrum and those of some deuterated and C13 isotopomers were calculated. The ability of this scaling approach (transferring of scale factors) to predict the vibrational frequencies of rotational conformers and their isotopomers, as well as other molecular characteristics, and to permit detection of perturbations of the experimental bands are discussed.
BibTeX: @article{Panchenko2003337, author = {Panchenko, Yurii N. and Auwera, Jean Vander and Moussaoui, Yahia and De Maré, George R.}, title = {Predictive Abilities of Scaled Quantum Mechanical Molecular Force Fields: Application to 1,3-Butadiene}, journal = {Structural Chemistry}, year = {2003}, volume = {14}, number = {4}, pages = {337 – 348}, doi = {10.1023/A:1024445810013} }
Ram R, Liévin J, Bernath P and Davis S (2003), "Infrared emission spectroscopy and ab initio calculations on VCl", Journal of Molecular Spectroscopy. Vol. 217(2), pp. 186 – 194. [Abstract] [BibTeX] [DOI]
Abstract: The emission spectrum of VCl has been investigated at high resolution in the 3000-19 400 cm-1 region using a Fourier transform spectrometer. The bands were excited in a high temperature carbon tube furnace by the reaction of vanadium metal vapor and a trace of BCl3 as well as in a microwave discharge lamp by the reaction of VOCl3 vapor with active nitrogen. The spectra were recorded using the Fourier transform spectrometer associated with the McMath-Pierce telescope of the National Solar Observatory at Kitt Peak. The analysis of the E5 Δ-X5 Δ system of VCl (previously labeled as [7.0]5 Δ-X5Δ) has been extended by analyzing the rotational structure of some additional bands. A rotational analysis of the 5Δ1-5Δ1, 5Δ3-5Δ3, and 5Δ4-5Δ4 subbands of the 0-2, 0-1, 0-0, and 1-0 bands, and the 5Δ2 - 5Δ2 subband of the 0-1 and 0-0 bands has been obtained and molecular constants have been extracted. The 5Δ0± - 5Δ0± subband was not identified in any of the assigned bands. The spectroscopic properties of the low-lying electronic states of VCl have been predicted by CASSCF/CMRCI ab initio calculations and the experimental assignments are supported by the ab initio results.
BibTeX: @article{Ram2003186, author = {Ram, R.S. and Liévin, J. and Bernath, P.F. and Davis, S.P.}, title = {Infrared emission spectroscopy and ab initio calculations on VCl}, journal = {Journal of Molecular Spectroscopy}, year = {2003}, volume = {217}, number = {2}, pages = {186 – 194}, doi = {10.1016/S0022-2852(02)00016-4} }
Rothman L, Barbe A, Benner DC, Brown L, Camy-Peyret C, Carleer M, Chance K, Clerbaux C, Dana V, Devi V, Fayt A, Flaud J-M, Gamache R, Goldman A, Jacquemart D, Jucks K, Lafferty W, Mandin J-Y, Massie S, Nemtchinov V, Newnham D, Perrin A, Rinsland C, Schroeder J, Smith K, Smith M, Tang K, Toth R, Vander Auwera J, Varanasi P and Yoshino K (2003), "The HITRAN molecular spectroscopic database: Edition of 2000 including updates through 2001", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 82(1-4), pp. 5 – 44. [Abstract] [BibTeX] [DOI]
Abstract: This paper describes the status circa 2001, of the HITRAN compilation that comprises the public edition available through 2001. The HITRAN compilation consists of several components useful for radiative transfer calculation codes: high-resolution spectroscopic parameters of molecules in the gas phase, absorption cross-sections for molecules with very dense spectral features, aerosol refractive indices, ultraviolet line-by-line parameters and absorption cross-sections, and associated database management software. The line-by-line portion of the database contains spectroscopic parameters for 38 molecules and their isotopologues and isotopomers suitable for calculating atmospheric transmission and radiance properties. Many more molecular species are presented in the infrared cross-section data than in the previous edition, especially the chlorofluorocarbons and their replacement gases. There is now sufficient representation so that quasi-quantitative simulations can be obtained with the standard radiance codes. In addition to the description and justification of new or modified data that have been incorporated since the last edition of HITRAN (1996), future modifications are indicated for cases considered to have a significant impact on remote-sensing experiments. © 2003 Elsevier Ltd. All rights reserved.
BibTeX: @article{Rothman20035, author = {Rothman, L.S. and Barbe, A. and Benner, D. Chris and Brown, L.R. and Camy-Peyret, C. and Carleer, M.R. and Chance, K. and Clerbaux, C. and Dana, V. and Devi, V.M. and Fayt, A. and Flaud, J.-M. and Gamache, R.R. and Goldman, A. and Jacquemart, D. and Jucks, K.W. and Lafferty, W.J. and Mandin, J.-Y. and Massie, S.T. and Nemtchinov, V. and Newnham, D.A. and Perrin, A. and Rinsland, C.P. and Schroeder, J. and Smith, K.M. and Smith, M.A.H. and Tang, K. and Toth, R.A. and Vander Auwera, J. and Varanasi, P. and Yoshino, K.}, title = {The HITRAN molecular spectroscopic database: Edition of 2000 including updates through 2001}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2003}, volume = {82}, number = {1-4}, pages = {5 – 44}, doi = {10.1016/S0022-4073(03)00146-8} }
Shayesteh A, Tereszchuk K, Bernath P and Colin R (2003), "Fourier transform infrared emission spectra of BeH/BeD and BeH2/BeD2", Optics InfoBase Conference Papers. [Abstract] [BibTeX]
Abstract: High resolution infrared emission spectra of BeH/BeD and BeH2/BeD2 have been recorded with a Fourier transform spectrometer. Some vibrational bands of BeH/BeD and several bands of BeH2/BeD2 were rotationally analyzed, and the equilibrium structures were determined. © 2003 OSA/FTS.
BibTeX: @conference{Shayesteh2003, author = {Shayesteh, A. and Tereszchuk, K. and Bernath, P. and Colin, R.}, title = {Fourier transform infrared emission spectra of BeH/BeD and BeH2/BeD2}, journal = {Optics InfoBase Conference Papers}, year = {2003} }
Shayesteh A, Tereszchuk K, Bernath P and Colin R (2003), "Infrared emission spectra of BeH and BeD", Journal of Chemical Physics. Vol. 118(3), pp. 1158 – 1161. [Abstract] [BibTeX] [DOI]
Abstract: The high resolution infrared emission spectra of BeH and BeD were recorded with a Bruker IFS 120 HR Fourier transform spectrometer. Thus, a new emission source with an electrical discharge inside a high temperature furnace was used to make the molecules. In the overview spectrum recorded with the InSb detector, it was found that the strongest emission lines were the R branch lines of the BeH v=1→0 band.
BibTeX: @article{Shayesteh20031158, author = {Shayesteh, A. and Tereszchuk, K. and Bernath, P.F. and Colin, R.}, title = {Infrared emission spectra of BeH and BeD}, journal = {Journal of Chemical Physics}, year = {2003}, volume = {118}, number = {3}, pages = {1158 – 1161}, doi = {10.1063/1.1528606} }
Shayesteh A, Tereszchuk K, Bernath P and Colin R (2003), "Infrared emission spectra of BeH2 and BeD2", Journal of Chemical Physics. Vol. 118(8), pp. 3622 – 3627. [Abstract] [BibTeX] [DOI]
Abstract: Fourier transform spectrometer was used to record high resolution infrared spectra of beryllium dihydride (BeH2) and dideuteride. The BeH2 spectrum was recorded in the 1800-2900 cm-1 spectral region at an instrumental resolution of 0.03 cm-1 using a CaF2 beamsplitter. The equilibrium rotational constant of BeH2 was found to be 4.75366(2) cm-1.
BibTeX: @article{Shayesteh20033622, author = {Shayesteh, A. and Tereszchuk, K. and Bernath, P.F. and Colin, R.}, title = {Infrared emission spectra of BeH2 and BeD2}, journal = {Journal of Chemical Physics}, year = {2003}, volume = {118}, number = {8}, pages = {3622 – 3627}, doi = {10.1063/1.1539850} }
Tjemkes S, Patterson T, Rizzi R, Shephard M, Clough S, Matricardi M, Haigh J, Höpfner M, Payan S, Trotsenko A, Scott N, Rayer P, Taylor J, Clerbaux C, Strow L, DeSouza-Machado S, Tobin D and Knuteson R (2003), "The ISSWG line-by-line inter-comparison experiment", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 77(4), pp. 433 – 453. [Abstract] [BibTeX] [DOI]
Abstract: To document the performance of current line-by-line radiative transfer models, a study was performed to compare the model simulations with real observations and also inter-compare the simulations themselves. Two broadband mid-IR observed spectra with high spectral resolution were analyzed. The observations were done in nadir mode, and at the same time the atmospheric state was carefully monitored. The first dataset consisted of radiance observations using the HIS interferometer during the CAMEX-I campaign off the east coast of the USA. The second dataset consisted of observations from the ARIES interferometer collected during the Ascension Island campaign over the tropical Atlantic. These two cases are very different with the Ascension Island case being much warmer and more humid than the CAMEX case. In total 13 different research groups participated with seven different line-by-line models. The results of this study indicated that in many spectral regions the models are capable of reproducing the observations to within the observed noise. In some spectral regions relatively large differences between the simulations and observations exist. Crown Copyright © 2002 Published by Elsevier Science Ltd. All rights reserved.
BibTeX: @article{Tjemkes2003433, author = {Tjemkes, S.A. and Patterson, T. and Rizzi, R. and Shephard, M.W. and Clough, S.A. and Matricardi, M. and Haigh, J.D. and Höpfner, M. and Payan, S. and Trotsenko, A. and Scott, N. and Rayer, P. and Taylor, J.P. and Clerbaux, C. and Strow, L.L. and DeSouza-Machado, S. and Tobin, D. and Knuteson, R.}, title = {The ISSWG line-by-line inter-comparison experiment}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2003}, volume = {77}, number = {4}, pages = {433 – 453}, doi = {10.1016/S0022-4073(02)00174-7} }
Vandaele A, Hermans C, Fally S, Carleer M, Mérienne M-F, Jenouvrier A, Coquart B and Colin R (2003), "Absorption cross-sections of NO2: Simulation of temperature and pressure effects", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 76(3-4), pp. 373 – 391. [Abstract] [BibTeX] [DOI]
Abstract: The measurements of the NO2 absorption cross sections by several authors have been considered in order to derive its temperature and pressure dependences in the 13 200-42 000 cm-1 spectral range. The temperature dependence is assumed to be linear in the temperature range investigated (217.0-298.5 K), whereas the influence of the total pressure is expressed as a temperature-dependent broadening coefficient. From measurements performed with mixtures of NO2 in air and in N2, values of γ0air (296 K) and γ0N2 (296 K) were found to be, respectively, 0.081 ± 0.002 and 0.069 ± 0.003 cm-1 atm-1. The temperature coefficient n obtained in the present work is 0.8 ± 0.1. The parameterization of the cross sections developed in this work can reproduce measured cross sections within 4%. © 2002 Elsevier Science Ltd. All rights reserved.
BibTeX: @article{Vandaele2003373, author = {Vandaele, A.C. and Hermans, C. and Fally, S. and Carleer, M. and Mérienne, M.-F. and Jenouvrier, A. and Coquart, B. and Colin, R.}, title = {Absorption cross-sections of NO2: Simulation of temperature and pressure effects}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2003}, volume = {76}, number = {3-4}, pages = {373 – 391}, doi = {10.1016/S0022-4073(02)00064-X} }
Vander Auwera J, Daumont L, Teffo J, Perevalov V and Tashkun S (2003), "Infrared absolute line intensities for minor atmospheric constituents", Optics InfoBase Conference Papers. [Abstract] [BibTeX]
Abstract: We present recent laboratory measurements of absolute line intensities for carbonyl sulfide and nitrous oxide in the infrared and near infrared spectral ranges respectively, using high-resolution Fourier transform spectroscopy. © 2003 OSA/FTS.
BibTeX: @conference{VanderAuwera2003, author = {Vander Auwera, J. and Daumont, L. and Teffo, J. and Perevalov, V. and Tashkun, S.}, title = {Infrared absolute line intensities for minor atmospheric constituents}, journal = {Optics InfoBase Conference Papers}, year = {2003} }
Wintjens R, Biot C, Rooman M and Liévin J (2003), "Basis set and electron correlation effects on ab initio calculations of cation-π/H-bond stair motifs", Journal of Physical Chemistry A. Vol. 107(32), pp. 6249 – 6258. [Abstract] [BibTeX] [DOI]
Abstract: Cation-π/H-bond stair motifs are recurrently found at the binding interface between protein and DNA. They involve two nucleobases and an amino acid side chain, and encompass three different types of interactions: nucleobase stacking, nucleobase-amino acid H-bond and nucleobase-amino acid cation-π interaction. The interaction energies of the 77 stair motif geometries identified in a data set of 52 high-resolution protein - DNA complexes were investigated by means of ab initio quantum chemistry calculations. Using the standard 6-3IG* basis set, we first establish the value of the Gaussian αd-exponent of d-polarization functions on heavy atoms, which optimizes the MP2 interaction energies. We show that, although the default value of αd = 0.8 is appropriate to minimize the total MP2 energy of a system, the value of αd = 0.2 is optimal for the three types of pairwise interactions studied and yields MP2 interaction energies quite similar to those calculated with more extended basis sets. Indeed, the more diffuse nature of the αd = 0.2 basis functions allows a spatial overlap between the orbitals of the interacting partners. Such functions are also shown to improve the multipole electric moments in the interaction region, which results in a stabilizing polarization effect and a better description of the dispersive energy contributions. Using the MP2 computation level and the 6-31G* basis set with αd = 0.2 instead of αd = 0.8, we computed the interaction energies of the 77 observed stair motif geometries and found that, in a vacuum, the cation-π energy is much less favorable, about 3 times, than the H-bond energy and of the same order of magnitude as the π-π stacking energy. Furthermore, the convergence of the MP perturbation theory expansions was analyzed by computing the MP3 and MP4 corrections on simplified complexes. These expansions exhibited an oscillatory behavior, where MP2 seems to provide a satisfactory approximation, albeit slightly overestimated, to the interaction energy.
BibTeX: @article{Wintjens20036249, author = {Wintjens, René and Biot, Christophe and Rooman, Marianne and Liévin, Jacky}, title = {Basis set and electron correlation effects on ab initio calculations of cation-π/H-bond stair motifs}, journal = {Journal of Physical Chemistry A}, year = {2003}, volume = {107}, number = {32}, pages = {6249 – 6258}, doi = {10.1021/jp034103q} }
Bacchus-Montabonel M-C, Baloïtcha E, Desouter-Lecomte M and Vaeck N (2002), "Rate coefficient determination in charge transfer reactions", International Journal of Molecular Sciences. Vol. 3(3), pp. 176 – 189. [Abstract] [BibTeX] [DOI]
Abstract: The development of experimental ion-trap techniques provides the opportunity to compare directly theoretical rate coefficients to experimental data in the low-temperature regime. In the present work, we consider the ion-atom collisional systems, N2+, O2+, Si3+ and Si4+ on a He target, in order to examine the present status of the agreement between theory and experiment.
BibTeX: @article{Bacchus-Montabonel2002176, author = {Bacchus-Montabonel, Marie-Christine and Baloïtcha, Ezinvi and Desouter-Lecomte, Michèle and Vaeck, Nathalie}, title = {Rate coefficient determination in charge transfer reactions}, journal = {International Journal of Molecular Sciences}, year = {2002}, volume = {3}, number = {3}, pages = {176 – 189}, note = {All Open Access, Gold Open Access}, doi = {10.3390/i3030176} }
Belyaev A, Grosser J, Liévin J and Vaeck N (2002), "Charge exchange in low-energy H, D + C4+ collisions with full account of electron translation", International Journal of Molecular Sciences. Vol. 3(3), pp. 190 – 208. [Abstract] [BibTeX] [DOI]
Abstract: We report the application of the quantum approach, which takes full account of electron translation at low collisional energies, to the charge exchange process H, D + C4+ → H+, D+ + C 3+(3s; 3p; 3d). The partial and the total integral cross sections of the process are calculated in the energy range from 1 till 60 eV/amu. It is shown that the present results are independent from the upper integration limit for numerical solution of the coupled channel equations although nonadiabatic couplings remain nonzero up to infinity. The calculated partial and total cross sections are in agreement with the previous low-energy calculations and the available experimental data. It is shown that for low collisional energies the isotopic effect takes place. The observed effect is explained in terms of the nonadiabatic dynamics.
BibTeX: @article{Belyaev2002190, author = {Belyaev, A.K. and Grosser, J. and Liévin, J. and Vaeck, N.}, title = {Charge exchange in low-energy H, D + C4+ collisions with full account of electron translation}, journal = {International Journal of Molecular Sciences}, year = {2002}, volume = {3}, number = {3}, pages = {190 – 208}, note = {All Open Access, Gold Open Access}, doi = {10.3390/i3030190} }
Bernath PF, Shayesteh A, Tereszchuk K and Colin R (2002), "The vibration-rotation emission spectrum of free BeH2", Science. Vol. 297(5585), pp. 1323 – 1324. [Abstract] [BibTeX] [DOI]
Abstract: The gaseous BeH2 molecule has been synthesized by means of an electrical discharge inside a high-temperature furnace and identified with infrared emission spectroscopy. The antisymmetric stretching mode v3 has been detected near 2179 reciprocal centimeters. The BeH2 molecule has a linear, symmetric structure with an ro BeH bond length of 1.333761(2) angstroms.
BibTeX: @article{Bernath20021323, author = {Bernath, Peter F. and Shayesteh, Alireza and Tereszchuk, Keith and Colin, Reginald}, title = {The vibration-rotation emission spectrum of free BeH2}, journal = {Science}, year = {2002}, volume = {297}, number = {5585}, pages = {1323 – 1324}, doi = {10.1126/science.1074580} }
Bieron J, Fischer CF and Godefroid M (2002), "Hyperfine-structure calculations of excited levels in neutral scandium", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 35(15), pp. 3337 – 3345. [Abstract] [BibTeX] [DOI]
Abstract: The multi-configuration Dirac-Fock model is used to evaluate the magnetic dipole hyperfine interaction constants of the 3d4s(1D)4p 2D3/2,5/20, 3d4s(3D)4p 4F9/20, 3d4s(1D)4p 2F5/2,7/20 and 3d2(1D)4s 2D3/2,5/2 levels of atomic scandium. The wavefunctions are obtained with the active space expansion method, where configuration state functions of a specific parity and J value are generated by substitutions from the reference configurations to an active set of orbitals. The active set is then increased in a systematic way, allowing the convergence of the expectation values to be monitored. The calculated magnetic dipole hyperfine interaction constants are compared with experimentally determined values. On the grounds of the level of agreement between experiment and theory, we confirm three of the hypothetical A-values, previously deduced from high-resolution Fourier transform spectroscopy.
BibTeX: @article{Bieron20023337, author = {Bieron, Jacek and Fischer, Charlotte Froese and Godefroid, Michel}, title = {Hyperfine-structure calculations of excited levels in neutral scandium}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2002}, volume = {35}, number = {15}, pages = {3337 – 3345}, doi = {10.1088/0953-4075/35/15/308} }
Claveau C, Henry A, Lepère M, Valentin A and Hurtmans D (2002), "Narrowing and broadening parameters for H2O lines in the v2 band perturbed by nitrogen from fourier transform and tunable diode laser spectroscopy", Journal of Molecular Spectroscopy. Vol. 212(2), pp. 171 – 185. [Abstract] [BibTeX] [DOI]
Abstract: Collision effects on water vapor line profiles perturbed by nitrogen at room temperature have been studied by Fourier transform and tunable diode laser spectroscopy. Narrowing effect due to molecular confinement (Dicke effect) has been observed for P and Q branch lines of the v2 band of H2O with Fourier transform spectrometer. Narrowing and broadening parameters have been determined using the soft and hard collision models. A more precise study on three R-branch lines with a frequency stabilized diode laser spectrometer allows to perform the comparison between the two collision models at low pressure and to analyze the different narrowing effects when the pressure increases taking into account the molecular confinement and the absorber speed dependent effects. © 2002 Elsevier Science (USA).
BibTeX: @article{Claveau2002171, author = {Claveau, C. and Henry, A. and Lepère, M. and Valentin, A. and Hurtmans, D.}, title = {Narrowing and broadening parameters for H2O lines in the v2 band perturbed by nitrogen from fourier transform and tunable diode laser spectroscopy}, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {212}, number = {2}, pages = {171 – 185}, doi = {10.1006/jmsp.2002.8539} }
Claveau C, Lepère M, Dufour G, Valentin A, Henry A, Camy-Peyret C and Hurtmans D (2002), "Diode laser emission linewidth determination: Application to H2O line profile studies in the 5 and 1.4 μm regions", Spectrochimica Acta - Part A Molecular and Biomolecular Spectroscopy. Vol. 58(11), pp. 2313 – 2321. [Abstract] [BibTeX] [DOI]
Abstract: In order to study absorption line profiles using the stabilized diode laser spectrometer of Laboratoire de Physique Moléculaire et Applications (LPMA), a reliable determination of the emission line shape of different diodes laser is needed. In the near infrared region (1.39 and 1.66 μm) we used Distributed Feed Back diode lasers which operate around room temperature and in the middle infrared (5 and 8 μm) we used lead salt diode lasers cooled in a helium closed cycle cryostat or in a liquid nitrogen dewar. Some results obtained in H2O line profile studies in the 1.39 and 5 μm regions are presented as examples demonstrating how absorption line profile measurements can lead to erroneous values of the spectroscopic parameters when the contribution of the diode laser emission line width is neglected. © 2002 Elsevier Science B.V. All rights reserved.
BibTeX: @article{Claveau20022313, author = {Claveau, C. and Lepère, M. and Dufour, G. and Valentin, A. and Henry, A. and Camy-Peyret, C. and Hurtmans, D.}, title = {Diode laser emission linewidth determination: Application to H2O line profile studies in the 5 and 1.4 μm regions}, journal = {Spectrochimica Acta - Part A Molecular and Biomolecular Spectroscopy}, year = {2002}, volume = {58}, number = {11}, pages = {2313 – 2321}, doi = {10.1016/S1386-1425(02)00046-X} }
Clerbaux C, Hadji-Lazaro J, Payan S, Camy-Peyret C, Wang J, Edwards DP and Luo M (2002), "Retrieval of CO from nadir remote-sensing measurements in the infrared by use of four different inversion algorithms", Applied Optics. Vol. 41(33), pp. 7068 – 7078. [Abstract] [BibTeX] [DOI]
Abstract: Four inversion schemes based on various retrieval approaches (digital gas correlation, nonlinear least squares, global fit adjustment, and neural networks) developed to retrieve CO from nadir radiances measured by such downward-looking satelliteborne instruments as the Measurement of Pollution in the Troposphere (MOPITT), the Tropospheric Emission Spectrometer (TES), and the Infrared Atmospheric Sounding Interferometer (IASI) instruments were compared both for simulated cases and for atmospheric spectra recorded by the Interferometric Monitor for Greenhouse Gases (IMG). The sensitivity of the retrieved CO total column amount to properties that may affect the inversion accuracy (noise, ancillary temperature profile, and water-vapor content) was investigated. The CO column amounts for the simulated radiance spectra agreed within 4%, whereas larger discrepancies were obtained when atmospheric spectra recorded by the IMG instrument were analyzed. The assumed vertical temperature profile is shown to be a critical parameter for accurate CO retrieval. The instrument’s line shape was also identified as a possible cause of disagreement among the results provided by the groups of scientists who are participating in this study. © 2002 Optical Society of America.
BibTeX: @article{Clerbaux20027068, author = {Clerbaux, Cathy and Hadji-Lazaro, Juliette and Payan, Sébastien and Camy-Peyret, Claude and Wang, Jinxue and Edwards, David P. and Luo, Ming}, title = {Retrieval of CO from nadir remote-sensing measurements in the infrared by use of four different inversion algorithms}, journal = {Applied Optics}, year = {2002}, volume = {41}, number = {33}, pages = {7068 – 7078}, doi = {10.1364/AO.41.007068} }
Coheur P-F, Fally S, Carleer M, Clerbaux C, Colin R, Jenouvrier A, Mérienne M-F, Hermans C and Vandaele AC (2002), "New water vapor line parameters in the 26000-13000 cm-1 region", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 74(4), pp. 493 – 510. [Abstract] [BibTeX] [DOI]
Abstract: The radiative properties of water vapor play an important role in the physical and chemical processes occurring in the atmosphere. Accurate knowledge of the line parameters for this species is therefore needed. This work presents new measurements of water vapor line parameters in the 26000-13000 cm-1 spectral region. The measurements were obtained by combining a high-resolution Fourier transform spectrometer with a long-path absorption cell, thus allowing the observation of very weak, previously unobserved, lines. A total of more than 9000 lines have been identified and their position, integrated cross section and self-broadening parameter have been determined. The dependence of the line parameters on nitrogen buffer gas pressure (0-800 hPa) has also been studied. The complete line list presented here is primarily compared to the HITRAN spectroscopic database, most frequently used in atmospheric calculations. © 2002 Elsevier Science Ltd. All rights reserved.
BibTeX: @article{Coheur2002493, author = {Coheur, Pierre-François and Fally, Sophie and Carleer, Michel and Clerbaux, Cathy and Colin, Réginald and Jenouvrier, Alain and Mérienne, Marie-France and Hermans, Christian and Vandaele, Ann Carine}, title = {New water vapor line parameters in the 26000-13000 cm-1 region}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2002}, volume = {74}, number = {4}, pages = {493 – 510}, note = {All Open Access, Green Open Access}, doi = {10.1016/S0022-4073(01)00269-2} }
Colin R, Coheur P-F, Kiseleva M, Vandaele AC and Bernath PF (2002), " Spectroscopic constants and term values for the X 2 π i state of OH (v = 0-10) ", Journal of Molecular Spectroscopy. Vol. 214(2), pp. 225 – 226. [BibTeX] [DOI]
BibTeX: @article{Colin2002225, author = {Colin, Reginald and Coheur, Pierre-François and Kiseleva, Maria and Vandaele, Ann Carine and Bernath, Peter F.}, title = { Spectroscopic constants and term values for the X 2 π i state of OH (v = 0-10) }, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {214}, number = {2}, pages = {225 – 226}, doi = {10.1006/jmsp.2002.8591} }
Coudert L, Çarçabal P, Chevalier M, Broquier M, Hepp M and Herman M (2002), "High-resolution analysis of the v6, v17, and v21 bands of dimethyl ether", Journal of Molecular Spectroscopy. Vol. 212(2), pp. 203 – 207. [Abstract] [BibTeX] [DOI]
Abstract: The v6, v17, and v21 fundamental bands of dimethyl ether have been assigned and rotationally analyzed. The spectra used were recorded at 0.005 cm−1 spectral resolution with a Fourier-transform spectrometer coupled to a supersonic molecular beam leading to a rotational temperature of about 70 K. The v6 and v21 bands do not seem to be perturbed and the analysis of the rotational structure leads to band centers located at 933.906 6(9) and 1 103.951(1) cm−1, respectively, and to accurate rotational and centrifugal distortion constants. For the v17 band at 2817.385(2) cm−1, only the P and R branches could be assigned. © 2002 Elsevier Science (USA).
BibTeX: @article{Coudert2002203, author = {Coudert, L.H. and Çarçabal, P. and Chevalier, M. and Broquier, M. and Hepp, M. and Herman, M.}, title = {High-resolution analysis of the v6, v17, and v21 bands of dimethyl ether}, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {212}, number = {2}, pages = {203 – 207}, doi = {10.1006/jmsp.2002.8541} }
Ding Y, Herman M and Campargue A (2002), "Iclas of 12c2h2 between 10 140 and 10 600 cm−1", Journal of Molecular Spectroscopy. Vol. 212(1), pp. 125 – 129. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of 12C2H2 has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the spectral region 10 140-10 600 cm−1, where three absorption bands were previously observed by Fourier transform spectroscopy. Thirteen bands starting from the vibrational ground state could be detected and rotationally analyzed. All corresponding excited vibrational levels could be assigned using the polyad model (M. I. El Idrissi, J. Liévin, A. Campargue, and M. Herman, J. Chem. Phys. 110, 2074-2086 (1999)). The assignment procedure is detailed and relative intensity features are discussed. © 2002 Elsevier Science (USA).
BibTeX: @article{Ding2002125, author = {Ding, Y. and Herman, M. and Campargue, Alain}, title = {Iclas of 12c2h2 between 10 140 and 10 600 cm−1}, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {212}, number = {1}, pages = {125 – 129}, doi = {10.1006/jmsp.2002.8518} }
El Hachtouki R and Vander Auwera J (2002), "Absolute line intensities in acetylene: The 1.5-μm region", Journal of Molecular Spectroscopy. Vol. 216(2), pp. 355 – 362. [Abstract] [BibTeX] [DOI]
Abstract: We measured 305 absolute line intensities in the ν1 + ν3(∑u+)-0(∑8 +) band of 12C2H2 and 13C12CH2 and the ν1 + ν2 + (ν41 + ν5-1)0(∑u+)- 0(∑8+), ν1 + ν3 + ν41 (Πg)-ν41 (Πg), and ν1 + ν3 + ν51 (Πu)-ν51(Πu) bands of the main isotopomer, all observed near 1.5 μm. The absolute intensity of these bands are respectively 6.4882 (34), 0.12337 (10), 0.083746 (71), 0.58771 (28), and 0.32126 (11) cm-2 atm-1 at 296 K. In addition, we also determined Herman-Wallis factors for the first time in this spectral region. © 2002 Elsevier Science (USA).
BibTeX: @article{ElHachtouki2002355, author = {El Hachtouki, R. and Vander Auwera, J.}, title = {Absolute line intensities in acetylene: The 1.5-μm region}, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {216}, number = {2}, pages = {355 – 362}, doi = {10.1006/jmsp.2002.8660} }
Freytes M, Hurtmans D, Kassi S, Liévin J, Vander Auwera J, Campargue A and Herman M (2002), "Overtone spectroscopy of formic acid", Chemical Physics. Vol. 283(1-2), pp. 47 – 61. [Abstract] [BibTeX] [DOI]
Abstract: Vibrational assignments of fundamental, combination and overtone bands in the main isotopomer of gaseous transformic acid are reported from spectra either newly or previously [J. Chem. Phys. 113 (2000) 1535] recorded using high-resolution Fourier transform and intracavity laser absorption spectroscopies. A total of 62 bands, with 32 newly reported ones, are observed from the lowest energy band, v7 at 626.16 cm-1 up to 4v1 at 13284.1 cm-1. Among these bands, 43 are firmly assigned, and 16 tentatively. Effective vibrational constants are obtained. The normal modes of vibrations are further characterised using ab initio calculations providing fundamental band intensities and picturing normal mode nuclear displacements. The effective investigation of the rotational structure in the first CH stretch overtone band (2v2) and in the second OH stretch overtone band (3v1) is detailed. Rotational information is also presented for 3v2 and two close-lying bands, that could be extracted from the strong overlapping formic acid dimer bands using artificial filtering procedures. © 2002 Elsevier Science B.V. All rights reserved.
BibTeX: @article{Freytes200247, author = {Freytes, M. and Hurtmans, D. and Kassi, S. and Liévin, J. and Vander Auwera, J. and Campargue, A. and Herman, M.}, title = {Overtone spectroscopy of formic acid}, journal = {Chemical Physics}, year = {2002}, volume = {283}, number = {1-2}, pages = {47 – 61}, doi = {10.1016/S0301-0104(02)00507-4} }
Hadji-Lazaro J, Clerbaux C, Turquety S, Hauglustaine D and Khattatov B (2002), "Trace gases concentrations retrieval from measurements provided by a nadir-looking Fourier transform spectrometer", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4485, pp. 1 – 8. [Abstract] [BibTeX] [DOI]
Abstract: To prepare the mission of the Infrared Atmospheric Sounding Interferometer (IASI), which will be launched in 2005 aboard the European METOP satellite, the measurement capability to retrieve trace gases concentrations from nadir radiances was investigated. This included sensitivity studies, development of an innovating inversion algorithm, cloud-filtering, and use of data assimilation techniques for validation purposes. The availability of nadir radiances measured by the IMG instrument allowed us to test the tools under development on real data. This paper summarizes the current status of the work.
BibTeX: @article{Hadji-Lazaro20021, author = {Hadji-Lazaro, Juliette and Clerbaux, Cathy and Turquety, Solène and Hauglustaine, Didier and Khattatov, Boris}, title = {Trace gases concentrations retrieval from measurements provided by a nadir-looking Fourier transform spectrometer}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2002}, volume = {4485}, pages = {1 – 8}, doi = {10.1117/12.454245} }
Hartmann J, Brodbeck C, Flaud P-M, Tipping R, Brown A, Ma Q and Liévin J (2002), "Collision-induced absorption in the ν2 fundamental band of CH4. II. Dependence on the perturber gas", Journal of Chemical Physics. Vol. 116(1), pp. 123 – 127. [Abstract] [BibTeX] [DOI]
Abstract: The theory of CH4-X was generalized for linear molecular perturbers (N2, H2, or CO2). Contributions from the anisotropic quadropolar mechanism were calculated for CH4-N2, CH4-H2, and CH4-CO2. Evidence was obtained that collision-induced absorption arises primarily through the quadrupolar induction mechanism.
BibTeX: @article{Hartmann2002123, author = {Hartmann, J.M. and Brodbeck, C. and Flaud, P.-M. and Tipping, R.H. and Brown, Alex and Ma, Q. and Liévin, J.}, title = {Collision-induced absorption in the ν2 fundamental band of CH4. II. Dependence on the perturber gas}, journal = {Journal of Chemical Physics}, year = {2002}, volume = {116}, number = {1}, pages = {123 – 127}, doi = {10.1063/1.1424311} }
Henry A, Claveau C, Valentin A, Hurtmans D and Mantz A (2002), "Confinement narrowing of the R(0) line in the 13CO fundamental band broadened by helium from room temperature down to 40 K", Journal of Molecular Spectroscopy. Vol. 214(1), pp. 28 – 34. [Abstract] [BibTeX] [DOI]
Abstract: The R(0) line profile of the 13CO fundamental band is studied at low concentration in helium from room temperature (296.7 K) to 40 K. A narrowing effect due to molecular confinement (Dicke effect) is observed and analyzed using the Galatry soft collision model. The narrowing parameter is found to be in good agreement with the dynamic friction coefficient deduced from the diffusion coefficient over the entire temperature range. © 2002 Elsevier Science (USA).
BibTeX: @article{Henry200228, author = {Henry, A. and Claveau, C. and Valentin, A. and Hurtmans, D. and Mantz, A.W.}, title = {Confinement narrowing of the R(0) line in the 13CO fundamental band broadened by helium from room temperature down to 40 K}, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {214}, number = {1}, pages = {28 – 34}, doi = {10.1006/jmsp.2002.8576} }
Hurtmans D, Dufour G, Bell W, Henry A, Valentin A and Camy-Peyret C (2002), "Line intensity of R(0) and R(3) of the 12CH4 2ν3 band from diode laser spectroscopy", Journal of Molecular Spectroscopy. Vol. 215(1), pp. 128 – 133. [Abstract] [BibTeX] [DOI]
Abstract: We have determined the spectroscopic parameters that are necessary to describe accurately the R(0) line profile of the CH4 2ν3 band from about 1 Torr to a few hundred Torr of pure CH4. The intensities determined at each pressure are in overall agreement to better than 0.7%. The R(3) manifold of the same band has also been investigated. Relative positions and absolute intensities of the three transitions composing the triplet have been determined. The intensity distribution inside the triplet is in fair agreement with recent theoretical predictions. © 2002 Elsevier Science (USA).
BibTeX: @article{Hurtmans2002128, author = {Hurtmans, D. and Dufour, G. and Bell, W. and Henry, A. and Valentin, A. and Camy-Peyret, C.}, title = {Line intensity of R(0) and R(3) of the 12CH4 2ν3 band from diode laser spectroscopy}, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {215}, number = {1}, pages = {128 – 133}, doi = {10.1006/jmsp.2002.8620} }
Hurtmans D, Kassi S, Depiesse C and Herman M (2002), "Assignment of a perturbation in the FT-ICLAS spectrum of 12C2H2 around 12 709.5 cm-1", Molecular Physics. Vol. 100(22), pp. 3507 – 3511. [Abstract] [BibTeX] [DOI]
Abstract: The vibrational state perturbing the J = 17 and 18 rotational states of the zero-order v1 + 3v3 state of 12C2H2 is assigned to the state with vibrational energy predicted at Gv = 12 685.1 cm-1 using the cluster model (EL IDRISSI, M.I., LIÉVIN, J., CAMPARGUE, A. and HERMAN, M., 1999, J. chem. Phys., 110, 2074). The assignment is discussed also in terms of the very special pressure shift behaviour demonstrated previously for absorption lines reaching these levels (HERREGODTS, F., HEPP, M., HURTMANS, D., VANDER AUWERA, J. and HERMAN, M., 1999, J. chem. Phys., 111, 7961). The experimental information arising from a set-up newly running at ULB, called FT-ICLAS brings decisive information in the assignment process. This set-up is described briefly.
BibTeX: @article{Hurtmans20023507, author = {Hurtmans, D. and Kassi, S. and Depiesse, C. and Herman, M.}, title = {Assignment of a perturbation in the FT-ICLAS spectrum of 12C2H2 around 12 709.5 cm-1}, journal = {Molecular Physics}, year = {2002}, volume = {100}, number = {22}, pages = {3507 – 3511}, doi = {10.1080/00268970210138904} }
Lattanzi F, Di Lauro C, Herman M and Vander Auwera J (2002), "Torsional line splittings in the (ν4 + ν8) - ν4 hot transitions of C2H6 between 1400 and 1510 cm-1", Journal of Molecular Spectroscopy. Vol. 216(2), pp. 308 – 314. [Abstract] [BibTeX] [DOI]
Abstract: A detailed investigation of the high-resolution infrared spectrum of ethane revealed the occurrence of features belonging to the hot perpendicular system (ν4 + ν8) - ν4 between 1400 and 1510 cm-1. Transition lines of the subbranches with K″ ΔK from -7 to 4, exhibiting torsional splittings of several tenths of a cm-1, were observed and measured in this region. The observed line splittings are strongly influenced by the interaction between the ν4 + ν8 and 2ν4 + ν12 states and change with the values of K″ ΔK, depending on the zero-order energy separation of the interacting levels. We found by numerical extrapolation that splittings still occur far from resonance, showing that the intrinsic torsional splittings of the combining states ν4 + ν8 and ν4 are quite different. We determined the intrinsic torsional splitting of ν4 + ν8 to be less than 0.083 cm-1 estimated for the ν4 state. This result is in agreement with the expected effects of torsional Coriolis and head-tail coupling and is consistent with previous observations on vibrationally degenerate states of ethane-like molecules. © 2002 Elsevier Science (USA).
BibTeX: @article{Lattanzi2002308, author = {Lattanzi, F. and Di Lauro, C. and Herman, M. and Vander Auwera, J.}, title = {Torsional line splittings in the (ν4 + ν8) - ν4 hot transitions of C2H6 between 1400 and 1510 cm-1}, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {216}, number = {2}, pages = {308 – 314}, doi = {10.1006/jmsp.2002.8628} }
Perrin A, Flaud J-M, Bakri B, Demaison J, Baskakov O, Sirota S, Herman M and Vander Auwera J (2002), "New high-resolution analysis of the ν7 and ν9 fundamental bands of trans-formic acid by fourier transform infrared and millimeter-wave spectroscopy", Journal of Molecular Spectroscopy. Vol. 216(2), pp. 203 – 213. [Abstract] [BibTeX] [DOI]
Abstract: The high-resolution (0.002 cm-1) spectrum of the ν7 (OCO scissor mode) and ν9 (COH torsion mode) fundamental bands of trans-formic acid (HCOOH) at 15.8 μm was recorded by Fourier transform infrared spectroscopy. In addition, millimeter-wave transitions within the 71 and 91 vibrational states were measured in the spectral range 340-600 GHz. Using these new experimental data, an extensive analysis of the ν7 and ν9 bands was performed. The model we have used accounts for the strong A- and B-type Coriolis interactions which couple the 71 and 91 vibrational states and which were already pointed out in the literature [J. C. Deroche, J. Kauppinen and E. Kyrö, J. Mol. Spectrosc. 78, 379-394 (1979); E. Willemot, J. Mol. Spectrosc. 120, 246-275 (1986)]. The observed levels are fit to within the experimental accuracy leading to the determination of a precise set of band centers of ν7 and ν9 at 686.1656 cm-1 and 640.7251 cm-1, respectively, and rotational and Coriolis constants. © 2002 Elsevier Science (USA).
BibTeX: @article{Perrin2002203, author = {Perrin, A. and Flaud, J.-M. and Bakri, B. and Demaison, J. and Baskakov, O. and Sirota, S.V. and Herman, M. and Vander Auwera, J.}, title = {New high-resolution analysis of the ν7 and ν9 fundamental bands of trans-formic acid by fourier transform infrared and millimeter-wave spectroscopy}, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {216}, number = {2}, pages = {203 – 213}, doi = {10.1006/jmsp.2002.8659} }
Ram R, Liévin J and Bernath P (2002), "Emission spectroscopy and ab initio calculations for TaN", Journal of Molecular Spectroscopy. Vol. 215(2), pp. 275 – 284. [Abstract] [BibTeX] [DOI]
Abstract: The emission spectra of TaN have been investigated in the region 3000-35 000 cm-1 using a Fourier transform spectrometer. The spectra were observed in a tantalum hollow-cathode lamp by discharging a mixture of 1.5 Torr of Ne and about 6 mTorr of N2. In addition to previously known bands, numerous additional bands were observed and assigned to a number of new transitions. The spectroscopic properties of the low-lying electronic states of TaN were also predicted by ab initio calculations. A 1Σ+ state, with equilibrium constants of Be = 0.457 852 1(48) cm-1, αe = 0.002 235 9(67) cm-1, and Re = 1.683 099 9(88) A, has been identified as the ground state of TaN based on our experimental observations supported by the ab initio results. The first excited state has been identified as the a3 Δ1 spin component at 2827 cm-1 above the ground state. To higher energies, the states become difficult to assign because of their Hund’s case (c) behavior and extensive interactions between the spin components of the electronic terms. © 2002 Elsevier Science (USA).
BibTeX: @article{Ram2002275, author = {Ram, R.S. and Liévin, J. and Bernath, P.F.}, title = {Emission spectroscopy and ab initio calculations for TaN}, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {215}, number = {2}, pages = {275 – 284}, doi = {10.1016/S0022-2852(02)98654-6} }
Ram R, Liévin J and Bernath P (2002), "Emission spectroscopy and ab initio calculations for TaN", Journal of Molecular Spectroscopy. Vol. 215(2), pp. 275 – 284. [Abstract] [BibTeX] [DOI]
Abstract: The emission spectra of TaN have been investigated in the region 3000-35 000 cm-1 using a Fourier transform spectrometer. The spectra were observed in a tantalum hollow-cathode lamp by discharging a mixture of 1.5 Torr of Ne and about 6 mTorr of N2. In addition to previously known bands, numerous additional bands were observed and assigned to a number of new transitions. The spectroscopic properties of the low-lying electronic states of TaN were also predicted by ab initio calculations. A 1Σ+ state, with equilibrium constants of Be = 0.457 852 1(48) cm-1, αe = 0.002 235 9(67) cm-1, and Re = 1.683 099 9(88) Å, has been identified as the ground state of TaN based on our experimental observations supported by the ab initio results. The first excited state has been identified as the a3 Δ1 spin component at 2827 cm-1 above the ground state. To higher energies, the states become difficult to assign because of their Hund's case (c) behavior and extensive interactions between the spin components of the electronic terms. © 2002 Elsevier Science (USA).
BibTeX: @article{Ram2002275, author = {Ram, R.S. and Liévin, J. and Bernath, P.F.}, title = {Emission spectroscopy and ab initio calculations for TaN}, journal = {Journal of Molecular Spectroscopy}, year = {2002}, volume = {215}, number = {2}, pages = {275 – 284}, doi = {10.1006/jmsp.2002.8654} }
Razbirin B, Starukhin A, Chugreev A, Zgoda A, Smirnov V, Grushko Y, Kolesnik S, Coheur P-F, Liévin J and Colin R (2002), "Absorption line spectrum of the C60Cl24 halofullerene", Physics of the Solid State. Vol. 44(11), pp. 2204 – 2209. [Abstract] [BibTeX] [DOI]
Abstract: Optical spectra of the C60Cl24 halofullerene in the crystalline state, as well as of C60Cl24 matrixisolated molecules, were studied. In both cases, a rich line structure was revealed in absorption spectra in the energy region 1.5-3.0 eV. An energy diagram of the electronic levels of the molecule which are responsible for the observed optical transitions is proposed. The parameters of the geometrical structure of the C60Cl24 molecule were calculated under the assumption of its having Th symmetry. These data were used in a theoretical study of the embedment of the C60Cl24 molecule in a toluene crystal matrix, which leads to the formation of a fine spectral structure (an analog of the Shpol'skii effect) observed experimentally in this study. © 2002 MAIK "Nauka/Interperiodica".
BibTeX: @article{Razbirin20022204, author = {Razbirin, B.S. and Starukhin, A.N. and Chugreev, A.V. and Zgoda, A.S. and Smirnov, V.P. and Grushko, Yu.S. and Kolesnik, S.G. and Coheur, P.-F. and Liévin, J. and Colin, R.}, title = {Absorption line spectrum of the C60Cl24 halofullerene}, journal = {Physics of the Solid State}, year = {2002}, volume = {44}, number = {11}, pages = {2204 – 2209}, doi = {10.1134/1.1521480} }
Rooman M, Liévin J, Buisine E and Wintjens R (2002), "Cation-π/H-bond stair motifs at protein-DNA interfaces", Journal of Molecular Biology. Vol. 319(1), pp. 67 – 76. [Abstract] [BibTeX] [DOI]
Abstract: H-bonds and cation-π interactions between nucleic acid bases and amino acid side-chains are known to occur often concomitantly at the interface between protein and double-stranded DNA. Here we define and analyze stair-shaped motifs, which simultaneously involve base stacking, H-bond and cation-π interactions. They consist of two successive bases along the DNA stack, one in cation-π interaction with an amino acid side-chain that carries a total or partial positive charge, and the other H-bonded with the same side-chain. A survey of 52 high-resolution structures of protein/DNA complexes reveals the occurrence of such motifs in the majority of the complexes, the most frequent of these motifs involving Arg side-chains and G bases. These stair motifs are sometimes part of larger motifs, called multiple stair motifs, which contain several successive stairs; zinc finger proteins for example exhibit up to quadruple stairs. In another kind of stair motif extension, termed cation-π chain motif, an amino acid side-chain or a nucleic acid base forms simultaneously two cation-π interactions. Such a motif is observed in several homeodomains, where it involves a DNA base in cation-π interactions with an Arg in the minor groove and an Asn in the major groove. A different cation-π chain motif contains an Arg in cation-π with a G and a Tyr, and is found in ets transcription factors. Still another chain motif is encountered in proteins that expulse a base from the DNA stack and replace it by an amino acid side-chain carrying a net or partial positive charge, which forms cation-π interactions with the two neighboring bases along the DNA strand. The striking conservation of typical stair and cation-π chain motifs within families of protein/DNA complexes suggests that they might play a structural and/or functional role and might moreover influence electron migration through the DNA double helix. © 2002 Elsevier Science Ltd. All rights reserved.
BibTeX: @article{Rooman200267, author = {Rooman, Marianne and Liévin, Jacky and Buisine, Eric and Wintjens, René}, title = {Cation-π/H-bond stair motifs at protein-DNA interfaces}, journal = {Journal of Molecular Biology}, year = {2002}, volume = {319}, number = {1}, pages = {67 – 76}, doi = {10.1016/S0022-2836(02)00263-2} }
Sutcliffe B (2002), "Some observations on P.-O. Löwdin's definition of a molecule", International Journal of Quantum Chemistry. Vol. 90(1), pp. 66 – 79. [Abstract] [BibTeX] [DOI]
Abstract: In a talk given in 1986 in honor of Prof. Raymond Daudel, Löwdin famously defined a molecule in the following quantum mechanical terms: "A system of electrons and atomic nuclei is said to form a molecule if the Coulombic Hamiltonian H′ - with the centre of mass motion removed - has a discrete ground state energy E0." We examine this definition in the context of chemical thinking about a molecule and attempt to place it in the context of the developments since the time of that talk. © 2002 Wiley Periodicals, Inc. Int. J. Quantum. Chem.
BibTeX: @article{Sutcliffe200266, author = {Sutcliffe, Brian}, title = {Some observations on P.-O. Löwdin's definition of a molecule}, journal = {International Journal of Quantum Chemistry}, year = {2002}, volume = {90}, number = {1}, pages = {66 – 79}, doi = {10.1002/qua.1819} }
Sutcliffe B (2002), "The quantum dynamics of a system of two polyatomic fragments", Journal of Physical Chemistry A. Vol. 106(45), pp. 10806 – 10809. [Abstract] [BibTeX] [DOI]
Abstract: The quantum dynamics of a system of two polyatomic fragments was studied. The Hamiltonian, designed to describe the quantum dynamics of a nonrigid system comprising two polyatomic molecules in terms of the separation of their centers of mass, was generalized. It was found that the fragments corresponded to a pair of electrons in a diatomic and the angular momentum of the polyatomic fragments played the same role as does the electronic angular momentum in the diatomic case.
BibTeX: @article{Sutcliffe200210806, author = {Sutcliffe, Brian}, title = {The quantum dynamics of a system of two polyatomic fragments}, journal = {Journal of Physical Chemistry A}, year = {2002}, volume = {106}, number = {45}, pages = {10806 – 10809}, doi = {10.1021/jp021638v} }
Timmermans B, Vaeck N, Hubin A and Reniers F (2002), "Chemical effects in Auger electron spectra of aluminium", Surface and Interface Analysis. Vol. 34(1), pp. 356 – 359. [Abstract] [BibTeX] [DOI]
Abstract: The bonding and electronic structure of surface is most often studied by XPS, where the energy shift of a photoelectron peak can be ascribed to a change in the chemical environment. Because three atomic levels are involved in the Auger emission process, the use of Auger spectroscopy to obtain this information from peak positions and lineshape is more difficult. However, new progress in signal analysis techniques makes the extraction of chemical information intrinsically present in the Auger spectra possible. The advantage of AES over XPS is its higher lateral resolution, allowing study of the surface distribution of the elements (Auger mapping). This, combined with modern computational methods, opens up new opportunities in surface analysis. In order to try to correlate the changes in the Auger peak energies with the changes in the chemical environment, we performed a full experimental and theoretical study of the Auger KLL lines of aluminium in several compounds (Al2O3, AlN, AlB2 and AlF3) by AES and x-ray-induced AES, the peak position for AlB2 being reported for the first time. The inner-shell KLL peaks of Al show large energy shifts, depending on the chemical environment. The experimental results are compared to ab initio calculations based on a new cluster model including chemical, structural and relaxation effects.
BibTeX: @article{Timmermans2002356, author = {Timmermans, B. and Vaeck, N. and Hubin, A. and Reniers, F.}, title = {Chemical effects in Auger electron spectra of aluminium}, journal = {Surface and Interface Analysis}, year = {2002}, volume = {34}, number = {1}, pages = {356 – 359}, doi = {10.1002/sia.1316} }
Turquety S, Hadji-Lazaro J and Clerbaux C (2002), "First satellite ozone distributions retrieved from nadir high-resolution infrared spectra", Geophysical Research Letters. Vol. 29(24) [Abstract] [BibTeX] [DOI]
Abstract: The Interferometric Monitor for Greenhouse Gases (IMG) on board the Japanese ADEOS platform provided the first high resolution atmospheric spectra allowing the simultaneous measurement of several IR absorbing species, including ozone. The paper describes the retrieval of total column ozone fields from nadir radiances, using an inversion algorithm developed for the Infrared Atmospheric Sounding Interferometer (IASI). The accuracy and sensitivity of the retrieved concentrations are assessed. The global distributions obtained from the available IMG/ADEOS Level 1C data are shown to be in good agreement with the TOMS/ADEOS (Total Ozone Mapping Spectrometer) Level 2 measurements. © 2002 by the American Geophysical Union.
BibTeX: @article{Turquety2002, author = {Turquety, Solène and Hadji-Lazaro, Juliette and Clerbaux, Cathy}, title = {First satellite ozone distributions retrieved from nadir high-resolution infrared spectra}, journal = {Geophysical Research Letters}, year = {2002}, volume = {29}, number = {24}, note = {All Open Access, Green Open Access}, doi = {10.1029/2002GL016431} }
Turquety S, Hadji-Lazaro J and Clerbaux C (2002), "Retrieval of ozone from infrared IASI measurements", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4539, pp. 106 – 115. [Abstract] [BibTeX] [DOI]
Abstract: The Infrared Atmospheric Sounding Interferometer (IASI), which is due for launch in 2005 aboard the European METOP satellite, will record the infrared radiation of the Earth/atmosphere system in a nadir-viewing geometry. The sensitivity studies carried out on simulated IASI spectra allowed us to highlight its capability to retrieve both total and tropospheric column amounts of ozone. Two algorithms based on neural network techniques have been developed to retrieve these quantities. The averaging kernels characterizing the results show that the information corresponding to the different atmospheric layers can be isolated. However, for the tropospheric ozone retrieval, the lower stratosphere is not totally decoupled, which induces larger uncertainties for the tropospheric columns than for the total columns. Nevertheless, very satisfactory performance has been achieved for both algorithms, with inversion errors smaller than 5 % for the total column retrieval and smaller than 20 % for the tropospheric column retrieval. The Interferometer Monitor for Greenhouse Gases (IMG), which flew aboard the Japanese ADEOS platform was based on the same observation technique as IASI, which enabled us to test our algorithms on real data. Both algorithms have been applied to these data for June 1997. The distributions obtained are in good agreement with the Total Ozone Mapping Spectrometer (TOMS) measurements.
BibTeX: @conference{Turquety2002106, author = {Turquety, Solène and Hadji-Lazaro, Juliette and Clerbaux, Cathy}, title = {Retrieval of ozone from infrared IASI measurements}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2002}, volume = {4539}, pages = {106 – 115}, doi = {10.1117/12.454426} }
Vaeck N and Kylstra NJ (2002), "Statistical properties of hollow atoms", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 65(6 A), pp. 625021 – 625028. [Abstract] [BibTeX]
Abstract: The statistical properties of a prototype of an atom having a large number of empty inner shells was investigated. The resonance states were found to be strongly overlapping and the number of decay channels was much larger than the number of states. The results showed that the distribution of the nearest-neighbor energy-level spacings followed a Wigner distribution.
BibTeX: @article{Vaeck2002625021, author = {Vaeck, Nathalie and Kylstra, Niels J.}, title = {Statistical properties of hollow atoms}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2002}, volume = {65}, number = {6 A}, pages = {625021 – 625028} }
Vaeck N and Kylstra NJ (2002), "Statistical properties of hollow atoms", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 65(6), pp. 8. [Abstract] [BibTeX] [DOI]
Abstract: We investigate the statistical properties of a prototype of a “hollow atom", i.e., an atom having a large number of empty inner shells. In particular, we have carried out ab initio calculations of the positions and widths of the [Formula Presented] states of nitrogen. These states give rise to a dense spectrum of strongly overlapping resonances. Due to the large number of open channels, the statistical description of the system simplifies considerably. We find that the distribution of the nearest-neighbor energy-level spacings follows a Wigner distribution, while the widths of the states are narrowly distributed about the average perturbative width. © 2002 The American Physical Society.
BibTeX: @article{Vaeck20028, author = {Vaeck, Nathalie and Kylstra, Niels J.}, title = {Statistical properties of hollow atoms}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2002}, volume = {65}, number = {6}, pages = {8}, doi = {10.1103/PhysRevA.65.062502} }
Vandaele A, Hermans C, Fally S, Carleer M, Colin R, Mérienne M-F, Jenouvrier A and Coquart B (2002), "High-resolution Fourier transform measurement of the NO2 visible and near-infrared absorption cross sections: Temperature and pressure effects", Journal of Geophysical Research Atmospheres. Vol. 107(18), pp. ACH 3–1 – ACH 3–12. [Abstract] [BibTeX] [DOI]
Abstract: High-resolution NO2 absorption cross sections have been obtained in the near-IR (NIR) and visible regions using a Fourier transform spectrometer coupled to a multiple reflection cell. Spectra were recorded at 0.05 cm-1 in the NIR region (10,800-15,100 cm-1) and at 0.1 cm-1 in the visible region (13,800-26,000 cm-1), under various pressure conditions (pure NO2 and NO2/air mixtures) and at three temperatures (220, 240, and 294 K). The effects of the temperature and the pressure on the NO2 cross sections have been investigated. As expected, an increase of temperature results in a decrease of the absorption at the maxima of the absorption bands and an increase at the minima. From the measurements performed with pure NO2 at different temperatures a linear regression of the cross section with temperature has been carried out. This enabled the cross sections to be reproduced within 2% at room temperature and 7% at the lower temperatures. The variation of the cross sections with the total pressure of NO2/air mixtures has also been investigated at high resolution. Copyright 2002 by the American Geophysical Union.
BibTeX: @article{Vandaele2002ACH3, author = {Vandaele, A.C. and Hermans, C. and Fally, S. and Carleer, M. and Colin, R. and Mérienne, M.-F. and Jenouvrier, A. and Coquart, B.}, title = {High-resolution Fourier transform measurement of the NO2 visible and near-infrared absorption cross sections: Temperature and pressure effects}, journal = {Journal of Geophysical Research Atmospheres}, year = {2002}, volume = {107}, number = {18}, pages = {ACH 3–1 – ACH 3–12}, doi = {10.1029/2001JD000971} }
Vandaele A, Tsouli A, Carleer M and Colin R (2002), "UV Fourier transform measurements of tropospheric O3, NO2, SO2, benzene, and toluene", Environmental Pollution. Vol. 116(2), pp. 193 – 201. [Abstract] [BibTeX] [DOI]
Abstract: Using the differential optical absorption spectroscopy (DOAS) technique and a Fourier transform spectrometer, NO2, SO2, O3, benzene, and toluene were measured during three measurement campaigns held in Brussels in 1995, 1996, and 1997. The O3 concentrations could be explained as the results of the local photochemistry and the dynamical properties of the mixing layer. NO2 concentrations were anti-correlated to the O3 concentrations, as expected. SO2 also showed a pronounced dependence on car traffic. Average benzene and toluene concentrations were, respectively 1.7 ppb and between 4.4 and 6.6 pbb, but high values of toluene up to 98.8 ppb were observed. SO2 concentrations and to a lesser extent, those of NO2 and O3, were dependent on the wind direction. Ozone in Brussels has been found to be influenced by the meteorological conditions prevailing in central Europe. Comparisons with other measurements have shown that O3 and SO2 data are in general in good agreement, but our NO2 concentrations seem to be generally higher. © 2001 Elsevier Science Ltd. All rights reserved.
BibTeX: @article{Vandaele2002193, author = {Vandaele, A.C. and Tsouli, A. and Carleer, M. and Colin, R.}, title = {UV Fourier transform measurements of tropospheric O3, NO2, SO2, benzene, and toluene}, journal = {Environmental Pollution}, year = {2002}, volume = {116}, number = {2}, pages = {193 – 201}, doi = {10.1016/S0269-7491(01)00141-5} }
Weirauch G, Campargue A, El Idrissi M and Herman M (2002), "The absorption spectrum of 12C2H2 IV. The regions 7600-9200 cm-1 and 10600-11500 cm-1", Molecular Physics. Vol. 99(2), pp. 143 – 149. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of 12C2H2 has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the 10 600-11 500 cm-1 spectral region, where no absorption bands were previously reported. Fifteen bands starting from the vibrational ground state are observed and rotationally analysed. All corresponding excited vibrational levels were assigned using the polyad model, the so-called cluster model (El Idrissi, M.I., Liévin, J., Campargue, A., and Herman, M., 1999, J. chem. Phys., 110, 2074) which allows vibrational energies, rotational BV constants and, to some respect, relative band intensities to be predicted. Additional data and constants are also provided in the range 7600-9200 cm-1, whenever improving the literature results, from spectra recorded previously at ULB using Fourier transform spectroscopy. The assignment procedure in the range recorded by ICLAS is detailed, leading to a deeper understanding of vibration-rotation and intensity features of the absorption bands within the frame of the cluster model.
BibTeX: @article{Weirauch2002143, author = {Weirauch, G. and Campargue, A. and El Idrissi, M.I. and Herman, M.}, title = {The absorption spectrum of 12C2H2 IV. The regions 7600-9200 cm-1 and 10600-11500 cm-1}, journal = {Molecular Physics}, year = {2002}, volume = {99}, number = {2}, pages = {143 – 149}, doi = {10.1080/00268970010008388} }
Baloïtcha E, Desouter-Lecomte M, Bacchus-Montabonel M-C and Vaeck N (2001), "Wave packet methods for charge exchange processes in ion-atom collisions", Journal of Chemical Physics. Vol. 114(20), pp. 8741 – 8751. [Abstract] [BibTeX] [DOI]
Abstract: Efficiency of different time-dependent and time-independent wave packet methods for charge-exchange cross sections in ion-atom collisions was discussed. The time-independent spectral projection method, based on the Chebyshev expansion of the resolvent function involved a time propagation while the flux operator method required propagation in time. Flux operator method used the properties of absorbing potentials in order to calculate the flux operator matrix elements.
BibTeX: @article{Baloïtcha20018741, author = {Baloïtcha, E. and Desouter-Lecomte, M. and Bacchus-Montabonel, M.-C. and Vaeck, N.}, title = {Wave packet methods for charge exchange processes in ion-atom collisions}, journal = {Journal of Chemical Physics}, year = {2001}, volume = {114}, number = {20}, pages = {8741 – 8751}, doi = {10.1063/1.1367378} }
Blondel C, Delsart C, Valli C, Yiou S, Godefroid M and Van Eck S (2001), "Electron affinities of [Formula Presented] [Formula Presented] [Formula Presented] the fine structure of [Formula Presented] and the hyperfine structure of [Formula Presented]", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 64(5), pp. 14. [Abstract] [BibTeX] [DOI]
Abstract: Photodetachment microscopy has been used in a double-pass, field-collinear scheme in order to measure the electron affinity of atomic oxygen. As an illustration of the sensitivity of the method, electron images could be recorded even from the rarest [Formula Presented] ion. Analysis of photodetachment images recorded with this odd isotope, however, requires that one knows the unresolved hyperfine structures of the ground states of both the neutral atom [Formula Presented] and the negative ion. Calculation of the hyperfine structure of [Formula Presented] was achieved, which permitted to add the electron affinity of [Formula Presented] to the series of the measured electron affinities of oxygen isotopes. The anomalous isotope shift of these electron affinities is finally compared with ab initio calculations. © 2001 The American Physical Society.
BibTeX: @article{Blondel200114, author = {Blondel, C. and Delsart, C. and Valli, C. and Yiou, S. and Godefroid, M.R. and Van Eck, S.}, title = {Electron affinities of [Formula Presented] [Formula Presented] [Formula Presented] the fine structure of [Formula Presented] and the hyperfine structure of [Formula Presented]}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2001}, volume = {64}, number = {5}, pages = {14}, doi = {10.1103/PhysRevA.64.052504} }
Blondel C, Delsart C, Valli C, Yiou S, Godefroid M and Van Eck S (2001), "Electron affinities of 16O, 17O, 18O, the fine structure of 16O-, and the hyperfine structure of 17O-", Physical Review A. Atomic, Molecular, and Optical Physics. Vol. 64(5), pp. 525041 – 5250414. [Abstract] [BibTeX]
Abstract: Measurement of electron affinity of atomic oxygen was done using a photodetachment microscopy. For 17O-, calculation of the hyperfine structure was done, which permitted to add the electron affinity of 17O to the series of the measured electron affinities of oxygen isotopes. Comparison of the anomalous isotope shift of these electron affinities was done with ab initio calculations.
BibTeX: @article{Blondel2001525041, author = {Blondel, C. and Delsart, C. and Valli, C. and Yiou, S. and Godefroid, M.R. and Van Eck, S.}, title = {Electron affinities of 16O, 17O, 18O, the fine structure of 16O-, and the hyperfine structure of 17O-}, journal = {Physical Review A. Atomic, Molecular, and Optical Physics}, year = {2001}, volume = {64}, number = {5}, pages = {525041 – 5250414} }
Carleer M (2001), "WSpectra: A Windows® program to measure accurately the line intensities of high resolution Fourier transform spectra", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4168, pp. 337 – 342. [Abstract] [BibTeX] [DOI]
Abstract: A program to measure with the highest accuracy the line parameters of high resolution Fourier transform spectra recorded in the laboratory has been written. Tests of the accuracy of the calculated parameters have been performed by comparing the results of the analysis of the 2-0 band of CO and of the v3 + v4 band of CO2. The line position accuracy has been found to be 9×10-6 cm-1, and the line intensity accuracy is of the order of 1 % or better.
BibTeX: @conference{Carleer2001337, author = {Carleer, M.R.}, title = {WSpectra: A Windows® program to measure accurately the line intensities of high resolution Fourier transform spectra}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2001}, volume = {4168}, pages = {337 – 342}, doi = {10.1117/12.413851} }
Claveau C, Henry A, Hurtmans D and Valentin A (2001), "Narrowing and broadening parameters of H2O lines perturbed by He, Ne, Ar, Kr and nitrogen in the spectral range 1850-2140 cm-1", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 68(3), pp. 273 – 298. [Abstract] [BibTeX] [DOI]
Abstract: Collision effects on water vapor at low concentration in mixture with noble gases and nitrogen have been studied by Fourier transform spectroscopy in a pressure range where line narrowing by dynamic confinement (Dicke effect) and collision broadening are observable, i.e. when the Voigt function cannot reproduce the observed profiles. Precise values of the broadening parameter have been obtained for R branch lines of the ν2 band of H2O and narrowing parameter values were derived using the soft and hard collision models. Furthermore, it is shown that, when neglecting the confinement effect, systematic errors on the broadening parameters may be introduced and reach several percents for the narrowest lines corresponding to the highest J values. © 2000 Elsevier Science Ltd. All rights reserved.
BibTeX: @article{Claveau2001273, author = {Claveau, C. and Henry, A. and Hurtmans, D. and Valentin, A.}, title = {Narrowing and broadening parameters of H2O lines perturbed by He, Ne, Ar, Kr and nitrogen in the spectral range 1850-2140 cm-1}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2001}, volume = {68}, number = {3}, pages = {273 – 298}, doi = {10.1016/S0022-4073(00)00025-X} }
Clerbaux C, Hadji-Lazaro J, Hauglustaine D, Mégie G, Khattatov B and Lamarque J-F (2001), "Assimilation of carbon monoxide measured from satellite in a three-dimensional chemistry-transport model", Journal of Geophysical Research Atmospheres. Vol. 106(D14), pp. 15385 – 15394. [Abstract] [BibTeX] [DOI]
Abstract: Carbon monoxide measurements are obtained from the analysis of the spectra provided by the Interferometric Monitor for Greenhouse Gases (IMG) instrument, which flew on board the Japanese ADEOS satellite. The averaging kernel function of the instrument, which provides the sensitivity of retrieved CO to the vertical atmospheric layers, is calculated. A sequential assimilation approach is used to incorporate this CO data set, along with a detailed associated error budget, into a global three-dimensional chemistry-transport model (MOZART version 2). We show how data assimilation allows one to highlight the differences between modeled and observed CO global distribution. Surface CO mixing ratios computed after assimilation of total columns provided by the IMG instrument are compared with the National Oceanic and Atmospheric Administration (NOAA) - Climate Monitoring and Diagnostics Laboratory (CMDL) in situ measurements, and a good agreement is found between the two data sets. Copyright 2001 by the American Geophysical Union.
BibTeX: @article{Clerbaux200115385, author = {Clerbaux, Cathy and Hadji-Lazaro, Juliette and Hauglustaine, Didier and Mégie, Gérard and Khattatov, Boris and Lamarque, Jean-François}, title = {Assimilation of carbon monoxide measured from satellite in a three-dimensional chemistry-transport model}, journal = {Journal of Geophysical Research Atmospheres}, year = {2001}, volume = {106}, number = {D14}, pages = {15385 – 15394}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/2000JD900682} }
Coheur P-F, Fally S, Vandaele A, Hermans C, Jenouvrier A, Carleer M, Mérienne M-F, Clerbaux C and Colin R (2001), "Absolute intensities of water vapor lines in the near ultraviolet and visible regions", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4168, pp. 97 – 105. [Abstract] [BibTeX] [DOI]
Abstract: This work reports on the analysis of the near-UV and visible absorption spectrum of water vapor, obtained by combining a high-resolution FT spectrometer and a long path White multiple-reflection cell (total path length of 602 m). A large number of water vapor lines belonging to highly excited vibrational levels (polyads up to 8 v) are identified. Most of these lines have not been observed previously and do not appear in the spectroscopic databases HITRAN and GEISA, widely used for atmospheric calculations. All identified lines are fitted with a Voigt profile using the WSPECTRA program and their cross section and self-broadening parameters at 291 K are determined. A particular attention is given to the integrated cross section over the total spectral range investigated (25000-20000 cm-1), in order to estimate the contribution of the weak UV-visible water vapor absorption lines to the earth's radiation balance. Preliminary measurements of cross section in the 20000-16000 cm-1 spectral range are also presented.
BibTeX: @conference{Coheur200197, author = {Coheur, P.-F. and Fally, S. and Vandaele, A.C. and Hermans, C. and Jenouvrier, A. and Carleer, M. and Mérienne, M.-F. and Clerbaux, C. and Colin, R.}, title = {Absolute intensities of water vapor lines in the near ultraviolet and visible regions}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {2001}, volume = {4168}, pages = {97 – 105}, doi = {10.1117/12.413853} }
Daumont L, Vander Auwera J, Teffo J-L, Perevalov V and Tashkun S (2001), "Line intensity measurements in 14N2 16O and their treatment using the effective dipole moment approach: I. The 4300- to 5200-cm−1 Region", Journal of Molecular Spectroscopy. Vol. 208(2), pp. 281 – 291. [Abstract] [BibTeX] [DOI]
Abstract: This work continues a series of publications devoted to the application of the effective operator approach to the vibrational-rotational treatment of linear triatomic molecules, aiming at the analysis and prediction of their infrared spectra. In that frame work, we have started a large-scale work aiming at the global description of line intensities of cold and hot bands of 14N2 16O in its ground electronic state in the spectral range above 3600 cm−1. In 14N2 16O, vibrational interacting levels group in polyads as a result of the relation 2ω1 ≈ 4ω2 ≈ ω3 existing between the harmonic frequencies. The polyads are identified by the so-called polyad number P = 2V1 + V2 + 4V3. The work described in the present paper concerns bands associated with transitions corresponding to ΔP = 7, 8, and 9. The absorption spectra of N2O at room temperature have been recorded at a resolution of 0.007 cm−1 in the range from 4300 to 5200 cm−1 using a Bruker IFS120HR Fourier transform spectrometer. Sample pressure/absorption path length products ranging from 7 to 1753 mbar x m have been used. More than 3000 absolute line intensities have been measured in 66 different bands belonging to the ΔP = 7, 8, and 9 series. Dicke narrowing has been observed in the high-pressure spectra. Using wavefunctions previously determined from a global fit of an effective Hamiltonian to about 18, 000 line positions (S. A. Tashkun, V. I. Perevalov, and J.-L. Teffo to be published), the experimental intensities measured in this work and by R. A. Toth (J. Mol. Spectrosc. 197, 158-187 (1999)) were fitted to 47 parameters of a corresponding effective dipole moment, with residuals very close to the experimental uncertainty. Examples are given showing that the modeling reproduces intensities of perturbed lines well. © 2001 Academic Press.
BibTeX: @article{Daumont2001281, author = {Daumont, L. and Vander Auwera, J. and Teffo, J.-L. and Perevalov, V.I. and Tashkun, S.A.}, title = {Line intensity measurements in 14N2 16O and their treatment using the effective dipole moment approach: I. The 4300- to 5200-cm−1 Region}, journal = {Journal of Molecular Spectroscopy}, year = {2001}, volume = {208}, number = {2}, pages = {281 – 291}, doi = {10.1006/jmsp.2001.8400} }
El Idrissi M, Liévin J, Herman M, Campargue A and Graner G (2001), "The vibrational energy pattern in propyne (12CH312C2H)", Chemical Physics. Vol. 265(3), pp. 273 – 289. [Abstract] [BibTeX] [DOI]
Abstract: The results of ab initio calculations at the MP2 level of theory are presented, which provide refined equilibrium geometrical parameters and better characterization of the vibrational normal modes in propyne (CH3C2H). These results help performing the vibrational analysis of the high resolution Fourier transform absorption spectrum of this molecule which has been recorded between 2000 and 10 200 cm-1. The vibrational assignment criteria also include, in particular, the detailed identification of the band shape based on the observed rotational structure that is resolved for most bands. Some 46 bands are observed and their band shape identified in most cases. Among the bands newly reported, some 14 are vibrationally assigned, three of them tentatively. The relative intensity of all observed bands is estimated from the spectra. Approximate ζ rotational constants are obtained for ν3 + ν6 (0.074) and 2ν1 +ν8 (0.38). The results are merged with those of the previous literature, leading to list the origin of 118 vibrational bands, from which an extensive set of vibrational constants is extracted. Two polyad quantum numbers emerge from the vibrational energy pattern: Nsb = 3v1 + v3 + 2v5 + v9 and Ns = v1 + v3, supported by the ν1 with ν3+ ν5 and ν1 with ν3+ 2ν9 anharmonic resonances. © 2001 Elsevier Science B.V.
BibTeX: @article{ElIdrissi2001273, author = {El Idrissi, M.I. and Liévin, J. and Herman, M. and Campargue, A. and Graner, G.}, title = {The vibrational energy pattern in propyne (12CH312C2H)}, journal = {Chemical Physics}, year = {2001}, volume = {265}, number = {3}, pages = {273 – 289}, doi = {10.1016/S0301-0104(01)00308-1} }
Flaud J-M, Lafferty W and Herman M (2001), "First high resolution analysis of the absorption spectrum of propane in the 6.7 μm to 7.5 μm spectral region", Journal of Chemical Physics. Vol. 114(21), pp. 9361 – 9366. [Abstract] [BibTeX] [DOI]
Abstract: A molecular beam coupled to a Fourier transform spectrometer was used to analyze the rotational structure and vibrational fundamentals of the various propane molecules. Watson type Hamiltonians were used to analyze the two isolated bands while the two higher frequency bands were analyzed using the Coriolis interaction coupling. The standard uncertainties of the values include the calibration errors as well as the the statistical uncertainty of the fittings.
BibTeX: @article{Flaud20019361, author = {Flaud, J.-M. and Lafferty, W.J. and Herman, M.}, title = {First high resolution analysis of the absorption spectrum of propane in the 6.7 μm to 7.5 μm spectral region}, journal = {Journal of Chemical Physics}, year = {2001}, volume = {114}, number = {21}, pages = {9361 – 9366}, doi = {10.1063/1.1368386} }
Godefroid M, Froese Fischer C and Jönsson P (2001), "Non-relativistic variational calculations of atomic properties in Li-like ions: Li I to O VI", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 34(6), pp. 1079 – 1104. [Abstract] [BibTeX] [DOI]
Abstract: The multiconfiguration Hartree-Fock method is used to calculate wavefunctions in the infinite nuclear mass limit for the terms 2s 2S, 2p 2P o, 3s 2S, 3p 2P o, 3d 2D and 4s 2S of lithium-like ions (3 ≤ Z ≤ 8). Transition data, isotope shift parameters and hyperfine structure electronic contributions involving the six terms of the six ions are evaluated ab initio and compared with the most recent observations and other theoretical calculations when available. The isotopes 7,6Li I, 11,10,9,7Be II, 14,13,12C IV, 15,14N V and 18,17,16 O VI are considered in the analysis of the mass isotope shifts.
BibTeX: @article{Godefroid20011079, author = {Godefroid, M. and Froese Fischer, C. and Jönsson, P.}, title = {Non-relativistic variational calculations of atomic properties in Li-like ions: Li I to O VI}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2001}, volume = {34}, number = {6}, pages = {1079 – 1104}, doi = {10.1088/0953-4075/34/6/308} }
Hadji-Lazaro J, Clerbaux C, Couvert P, Chazette P and Boonne C (2001), "Cloud filter for CO retrieval from IMG infrared spectra using ECMWF temperatures and POLDER cloud data", Geophysical Research Letters. Vol. 28(12), pp. 2397 – 2400. [Abstract] [BibTeX] [DOI]
Abstract: Infrared atmospheric measurements provided by space nadir looking remote sensors are affected by the presence of clouds. To obtain cloud-free CO global distributions from the radiance spectra measured by the IMG instrument, we have developed a simple method of spectra selection using skin temperatures provided by the ECMWF model. Information on the cloud cover was provided by the cloud data of the POLDER instrument which flew aboard the same platform as IMG. We show that a filter based on skin temperature, with thresholds of 8 K over sea and 15.3 K over land, allows to remove most of the cloudy cases.
BibTeX: @article{Hadji-Lazaro20012397, author = {Hadji-Lazaro, Juliette and Clerbaux, Cathy and Couvert, Pierre and Chazette, Patrick and Boonne, Cathy}, title = {Cloud filter for CO retrieval from IMG infrared spectra using ECMWF temperatures and POLDER cloud data}, journal = {Geophysical Research Letters}, year = {2001}, volume = {28}, number = {12}, pages = {2397 – 2400}, note = {All Open Access, Green Open Access}, doi = {10.1029/2000GL012342} }
Hurtmans D, Rizopoulos A, Herman M, Hassan L and Perrin A (2001), "Vibration-rotation analysis of the jet-cooled v12, v7 + v8 and v6 + v10 absorption bands of 12C2H4", Molecular Physics. Vol. 99(5), pp. 455 – 461. [Abstract] [BibTeX] [DOI]
Abstract: A Fourier transform interferometer was used to record the slit-jet cooled absorption spectrum of 12C2H4 between 700 and 2400 cm-1, at a spectral resolution of 0.005cm-1. Three bands, v12 at 1442.44270(1) cm-1, v7 + v8 at 1888.978 23(3)cm-1 and v6 + v10 at 2047.775832(2) cm-1, were rotationally analysed. In the case of 7181, a known Coriolis perturbation mechanism involving the nearby 4181 (1958.264 cm-1) and 81101 (1766.391 cm-1) states was accounted for in the analysis. The latter fitting procedure included 12 levels from the 4181 state which are observed because lines from v4 + v8 borrow intensity from v7 + v8. Compared to the literature, significantly improved vibration-rotation constants were obtained for all upper states reported in the present study.
BibTeX: @article{Hurtmans2001455, author = {Hurtmans, D. and Rizopoulos, A. and Herman, M. and Hassan, L.M.S. and Perrin, A.}, title = {Vibration-rotation analysis of the jet-cooled v12, v7 + v8 and v6 + v10 absorption bands of 12C2H4}, journal = {Molecular Physics}, year = {2001}, volume = {99}, number = {5}, pages = {455 – 461}, doi = {10.1080/00268970010017018} }
Jenouvrier A, Mérienne M, Carleer M, Colin R, Vandaele A-C, Bernath P, Polyansky OL and Tennyson J (2001), "The visible and near ultraviolet rotation-vibration spectrum of HOD", Journal of Molecular Spectroscopy. Vol. 209(2), pp. 165 – 168. [Abstract] [BibTeX] [DOI]
Abstract: A Fourier transform spectrum has been recorded of a H2O/D2O vapor mixture in the wavenumber range 16, 300 to 22, 800 cm−1 using a long path cell. 410 lines of HDO are assigned to the OH stretching overtone bands 5v3, 6v3 and 7v3 plus combination bands. Assignments for the 6v3 and 7v3 bands represent the first data for the 006 and 007 states and give band origins of 19, 836.88 cm−1 and 22, 625.50 cm−1, respectively. Rotational term values for these states are also obtained. © 2001 Academic Press.
BibTeX: @article{Jenouvrier2001165, author = {Jenouvrier, A. and Mérienne, M.F. and Carleer, M. and Colin, R. and Vandaele, A.-C. and Bernath, P.F. and Polyansky, Oleg L. and Tennyson, Jonathan}, title = {The visible and near ultraviolet rotation-vibration spectrum of HOD}, journal = {Journal of Molecular Spectroscopy}, year = {2001}, volume = {209}, number = {2}, pages = {165 – 168}, note = {All Open Access, Green Open Access}, doi = {10.1006/jmsp.2001.8418} }
Mellouki A, Liévin J and Herman M (2001), "The vibrational spectrum of pyrrole (C4H5N) and furan (C4H4O) in the gas phase", Chemical Physics. Vol. 271(3), pp. 239 – 266. [Abstract] [BibTeX] [DOI]
Abstract: We have recorded the absorption spectrum of pyrrole (C5H5N) and furan (C4H4O) on a broad spectral range in the infrared region and under various experimental conditions, using a Fourier transform interferometer. The resolution was good enough to reliably identify band shapes. We have performed the vibrational assignment of the vibration-rotation bands observed between 500 and 12,000 cm-1 for pyrrole, and 500 and 9000 cm-1 for furan. The assignment of the fundamental bands is supported by ab initio calculations at the MP2 level of approximation, considering both band positions and absolute absorption intensities. These calculations also allowed the normal mode coordinates to be drawn for the two species and their geometrical structure to be calculated. Vibrational mode numbering and symmetries are updated to latest conventions in the literature. In the combination and overtone spectral ranges, the band shape information guided the assignment, which could be achieved for most of the numerous observed bands. An extensive set of vibration constants was obtained for each species. The results from the literature available on each species are considered at each step of the investigation. © 2001 Elsevier Science B.V. All rights reserved.
BibTeX: @article{Mellouki2001239, author = {Mellouki, A. and Liévin, J. and Herman, M.}, title = {The vibrational spectrum of pyrrole (C4H5N) and furan (C4H4O) in the gas phase}, journal = {Chemical Physics}, year = {2001}, volume = {271}, number = {3}, pages = {239 – 266}, doi = {10.1016/S0301-0104(01)00447-5} }
Mellouki A, Vander Auwera J, Demaison J and Herman M (2001), "Rotational analysis of the v6 band in furan (C4H4O)", Journal of Molecular Spectroscopy. Vol. 209(1), pp. 136 – 138. [BibTeX] [DOI]
BibTeX: @article{Mellouki2001136, author = {Mellouki, Abdeloihid and Vander Auwera, Jean and Demaison, J. and Herman, Michel}, title = {Rotational analysis of the v6 band in furan (C4H4O)}, journal = {Journal of Molecular Spectroscopy}, year = {2001}, volume = {209}, number = {1}, pages = {136 – 138}, doi = {10.1006/jmsp.2001.8393} }
Mérienne M-F, Jenouvrier A, Coquart B, Carleer M, Fally S, Colin R, Vandaele A and Hermans C (2001), "Improved data set for the herzberg band systems of 16o2 ", Journal of Molecular Spectroscopy. Vol. 207(1), pp. 120. [BibTeX] [DOI]
BibTeX: @article{Mérienne2001120, author = {Mérienne, Marie-France and Jenouvrier, Alain and Coquart, Bernard and Carleer, Michel and Fally, Sophie and Colin, Reginald and Vandaele, A.C. and Hermans, Christian}, title = {Improved data set for the herzberg band systems of 16o2 }, journal = {Journal of Molecular Spectroscopy}, year = {2001}, volume = {207}, number = {1}, pages = {120}, note = {All Open Access, Green Open Access}, doi = {10.1006/jmsp.2001.8314} }
Palmeri P, Quinet P, Zitane N and Vaeck N (2001), "Calculation of Auger rates for complex hollow-atom configurations", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 34(21), pp. 4125 – 4139. [Abstract] [BibTeX] [DOI]
Abstract: In this paper, the general behaviour of the Auger rates of hollow atoms for different types of configurations involving identical or non-identical electrons is studied in order to reveal trends in the decay properties of these complex systems. For highly charged ions neutralized with electrons in excited configurations, conventional calculations such as those using available atomic structure codes are generally out of reach. Therefore, we have developed a global approach which allows one to estimate the Auger rates for these 'exotic' systems. When using this method in several simple cases (nitrogen, neon), it has been possible to reproduce level-by-level calculations with good accuracy. Our new approach has allowed us to calculate lifetimes for hollow xenon, lead and thorium ions and the results are discussed in connection with recent experimental data on ion-fullerene collisions.
BibTeX: @article{Palmeri20014125, author = {Palmeri, P. and Quinet, P. and Zitane, N. and Vaeck, N.}, title = {Calculation of Auger rates for complex hollow-atom configurations}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {2001}, volume = {34}, number = {21}, pages = {4125 – 4139}, doi = {10.1088/0953-4075/34/21/305} }
Ram R, Adam A, Sha W, Tsouli A, Liévin J and Bernath P (2001), "The electronic structure of ZrCl", Journal of Chemical Physics. Vol. 114(9), pp. 3977 – 3987. [Abstract] [BibTeX]
Abstract: The proposed electronic assignments of our previously reported near infrared transitions of ZrCl [J. Mol. Spectrosc. 186, 335 (1997); 196, 235 (1999)] have been revised following the suggestion of Sakai, Mogi, and Miyoshi [J. Chem. Phys. 111, 3989 (1999)]. The ground state is now assigned as the X2Δ state followed by the a 4Φ state being the lowest in the quartet manifold. The previously reported transitions [7.3]2Δ-a2Φ, [9.4]2Φ-a2Φ, and C4Δ-X4Φ are now reassigned to C2Φ-X2Δ, E2Φ-X2Δ, and d4Δ-a4Φ, respectively. The new assignments are supported by our own ab initio calculations. Laser excitation spectra of the 414 nm band system have also been observed at low resolution and are attributed to a 4Γ-a4Φ transition. © 2001 American Institute of Physics.
BibTeX: @article{Ram20013977, author = {Ram, R.S. and Adam, A.G. and Sha, W. and Tsouli, A. and Liévin, J. and Bernath, P.F.}, title = {The electronic structure of ZrCl}, journal = {Journal of Chemical Physics}, year = {2001}, volume = {114}, number = {9}, pages = {3977 – 3987} }
Ram RS, Liévin J, Li G, Hirao T and Bernath PF (2001), "The X3Σ- ground state of WO", Chemical Physics Letters. Vol. 343(3-4), pp. 437 – 445. [Abstract] [BibTeX] [DOI]
Abstract: The WO molecule was formed as an impurity during the excitation of a mixture of WCl6 vapor and He in a microwave discharge lamp. The emission spectra were recorded using a high-resolution Fourier transform spectrometer. A rotational analysis of the strong bands in the 9000-25000 cm-1 interval has been carried out and the bands have been classified into two groups with different lower states. The two lower states have been assigned as the Ω=0+ and Ω=1 spin components of the X3Σ- ground state. Ab initio calculations have also been performed and they confirm our experimental assignments. © 2001 Elsevier Science B.V.
BibTeX: @article{Ram2001437, author = {Ram, Ram S. and Liévin, Jacky and Li, Gang and Hirao, Tsuyoshi and Bernath, Peter F.}, title = {The X3Σ- ground state of WO}, journal = {Chemical Physics Letters}, year = {2001}, volume = {343}, number = {3-4}, pages = {437 – 445}, doi = {10.1016/S0009-2614(01)00704-7} }
Sutcliffe B (2001), "Some mathematical problems in the description of dissociating molecules", Advances in Quantum Chemistry. Vol. 40, pp. 17 – 36. [Abstract] [BibTeX] [DOI]
Abstract: When separating the centre of mass motion from the Schrödinger problem for a system, some apparently reasonable choices of space fixed coordinates have transformation properties under nuclear permutations that mix variables that are formally nuclear with those that are formally electronic variables. This renders the idea of a potential surface expressed in such coordinates, problematic. The problems are discussed and some solutions suggested. © 2001.
BibTeX: @article{Sutcliffe200117, author = {Sutcliffe, Brian}, title = {Some mathematical problems in the description of dissociating molecules}, journal = {Advances in Quantum Chemistry}, year = {2001}, volume = {40}, pages = {17 – 36}, doi = {10.1016/s0065-3276(01)40007-4} }
Tipping R, Brown A, Ma Q, Hartmann J, Boulet C and Liévin J (2001), "Collision-induced absorption in the v2 fundamental band of CH4. I. Determination of the quadrupole transition moment", Journal of Chemical Physics. Vol. 115(19), pp. 8852 – 8857. [Abstract] [BibTeX] [DOI]
Abstract: The vibrating quadrupole of CH4 interacting with the polarizability of the perturber is proposed as another collision-induced dipole mechanism. This mechanism would be present for absorption in the v2 region. For demonstration purposes, the simplest case of CH4-Ar is considered.
BibTeX: @article{Tipping20018852, author = {Tipping, R.H. and Brown, Alex and Ma, Q. and Hartmann, J.M. and Boulet, C. and Liévin, J.}, title = {Collision-induced absorption in the v2 fundamental band of CH4. I. Determination of the quadrupole transition moment}, journal = {Journal of Chemical Physics}, year = {2001}, volume = {115}, number = {19}, pages = {8852 – 8857}, doi = {10.1063/1.1408915} }
Vaeck N, Bacchus-Montabonel M-C, Baloïtcha E and Desouter-Lecomte M (2001), "Time-dependent wave-packet treatment of the Si4+ + He collision", Physical Review A. Atomic, Molecular, and Optical Physics. Vol. 63(4), pp. 427041 – 427048. [Abstract] [BibTeX]
Abstract: The charge exchange Si 4+ + He reaction at low energy and high energy was studied. A time-dependent wave-packet approach was used in low energy range using two different propagator techniques. In high energy range, a semiclassical approach which included Coriolis effects was used. Split-operator technique was used in diabatic representaion and Chebyshev method was used in adiabatic representation for time-dependent approach. Two results were found to be in agreement and thus approved the accuracy of present approach. The order of the magnitude of theoretical values was confirmed by the rate constant of electron transfer reaction calculations.
BibTeX: @article{Vaeck2001427041, author = {Vaeck, Nathalie and Bacchus-Montabonel, Marie-Christine and Baloïtcha, Ezinvi and Desouter-Lecomte, Michèle}, title = {Time-dependent wave-packet treatment of the Si4+ + He collision}, journal = {Physical Review A. Atomic, Molecular, and Optical Physics}, year = {2001}, volume = {63}, number = {4}, pages = {427041 – 427048} }
Vaeck N, Bacchus-Montabonel M-C, Baloïtcha E and Desouter-Lecomte M (2001), "Time-dependent wave-packet treatment of the Si4++He collision", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 63(4), pp. 1 – 8. [Abstract] [BibTeX] [DOI]
Abstract: The collisional system Si4++He has been studied over a range of mean relative ion kinetic energy going from 10-2 to 102 eV/amu. In the low-energy range, a time-dependent wave-packet approach is used both in the diabatic and the adiabatic representation using two different propagator techniques. The agreement between the two sets of results assess the accuracy of the present numerical approach. Above 2.5 eV/amu., a semiclassical eikonal calculation is performed, which includes the Coriolis couplings. Finally, the rate constant is calculated and compared with the other theoretical data as well as with the experimental value of [Fang and Kwong, Phys. Rev. A 59, 342 (1999)]. The present results confirm the order of magnitude of previous theoretical values. ©2001 The American Physical Society.
BibTeX: @article{Vaeck20011, author = {Vaeck, Nathalie and Bacchus-Montabonel, Marie-Christine and Baloïtcha, Ezinvi and Desouter-Lecomte, Michèle}, title = {Time-dependent wave-packet treatment of the Si4++He collision}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2001}, volume = {63}, number = {4}, pages = {1 – 8}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.63.042704} }
Vaeck N, Hansen J, Palmeri P, Quinet P, Zitane N, Godefroid M, Fritzsche S and Kylstra N (2001), "Hollow atoms: A theoretical challenge", Physica Scripta T. Vol. 95, pp. 68 – 75. [Abstract] [BibTeX]
Abstract: Hollow atoms are characterized by a large number of vacant inner shells and electrons occupying the outer shells. These "exotic" atomic species are formed in collision processes between highly-charged ions and several types of targets. The scope of the present contribution is to examine the decay properties of hollow atom states populated in collision with atoms, molecules, solid surfaces and clusters.
BibTeX: @conference{Vaeck200168, author = {Vaeck, N. and Hansen, J.E. and Palmeri, P. and Quinet, P. and Zitane, N. and Godefroid, M. and Fritzsche, S. and Kylstra, N.}, title = {Hollow atoms: A theoretical challenge}, journal = {Physica Scripta T}, year = {2001}, volume = {95}, pages = {68 – 75} }
Vander Auwera J (2001), "Analysis of high-resolution FTS spectra", Optics InfoBase Conference Papers. [Abstract] [BibTeX]
Abstract: The talk presents recent measurements of accurate infrared absolute absorption intensities performed for chemically stable species, such as CFC replacements, OCS, N2O and C2H2, and a chemically unstable compound, HOCl. © 2000 Optical Society of America.
BibTeX: @conference{VanderAuwera2001, author = {Vander Auwera, J.}, title = {Analysis of high-resolution FTS spectra}, journal = {Optics InfoBase Conference Papers}, year = {2001} }
Weirauch G, El Idrissi M, Vander Auwera J, Herman M and Campargue A (2001), "The absorption spectrum of 12C2D2 in the 10 000-12 500 cm-1 spectral region", Molecular Physics. Vol. 99(11), pp. 969 – 980. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of dideuteroacetylene has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the 10 200-12 500 cm-1 spectral region. Among 25 absorption bands of 12C2D2 rotationally analysed in this spectral region, 17 are newly observed. They include one Πu-∑g+ and thirteen ∑u+-∑g+ bands starting from the vibrational ground state and eleven hot bands from the V4 = 1 and V5 = 1 lower states. The rotational structure of two excited levels is affected by a strongly J-dependent interaction with a perturber which induces intensity transfer to extra lines. The coupling is identified as a l-resonance interaction with Δu dark states and the vibrational assignment of the perturbers is discussed. Two ∑-∑ bands of the 12C13CD2 species, present in natural abundance in the sample, could also be identified and rotationally analysed. Most of the corresponding excited vibrational levels of 12C2D2 were unambiguously assigned using the polyad model [Herman, M., El Edrissi, M. I., Pisarchik, A., Campargue, A., Gaillot, A.-C., Biennier, L., Di Lonardo, G. and Fusina, L., 1998, J. chem. Phys., 108, 1377] which allows vibrational energies and Bv rotational constants to be predicted. In particular the previously highlighted 1/244 anharmonic resonance is confirmed by energy and intensity features in several (V1, V2, V3, V4 = 0, V5 = 0), (V1 - 1, V2 + 1, V3, V4 = 2, V5 = 0) dyads. Significant deviations between predicted and experimental energy levels are observed for a new levels and discussed.
BibTeX: @article{Weirauch2001969, author = {Weirauch, G. and El Idrissi, M.I. and Vander Auwera, J. and Herman, M. and Campargue, A.}, title = {The absorption spectrum of 12C2D2 in the 10 000-12 500 cm-1 spectral region}, journal = {Molecular Physics}, year = {2001}, volume = {99}, number = {11}, pages = {969 – 980}, doi = {10.1080/00268970010039572} }
Ballard J, Knight R, Newnham D, Vander Auwera J, Herman M, Di Lonardo G, Masciarelli G, Nicolaisen F, Beukes J, Christensen L, McPheat R, Duxbury G, Freckleton R and Shine K (2000), "An intercomparison of laboratory measurements of absorption cross-sections and integrated absorption intensities for HCFC-22", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 66(2), pp. 109 – 128. [Abstract] [BibTeX] [DOI]
Abstract: An intercomparison of measurements of infra-red absorption cross-sections and integrated absorption intensities in HCFC-22 has been carried out. Independent measurements were made by five spectroscopy groups so that their experimental methods and data reduction techniques could be critically examined. The initial results showed a spread in reported values for integrated absorption intensity over the mid infra-red spectral region that were larger than the reported uncertainties. Re-examination of experimental and data reduction methods resulted in consistency of results within the reported errors. It was found that particular attention had to be paid to controlling and characterising errors associated with the non-linear response of MCT detectors and pre-amplifiers, adsorption of the sample on surfaces in the absorption cell, effectiveness of mixing when making measurements on mixtures of absorber gas and a buffer gas, and location of the photometric "full-scale" and "zero" levels. © 2000 Elsevier Science Ltd. All rights reserved.
BibTeX: @article{Ballard2000109, author = {Ballard, J. and Knight, R.J. and Newnham, D.A. and Vander Auwera, J. and Herman, M. and Di Lonardo, G. and Masciarelli, G. and Nicolaisen, F.M. and Beukes, J.A. and Christensen, L.K. and McPheat, R. and Duxbury, G. and Freckleton, R. and Shine, K.P.}, title = {An intercomparison of laboratory measurements of absorption cross-sections and integrated absorption intensities for HCFC-22}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2000}, volume = {66}, number = {2}, pages = {109 – 128}, doi = {10.1016/S0022-4073(99)00211-3} }
Biémont E, Fischer CF, Godefroid MR, Palmeri P and Quinet P (2000), "Core-polarization effects in the cadmium isoelectronic sequence", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 62(3), pp. 032512 – 032511. [Abstract] [BibTeX]
Abstract: In this study, experimental and theoretical values for the oscillator strengths of the 5s2 1S0-5s5p 1,3P10 transitions and for the lifetimes of the 5s5p 1,3P10 levels in the Cd isoelectronic sequence were examined in the context of the evaluation of the importance of core-polarization effects. Erroneous or inaccurate measurements were identified using regularities along the sequence and coherence among the HFR and MCDF results.
BibTeX: @article{Biémont2000032512, author = {Biémont, Emile and Fischer, Charlotte Froese and Godefroid, Michel R. and Palmeri, Patrick and Quinet, Pascal}, title = {Core-polarization effects in the cadmium isoelectronic sequence}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2000}, volume = {62}, number = {3}, pages = {032512 – 032511} }
Biémont E, Fischer CF, Godefroid MR, Palmeri P and Quinet P (2000), "Core-polarization effects in the cadmium isoelectronic sequence", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 62(3), pp. 8. [Abstract] [BibTeX] [DOI]
Abstract: The oscillator strengths of the allowed and spin-forbidden [Formula Presented] transitions in the cadmium isoelectronic sequence are evaluated for [Formula Presented] using the relativistic Hartree-Fock approach, including a core-polarization potential, and the multiconfiguration Dirac-Fock method, taking the valence and core-valence correlation effects into account. A good agreement is noted when comparing the two sets of theoretical data and when comparing theory with experiment for the spin-forbidden transition. The discrepancies observed between theory (both theories being in agreement) and experiment for the singlet-singlet transition indicate that some experimental data are in need of revision. © 2000 The American Physical Society.
BibTeX: @article{Biémont20008, author = {Biémont, Emile and Fischer, Charlotte Froese and Godefroid, Michel R. and Palmeri, Patrick and Quinet, Pascal}, title = {Core-polarization effects in the cadmium isoelectronic sequence}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {2000}, volume = {62}, number = {3}, pages = {8}, doi = {10.1103/PhysRevA.62.032512} }
Campargue A, Bertseva E, Graner G and Herman M (2000), "High-Resolution Absorption Spectroscopy of the 3ν1 and 3ν1 + ν3 Bands of Propyne", Journal of Molecular Spectroscopy. Vol. 201(1), pp. 156 – 163. [Abstract] [BibTeX] [DOI]
Abstract: The 3ν1 and 3ν1 + ν3 bands of propyne have been recorded at Doppler-limited resolution by Fourier transform spectroscopy and intracavity laser absorption spectroscopy, respectively. The two bands show a mostly unperturbed J rotational structure for each individual K subband. However, as a rule the K structure ordering is perturbed in overtone transitions of propyne and different effective parameters associated with each K subband have been determined. From the vibrational energy levels, a value of -6.6 cm-1 has been obtained for the χ13 cross anharmonicity in perfect agreement with the origins of the ν1 + ν3 and 2ν1 + ν3 combination bands estimated from the FTIR spectrum. Hot bands from the ν9 = 1 and ν10 = 1 levels associated with the 3ν1 + ν3 combination band have been partly rotationally analyzed and the retrieved values of χ39 and χ3,10 are in good agreement with literature values. Finally, the 4ν1 + ν9 - ν9 band centered at 12 636.6 cm-1 has been recorded by ICLAS. The red shift of this hot band relative to 4ν1 and the ΔBν, value are discussed in relation to the anharmonic interaction between the 4ν1 and 3ν1 + ν3 + ν5 levels. © 2000 Academic Press.
BibTeX: @article{Campargue2000156, author = {Campargue, Alain and Bertseva, Elena and Graner, Georges and Herman, Michel}, title = {High-Resolution Absorption Spectroscopy of the 3ν1 and 3ν1 + ν3 Bands of Propyne}, journal = {Journal of Molecular Spectroscopy}, year = {2000}, volume = {201}, number = {1}, pages = {156 – 163}, doi = {10.1006/jmsp.2000.8073} }
Coheur P-F, Cornil J, Dos Santos D, Birkett P, Liévin J, Brédas J, Walton D, Taylor R, Kroto H and Colin R (2000), "Photophysical properties of hexa-functionalized C60 derivatives: Spectroscopic and quantum-chemical investigations", Journal of Chemical Physics. Vol. 112(19), pp. 8555 – 8566. [Abstract] [BibTeX] [DOI]
Abstract: The photophysical properties of hexa-functionalized C60 derivatives (C60Cl6, C60Ph5Cl, C60Ph5H, and two C60Ph5OH isomers) have been investigated by means of UV-visible absorption and fluorescence spectroscopy in cyclohexane solution and quantum-chemical calculations derived from semiempirical Hartree-Fock approaches. A very good agreement is obtained between the measured absorption and fluorescence spectra and the calculated excitation energies, thus allowing for a detailed assignment of the optical features. The effects of symmetry and chemical nature of the functional groups on the ground-state and spectroscopic properties of the C60 derivatives are discussed. © 2000 American Institute of Physics.
BibTeX: @article{Coheur20008555, author = {Coheur, P.-F. and Cornil, J. and Dos Santos, D.A. and Birkett, P.R. and Liévin, J. and Brédas, J.L. and Walton, D.R.M. and Taylor, R. and Kroto, H.W. and Colin, R.}, title = {Photophysical properties of hexa-functionalized C60 derivatives: Spectroscopic and quantum-chemical investigations}, journal = {Journal of Chemical Physics}, year = {2000}, volume = {112}, number = {19}, pages = {8555 – 8566}, doi = {10.1063/1.481485} }
Coheur P-F, Cornil J, Dos Santos D, Birkett P, Liévin J, Brédas J, Walton D, Taylor R, Kroto H and Colin R (2000), "Photophysical properties of multiply phenylated C70 derivatives: Spectroscopic and quantum-chemical investigations", Journal of Chemical Physics. Vol. 112(14), pp. 6371 – 6381. [Abstract] [BibTeX] [DOI]
Abstract: The photophysics of six multiply phenylated C70 derivatives [C70Ph2, C70Ph4, C70Ph6 (two regioisomers), C70Ph8 and C70Ph10] have been investigated by means of steady state spectroscopy in cyclohexane solution and quantum-chemical calculations derived from semiempirical Hartree-Fock approaches. There is good agreement between the measured absorption spectra and the INDO/SCI calculated excitation energies for each derivative. The foregoing results and some additional ground state properties calculated at the AMI level have been used to predict that the perturbation of the π electronic system of the cage results in significant changes in the photophysics of the fullerene derivatives. The effects of conjugation and spatial localization of the HOMO and LUMO orbitals on the energy of the first electronic transition are discussed in greater detail. © 2000 American Institute of Physics.
BibTeX: @article{Coheur20006371, author = {Coheur, P.-F. and Cornil, J. and Dos Santos, D.A. and Birkett, P.R. and Liévin, J. and Brédas, J.L. and Walton, D.R.M. and Taylor, R. and Kroto, H.W. and Colin, R.}, title = {Photophysical properties of multiply phenylated C70 derivatives: Spectroscopic and quantum-chemical investigations}, journal = {Journal of Chemical Physics}, year = {2000}, volume = {112}, number = {14}, pages = {6371 – 6381}, doi = {10.1063/1.481198} }
Fally S, Vandaele A, Carleer M, Hermans C, Jenouvrier A, Mérienne M-F, Coquart B and Colin R (2000), "Fourier transform spectroscopy of the O2 Herzberg bands. III. Absorption cross sections of the collision-induced bands and of the Herzberg continuum", Journal of molecular spectroscopy. Vol. 204(1), pp. 10 – 20. [Abstract] [BibTeX] [DOI]
Abstract: Absorption spectra of molecular oxygen were measured in the laboratory under temperature and pressure conditions prevailing in the Earth's atmosphere. Spectra of pure O2, O2+N2, and O2+Ar were recorded in the 41 700 to 33 000 cm-1 region (240-300 nm) at a maximal optical path difference of 0.45 cm using a Fourier transform spectrometer and a multiple reflection gas cell. The different components of the spectra, namely the discrete bands of the three Herzberg systems, the Herzberg continuum, and the collision-induced diffuse Wulf bands, were separated. The contribution of the Herzberg bands was first subtracted using the line parameters determined previously from high-resolution data. Spectra recorded at various pressures then made it possible to determine by linear regression the intensity of the Wulf bands and the Herzberg continuum. The characteristics of the Wulf bands have been investigated in details: vibrational analysis, pressure effect, foreign gas effect, and a simulated spectrum are reported. The Herzberg continuum cross section is determined below the dissociation limit. A comparison with literature data is given. The new O2 absorption cross sections and O2-O2 collision-induced absorption cross sections are useful in connection with atmospheric measurements of ozone and other trace gases in the UV spectral region.
BibTeX: @article{Fally200010, author = {Fally, S. and Vandaele, A.C. and Carleer, M. and Hermans, C. and Jenouvrier, A. and Mérienne, M.-F. and Coquart, B. and Colin, R.}, title = {Fourier transform spectroscopy of the O2 Herzberg bands. III. Absorption cross sections of the collision-induced bands and of the Herzberg continuum}, journal = {Journal of molecular spectroscopy}, year = {2000}, volume = {204}, number = {1}, pages = {10 – 20}, doi = {10.1006/jmsp.2000.8204} }
Godefroid M and Hibbert A (2000), "Theoretical lifetimes and branching fractions of 2p4(3P)3d 4D7/2, 2F7/2 and 4F7/2 in Ne II", Molecular Physics. Vol. 98(16), pp. 1099 – 1106. [Abstract] [BibTeX] [DOI]
Abstract: Transition probabilities of the radiative decay processes of the excited levels 2p4(3P)3d 4D7/2, 2F7/2 and 4F7/2 of the fluorine-like neon ion (Ne+) are evaluated by variational calculations using superposition of configurations in the Breit-Pauli approximation. The strong 2F7/2-4F7/2 relativistic mixing is discussed in terms of level designation and doublet-quartet intensity transfer. A detailed comparison of the results with other theories and with the NIST measurements of branching fractions, combined with lifetime measurements, confirms problems on the experimental side.
BibTeX: @article{Godefroid20001099, author = {Godefroid, M.R. and Hibbert, A.}, title = {Theoretical lifetimes and branching fractions of 2p4(3P)3d 4D7/2, 2F7/2 and 4F7/2 in Ne II}, journal = {Molecular Physics}, year = {2000}, volume = {98}, number = {16}, pages = {1099 – 1106}, doi = {10.1080/00268970050080465} }
Hepp M, Georges R, Herman M, Flaud J-M and Lafferty W (2000), "Striking anharmonic resonances in N2O4: Supersonic jet fourier transform spectra at 13.3, 7.9, 5.7 and 3.2 μm", Journal of Molecular Structure. Vol. 517-518, pp. 171 – 180. [Abstract] [BibTeX] [DOI]
Abstract: The spectrum of N2O4 has been obtained in the 3.2, 5.7, 7.9 and 13.3 μm regions, using a supersonic slit jet system coupled to a Fourier transform spectrometer with a spectral resolution of 0.005 cm-1. Analysis of the spectra obtained indicates that the temperature of the molecular beam is close to 30 K. In the three lowest frequency spectral regions, not only were the v9, v11 and v12 fundamental bands observed, but each fundamental was accompanied by an intense combination band which appears because of a strong anharmonic resonance leading to a transfer of intensity from the fundamental band to the combination band. In the 13.3 μm region, two a-type bands with nearly equal intensities, are seen. Their band centers are v0(v12) = 747.85495(20) cm-1 and v0(v6 + v10) = 755.37492(20) cm-1. The 7.9 μm region also contains two a-type bands whose band centers are v0(v11) = 1261.08011(20) cm-1 and v0(DB) = 1265.03219(20) cm-1 where DB stands for 'dark band'. This label is chosen because the assignment of the perturbing state can not be well established. In this region the combination band has about one-third the intensity of the fundamental. In the 5.7 μm region, two b-type bands are observed with band centers v0(v9) = 1756.76217(20)cm-1 and v0(v6 + v11) = 1733.15573(20) cm-1 with the combination band having about a quarter of the intensity of the fundamental band. In addition, a much weaker combination band, v1 + v9, was observed in the 3.2 μm region: V0(V1 + v9) = 3125.25987(30) cm-1. All the bands were successfully analyzed leading to ground state combination differences which were combined with those obtained in a previous diode-laser study and fit to obtain ground state rotational constants. The upper state energy levels were fit using a Hamiltonian that explicitly takes into account the anharmonic resonances. The experimental data could be fitted to within their experimental uncertainties. (C) 2000 Elsevier Science B.V.
BibTeX: @article{Hepp2000171, author = {Hepp, M. and Georges, R. and Herman, M. and Flaud, J.-M. and Lafferty, W.J.}, title = {Striking anharmonic resonances in N2O4: Supersonic jet fourier transform spectra at 13.3, 7.9, 5.7 and 3.2 μm}, journal = {Journal of Molecular Structure}, year = {2000}, volume = {517-518}, pages = {171 – 180}, doi = {10.1016/S0022-2860(99)00248-3} }
Hepp M and Herman M (2000), "Vibration-rotation bands in ethane", Molecular Physics. Vol. 98(1), pp. 57 – 61. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of ethane was recorded at 0.014 cm−1 resolution in the range 4500–6500 cm−1 using a Fourier transform spectrometer and at room temperature. Eighteen bands could be identified and their type assigned. Upper state rotational constants are provided for the band at 5948.338 cm−1 and Coriolis constants are obtained for most perpendicular bands. Vibrational assignments are suggested for the bands at 5948 cm−1 (v7 + v10), 5914 cm−1(v8 + v 10+ v 11), and 5852cm−1 (v 5+v 10). All vibrational bands reported in the literature are gathered. © 2000 Taylor & Francis Group, LLC.
BibTeX: @article{Hepp200057, author = {Hepp, M. and Herman, M.}, title = {Vibration-rotation bands in ethane}, journal = {Molecular Physics}, year = {2000}, volume = {98}, number = {1}, pages = {57 – 61}, doi = {10.1080/00268970009483269} }
Herman M, Georges R, Hepp M and Hurtmans D (2000), "High resolution Fourier transform spectroscopy of jet-cooled molecules", International Reviews in Physical Chemistry. Vol. 19(2), pp. 277 – 325. [Abstract] [BibTeX] [DOI]
Abstract: The spectroscopic literature reporting on the coupling between Fourier transform spectrometers and supersonic jet expansions is reviewed. Particular attention is devoted to high resolution infrared absorption experiments. Short and much longer introductions are provided on Fourier transform spectrometers and jets, respectively, with emphasis on the problems raised by coupling the two techniques. Details of the optical designs reported in the literature are considered. The literature on all the molecules studied is tabulated. Some of the spectroscopic results are highlighted, in particular those obtained at Universite Libre de Bruxelles.
BibTeX: @article{Herman2000277, author = {Herman, M. and Georges, R. and Hepp, M. and Hurtmans, D.}, title = {High resolution Fourier transform spectroscopy of jet-cooled molecules}, journal = {International Reviews in Physical Chemistry}, year = {2000}, volume = {19}, number = {2}, pages = {277 – 325}, doi = {10.1080/01442350050020905} }
Herregodts F, Hurtmans D, Auwera JV and Herman M (2000), "Ar-induced pressure effects in the ν1+3ν3 absorption band in 12C2 H2", Chemical Physics Letters. Vol. 316(5-6), pp. 460 – 464. [Abstract] [BibTeX] [DOI]
Abstract: We have used a Ti:sapphire autoscan laser spectrometer to measure Ar-induced pressure-broadening, narrowing and shift effects for 24 individual vibration-rotation lines in the ν1+3ν3 band of 12C2H2. The acetylene and total pressures ranged between 10 and 20 Torr, and between 30 and 310 Torr, respectively. The Voigt profile accounted for the higher pressure measurements while the soft and hard collision profiles were required to fit the lower pressure measurements. Lineshift parameters that are significantly different from the overall behaviour in the band were observed for the R(17) and P(19) lines and are qualitatively attributed to the influence of an intramolecular Coriolis-type coupling on the interparticle interaction potential. Those results confirm all trends of self-collisional measurements recently reported for this band.
BibTeX: @article{Herregodts2000460, author = {Herregodts, F. and Hurtmans, D. and Auwera, J. Vander and Herman, M.}, title = {Ar-induced pressure effects in the ν1+3ν3 absorption band in 12C2 H2}, journal = {Chemical Physics Letters}, year = {2000}, volume = {316}, number = {5-6}, pages = {460 – 464}, doi = {10.1016/S0009-2614(99)01324-X} }
Hurtmans D, Herregodts F, Herman M, Liévin J, Campargue A, Garnache A and Kachanov A (2000), "Spectroscopic and ab initio investigation of the vOH overtone excitation in trans-formic acid", Journal of Chemical Physics. Vol. 113(4), pp. 1535 – 1545. [Abstract] [BibTeX] [DOI]
Abstract: In this study, three different inputs dedicated to the OH bond excitation in trans-formic acid were merged. First, experiments were carried out using FTS. Following this, ICLAS was used to record the 4vOH band at high spectral region. Finally, ab initio calculations were performed. Overall, the results indicate the occurrence of a chemical mechanism different from those usually probed with overtone spectroscopy.
BibTeX: @article{Hurtmans20001535, author = {Hurtmans, D. and Herregodts, F. and Herman, M. and Liévin, J. and Campargue, A. and Garnache, A. and Kachanov, A.A.}, title = {Spectroscopic and ab initio investigation of the vOH overtone excitation in trans-formic acid}, journal = {Journal of Chemical Physics}, year = {2000}, volume = {113}, number = {4}, pages = {1535 – 1545}, doi = {10.1063/1.481939} }
Jönsson P and Godefroid M (2000), "Theoretical studies of isotope shifts, hyperfine structures and oscillator strengths in transitions between low-lying levels in O I", Molecular Physics. Vol. 98(16), pp. 1141 – 1149. [Abstract] [BibTeX] [DOI]
Abstract: Multiconfiguration Hartree-Fock (MCHF) and configuration interaction (CI) calculations have been performed for the low-lying levels 2p4 3P, 2p3(4S0)3s 3,5S0 and 2p3(4S0)3p 3,5P0 of neutral oxygen. Different cancellation effects on the specific mass shift, on the electronic contributions to hyperfine interaction constants and on the length and velocity forms of oscillator strengths are illustrated. The final CI values are compared with experimental values and, when available, with values from other theories.
BibTeX: @article{Jönsson20001141, author = {Jönsson, P. and Godefroid, M.R.}, title = {Theoretical studies of isotope shifts, hyperfine structures and oscillator strengths in transitions between low-lying levels in O I}, journal = {Molecular Physics}, year = {2000}, volume = {98}, number = {16}, pages = {1141 – 1149}, doi = {10.1080/00268970050080500} }
Mérienne M-F, Jenouvrier A, Coquart B, Carleer M, Fally S, Colin R, Vandaele A and Hermans C (2000), "Fourier transform spectroscopy of the O2 Herzberg bands. II. Band oscillator strengths and transition moments", Journal of molecular spectroscopy. Vol. 202(2), pp. 171 – 193. [Abstract] [BibTeX] [DOI]
Abstract: From absorption spectra obtained at high resolution by coupling a Fourier transform spectrometer to a long-path multiple reflection cell the intensities of the O2 Herzberg bands (A3Σu+-X3Σg-, c1Σu-, A′ 3Δu-X3Σg-) have been studied at ambient temperature. The integrated cross section values are given for the lines of the (v′-0) bands in the A3ΣuPLU-X3Σg-, c1Σu--X3Σg-, and A′ 3Δu-X3Σg- transitions with v′ = 0-11, v′ = 2-19, and v′ = 2-12, respectively. The band oscillator strengths have been deduced and transition moments have been calculated. The total absorption values in the region of the Herzberg bands together with the photoabsorption values determined previously above the dissociation limit can be modeled by a single curve, in agreement with the continuity relationship of the cross sections through the dissociation limit.
BibTeX: @article{Mérienne2000171, author = {Mérienne, M.-F. and Jenouvrier, A. and Coquart, B. and Carleer, M. and Fally, S. and Colin, R. and Vandaele, A.C. and Hermans, C.}, title = {Fourier transform spectroscopy of the O2 Herzberg bands. II. Band oscillator strengths and transition moments}, journal = {Journal of molecular spectroscopy}, year = {2000}, volume = {202}, number = {2}, pages = {171 – 193}, doi = {10.1006/jmsp.2000.8126} }
Ram R, Adam A, Tsouli A, Liévin J and Bernath P (2000), "High-resolution spectroscopy and Ab initio calculations on HfCl", Journal of molecular spectroscopy. Vol. 202(1), pp. 116 – 130. [Abstract] [BibTeX] [DOI]
Abstract: The emission spectrum of HfCl has been investigated in the 3000-18 500 cm-1 region at high resolution using a Fourier transform spectrometer. The bands were excited in a microwave discharge through a flowing mixture of HfCl4 and helium. Two bands near 17 140 and 17 490 cm-1 were also measured in absorption using laser excitation spectroscopy. In this instance the molecules were created by laser ablation in a molecular beam apparatus. The observed bands have been classified into two electronic transitions, [7.6]4Δ3/2-X2Δ3/2 and [17.1]2Δ3/2-X2Δ3/2 involving a common lower state. A rotational analysis of the 0-0 and 1-1 bands of [7.6]4Δ3/2-X2Δ3/2 and 0-0, 1-1, and 1-0 bands of the [17.1]2Δ3/2-X2Δ3/2 transitions has been carried out and the equilibrium spectroscopic constants have been determined. The ground state principal molecular constants are Be = 0.1097404(54) cm-1, αe = 0.0004101(54) cm-1, and re = 2.290532(57) angstrom. Ab initio calculations have been performed on HfCl and spectroscopic properties of the low-lying electronic states have been predicted. The ground state is predicted to be a regular 2Δ state arising from the valence electron configuration, 1σ22σ23σ21π41δ1. On the basis of our ab initio calculations, we assign the observed transitions as [7.6]4Δ3/2-X2Δ3/2 and [17.1]2Δ3/2-X2Δ3/2.
BibTeX: @article{Ram2000116, author = {Ram, R.S. and Adam, A.G. and Tsouli, A. and Liévin, J. and Bernath, P.F.}, title = {High-resolution spectroscopy and Ab initio calculations on HfCl}, journal = {Journal of molecular spectroscopy}, year = {2000}, volume = {202}, number = {1}, pages = {116 – 130}, doi = {10.1006/jmsp.2000.8120} }
Sutcliffe B (2000), "The decoupling of electronic and nuclear motions in the isolated molecule SchröDinger Hamiltonian", Advances in Chemical Physics. Vol. 114, pp. 118 – 121. [BibTeX]
BibTeX: @article{Sutcliffe2000118, author = {Sutcliffe, Brian}, title = {The decoupling of electronic and nuclear motions in the isolated molecule SchröDinger Hamiltonian}, journal = {Advances in Chemical Physics}, year = {2000}, volume = {114}, pages = {118 – 121} }
Vander Auwera J (2000), "Absolute Intensities Measurements in the ν4 + ν5 Band of 12C2H2: Analysis of Herman-Wallis Effects and Forbidden Transitions", Journal of Molecular Spectroscopy. Vol. 201(1), pp. 143 – 150. [Abstract] [BibTeX] [DOI]
Abstract: We measured absolute line intensities in two bands of 12C2H2 near 7.5 μm, namely the ν4 + ν5(Σ+u)-0(Σ+ g) and ν4 + ν5(Δu)-0(Σ+g) bands, using Fourier transform spectroscopy with an accuracy estimated to be better than 2%. Using theoretical predictions from Watson [J. K. G. Watson, J. Mol. Spectrosc. 188, 78 (1998)], the observation of the forbidden ν4 + ν5(Δu)-0(Σ+g) band and the Herman-Wallis behavior exhibited by its rotational lines were studied quantitatively in terms of two types of interactions affecting the levels involved by the band: ℓ-type resonance and Coriolis interaction. In the case of the ν4 + ν5(Σ+u)-0(Σ+ g) band, the influence of ℓ-type resonance is also confirmed. We also attributed the intensity asymmetry observed between the R and P branches of that latter band to a Coriolis interaction with ℓ = 1 levels. We did not observe the ν4 + ν5(Σ-u)-0(Σ+ g) band, consisting only of a Q branch, in agreement with Watson's prediction. © 2000 Academic Press.
BibTeX: @article{VanderAuwera2000143, author = {Vander Auwera, J.}, title = {Absolute Intensities Measurements in the ν4 + ν5 Band of 12C2H2: Analysis of Herman-Wallis Effects and Forbidden Transitions}, journal = {Journal of Molecular Spectroscopy}, year = {2000}, volume = {201}, number = {1}, pages = {143 – 150}, doi = {10.1006/jmsp.2000.8079} }
Vander Auwera J (2000), "Infrared absorption cross-sections for two substituted ethanes: 1,1-difluoroethane (HFC-152a) and 1,2-dichloroethane", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 66(2), pp. 143 – 151. [Abstract] [BibTeX] [DOI]
Abstract: Absorption cross sections have been measured between 600 and 1700 cm-1 for two substituted ethanes, 1,1-difluoroethane (HFC-152a) and 1,2-dichloroethane, either as pure gases or in mixtures with dry air at total pressures of 200 and 800 hPa. Cross sections have been obtained at six temperatures between 293 and 203 K for HFC-152a. Measurements were made at 293 and 273 K for 1,2-dichloroethane. The absolute uncertainty (1σ) of the cross sections was estimated. © 2000 Elsevier Science Ltd. All rights reserved.
BibTeX: @article{VanderAuwera2000143, author = {Vander Auwera, J.}, title = {Infrared absorption cross-sections for two substituted ethanes: 1,1-difluoroethane (HFC-152a) and 1,2-dichloroethane}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {2000}, volume = {66}, number = {2}, pages = {143 – 151}, doi = {10.1016/s0022-4073(99)00213-7} }
Vander Auwera J, Kleffmann J, Flaud J-M, Pawelke G, Bürger H, Hurtmans D and Pétrisse R (2000), "Absolute ν2 line intensities of HOCl by simultaneous measurements in the infrared with a tunable diode laser and far-infrared region using a Fourier transform spectrometer", Journal of molecular spectroscopy. Vol. 204(1), pp. 36 – 47. [Abstract] [BibTeX] [DOI]
Abstract: We have measured absolute line intensities in the ν2 fundamental band at 1238 cm-1 of both isotopomers of hypochlorous acid, HOCl. To obtain the partial pressure of the species in the sample mixture, unavailable through direct measurement since HOCl exists only in equilibrium with H2O and Cl2O and may decay by secondary reactions, we relied on known absolute line intensities in the pure rotational far-infrared (FIR) spectrum determined from Stark effect measurements. We have thus recorded simultaneously the FIR pure rotation spectrum of HOCl using a Bruker IFS120HR interferometer and the spectrum of a few vibration-rotation lines in the infrared (IR) ν2 band using a tunable diode laser spectrometer. The absolute intensities of these IR lines thus determined allowed us to `calibrate' the intensities of vibration-rotation lines in the whole ν2 band, measured previously using Fourier transform spectroscopy. The treatment of the data took into account the blackbody emission contribution in the FIR and the evolution of the HOCl amount during the recording of the spectra. The latter was found to be almost constant over hours after conditioning of the cell. The square of the ν2 band vibrational transition dipole moment was determined to be 0.013947(23) D2 and 0.013870(51) D2 for HO35Cl and HO37Cl, respectively, that is, 29 to 73% lower than previous measurements. A linear Herman-Wallis factor was also determined for both isotopomers. Finally, the line intensities were least-squares fitted using a model that takes into account a weak resonance between the (010) and (002) levels.
BibTeX: @article{VanderAuwera200036, author = {Vander Auwera, J. and Kleffmann, J. and Flaud, J.-M. and Pawelke, G. and Bürger, H. and Hurtmans, D. and Pétrisse, R.}, title = {Absolute ν2 line intensities of HOCl by simultaneous measurements in the infrared with a tunable diode laser and far-infrared region using a Fourier transform spectrometer}, journal = {Journal of molecular spectroscopy}, year = {2000}, volume = {204}, number = {1}, pages = {36 – 47}, doi = {10.1006/jmsp.2000.8197} }
Weirauch G, Kachanov A, Campargue A, Bach M, Herman M and Vander Auwera J (2000), "Refined investigation of the overtone spectrum of nitrous oxide", Journal of molecular spectroscopy. Vol. 202(1), pp. 98 – 106. [Abstract] [BibTeX] [DOI]
Abstract: Following our previous work [A. Campargue, D. Permogorov, M. Bach, M. Abbouti Temsamani, J. Vander Auwera, M. Herman, and M. Fujii, J. Chem. Phys. 103, 5931-5938 (1995)], we reinvestigated the overtone spectrum of nitrous oxide (14N216O) using intracavity laser absorption spectroscopy, observing seven new bands in the spectral range 10650-12200 cm-1 and improving the signal-to-noise ratio in two others previously reported using Fourier transform spectroscopy. The earlier FT line positions, in the range 6500-11000 cm-1, have been calibrated using the 3-0 vibration-rotation line wavenumbers in 12C16O as references. A previously unreported hot band is spotted on the FT spectrum, at 7229 cm-1. Vibration-rotation parameters are provided for all newly analyzed bands and significantly improved for most previously reported FT bands by accounting for more lines in the fitting procedure than earlier. All bands are vibrationally assigned in agreement with theoretical predictions. A table listing all levels above 6500 cm-1 reported in the literature is provided.
BibTeX: @article{Weirauch200098, author = {Weirauch, G. and Kachanov, A.A. and Campargue, A. and Bach, M. and Herman, M. and Vander Auwera, J.}, title = {Refined investigation of the overtone spectrum of nitrous oxide}, journal = {Journal of molecular spectroscopy}, year = {2000}, volume = {202}, number = {1}, pages = {98 – 106}, doi = {10.1006/jmsp.2000.8114} }
Wintjens R, Liévin J, Rooman M and Buisine E (2000), "Contribution of cation-π interactions to the stability of protein-DNA complexes", Journal of Molecular Biology. Vol. 302(2), pp. 393 – 408. [Abstract] [BibTeX] [DOI]
Abstract: Cation-π interactions between an aromatic ring and a positive charge located above it have proven to be important in protein structures and biomolecule associations. Here, the role of these interactions at the interface of protein-DNA complexes is investigated, by means of ab initio quantum mechanics energy calculations and X-ray structure analyses. Ab initio energy calculations indicate that Na ions and DNA bases can form stable cation-π complexes, whose binding strength strongly depends on the type of base, on the position of the Na ion, and whether the base is isolated or included in a double-stranded B-DNA. A survey of protein-DNA complex structures using appropriate geometrical criteria revealed cation-π interactions in 71% of the complexes. More than half of the cation-π pairs involve arginine residues, about one-third asparagine or glutamine residues that only carry a partial charge, and one-seventh lysine residues. The most frequently observed pair, which is also the most stable as monitored by ab initio energy calculations, is arginine-guanine. Arginine-adenine interactions are also favorable in general, although to a lesser extent, whereas those with thymine and cytosine are not. Our calculations show that the major contribution to cation-π interactions with DNA bases is of electrostatic nature. These interactions often occur concomitantly with hydrogen bonds with adjacent bases; their strength is estimated to be from three to four times lower than that of hydrogen bonds. Finally, the role of cation-π interactions in the stability and specificity of protein-DNA complexes is discussed. (C) 2000 Academic Press.
BibTeX: @article{Wintjens2000393, author = {Wintjens, René and Liévin, Jacky and Rooman, Marianne and Buisine, Eric}, title = {Contribution of cation-π interactions to the stability of protein-DNA complexes}, journal = {Journal of Molecular Biology}, year = {2000}, volume = {302}, number = {2}, pages = {393 – 408}, doi = {10.1006/jmbi.2000.4040} }
Zobov N, Belmiloud D, Polyansky OL, Tennyson J, Shirin S, Carleer M, Jenouvrier A, Vandaele A-C, Bernath P, Mérienne M and Colin R (2000), "Near ultraviolet rotation-vibration spectrum of water", Journal of Chemical Physics. Vol. 113(4), pp. 1546 – 1552. [Abstract] [BibTeX] [DOI]
Abstract: A newly recorded, long pathlength, room temperature, rotation-vibration spectrum of water in the near-ultraviolet was analyzed using a newly computed ab initio linelist. Five new vibration bands of water were observed. It was found that one of each of these new states belongs to the previously unobserved 6ν + δ and 7ν + δ polyads, two belong to the 7ν polyad, and one to the 8ν polyad.
BibTeX: @article{Zobov20001546, author = {Zobov, N.F. and Belmiloud, Djedjiga and Polyansky, Oleg L. and Tennyson, Jonathan and Shirin, S.V. and Carleer, M. and Jenouvrier, A. and Vandaele, A.-C. and Bernath, P.F. and Mérienne, M.F. and Colin, R.}, title = {Near ultraviolet rotation-vibration spectrum of water}, journal = {Journal of Chemical Physics}, year = {2000}, volume = {113}, number = {4}, pages = {1546 – 1552}, doi = {10.1063/1.481940} }
Bach M, Georges R, Herman M and Perrin A (1999), "Investigation of the fine structure in overtone absorption bands of 12C2H4", Molecular Physics. Vol. 97(1-2), pp. 265 – 277. [Abstract] [BibTeX] [DOI]
Abstract: A Fourier transform interferometer was used to record the slit-jet cooled overtone absorption spectrum of 12C2H4 between 3900 and 7900cm−1, at a spectral resolution of 0.02cm−1 and a rotational temperature of 53 K. Some 17 bands were observed and rotationally analysed, leading to effective vibration—rotation constants for all upper states. Coriolis perturbations were identified and refined vibration—rotation constants were produced for seven upper states as well as for 12 Coriolis interacting dark states. Symmetry conventions different from those of the previous literature are selected in the present work. © 1999 Taylor & Francis Group, LLC.
BibTeX: @article{Bach1999265, author = {Bach, M. and Georges, R. and Herman, M. and Perrin, A.}, title = {Investigation of the fine structure in overtone absorption bands of 12C2H4}, journal = {Molecular Physics}, year = {1999}, volume = {97}, number = {1-2}, pages = {265 – 277}, doi = {10.1080/00268979909482828} }
Barret B, Mahieu E, Carleer M, De Maziere M, Colin R and Zander R (1999), "Tropospheric boundary layer investigations by differential ground-based solar FTIR spectrometry", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3821, pp. 116 – 123. [Abstract] [BibTeX]
Abstract: In order to better understand the chemistry and the transport mechanisms in the lower troposphere, a new original technique has been developed and tested. The experiment consists in recording high resolution infrared solar absorption spectra containing signatures of important atmospheric constituents, simultaneously from the International Scientific Station of the Jungfraujoch in Switzerland (ISSJ, 3580 m a.s.l., 46.5°N, 8°E, Bruker 120HR Fourier transform spectrometer (FTS)) and from a nearby valley (Grindelwald, 1070 m a.s.l., Bruker 120M FTS). Analysis of individual spectra allows to determine vertical column abundances; differences between measurements at ISSJ and at Grindelwald enable us to retrieve the constituents' concentrations between 1070 m and 3580 m, assuming a constant volume mixing ratio in this layer. A first measurement campaign has been organized during the months of May and June 1998. After an initial period of instrument intercomparison at ISSJ, the mobile instrument was moved down in the valley and installed for one month in Grindelwald. When operated side by side at the Jungfraujoch, measurements made by both instruments showed a very good agreement (maximum bias of 1.5%). Analysis of spectra recorded synchronously at the Jungfraujoch and at Grindelwald gave average boundary layer concentrations for a selected set of tropospheric molecules, i.e. methane, nitrous oxide, carbon monoxide and ethane. Comparison with other results and with carbon monoxide in-situ measurements made at ISSJ showed a good agreement.
BibTeX: @conference{Barret1999116, author = {Barret, Brice and Mahieu, Emmanuel and Carleer, Michel and De Maziere, Martine and Colin, Reginald and Zander, Rodolphe}, title = {Tropospheric boundary layer investigations by differential ground-based solar FTIR spectrometry}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {1999}, volume = {3821}, pages = {116 – 123} }
Bedouet C, Frémont F, Chesnel J, Husson X, Merabet H, Vaeck N, Zitane N, Sulik B, Grether M, Spieler A and Stolterfoht N (1999), "Dielectronic excitation of Ne K-shell electrons in 2–170-keV [Formula Presented] collisions", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 59(6), pp. 4399 – 4406. [Abstract] [BibTeX] [DOI]
Abstract: We report on the projectile energy dependence of the cross sections for producing K Auger electrons in 2–170-keV [Formula Presented] collisions. The present studies, which extend previous work performed at the impact energy of 35 keV, give evidence for a dielectronic excitation process produced by electron-electron interaction. At impact energies in the range 5–170 keV, the cross sections are found to be larger than [Formula Presented] Molecular-orbital energy diagrams were determined to analyze details of the collision. Analytic models were used to evaluate cross sections associated with dielectronic excitation. The results show good agreement with experiment. The dielectronic excitation process is dominant when three electrons from the target are transferred into an excited state of the projectile. © 1999 The American Physical Society.
BibTeX: @article{Bedouet19994399, author = {Bedouet, C. and Frémont, F. and Chesnel, J.Y. and Husson, X. and Merabet, H. and Vaeck, N. and Zitane, N. and Sulik, B. and Grether, M. and Spieler, A. and Stolterfoht, N.}, title = {Dielectronic excitation of Ne K-shell electrons in 2–170-keV [Formula Presented] collisions}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {1999}, volume = {59}, number = {6}, pages = {4399 – 4406}, doi = {10.1103/PhysRevA.59.4399} }
Campargue A, Biennier L, Garnache A, Kachanov A, Romanini D and Herman M (1999), "High resolution absorption spectroscopy of the v1 = 2 - 6 acetylenic overtone bands of propyne: Spectroscopy and dynamics", Journal of Chemical Physics. Vol. 111(17), pp. 7888 – 7903. [Abstract] [BibTeX] [DOI]
Abstract: The rotationally resolved nv1 (n = 2 - 6) overtone transitions of the CH acetylenic stretching of propyne (CH3-C≡C-H) have been recorded by using Fourier transform spectroscopy (n = 2), various intracavity laser absorption spectrometers (n = 3, 4, and 6) and cavity ring down spectroscopy (CRDS) (n = 5). The 2v1, 3v1, and 6v1, bands exhibit a well-resolved and mostly unperturbed J-rotational structure, whose analysis is reported. The 5v1 band recorded by pulsed CRDS shows an unresolved rotational envelope. In the region of 12 700 cm-1, an anharmonic interaction is confirmed between 4v1 and 3v1 + v3 + v5. The band at a higher wave number in this dyad exhibits a partly resolved K-structure, whose analysis is reported. The mixing coefficient of the two interacting states is determined consistently using different procedures. The 1/35 anharmonic resonance evidenced in the 4v1 manifold induces weaker intensity borrowing from the 2v1 and 3v1 levels to the v1 + v3 + v5 and 2v1 + v3 + v5 level, respectively, which have been predicted and identified. Several hot bands around the 2v1, 3v1, and 3v1 + v3 + v5 bands arising from the v9 = 1 and v10= 1 and 2 bending levels are identified and rotationally analyzed, also leading to determine x1,9 [-20.3(3) cm-1], x1,10 [-1.7975(75) cm-1], and x3,10 [-6.56 cm-1]. The J-clumps of the P and R branches in the 6v1 band at 18 499 cm-1 show a Lorentzian homogeneous profile mostly J-independent with an average full width at half maximum (FWHM) of 0.17 cm-1, attributed to arising from the intramolecular vibrational energy redistribution towards the bath of vibrational states. A detailed comparative examination of the fine structure in all investigated nv1 (n = 2 to 7) overtone bands and the similar behavior of the cold and hot bands arising from v10= 1 definitively suggests that a highly specific low-order anharmonic coupling, still unidentified, dominates the hierarchy of interaction mechanisms connecting the nv1 levels to the background states. © 1999 American Institute of Physics.
BibTeX: @article{Campargue19997888, author = {Campargue, A. and Biennier, L. and Garnache, A. and Kachanov, A. and Romanini, D. and Herman, M.}, title = {High resolution absorption spectroscopy of the v1 = 2 - 6 acetylenic overtone bands of propyne: Spectroscopy and dynamics}, journal = {Journal of Chemical Physics}, year = {1999}, volume = {111}, number = {17}, pages = {7888 – 7903}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.480124} }
Carleer M (1999), "FTS line shapes and their importance in atmospheric measurements in the UV-Vis and the IR", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3821, pp. 70 – 87. [Abstract] [BibTeX]
Abstract: Concentration measurements of trace gases in the atmosphere require the use of highly sensitive and precise techniques. The Fourier transform absorption spectroscopy technique is one of them heavily used for atmospheric measurements. It is currently used in all spectral regions, from the far-IR to the near-UV. The spectra recorded will be either fully resolved, showing well separated lines, or will only show absorption bands consisting of a great number of overlapping lines. The algorithm used to retrieve the concentrations of the atmospherically important molecules depends on this, as well as the resolution used to record the spectra. In both cases however, the instrumental function will modify the spectrum shape and has to be taken into account. In order to retrieve concentrations with the best possible accuracy, a thorough understanding of how the instrumental function affects line profiles or absorbances is essential.
BibTeX: @conference{Carleer199970, author = {Carleer, Michel}, title = {FTS line shapes and their importance in atmospheric measurements in the UV-Vis and the IR}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {1999}, volume = {3821}, pages = {70 – 87} }
Carleer M, Jenouvrier A, Vandaele A-C, Bemath P, Mérienne M, Colin R, Zobov N, Polyansky OL, Tennyson J and Savin V (1999), "The near infrared, visible, and near ultraviolet overtone spectrum of water", Journal of Chemical Physics. Vol. 111(6), pp. 2444 – 2450. [Abstract] [BibTeX] [DOI]
Abstract: New long path length, high resolution, Fourier transform spectrometer measurements for water are presented. These spectra cover the near infrared, visible, and near ultraviolet regions and contain water transitions belonging to all polyads from 3v to 8v. Transitions in the range 13 100-21 400 cm-1 are analyzed using line lists computed using variational first-principles calculations. 2286 new transitions are assigned to H216O. These result in the observation of transitions in 15 new overtone and combination bands of water. Energy levels for these and other newly observed levels are presented. It is suggested that local mode rather than normal mode vibrational assignments are more appropriate for the vibrational states of water in polyads 4v and above. © 7999 American Institute of Physics.
BibTeX: @article{Carleer19992444, author = {Carleer, M. and Jenouvrier, A. and Vandaele, A.-C. and Bemath, P.F. and Mérienne, M.F. and Colin, R. and Zobov, N.F. and Polyansky, Oleg L. and Tennyson, Jonathan and Savin, V.A.}, title = {The near infrared, visible, and near ultraviolet overtone spectrum of water}, journal = {Journal of Chemical Physics}, year = {1999}, volume = {111}, number = {6}, pages = {2444 – 2450}, doi = {10.1063/1.479859} }
Claveau C, Teffo J-L, Hurtmans D, Valentin A and Gamache R (1999), "Line positions and absolute intensities in the laser bands of carbon-12 oxygen-17 isotopic species of carbon dioxide", Journal of Molecular Spectroscopy. Vol. 193(1), pp. 15 – 32. [Abstract] [BibTeX] [DOI]
Abstract: Infrared spectra of a carbon dioxide sample enriched with oxygen-17 have been recorded with a resolution of about 0.0025 cm-1 in the region of the laser bands near 10 and 9 μm, using the long path difference Fourier Transform Spectrometer of the LPMA in Paris. The two laser bands of the 16O12C17O and 17O12C18O species have been analyzed for the first time. Line intensities for several isotopic species have been measured in this region and the rotationless transition dipole moments and Herman-Wallis coefficients of the corresponding bands have been reported. In particular intensities, alternation in the spectra of 17O12C17O has been analyzed. © 1999 Academic Press.
BibTeX: @article{Claveau199915, author = {Claveau, C. and Teffo, J.-L. and Hurtmans, D. and Valentin, A. and Gamache, R.R.}, title = {Line positions and absolute intensities in the laser bands of carbon-12 oxygen-17 isotopic species of carbon dioxide}, journal = {Journal of Molecular Spectroscopy}, year = {1999}, volume = {193}, number = {1}, pages = {15 – 32}, doi = {10.1006/jmsp.1998.7704} }
Clerbaux C, Hadji-Lazaro J, Payan S, Camy-Peyret C and Megie G (1999), "Retrieval of CO columns from IMG/ADEOS spectra", IEEE Transactions on Geoscience and Remote Sensing. Vol. 37(3 II), pp. 1657 – 1661. [Abstract] [BibTeX] [DOI]
Abstract: The high-resolution atmospheric spectra recorded by the Interferometric Monitor for Greenhouse gases instrument on the ADvanced Earth Observing System (IMG/ADEOS) in June, 1997, were analyzed by two different and complementary inversion algorithms to retrieve CO total columns. Spectral fits of high quality were obtained using a global fit algorithm on selected cloud-free measurements. Global distribution maps of CO obtained using a fast neural network retrieval algorithm are compared to the results provided by current chemistry-transport models. These studies highlight the need for complementary information (temperature, emissivity, instrumental function, and cloud content) to retrieve accurate CO vertical columns.
BibTeX: @article{Clerbaux19991657, author = {Clerbaux, Cathy and Hadji-Lazaro, Juliette and Payan, Sebastien and Camy-Peyret, Claude and Megie, Gerard}, title = {Retrieval of CO columns from IMG/ADEOS spectra}, journal = {IEEE Transactions on Geoscience and Remote Sensing}, year = {1999}, volume = {37}, number = {3 II}, pages = {1657 – 1661}, doi = {10.1109/36.763283} }
Clerbaux C, Hadji-Lazaro J, Payan S, Camy-Peyret C and Mégie G (1999), "Retrieval of CO Columns from IMG/ADEOS Spectra", IEEE Transactions on Geoscience and Remote Sensing. Vol. 37(3 II), pp. 1645 – 1656. [Abstract] [BibTeX] [DOI]
Abstract: The high-resolution atmospheric spectra recorded by the Interferometric Monitor for Greenhouse gases instrument on the ADvanced Earth Observing System (IMG/ADEOS) in June, 1997, were analyzed by two different and complementary inversion algorithms to retrieve CO total columns. Spectral fits of high quality were obtained using a global fit algorithm on selected cloud-free measurements. Global distribution maps of CO obtained using a fast neural network retrieval algorithm are compared to the results provided by current chemistry-transport models. These studies highlight the need for complementary information (temperature, emissivity, instrumental function, and cloud content) to retrieve accurate CO vertical columns. Index Terms - Atmospheric measurements, infrared spectroscopy, least square method, neural networks. © 1999 IEEE.
BibTeX: @article{Clerbaux19991645, author = {Clerbaux, Cathy and Hadji-Lazaro, Juliette and Payan, Sébastien and Camy-Peyret, Claude and Mégie, Gérard}, title = {Retrieval of CO Columns from IMG/ADEOS Spectra}, journal = {IEEE Transactions on Geoscience and Remote Sensing}, year = {1999}, volume = {37}, number = {3 II}, pages = {1645 – 1656}, doi = {10.1109/36.763281} }
Coheur P-F, Cornil J, Dos Santos D, Birkett P, Liévin J, Brédas J, Janot J-M, Seta P, Leach S, Walton D, Taylor R, Kroto H and Colin R (1999), "Photophysical properties of C60Cl6, C60Ph5Cl and C60Ph5H", Synthetic Metals. Vol. 103(1-3), pp. 2407 – 2410. [Abstract] [BibTeX] [DOI]
Abstract: The geometry and electronic structure of three C60 derivatives (C60Cl6, C60Ph5Cl and C60Ph5H) are studied by means of spectroscopic measurements in cyclohexane solution and semi-empirical Hartree-Fock quantum-chemical calculations. A good agreement between observed and simulated spectra is reported. Based on the latter, the importance of symmetry and nature of the functional groups on the properties of the C60 cages is discussed.
BibTeX: @article{Coheur19992407, author = {Coheur, P.-F. and Cornil, J. and Dos Santos, D.A. and Birkett, P.R. and Liévin, J. and Brédas, J.L. and Janot, J.-M. and Seta, P. and Leach, S. and Walton, D.R.M. and Taylor, R. and Kroto, H.W. and Colin, R.}, title = {Photophysical properties of C60Cl6, C60Ph5Cl and C60Ph5H}, journal = {Synthetic Metals}, year = {1999}, volume = {103}, number = {1-3}, pages = {2407 – 2410}, doi = {10.1016/S0379-6779(98)00250-1} }
Di Lonardo G, Fusina L, Venuti E, Johns J, El Idrissi M, Liévin J and Herman M (1999), "The vibrational energy pattern in acetylene. V. 13C2H2", Journal of Chemical Physics. Vol. 111(3), pp. 1008 – 1016. [Abstract] [BibTeX] [DOI]
Abstract: A total of 134 vibrational levels with assigned rotational structure have been gathered in the ground electronic state of 13C2H2. Most of these measurements are updated or new compared to the previously published data. Altogether, they cover the range up to 23 670 cm-1. 118 out of the 119 levels observed below 13 000 cm-1 have been simultaneously fitted using the so-called cluster model, already used to deal with the vibrational energy levels in other isotopomers of acetylene [El Idrissi et al., J. Chem. Phys. 110, 2074 (1999), and references therein]. Twenty-nine vibrational constants have been determined, including the off-diagonal parameters K3/245, K1/244, K1/255, K11/33, K14/35, and r45, with a rms of the fit equal to 0.52 cm-1. The same three constants of the motion as in 12C2H2 emerged, Ns = v1+v2+v3, Nr=5v1+3v2+5v3+v4+v 5 and k=l4+l5. The energies of the levels above 13 000 cm-1 calculated with the obtained parameters compare reasonably well with the experimental values. For all levels the predicted rotational constants compare satisfactorily with the experimental results. © 1999 American Institute of Physics.
BibTeX: @article{DiLonardo19991008, author = {Di Lonardo, G. and Fusina, L. and Venuti, E. and Johns, J.W.C. and El Idrissi, M.I. and Liévin, J. and Herman, M.}, title = {The vibrational energy pattern in acetylene. V. 13C2H2}, journal = {Journal of Chemical Physics}, year = {1999}, volume = {111}, number = {3}, pages = {1008 – 1016}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.479381} }
El Idrissi M, Liévin J, Campargue A and Herman M (1999), "The vibrational energy pattern in acetylene (IV): Updated global vibration constants for 12C2H2", Journal of Chemical Physics. Vol. 110(4), pp. 2074 – 2086. [Abstract] [BibTeX] [DOI]
Abstract: All 253 vibrational levels in the ground electronic state of 12C2H2 with assigned rotational structure reported in the literature from absorption, stimulated emission pumping, and dispersed laser induced fluorescence spectroscopic investigations are gathered. They cover the range up to 18915 cm-1. Some 219 of these energies are simultaneously fitted using the same so-called Cluster model based on the emergence of three constants of the motion, as previously used to deal with the vibrational energy levels up to 12 000 cm-1 [Abbouti Temsamani and Herman, J. Chem. Phys. 103, 5931 (1995)]. Thirty-nine vibrational constants are produced. The rms value of the fit is 0.81 cm-1. Principal rotational constants are predicted for all levels, which satisfactorily compare with the experimental results. Problems are demonstrated to concern a fraction of the 34 remaining levels only. Thus, the adequacy of the model is fully confirmed. The remaining problems are discussed and globally attributed to problems of a vibration-rotation nature. A comprehensive listing of calculated vibrational energies for all k sublevels up to 15 000 cm-1, including predicted Bv, values and assignments is made available. © 1999 American Institute of Physics.
BibTeX: @article{ElIdrissi19992074, author = {El Idrissi, M.I. and Liévin, J. and Campargue, A. and Herman, M.}, title = {The vibrational energy pattern in acetylene (IV): Updated global vibration constants for 12C2H2}, journal = {Journal of Chemical Physics}, year = {1999}, volume = {110}, number = {4}, pages = {2074 – 2086}, doi = {10.1063/1.477817} }
Fritzsche S, Koike F, Sienkiewicz J and Vaeck N (1999), "Calculation of relativistic atomic transition and ionization properties for highly-charged ions", Physica Scripta T. Vol. 80(B), pp. 479 – 481. [Abstract] [BibTeX]
Abstract: Recent years have seen a growing number of large-scale atomic structure calculations using both nonrelativistic and relativistic theories. For investigations of multiple and highly charged ions, of course, a relativistic structure code like the widely known GRASP program is required. In a revised version of this program, namely GRASP92 [F.A. Parpia, C.F. Fischer, and I.P. Grant, Comput. Phys. Commun. 94, 249 (1996)], systematic studies of level energies and a few other bound-state properties are now being supported. - Here, we briefly introduce a new package RATIP which extends GRASP92 towards the computation of various Relativistic AtomicTransition and Ionization Properties. A short overview of the capabilities of RATIP along with current developments will be given.
BibTeX: @conference{Fritzsche1999479, author = {Fritzsche, S. and Koike, F. and Sienkiewicz, J.E. and Vaeck, N.}, title = {Calculation of relativistic atomic transition and ionization properties for highly-charged ions}, journal = {Physica Scripta T}, year = {1999}, volume = {80}, number = {B}, pages = {479 – 481} }
Georges R, Bach M and Herman M (1999), "The vibrational energy pattern in ethylene (12C2H4)", Molecular Physics. Vol. 97(1-2), pp. 279 – 292. [Abstract] [BibTeX] [DOI]
Abstract: All known vibrational energies in 12C2H4([Xtilde]1 Ag) are collected. A block-diagonalized vibrational matrix Hamiltonian is set up, combining a Dunham expansion with the 2/10,10, 11/2,12, and the 5,5/9,9, 1,1/11,11,1,9/5,11 and 1,11/5,9 anharmonic resonances, with the normal modes numbered according to the most usual conventions in the previous literature. A step by step fitting procedure is applied. Vibrational constants are obtained, and vibrational assignments are provided and discussed. A slightly modified ensemble of vibrational constants is also produced by taking care of a more extended set of resonances between the CH-type vibrations. A new constant of the motion N = 3ν1 + 3ν5 + 3ν9 + 3ν11 + 2ν2 + ν10 + ν12 is demonstrated to support the latter vibrational energy pattern. © 1999 Taylor & Francis Group, LLC.
BibTeX: @article{Georges1999279, author = {Georges, R. and Bach, M. and Herman, M.}, title = {The vibrational energy pattern in ethylene (12C2H4)}, journal = {Molecular Physics}, year = {1999}, volume = {97}, number = {1-2}, pages = {279 – 292}, doi = {10.1080/00268979909482829} }
Godefroid M and Froese Fischer C (1999), "Mg+ 3s 2S 1/2 -4p 2P3/2, 1/2 o weak transition probabilities revisited", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 32(18), pp. 4467 – 4483. [Abstract] [BibTeX] [DOI]
Abstract: The oscillator strengths of the Mg+ weak transitions 3s 2S 1/2 -4p 2P3/2, 1/2 o at λ = 1239, 1240 angstrom are evaluated using the multiconfiguration Hartree-Fock approach combined with the orbital active set method and configuration-interaction calculations, taking the effect of triple and quadruple excitations into account. The effects of core and core-valence correlation using different optimization schemes are discussed in detail. Relativistic corrections are calculated within the Breit-Pauli approximation.
BibTeX: @article{Godefroid19994467, author = {Godefroid, M. and Froese Fischer, C.}, title = {Mg+ 3s 2S 1/2 -4p 2P3/2, 1/2 o weak transition probabilities revisited}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1999}, volume = {32}, number = {18}, pages = {4467 – 4483}, doi = {10.1088/0953-4075/32/18/307} }
Godefroid MR and Fischer CF (1999), "Isotope shift in the oxygen electron affinity", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 60(4), pp. R2637 – R2640. [Abstract] [BibTeX] [DOI]
Abstract: The present paper reports the ab initio evaluation of the electron affinity of oxygen, and the value of its isotope shift. The theoretical results are in good agreement with the recent electron affinity measurements for [Formula Presented] [Formula Presented] by photodetachment microscopy, revealing an “anomalous” isotope shift. The theoretical fine structure of the negative ion [Formula Presented] is also in very good agreement with observation. © 1999 The American Physical Society.
BibTeX: @article{Godefroid1999R2637, author = {Godefroid, Michel R. and Fischer, Charlotte Froese}, title = {Isotope shift in the oxygen electron affinity}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {1999}, volume = {60}, number = {4}, pages = {R2637 – R2640}, doi = {10.1103/PhysRevA.60.R2637} }
Hadji-Lazaro J, Clerbaux C and Thiria S (1999), "An inversion algorithm using neural networks to retrieve atmospheric CO total columns from high-resolution nadir radiances", Journal of Geophysical Research Atmospheres. Vol. 104(D19), pp. 23841 – 23854. [Abstract] [BibTeX] [DOI]
Abstract: Up to the first years of the next millennium, several observation programs of the troposphere are scheduled, including the Infrared Atmospheric Sounding Interferometer, which uses Fourier transform spectroscopy to record the radiance of the Earth-atmosphere system with a nadir-viewing geometry. The Interferometric Monitor for Greenhouse Gases (IMG), launched aboard the Advanced Earth Observing System in August 1996, was a precursor of these forthcoming missions. A new inversion algorithm based on neural network techniques is in development to retrieve trace gases from high-resolution nadir radiances. Neural networks offer a technical alternative to classical methods and allow efficient inversion calculations as required to treat the huge volume of data which will be provided by continuous observation of the atmosphere from space. To develop a network to retrieve the carbon monoxide total column, realistic simulations of the IMG measurements were obtained by coupling a three-dimensional chemical-transport model with a high-resolution line-by-line radiative transfer code adjusted to the instrumental features. The application of the algorithm on simulated data allowed the checking of its performance: for about 99% of the cases, the relative inversion error was less than 10%. This algorithm has been applied to the spectra recorded by the IMG instrument between June 16 and 19, 1997. Global-scale distributions of CO total columns were obtained for the first time by using a neural network, and this technique proved its ability to achieve real-time inversion of atmospheric CO. Copyright 1999 by the American Geophysical Union.
BibTeX: @article{Hadji-Lazaro199923841, author = {Hadji-Lazaro, Juliette and Clerbaux, Cathy and Thiria, Sylvie}, title = {An inversion algorithm using neural networks to retrieve atmospheric CO total columns from high-resolution nadir radiances}, journal = {Journal of Geophysical Research Atmospheres}, year = {1999}, volume = {104}, number = {D19}, pages = {23841 – 23854}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/1999JD900431} }
Hadji-Lázaro J, Clerbaux C and Thiria S (1999), "An inversion algorithm using neural networks to retrieve atmospheric CO total columns from high-resolution nadir radiances", Journal of Geophysical Research: Atmospheres. Vol. 104(D19), pp. 23841 – 23854. [Abstract] [BibTeX] [DOI]
Abstract: Up to the first years of the next millennium, several observation programs of the troposphere are scheduled, including the Infrared Atmospheric Sounding Interferometer, which uses Fourier transform spectroscopy to record the radiance of the Earth-atmosphere system with a nadir-viewing geometry. The In-terferometric Monitor for Greenhouse Gases (IMG), launched aboard the Advanced Earth Observing System in August 1996, was a precursor of these forthcoming missions. A new inversion algorithm based on neural network techniques is in development to retrieve trace gases from high-resolution nadir radiances. Neural networks offer a technical alternative to classical methods and allow efficient inversion calculations as required to treat the huge volume of data which will be provided by continuous observation of the atmosphere from space. To develop a network to retrieve the carbon monoxide total column, realistic simulations of the IMG measurements were obtained by coupling a three-dimensional chemical-transport model with a high-resolution line-by-line radiative transfer code adjusted to the instrumental features. The application of the algorithm on simulated data allowed the checking of its performance: for about 99% of the cases, the relative inversion error was less than 10%. This algorithm has been applied to the spectra recorded by the IMG instrument between June 16 and 19, 1997. Global-scale distributions of CO total columns were obtained for the first time by using a neural network, and this technique proved its ability to achieve real-time inversion of atmospheric CO. Copyright 1999 by the American Geophysical Union.
BibTeX: @article{Hadji-Lázaro199923841, author = {Hadji-Lázaro, Juliette and Clerbaux, Cathy and Thiria, Sylvie}, title = {An inversion algorithm using neural networks to retrieve atmospheric CO total columns from high-resolution nadir radiances}, journal = {Journal of Geophysical Research: Atmospheres}, year = {1999}, volume = {104}, number = {D19}, pages = {23841 – 23854}, doi = {10.1029/1998JD900431} }
Henry A and Hurtmans D (1999), "Collision narrowing and speed dependent effect on broadening in vibration rotation line profiles perturbed by different buffer gases up to one atmosphere - difficulties in these analyses coming from the quality of the tunable diode laser emission", Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy. Vol. 55(10), pp. 1967 – 1986. [Abstract] [BibTeX] [DOI]
Abstract: Different tunable diode lasers (TDL), tightly controlled by a Michelson interferometer, have been used to study precisely the evolution of absorption line profiles when the pressure increases. For this purpose the spectral intensity distribution within each given TDL mode has been determined by comparing the observed spectrum of a narrow absorption line at very low pressure (Doppler line) with a calculated spectrum, convolution product of the TDL intensity distribution with the exact absorption line shape precisely described by a Gauss profile. Examples of confinement narrowing and absorber speed dependent effect are given with CO or HCl in different buffer gases (N2, He, Ne, Ar and Xe) and the line parameters have been deduced taking into account the intensity distribution of the TDL emission.
BibTeX: @article{Henry19991967, author = {Henry, A. and Hurtmans, D.}, title = {Collision narrowing and speed dependent effect on broadening in vibration rotation line profiles perturbed by different buffer gases up to one atmosphere - difficulties in these analyses coming from the quality of the tunable diode laser emission}, journal = {Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy}, year = {1999}, volume = {55}, number = {10}, pages = {1967 – 1986}, doi = {10.1016/S1386-1425(99)00069-4} }
Hepp M and Herman M (1999), "Effective Rotation-Vibration Parameters for the ν8and ν4+ ν12Bands of Ethane", Journal of Molecular Spectroscopy. Vol. 194(1), pp. 87 – 94. [Abstract] [BibTeX] [DOI]
Abstract: The jet-cooled spectrum of ethane in the region of the ν8perpendicular fundamental vibration at 1472 cm-1was recorded with a Fourier transform spectrometer at 0.01 cm-1instrumental resolution. About 1150 lines were assigned to 18 subbands of ν8ranging fromK″ΔK= -9 to +8. About 160 lines were assigned to three subbands (K″ΔK= 0 to +2) of the ν4+ ν12combination band near 1481 cm-1. Torsional splittings were observed for the majority of the transitions. A stack-by-stack analysis was performed, resulting in effective rovibrational parameters for the upper states ν8and ν4+ ν12. A number of perturbations was observed and is discussed. © 1999 Academic Press.
BibTeX: @article{Hepp199987, author = {Hepp, M. and Herman, M.}, title = {Effective Rotation-Vibration Parameters for the ν8and ν4+ ν12Bands of Ethane}, journal = {Journal of Molecular Spectroscopy}, year = {1999}, volume = {194}, number = {1}, pages = {87 – 94}, doi = {10.1006/jmsp.1998.7772} }
Hepp M and Herman M (1999), "Weak Combination Bands in the 3-μm Region of Ethane", Journal of Molecular Spectroscopy. Vol. 197(1), pp. 56 – 63. [Abstract] [BibTeX] [DOI]
Abstract: The infrared spectrum of ethane in the region of the CH-stretching fundamental vibrations, between 2600 and 3300 cm-1, was recorded with a Bruker IFS120HR Fourier transform spectrometer. Jet-cooled and room-temperature conditions were used at 0.01 and 0.005 cm-1 instrumental resolution, respectively. Ten weak combination bands were observed and vibrationally assigned, in addition to the three principal bands in the region (ν5, ν7, and ν8 + ν11 (∥ component)). A stack-by-stack analysis was performed for five of the combination bands. Their origins were determined as follows: ν8 + ν12 (∥ component) at 2665.1512(30) cm-1, ν2 + ν6 at 2753.326(32) cm-1, ν6 + ν11 at 2844.13069(75) cm-1, ν8 + ν11 (⊥ component) at 2930.705(90) cm-1, and ν4 + ν10 at 3255.568(50) cm-1. Effective rovibrational parameters were obtained for the corresponding upper states. New information was also obtained on the five remaining combination bands. Their approximate origins are: ν8 + ν12 (⊥ component) at 2660 cm-1, ν2 + ν4 + ν12 at 2860 cm-1, ν4 + 2ν9 + ν12 at 3090 cm-1, 3ν4 + ν8 + ν9 at 3157 cm-1, and ν4 + 2ν8 at 3225 cm-1. © 1999 Academic Press.
BibTeX: @article{Hepp199956, author = {Hepp, M. and Herman, M.}, title = {Weak Combination Bands in the 3-μm Region of Ethane}, journal = {Journal of Molecular Spectroscopy}, year = {1999}, volume = {197}, number = {1}, pages = {56 – 63}, doi = {10.1006/jmsp.1999.7893} }
Herman M, Herregodts F, Georges R, Hepp M, Hadj Bachir I, Lecoutre M and Kleiner I (1999), "Spectroscopic investigation of vibration-rotation bands in acetaldehyde:: Focus on the nν3 (n=1-5) aldehyde CH stretch bands", Chemical Physics. Vol. 246(1-3), pp. 433 – 443. [Abstract] [BibTeX] [DOI]
Abstract: We describe experiments on acetaldehyde (12CH312CH16O) resulting in new or improved spectroscopic data on the nν3 (n=1-5) aldehyde CH stretching vibrational bands. The n=1 component is rotationally resolved using room temperature and supersonic jet Fourier transform spectroscopy, and vibration-rotation assignments are reported. The next two components (n=2, 3) are recorded at room temperature using Fourier transform spectroscopy, and the K-structure is resolved and assigned. The last two series of bands (n=4, 5) are observed but not resolved, using laser opto-acoustic spectroscopy. Effective vibrational constants (ω̃eff3=2938.53 cm-1, xeff33=55.75 cm-1) are obtained. Information is also provided on additional bands in the spectrum from 1300 to 14 000 cm-1, involving, in particular, the assignment of the K-structure in ν11 and 2ν1, from the jet-cooled and the room-temperature Fourier transform spectral data, respectively. A table updating the origin of most vibration-rotation bands in acetaldehyde previously assigned in the literature is provided.
BibTeX: @article{Herman1999433, author = {Herman, Michel and Herregodts, Frédéric and Georges, Robert and Hepp, Martin and Hadj Bachir, Ikhlef and Lecoutre, Michaël and Kleiner, Isabelle}, title = {Spectroscopic investigation of vibration-rotation bands in acetaldehyde:: Focus on the nν3 (n=1-5) aldehyde CH stretch bands}, journal = {Chemical Physics}, year = {1999}, volume = {246}, number = {1-3}, pages = {433 – 443}, doi = {10.1016/S0301-0104(99)00167-6} }
Herman M, Lievin J, Vander Auwera J and Campargue A (1999), "Global and accurate vibration Hamiltonians from high-resolution molecular spectroscopy", Advances in Chemical Physics. Vol. 108, pp. 1 – 330. [BibTeX]
BibTeX: @article{Herman19991, author = {Herman, Michel and Lievin, Jacques and Vander Auwera, Jean and Campargue, Alain}, title = {Global and accurate vibration Hamiltonians from high-resolution molecular spectroscopy}, journal = {Advances in Chemical Physics}, year = {1999}, volume = {108}, pages = {1 – 330} }
Hermans C, Vandaele AC, Carleer M, Fally S, Colin R, Jenouvrier A, Coquart B and Mérienne M-F (1999), "Absorption cross-sections of atmospheric constituents: NO2, O2, and H2O", Environmental Science and Pollution Research. Vol. 6(3), pp. 151 – 158. [Abstract] [BibTeX] [DOI]
Abstract: Absorption spectroscopy, which is widely used for concentration measurements of tropospheric and stratospheric compounds, requires precise values of the absorption cross-sections of the measured species. NO2, O2 and its collision-induced absorption spectrum, and H2O absorption cross-sections have been measured at temperature and pressure conditions prevailing in the Earth's atmosphere. Corrections to the generally accepted analysis procedures used to resolve the convolution problem are also proposed.
BibTeX: @article{Hermans1999151, author = {Hermans, Christian and Vandaele, Ann C. and Carleer, Michel and Fally, Sophie and Colin, Réginald and Jenouvrier, Alain and Coquart, Bernard and Mérienne, Marie-France}, title = {Absorption cross-sections of atmospheric constituents: NO2, O2, and H2O}, journal = {Environmental Science and Pollution Research}, year = {1999}, volume = {6}, number = {3}, pages = {151 – 158}, doi = {10.1007/BF02987620} }
Herregodts F, Hepp M, Hurtmans D, Vander Auwera J and Herman M (1999), "Laser spectroscopy of the v1+3v3 absorption band in 12C2H2. II. Self-collisional lineshift measurements", Journal of Chemical Physics. Vol. 111(17), pp. 7961 – 7965. [Abstract] [BibTeX] [DOI]
Abstract: We have recorded the spectrum of the v1+3v3 band in 12C2H2, around 12676 cm-1, using an autoscan Ti:Sa spectrometer. Pressure-dependent line positions were determined from an absorption spectrum recorded using a long White-type multiple-pass cell. An optoacoustic cell with a constant, low acetylene pressure allowed reference line position wavenumbers to be measured simultaneously. In different experiments, the multiple-pass cell was filled with increasing acetylene pressures. Self-collisional lineshifts were determined for more than 30 P and R lines in the band. Line wavenumbers for the stronger lines were separately measured from an optoacoustic spectrum calibrated using the results of a previous investigation in the literature [X. Zhan and L. Halonen, J. Mol. Spectrosc. 160, 464 (1993)] and corrected for their pressure dependence using the presently determined self-collisional lineshifts. Lineshift parameters that are significantly different from the overall behavior in the band are unexpectedly observed for the R(17) and P(19) lines. This result is explained in terms of a different intermolecular behavior of the molecule in the upper J=18 rotation level, attributed to an intramolecular Coriolis-type coupling with a nearby state tentatively assigned as containing important excitation in v5, the cis-bend mode. © 1999 American Institute of Physics.
BibTeX: @article{Herregodts19997961, author = {Herregodts, F. and Hepp, M. and Hurtmans, D. and Vander Auwera, J. and Herman, M.}, title = {Laser spectroscopy of the v1+3v3 absorption band in 12C2H2. II. Self-collisional lineshift measurements}, journal = {Journal of Chemical Physics}, year = {1999}, volume = {111}, number = {17}, pages = {7961 – 7965}, doi = {10.1063/1.480130} }
Herregodts F, Hurtmans D, Vander Auwera J and Herman M (1999), "Laser spectroscopy of the v1+3v3 absorption band in 12C2H2. I. Pressure broadening and absolute line intensity measurements", Journal of Chemical Physics. Vol. 111(17), pp. 7954 – 7960. [Abstract] [BibTeX] [DOI]
Abstract: We have developed a Ti:Sa autoscan laser spectrometer and used it to perform a detailed investigation of individual line profiles in the v1 + 3v3 band of 12C2H2. Pressure self-broadening effects were measured for most lines with J″ values ranging from 0 to 22, and for pressures between 10 and 600 Torr. The high-pressure data points (p>250Torr) are fitted satisfactorily by a Voigt profile. Line narrowing, characterized by an underestimation of the Lorentz contribution to the Voigt profile, was observed for the low pressures range (p<150Torr), indicating the influence of molecular confinement. The two usual limit models (soft and hard collisions) were fitted to the observed line shapes in order to extract more precise information concerning the pressure broadening. The present results confirm the absence of strong vibrational dependence in the self-broadening coefficients. Absolute line intensities are also determined in the fitting procedure. No significant differences were found for the two pressure domains if the appropriate model in each range is used. © 1999 American Institute of Physics. 00141-5].
BibTeX: @article{Herregodts19997954, author = {Herregodts, F. and Hurtmans, D. and Vander Auwera, J. and Herman, M.}, title = {Laser spectroscopy of the v1+3v3 absorption band in 12C2H2. I. Pressure broadening and absolute line intensity measurements}, journal = {Journal of Chemical Physics}, year = {1999}, volume = {111}, number = {17}, pages = {7954 – 7960}, doi = {10.1063/1.480129} }
Jacquinet-Husson N, Arié E, Ballard J, Barbe A, Bjoraker G, Bonnet B, Brown L, Camy-Peyret C, Champion J, Chédin A, Chursin A, Clerbaux C, Duxbury G, Flaud J-M, Fourrié N, Fayt A, Graner G, Gamache R, Goldman A, Golovko V, Guelachvili G, Hartmann J, Hilico J, Hillman J, Lefèvre G, Lellouch E, Mikhaïlenko S, Naumenko O, Nemtchinov V, Newnham D, Nikitin A, Orphal J, Perrin A, Reuter D, Rinsland C, Rosenmann L, Rothman L, Scott N, Selby J, Sinitsa L, Sirota J, Smith A, Smith K, Tyuterev V, Tipping R, Urban S, Varanasi P and Weber M (1999), "The 1997 spectroscopic GEISA databank", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 62(2), pp. 205 – 254. [Abstract] [BibTeX] [DOI]
Abstract: The current version GEISA-97 of the computer-accessible database system GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information) is described. This catalogue contains 1,346,266 entries. These are spectroscopic parameters required to describe adequately the individual spectral lines belonging to 42 molecules (96 isotopic species) and located between 0 and 22,656 cm-1. The featured molecules are of interest in studies of the terrestrial as well as the other planetary atmospheres, especially those of the Giant Planets. GEISA-97 contains also a catalog of absorption cross-sections of molecules such as chlorofluorocarbons which exhibit unresolvable spectra. The modifications and improvements made to the earlier edition (GEISA-92) and the data management software are described. GEISA-97 and the associated management software are accessible from the ARA/LMD (Laboratoire de Météorologie Dynamique du CNRS, France) web site: http://ara01.polytechnique.fr/registration. © 1999 Elsevier Science Ltd. All rights reserved.
BibTeX: @article{Jacquinet-Husson1999205, author = {Jacquinet-Husson, N. and Arié, E. and Ballard, J. and Barbe, A. and Bjoraker, G. and Bonnet, B. and Brown, L.R. and Camy-Peyret, C. and Champion, J.P. and Chédin, A. and Chursin, A. and Clerbaux, C. and Duxbury, G. and Flaud, J.-M. and Fourrié, N. and Fayt, A. and Graner, G. and Gamache, R. and Goldman, A. and Golovko, Vl. and Guelachvili, G. and Hartmann, J.M. and Hilico, J.C. and Hillman, J. and Lefèvre, G. and Lellouch, E. and Mikhaïlenko, S.N. and Naumenko, O.V. and Nemtchinov, V. and Newnham, D.A. and Nikitin, A. and Orphal, J. and Perrin, A. and Reuter, D.C. and Rinsland, C.P. and Rosenmann, L. and Rothman, L.S. and Scott, N.A. and Selby, J. and Sinitsa, L.N. and Sirota, J.M. and Smith, A.M. and Smith, K.M. and Tyuterev, Vl.G. and Tipping, R.H. and Urban, S. and Varanasi, P. and Weber, M.}, title = {The 1997 spectroscopic GEISA databank}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {1999}, volume = {62}, number = {2}, pages = {205 – 254}, doi = {10.1016/S0022-4073(98)00111-3} }
Jenouvrier A, Mérienne M-F, Coquart B, Carleer M, Fally S, Vandaele AC, Hermans C and Colin R (1999), "Fourier Transform Spectroscopy of the O2 Herzberg Bands I. Rotational Analysis", Journal of Molecular Spectroscopy. Vol. 198(1), pp. 136 – 162. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectra of the O2 Herzberg band systems (A3Σ+u-X3Σ -g, c1Σ-u-X3Σ -g, and A′ 3Δu-X3Σ-g) lying in the wavelength region 240-300 nm were reinvestigated. The coupling of a long absorption cell and a high-resolution Fourier transform spectrometer has allowed the observation of numerous weak lines which were not reported previously. From the rotational analysis of the line positions, determined with an accuracy of 0.005 cm-1, the molecular constants of the A3Σ+u, v = 0-12, c1Σ-u, v = 2-19, and A′ 3Δu, v = 2-12 levels are improved significantly. The interaction between the A and c states is described quantitatively. A new interpretation of the perturbations observed in the energy region close to the dissociation limit is given which involves a weakly bound 3Πu state as the most probable perturbing state. © 1999 Academic Press.
BibTeX: @article{Jenouvrier1999136, author = {Jenouvrier, Alain and Mérienne, Marie-France and Coquart, Bernard and Carleer, Michel and Fally, Sophie and Vandaele, Ann Carine and Hermans, Christian and Colin, Reginald}, title = {Fourier Transform Spectroscopy of the O2 Herzberg Bands I. Rotational Analysis}, journal = {Journal of Molecular Spectroscopy}, year = {1999}, volume = {198}, number = {1}, pages = {136 – 162}, doi = {10.1006/jmsp.1999.7950} }
Jönsson P, Froese Fischer C and Godefroid M (1999), "MCHF calculations of isotope shifts and oscillator strengths for transitions between low-lying states in Be-like systems and neutral magnesium", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 32(5), pp. 1233 – 1245. [Abstract] [BibTeX] [DOI]
Abstract: Results from systematic multiconfiguration Hartree-Fock calculations of isotope shifts and oscillator strengths are reported for the 2s2 - 2s2p and 2s2p - 2p2 transitions in the Be isoelectronic sequence (Z = 4-10). In addition values for the same properties as well as for the hyperfine interaction constants are presented for the 3s2-3s3p transitions in Mg I. Different models for electron correlation are used, and it is shown that valence and core-valence effects alone are not sufficient to obtain accurate values for the isotope shifts, but that also core-core effects need to be accounted for.
BibTeX: @article{Jönsson19991233, author = {Jönsson, P. and Froese Fischer, C. and Godefroid, M.R.}, title = {MCHF calculations of isotope shifts and oscillator strengths for transitions between low-lying states in Be-like systems and neutral magnesium}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1999}, volume = {32}, number = {5}, pages = {1233 – 1245}, doi = {10.1088/0953-4075/32/5/015} }
Kleiner I, Georgest R, Heppt M and Herman M (1999), "High-resolution FT spectroscopic investigation of acetaldehyde around 7 μm", Journal of Molecular Spectroscopy. Vol. 193(1), pp. 228 – 230. [BibTeX] [DOI]
BibTeX: @article{Kleiner1999228, author = {Kleiner, I. and Georgest, R. and Heppt, M. and Herman, M.}, title = {High-resolution FT spectroscopic investigation of acetaldehyde around 7 μm}, journal = {Journal of Molecular Spectroscopy}, year = {1999}, volume = {193}, number = {1}, pages = {228 – 230}, doi = {10.1006/jmsp.1998.7721} }
Mellouki A, Herman M, Demaison J, Lemoine B and Margulès L (1999), "Rotational Analysis of the ν7 Band in Furan (C4H4O)", Journal of Molecular Spectroscopy. Vol. 198(2), pp. 348 – 357. [Abstract] [BibTeX] [DOI]
Abstract: We recorded and analyzed the absorption spectrum of the ν7 fundamental band in furan, observed around 995 cm-1. Fourier transform (FT) spectroscopy was used at ULB to record the spectrum under room-temperature conditions, at 0.01 cm-1 instrumental resolution. Diode-laser (DL) spectroscopy in a supersonic jet was used to record some portions of the band at Lille, revealing the fine structure around the band center. Pure rotation (MMW) data in the upper state were also recorded at Lille. Some 5559 FT, 101 DL, and 23 MMW data were assigned in this work. We fitted, on one hand, the MMW and DL data together and, on the other hand, the MMW, DL, and FT data simultaneously using a weighted procedure, constraining the ground state constants to their value determined from the microwave data in the literature. The results from these fits are provided and the constants discussed. Ab initio calculations are also performed to provide a force field which is used to support the very strong increase with the vibrational excitation observed in the inertial defect determined from the experimental rotational constants. © 1999 Academic Press.
BibTeX: @article{Mellouki1999348, author = {Mellouki, Abdeloihid and Herman, Michel and Demaison, Jean and Lemoine, Bernard and Margulès, Laurent}, title = {Rotational Analysis of the ν7 Band in Furan (C4H4O)}, journal = {Journal of Molecular Spectroscopy}, year = {1999}, volume = {198}, number = {2}, pages = {348 – 357}, doi = {10.1006/jmsp.1999.7955} }
Mellouki A, Vander Auwera J and Herman M (1999), "Rotation-vibration constants for the ν1, ν22, ν24, ν22 + ν24, and ground states in pyrrole (12C4H5N)", Journal of Molecular Spectroscopy. Vol. 193(1), pp. 195 – 203. [Abstract] [BibTeX] [DOI]
Abstract: We have recorded the infrared absorption spectrum of pyrrole at 0.005 cm-1 spectral resolution using a Fourier transform interferometer. The rotational analysis of the symmetric out-of-plane C-H bend 2201 fundamental band at 722.132993(5) cm-1 was performed, allowing 6760 lines to be assigned. These lines were fitted simultaneously to literature data on ν1 [A. Mellouki, R. Georges, M. Herman, D. L. Snavely, and S. Leytner, Chem. Phys. 220, 311-322 (1997)] and microwave lines [G. Wlodarczak, L. Martinache, J. Demaison, and B. P. Van Eijck, J. Mol. Spectrosc. 127, 200-208 (1988)]. A set of rotation parameters was determined for the ground state in Ir and IIIr representations, together with vibration-rotation constants for the ν1 = 1 and ν22 = 1 vibrational states. The fine structure in the strongest of the hot bands in that range was highlighted by division, from the experimental data, of the spectrum of the 2201 band, computed using the vibration-rotation parameters. The rotational assignment of 930 lines in the strongest hot band was performed. The 22012411 vibrational assignment is proposed, leading to x22,24 = 1.90 cm-1. The transition dipole matrix element for the 2201 band is estimated to \|〈ψ22\|μc\|ψ0〉\| = 2 × 10-4 D. © 1999 Academic Press.
BibTeX: @article{Mellouki1999195, author = {Mellouki, Abdeloihid and Vander Auwera, Jean and Herman, Michel}, title = {Rotation-vibration constants for the ν1, ν22, ν24, ν22 + ν24, and ground states in pyrrole (12C4H5N)}, journal = {Journal of Molecular Spectroscopy}, year = {1999}, volume = {193}, number = {1}, pages = {195 – 203}, doi = {10.1006/jmsp.1998.7724} }
Ram R, Liévin J and Bernath P (1999), "Emission Spectroscopy and Ab Initio Calculations on IrN", Journal of Molecular Spectroscopy. Vol. 197(2), pp. 133 – 146. [Abstract] [BibTeX] [DOI]
Abstract: The emission spectrum of IrN was recorded in the near infrared using a Fourier transform spectrometer. The IrN molecules were excited in an Ir hollow cathode lamp operated with a mixture of Ne and a trace of N2. Numerous IrN bands observed in the 7500-9200 cm-1 region were assigned to a new a3Π-X1Σ+ electronic transition with the 0-0 bands of the a3Π0-X1Σ+ and a3Π1-X1Σ+ subbands near 9175 and 8841 cm-1, respectively. A rotational analysis of several bands of the 0-0 and 0-1 sequences was obtained and molecular constants were extracted. The effective Hund's case (a) constants for the new a3Π state are: T00 = 8840.31747(88) cm-1, A0 = -340.53329(93) cm-1, ΔG(1/2) = 984.3629(23) cm-1, Be = 0.4699116(27) cm-1, αe = 0.0030058(50) cm-1, and re= 1.6576432(47) Å. The spectroscopic properties of the ground state and several low-lying electronic states of IrN were also predicted by ab initio calculations. These calculations are consistent with our assignment of the a3Π-X1Σ+ transition and also support our previous assignments of the A′ 1Π and A1Π electronic states [R. S. Ram and P. F. Bernath, J. Mol. Spectrosc. 193, 363 (1999)]. The excited a3Π state of IrN has an 1σ22σ21π43σ 11δ4π1 electron configuration and the configurations of the other low-lying electronic states are also discussed. © 1999 Academic Press.
BibTeX: @article{Ram1999133, author = {Ram, R.S. and Liévin, J. and Bernath, P.F.}, title = {Emission Spectroscopy and Ab Initio Calculations on IrN}, journal = {Journal of Molecular Spectroscopy}, year = {1999}, volume = {197}, number = {2}, pages = {133 – 146}, doi = {10.1006/jmsp.1999.7911} }
Ram R, Liévin J and Bernath P (1999), "Fourier transform emission spectroscopy and ab initio calculations on OsN", Journal of Chemical Physics. Vol. 111(8), pp. 3449 – 3456. [Abstract] [BibTeX] [DOI]
Abstract: The emission spectrum of OsN has been recorded in the 3000-13000 cm-1 region using a Fourier transform spectrometer. OsN molecules were excited in an osmium hollow cathode lamp operated with neon gas and a trace of nitrogen. Six bands observed in the 8000-12 200 cm-1 region have been classified into three transitions, a 4Π5/2-X2Δ5/2, b 4Φ5/2-X2Δ5/2, and b 4Φ5/2-X2Δ5/2 with the 0-0 band origins near 8381.7, 11 147.9, and 12 127.2 cm-1, respectively. A rotational analysis of these bands provides the following equilibrium constants for the ground electronic state: ωe = 1147.9492(77) cm-1, ωexe=5.4603(36) cm-1, Be=0.493 381(55) cm-1, αe = 0.002753(38) cm-1, and re = 1.618 023(91) Å. Ab initio calculations have been performed on OsN and the spectroscopic properties of the low-lying electronic states have been calculated. Our assignments are supported by these calculations. The ground state of OsN has been identified as a 2Δi state consistent with the observations for the isoelectronic IrC molecule [Jansson et al., Chem. Phys. Lett. 4, 188 (1969); J. Mol. Spectrosc. 36, 248 (1970)]. The 1σ22σ21π41δ 3σ2 electron configuration has been proposed for the ground state and the configurations for the other low-lying electronic states have also been discussed. This work represents the first experimental or theoretical investigation of the electronic spectra of OsN. © 1999 American Institute of Physics.
BibTeX: @article{Ram19993449, author = {Ram, R.S. and Liévin, J. and Bernath, P.F.}, title = {Fourier transform emission spectroscopy and ab initio calculations on OsN}, journal = {Journal of Chemical Physics}, year = {1999}, volume = {111}, number = {8}, pages = {3449 – 3456}, doi = {10.1063/1.479630} }
Sutcliffe BT (1999), "Dipole moment surfaces and spectroscopic calculations", International Journal of Quantum Chemistry. Vol. 74(6), pp. 681 – 695. [Abstract] [BibTeX] [DOI]
Abstract: Modern nonempirical calculations of the rotation-vibration spectra of small molecules often use a dipole moment surface computed from a clamped nuclei electronic structure calculation to determine the transition intensities. In this article, an attempt is made to analyze what exactly is involved in such an enterprise. © 1999 John Wiley & Sons, Inc. Int J Quant Chem 74: 681-695, 1999.
BibTeX: @article{Sutcliffe1999681, author = {Sutcliffe, Brian T.}, title = {Dipole moment surfaces and spectroscopic calculations}, journal = {International Journal of Quantum Chemistry}, year = {1999}, volume = {74}, number = {6}, pages = {681 – 695}, doi = {10.1002/(SICI)1097-461X(1999)74:6<681::AID-QUA9>3.0.CO;2-6} }
Sutcliffe BT (1999), "The born-oppenheimer correction terms for a triatomic system in the sutcliffe-tennyson formulation", International Journal of Quantum Chemistry. Vol. 74(2), pp. 109 – 121. [Abstract] [BibTeX] [DOI]
Abstract: An attempt is made to formulate the Born-Oppenheimer correction terms arising from the interaction of the electronic and nuclear motions in a triatomic system. The formulation for the nuclear motion problem is kept as general as possible while using the nuclei to define the instantaneous (x-z) plane, following the approach presented in Sutcliffe and Tennyson. © 1999 John Wiley & Sons, Inc.
BibTeX: @article{Sutcliffe1999109, author = {Sutcliffe, Brian T.}, title = {The born-oppenheimer correction terms for a triatomic system in the sutcliffe-tennyson formulation}, journal = {International Journal of Quantum Chemistry}, year = {1999}, volume = {74}, number = {2}, pages = {109 – 121}, doi = {10.1002/(SICI)1097-461X(1999)74:2<109::AID-QUA8>3.0.CO;2-K} }
Vaeck N, Desouter-Lecomte M and Liévin J (1999), "Non-adiabatic wavepacket dynamics for charge-exchange processes in ion-atom collisions: Application to C4+ + H", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 32(2), pp. 409 – 428. [Abstract] [BibTeX] [DOI]
Abstract: The collisional system C4+ + H is studied as a test case to assess the efficiency of a full quantum time-dependent method to calculate charge-exchange cross sections. The molecular diabatic electronic channels are calculated at the CASSCF level from the adiabatic potential energy curves and the radial coupling matrix. The elements of the collision matrix are extracted, for each value of the total angular momentum K, by Fourier transforming the post-collisional amplitudes of the wavepackets which are prepared in the entry channel C4+ + H and propagated on the coupled effective channels for each value of K. The results are compared with previous calculations of cross sections obtained by solving the stationary scattering equations and with recent experimental results. The close-coupling wavepacket method also provides a time-dependent picture of the collision dynamics for any K value. The kinematic isotopic effect is also examined.
BibTeX: @article{Vaeck1999409, author = {Vaeck, Nathalie and Desouter-Lecomte, Michèle and Liévin, Jacques}, title = {Non-adiabatic wavepacket dynamics for charge-exchange processes in ion-atom collisions: Application to C4+ + H}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1999}, volume = {32}, number = {2}, pages = {409 – 428}, doi = {10.1088/0953-4075/32/2/021} }
Vandaele AC and Carleer M (1999), "Development of Fourier transform spectrometry for UV–visible differential optical absorption spectroscopy measurements of tropospheric minor constituents", Applied Optics. Vol. 38(12), pp. 2630 – 2639. [Abstract] [BibTeX] [DOI]
Abstract: Concentration measurements of trace gases in the atmosphere require the use of highly sensitive and precise techniques. The UV–visible differential optical absorption spectroscopy technique is one that is heavily used for tropospheric measurements. To assess the advantages and drawbacks of using a Fourier transform spectrometer, we built a differential optical absorption spectroscopy optical setup based on a Bruker IFS 120M spectrometer. The characteristics and the capabilities of this setup have been studied and compared with those of the more conventional grating-based instruments. Two of the main advantages of the Fourier transform spectrometer are (1) the existence of a reproducible and precise wave-number scale, which greatly simplifies the algorithms used to analyze the atmospheric spectra, and (2) the possibility of recording large spectral regions at relatively high resolution, enabling the simultaneous detection of numerous chemical species with better discriminating properties. The main drawback, on the other hand, is due to the fact that a Fourier transform spectrometer is a scanning device for which the scanning time is small compared with the total measurement time. It does not have the signal integration capabilities of the CCD or photodiode array-based grating spectrographs. The Fourier transform spectrometer therefore needs fairly large amounts of light and is limited to short to medium absorption path lengths when working in the UV. © 1999 Optical Society of America.
BibTeX: @article{Vandaele19992630, author = {Vandaele, Ann Carine and Carleer, Michel}, title = {Development of Fourier transform spectrometry for UV–visible differential optical absorption spectroscopy measurements of tropospheric minor constituents}, journal = {Applied Optics}, year = {1999}, volume = {38}, number = {12}, pages = {2630 – 2639}, doi = {10.1364/AO.38.002630} }
Bach M, Georges R, Hepp M and Herman M (1998), "Slit-jet Fourier transform infrared spectroscopy in 12C2H4 : Cold and hot bands near 3000 cm-1", Chemical Physics Letters. Vol. 294(6), pp. 533 – 537. [Abstract] [BibTeX] [DOI]
Abstract: A Fourier transform interferometer was used to record the slit-jet absorption spectrum of 12C2H4 between 2500 and 3500 cm-1 at a spectral resolution of 0.02 cm-1. The rotational analysis of the ν9 and ν11 fundamental and ν2+ν12 combination bands is performed, effective rotational parameters are presented, and relative absorption intensities are measured. In addition, a few lines of the 2ν10+ν12 band are assigned. The selective sampling of vibrational hot bands in the jet is demonstrated using another experimental apparatus, with a heated slit.
BibTeX: @article{Bach1998533, author = {Bach, M. and Georges, R. and Hepp, M. and Herman, M.}, title = {Slit-jet Fourier transform infrared spectroscopy in 12C2H4 : Cold and hot bands near 3000 cm-1}, journal = {Chemical Physics Letters}, year = {1998}, volume = {294}, number = {6}, pages = {533 – 537}, doi = {10.1016/S0009-2614(98)00889-6} }
Bernath P, Carleer M, Fally S, Jenouvrier A, Vandaele AC, Hermans C, Mérienne M-F and Colin R (1998), "The Wulf bands of oxygen", Chemical Physics Letters. Vol. 297(3-4), pp. 293 – 299. [Abstract] [BibTeX] [DOI]
Abstract: The Wulf bands of oxygen in the 240-290 nm spectral region are caused by collision-induced absorption of the Herzberg III (A′3Δu-X3Σ- g) system. These bands had been previously attributed to the oxygen dimer, (O2)2. Under atmospheric conditions the Wulf bands are thus the long-wavelength extension of the Herzberg continuum. Absorption of solar radiation by the Wulf bands may be an additional source of NO in the stratosphere. © 1998 Elsevier Science B.V. All rights reserved.
BibTeX: @article{Bernath1998293, author = {Bernath, Peter and Carleer, Michel and Fally, Sophie and Jenouvrier, Alain and Vandaele, Ann Carine and Hermans, Christian and Mérienne, Marie-France and Colin, Reginald}, title = {The Wulf bands of oxygen}, journal = {Chemical Physics Letters}, year = {1998}, volume = {297}, number = {3-4}, pages = {293 – 299}, doi = {10.1016/S0009-2614(98)01149-X} }
Boudon V, Hepp M, Herman M, Pak I and Pierre G (1998), "High-Resolution Jet-Cooled Spectroscopy of SF6: The ν2 + ν6 Combination Band of 32SF6 and the ν3 Band of the Rare Isotopomers", Journal of Molecular Spectroscopy. Vol. 192(2), pp. 359 – 367. [Abstract] [BibTeX] [DOI]
Abstract: The Fourier transform infrared spectrum of SF6 was recorded in a supersonic expansion jet of an SF6/argon mixture. The SF6: Ar seeding ratio was 2:3. The instrumental bandwidth was 0.005 cm-1. A globar source and an MCT detector were used. A rotational temperature of approximately 30 K was achieved. The ν2 + ν6 combination band of 32SF6 was analyzed using a modified version of the spherical top data system (STDS) programs developed in Dijon. A very good fit was obtained for this band with an rms of 0.0036 cm-1. The effective Hamiltonian was developed up to fourth order for the ν2 + ν6 part, to second order for the ν2 and ground state parts, and to first order for the ν6 part. Five hundred twenty-one transitions were assigned, 40 of them reaching the F2u forbidden sublevel. The positions of the two F1u and F2u sublevels are found to be 991.276 and 989.487 cm-1, respectively. The ν3 band of the 33SF6 and 34SF6 isotopomers were also analyzed. Parameters and simulations are presented. A first detection of the ν3 Q branch of 36SF6 (0.02% natural abundance) is reported. © 1998 Academic Press.
BibTeX: @article{Boudon1998359, author = {Boudon, V. and Hepp, M. and Herman, M. and Pak, I. and Pierre, G.}, title = {High-Resolution Jet-Cooled Spectroscopy of SF6: The ν2 + ν6 Combination Band of 32SF6 and the ν3 Band of the Rare Isotopomers}, journal = {Journal of Molecular Spectroscopy}, year = {1998}, volume = {192}, number = {2}, pages = {359 – 367}, doi = {10.1006/jmsp.1998.7699} }
Brage T, Judge PG, Aboussaïd A, Godefroid MR, Jönsson P, Ynnerman A, Fischer CF and Leckrone DS (1998), "Hyperfine induced transitions as diagnostics of isotopic composition and densities of low-density plasmas", Astrophysical Journal. Vol. 500(1 PART I), pp. 507 – 521. [Abstract] [BibTeX] [DOI]
Abstract: The J = 0 → J′ = 0 radiative transitions, usually viewed as allowed through two-photon decay, may also be induced by the hyperfine (HPF) interaction in atoms or ions having a nonzero nuclear spin. We compute new and review existing decay rates for the nsnp 3PJo → ns2 1SJ′ = 0 transitions in ions of the Be (n = 2) and Mg (n = 3) isoelectronic sequences. The HPF induced decay rates for the J = 0 → J′ = 0 transitions are many orders of magnitude larger than those for the competing two-photon processes, and when present are typically 1 or 2 orders of magnitude smaller than the decay rates of the magnetic quadrupole (J = 2 → J′ = 0) transitions for these ions. Several HPF induced transitions are potentially of astrophysical interest in ions of C, N, Na, Mg, Al, Si, K, Cr, Fe, and Ni. We highlight those cases that may be of particular diagnostic value for determining isotopic abundance ratios and/or electron densities from UV or EUV emission-line data. We present our atomic data in the form of scaling laws so that, given the isotopic nuclear spin and magnetic moment, a simple expression yields estimates for HPF induced decay rates. We examine some UV and EUV solar and nebular data in light of these new results and suggest possible applications for future study. We could not find evidence for the existence of HPF induced lines in the spectra we examined, but we demonstrate that existing data have come close to providing interesting upper limits. For the planetary nebula SMC N2, we derive an upper limit of 0.1 for 13C/12C from Goddard High-Resolution Spectrograph data obtained by Clegg. It is likely that more stringent limits could be obtained using newer data with higher sensitivities in a variety of objects. © 1998. The American Astronomical Society. All rights reserved.
BibTeX: @article{Brage1998507, author = {Brage, Tomas and Judge, Philip G. and Aboussaïd, Abdellatif and Godefroid, Michel R. and Jönsson, Per and Ynnerman, Anders and Fischer, Charlotte Froese and Leckrone, David S.}, title = {Hyperfine induced transitions as diagnostics of isotopic composition and densities of low-density plasmas}, journal = {Astrophysical Journal}, year = {1998}, volume = {500}, number = {1 PART I}, pages = {507 – 521}, note = {All Open Access, Bronze Open Access}, doi = {10.1086/305690} }
Campargue A, Biennier L and Herman M (1998), "The visible absorption spectrum of 12C2 H2 III. The region 14500-17000 cm-1", Molecular Physics. Vol. 93(3), pp. 457 – 469. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of 12C2 H2 has been recorded at high resolution by intracavity laser absorption spectroscopy between 14 500 cm-1 and 17 000 cm-1. Among the 32 bands which have been rotationally analysed 15 are newly observed, and improved rovibrational parameters are obtained for the others. The new resulting set of 26 vibrational levels is assigned by extrapolating the cluster model built from lower energy data (Abbouti Temsamani, M., and Herman, M., 1995, J. chem. Phys., 102, 6371) which allows vibrational energies and Bv rotational constants to be predicted. Intensity features are also discussed. © 1998 Taylor & Francis Group, LLC.
BibTeX: @article{Campargue1998457, author = {Campargue, Alain and Biennier, Ludovic and Herman, Michel}, title = {The visible absorption spectrum of 12C2 H2 III. The region 14500-17000 cm-1}, journal = {Molecular Physics}, year = {1998}, volume = {93}, number = {3}, pages = {457 – 469}, doi = {10.1080/002689798169140} }
Carleer M, Colin R and Vandaele A (1998), "Using a Fourier transform spectrometer for tropospheric UV-Vis DOAS measurements", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3493, pp. 11 – 19. [Abstract] [BibTeX]
Abstract: Concentration measurements of trace gases in the atmosphere require the use of highly sensitive and precise techniques. The UV-Visible DOAS technique is one of them heavily used for tropospheric measurements. In order to assess the advantages and drawbacks of using a Fourier transform spectrometer, we have built a DOAS optical setup based on a Bruker IFS 120M spectrometer. The characteristics and capabilities of this setup have been studied and compared to those of the more conventional grating based instruments during several intercomparison campaigns. The main advantages of the FTS are: (i) the existence of a reproducible and precise wavenumber scale, which greatly simplifies the algorithms used to analyse the atmospheric spectra; and (ii) the possibility to record large spectral regions at relatively high resolution, enabling the simultaneous detection of numerous chemical species with better discriminating properties. The main drawback, on the other hand, is due to the fact that an FTS records high frequency signals and does not have the signal integration capabilities of the CCD based grating spectrographs. The FTS therefore needs fairly large amounts of light and is limited to short to medium absorption pathlengths.
BibTeX: @conference{Carleer199811, author = {Carleer, M. and Colin, R. and Vandaele, A.C.}, title = {Using a Fourier transform spectrometer for tropospheric UV-Vis DOAS measurements}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {1998}, volume = {3493}, pages = {11 – 19} }
Carleer M, Fally S, Colin R, Jenouvrier A, Coquart B, Merienne M-F, Vandaele A and Hermans C (1998), "Fourier transform spectroscopy of atmospheric gases", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3493, pp. 94 – 103. [Abstract] [BibTeX]
Abstract: NO2 absorption cross-sections have been obtained at 220 K and 294 K at a resolution of 2 cm-1 from a series of spectra recorded with pure NO2 at pressures from 0.007 to 2 torr. The N2O4 absorption cross-section has been obtained at 220 K. The uncertainty in the NO2 cross-sections is estimated to be less than 3% for the spectral region below 40000 cm-1 at 294 K, 3% below 30000 cm-1 at 220 K. Temperature and pressure effects have been observed. Comparison with literature data show good agreement (± 2%) between 37500 and 20000 cm-1. O2 absorption spectra have been recorded at high (0.12 cm-1) and low (2 and 16 cm-1) resolution in the UV. A re-analysis of the three Herzberg band systems has been performed, extending the rotational assignment up to N'' = 31 and identifying several new vibrational bands. Determination of the integrated intensities and oscillator strengths of the bands has been performed. These values have been compared with data of the literature. Spectra recorded with increasing pressures of N2 or Ar show that the structured continuum overlapping the Herzberg bands cannot be explained by O2-O2 absorption, but comes from collision induced absorption (CIA). Low resolution spectra (2 and 16 cm-1) have also been recorded in the visible region in order to determine the (O2)2 absorption cross-section.
BibTeX: @conference{Carleer199894, author = {Carleer, M. and Fally, S. and Colin, R. and Jenouvrier, A. and Coquart, B. and Merienne, M.-F. and Vandaele, A.C. and Hermans, Ch.}, title = {Fourier transform spectroscopy of atmospheric gases}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {1998}, volume = {3493}, pages = {94 – 103} }
Chazette P, Clerbaux C and Mégie G (1998), "Direct estimate of methane radiative forcing by use of nadir spectral radiances", Applied Optics. Vol. 37(15), pp. 3113 – 3120. [Abstract] [BibTeX] [DOI]
Abstract: Direct determination of the radiative forcing of trace gases will be made possible by use of the next generation of nadir-looking spaceborne instruments that provide measurements of atmospheric radiances in the infrared spectral range with improved spectral and spatial resolution. An inversion statistical method has thus been developed and applied to the direct determination of the radiative forcing of methane, based on such instruments as the Fourier-transform Interferometric Monitor for Greenhouse Gases launched onboard the Japanese Advanced Earth Observing Satellite in 1996 and the Infrared Atmospheric Sounding Interferometer planned for the European polar platform Meteorological Operational Satellite in 2000. The method is based on simple statistical laws that directly relate the measured radiances to the radiative forcing by use of an a priori selection of appropriate spectral intervals and global modeling of methane spatial variations. This procedure avoids the use of an indirect determination based on an inversion process that requires precise knowledge of the methane vertical profiles throughout the troposphere. The overall accuracy and precision of this new algorithm are studied, and interfering gases and instrumental characteristics are taken into account. It is shown that radiative forcing can be determined at high horizontal spatial resolution with a precision better than 7% in cloud-free conditions and with well-known surface properties. © 1998 Optical Society of America.
BibTeX: @article{Chazette19983113, author = {Chazette, Patrick and Clerbaux, Cathy and Mégie, Gérard}, title = {Direct estimate of methane radiative forcing by use of nadir spectral radiances}, journal = {Applied Optics}, year = {1998}, volume = {37}, number = {15}, pages = {3113 – 3120}, doi = {10.1364/AO.37.003113} }
Claveau C, Teffo J-L, Hurtmans D and Valentin A (1998), "Infrared fundamental and first hot bands of O12C17O isotopic variants of carbon dioxide", Journal of Molecular Spectroscopy. Vol. 189(2), pp. 153 – 195. [Abstract] [BibTeX] [DOI]
Abstract: Infrared spectra of 16O12C17O, 17O12C17O, and 17O12C18O in a carbon dioxide sample enriched with oxygen-17 have been recorded with a resolution of about 0.0025 cm-1 in the regions of the fundamental bands, v2 (600-800 cm-1) and v3 (2200-2400 cm-1), and in the region of the "forbidden" band, v1 (1200-1400 cm-1), using the long path difference Fourier transform spectrometer of the LPMA in Paris. For each species, the first hot band in the 4.5-μm region and two hot bands at least in the 15-μm region have been studied for the first time, and a simultaneous reduction of wavenumbers measured in different spectral regions has been carried out yielding new or improved spectroscopic constants. Line intensities have been measured in the region of the v2 and v3 bands of 16O12C17O, and the corresponding rotationless transition dipole moments and Herman-Wallis coefficients have been reported. © 1998 Academic Press.
BibTeX: @article{Claveau1998153, author = {Claveau, C. and Teffo, J.-L. and Hurtmans, D. and Valentin, A.}, title = {Infrared fundamental and first hot bands of O12C17O isotopic variants of carbon dioxide}, journal = {Journal of Molecular Spectroscopy}, year = {1998}, volume = {189}, number = {2}, pages = {153 – 195}, doi = {10.1006/jmsp.1998.7546} }
Clerbaux C, Chazette P, Hadji-Lazaro J, Mégie G, Müller J-F and Clough S (1998), "Remote sensing of CO, CH4, and O3 using a spaceborne nadir-viewing interferometer", Journal of Geophysical Research Atmospheres. Vol. 103(D15), pp. 18999 – 19013. [Abstract] [BibTeX] [DOI]
Abstract: Within the next 5 years, several instruments launched on polar orbiting satellites will provide high-resolution infrared remote-sensing measurements of CO, CH4, and O3 on a global scale. The upwelling spectral radiances to be recorded by a nadir-looking remote sensor have been simulated using a high-resolution radiative code (line-by-line radiative transfer model (LBLRTM)) coupled to a three-dimensional chemical transport model (intermediate model of the annual and global evolution of species (IMAGES)). The instrumental specifications of the Fourier transform interferometric monitor for greenhouse gases/Advanced Earth Observing System (IMG/ADEOS) and infrared atmospheric sounding interferometer ( IASI/METOP) were used to generate realistic data. Calculations have been performed to assess the sensitivity of the nadir spectral radiances to changes in the gas concentration, temperature profile and to instrumental characteristics. We provide spectral intervals for an efficient retrieval of these species, together with a set of climatological tropospheric standard mixing ratio profiles. Copyright 1998 by the American Geophysical Union.
BibTeX: @article{Clerbaux199818999, author = {Clerbaux, C. and Chazette, P. and Hadji-Lazaro, J. and Mégie, G. and Müller, J.-F. and Clough, S.A.}, title = {Remote sensing of CO, CH4, and O3 using a spaceborne nadir-viewing interferometer}, journal = {Journal of Geophysical Research Atmospheres}, year = {1998}, volume = {103}, number = {D15}, pages = {18999 – 19013}, note = {All Open Access, Bronze Open Access}, doi = {10.1029/98JD01422} }
Doggett G and Sutcliffe B (1998), "A modern approach to L-S coupling in the theory of atomic spectra", Journal of Chemical Education. Vol. 75(1), pp. 110 – 114. [BibTeX] [DOI]
BibTeX: @article{Doggett1998110, author = {Doggett, Graham and Sutcliffe, Brian}, title = {A modern approach to L-S coupling in the theory of atomic spectra}, journal = {Journal of Chemical Education}, year = {1998}, volume = {75}, number = {1}, pages = {110 – 114}, doi = {10.1021/ed075p110} }
Fischer CF, Saparov M, Gaigalas G and Godefroid M (1998), "Breit-pauli energies, transition probabilities, and lifetimes for 2s, 2p, 3s, 3p, 3d, 4s2llevels of the lithium sequence,Z= 3-8", Atomic Data and Nuclear Data Tables. Vol. 70(1), pp. 119 – 134. [Abstract] [BibTeX] [DOI]
Abstract: Multiconfiguration Breit-Pauli energy levels, lifetimes, and transition data are presented for the lithium sequence in the rangeZ≤ 8. Included are allJ-levels of the six lowest2Lterms, namely those with configuration labels 1s22s, 1s22p, 1s23s, 1s23p, 1s23d, and 1s24s. © 1998 Academic Press.
BibTeX: @article{Fischer1998119, author = {Fischer, C. Froese and Saparov, M. and Gaigalas, G. and Godefroid, M.}, title = {Breit-pauli energies, transition probabilities, and lifetimes for 2s, 2p, 3s, 3p, 3d, 4s2llevels of the lithium sequence,Z= 3-8}, journal = {Atomic Data and Nuclear Data Tables}, year = {1998}, volume = {70}, number = {1}, pages = {119 – 134}, doi = {10.1006/adnd.1998.0788} }
Fleming J, Hibbert A, Bell K and Vaeck N (1998), "The 3s 2S-4p 2Po transition probability in Mg II", Monthly Notices of the Royal Astronomical Society. Vol. 300(3), pp. 767 – 772. [Abstract] [BibTeX] [DOI]
Abstract: The superposition of configurations (SOC) method has been used to calculate f-values for the Mg H doublet at 1240 Å, which has been observed in the interstellar medium near stars such as ζ Ophiuchi. Our best value for the multiplet oscillator strength is 0.00083. SOC calculations have also been undertaken for the stronger (3s-3p) doublet at 2800 Å giving a multiplet f-value of 0.92.
BibTeX: @article{Fleming1998767, author = {Fleming, J. and Hibbert, A. and Bell, K.L. and Vaeck, N.}, title = {The 3s 2S-4p 2Po transition probability in Mg II}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {1998}, volume = {300}, number = {3}, pages = {767 – 772}, note = {All Open Access, Bronze Open Access}, doi = {10.1111/j.1365-8711.1998.01935.x} }
Focsa C, Bernath P and Colin R (1998), "The low-lying states of He2", Journal of Molecular Spectroscopy. Vol. 191(1), pp. 209 – 214. [Abstract] [BibTeX] [DOI]
Abstract: The near-infrared emission spectrum of He2, excited in a Be hollow cathode discharge, has been recorded at high resolution using a Fourier transform spectrometer. The c3Σg+-a3Σ u+ (0-0, 1-1, 2-2, 1-0, and 2-1) and C1Σg+-A1Σ u+ (0-0 and 1-1) transitions have been observed in the 9000-15000 cm spectral region. A global analysis of the six lowest excited states of He2 (C3Σg+, b3IIg, a3Σu+, C1Σg+, B1IIg, and A1Σu+) was carried out by combining our measurements with previously reported infrared data for the b3IIg-a3Σu+ system [S. A. Rogers et al., Mol. Phys. 63, 901 (1988)] and with laser measurements for the B1IIg-A1Σu+ transition [H. Solka et al., Mol. Phys. 60, 1179 (1987)]. To account for the fine structure in the a3Σu+ state, high precision r.f. measurements were included in the global fit. A consistent set of improved molecular constants was derived for the c3Σg+ (v = 0, 1, and 2), b3IIg (v = 0 and 1), a3Σu+ (v = 0, 1, and 2), C1Σg+ (v = 0 and 1), B1IIg (v = 0 and 1), and A1Σu+ (v = 0 and 1) levels. A study of the vibrational dependence of these constants was also performed, leading to the equilibrium parameters for the six electronic states. © 1998 Academic Press.
BibTeX: @article{Focsa1998209, author = {Focsa, C. and Bernath, P.F. and Colin, R.}, title = {The low-lying states of He2}, journal = {Journal of Molecular Spectroscopy}, year = {1998}, volume = {191}, number = {1}, pages = {209 – 214}, doi = {10.1006/jmsp.1998.7637} }
Focsa C, Bernath P, Mitzner R and Colin R (1998), "Fourier Transform Emission Spectroscopy of the A2Π-X2Σ+ Transition of BeD", Journal of Molecular Spectroscopy. Vol. 192(2), pp. 348 – 358. [Abstract] [BibTeX] [DOI]
Abstract: The A2Π-X2Σ+ Δv = 0 sequence of BeD was observed in the 19 500-20 800 cm-1 spectral region using a Fourier transform spectrometer. The emission spectrum was excited in a Be hollow cathode discharge lamp with a He/D2 gas mixture. The observed lines were assigned to the 0-0 to 6-6 bands. The Δν = -1 sequence was too weak to be seen in our Fourier transform spectra. We therefore used a previously recorded but unpublished arc emission spectrum to identify the 0-1 to 5-6 Δν = -1 bands. Consequently, all of the diagonal bands could be linked together and the vibrational intervals determined. The Δν = 0 and Δν = -1 data were fitted together in a global fit and effective constants derived. Using the information available from the study of the C2Σ+-X2Σ- system [R. Colin, C. Drèze, and M. Steinhauer, Can. J. Phys. 61, 641 (1983)], the ν = 8-12 vibrational levels of the ground state were added in a Dunham fit. A set of Dunham Y constants was determined for the X2Σ+ state along with traditional equilibrium parameters for the A2II excited state. The equilibrium bond lengths were found to be 1.341742(5) Å for the ground state and 1.33309(4) Å for the excited state. A reanalysis of the previously published A2Π-X2Σ+ 0-0 to 3-3 Δνv = 0 bands of BeT [D. De Greef and R. Colin, J. Mol. Spectrosc. 53, 455-465 (1974)] was also performed. © 1998 Academic Press.
BibTeX: @article{Focsa1998348, author = {Focsa, C. and Bernath, P.F. and Mitzner, R. and Colin, R.}, title = {Fourier Transform Emission Spectroscopy of the A2Π-X2Σ+ Transition of BeD}, journal = {Journal of Molecular Spectroscopy}, year = {1998}, volume = {192}, number = {2}, pages = {348 – 358}, doi = {10.1006/jmsp.1998.7700} }
Focsa C, Firth S, Bernath P and Colin R (1998), "Fourier transform emission spectroscopy of the A2Π-X2Σ+ system of BeH", Journal of Chemical Physics. Vol. 109(14), pp. 5795 – 5802. [Abstract] [BibTeX] [DOI]
Abstract: The A2Π-X2Σ+ transition of BeH was observed by Fourier transform emission spectroscopy using a hollow cathode discharge lamp. The 0-0 to 6-6 bands were rotationally analyzed and molecular constants extracted. The equilibrium rotational constants Be and bond lengths were found to be 10.33121(50) cm-1 and 1.34168(3) Å for the ground state and 10.46631(27) cm-1 and 1.33299(2) Å in the excited state. In order to link the diagonal bands together and to determine the vibrational constants, the 0-1 to 6-7 bands in an archival arc emission spectrum were also rotationally analyzed. In the X2Σ+ and A2Π states, the spectroscopic constants are nearly identical so the Δv=-1 bands were too weak to be seen in our Fourier transform spectra. Franck-Condon factors were calculated for the A2Π-X2Σ+ transition from Rydberg-Klein-Rees potential curves. These new rotational analyses now link up with the previous work on the 0-7, 0-8, 0-9, 1-9 and 1-10 bands of the C2Σ+-X2Σ+ system [R. Colin, C. Drèze, and M. Steinhauer, Can. J. Phys. 61, 641 (1983)]. Spectroscopic data are thus available for all bound ground state vibrational levels, v″=0-10, and a set of Dunham Y constants were determined. BeH joins the small group of chemically bound molecules for which a nearly complete set of ground state rovibronic energy levels are known experimentally. © 1998 American Institute of Physics.
BibTeX: @article{Focsa19985795, author = {Focsa, C. and Firth, S. and Bernath, P.F. and Colin, R.}, title = {Fourier transform emission spectroscopy of the A2Π-X2Σ+ system of BeH}, journal = {Journal of Chemical Physics}, year = {1998}, volume = {109}, number = {14}, pages = {5795 – 5802}, doi = {10.1063/1.477201} }
Froese Fischer C, Jönsson P and Godefroid M (1998), "Some two-electron properties of sodium", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 57(3), pp. 1753 – 1758. [Abstract] [BibTeX] [DOI]
Abstract: Some properties of atoms defined in terms of two-electron operators are investigated for sodium. Systematic multiconfiguration Hartree-Fock (MCHF) methods are used. Of particular interest are the energy, the isotope shift parameter, and a dipole-dipole parameter defined as the expectation value of the operator [Formula Presented]. Unlike the one-electron dipole operator, where the line strength was predicted accurately from single, double, and triple excitations, these properties require that quadruple excitations also be considered. © 1998 The American Physical Society.
BibTeX: @article{FroeseFischer19981753, author = {Froese Fischer, Charlotte and Jönsson, Per and Godefroid, Michel}, title = {Some two-electron properties of sodium}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {1998}, volume = {57}, number = {3}, pages = {1753 – 1758}, doi = {10.1103/PhysRevA.57.1753} }
Georges R, Herman M, Hilico J-C and Robert O (1998), "High-resolution FTIR spectroscopy using a jet: Sampling the rovibrational spectrum of 12CH4", Journal of Molecular Spectroscopy. Vol. 187(1), pp. 13 – 20. [Abstract] [BibTeX] [DOI]
Abstract: We have recorded high-resolution absorption spectra of 12CH4 cooled in ajet, using a Fourier transform interferometer. The expected nuclear spin symmetry conservation in the jet is exhibited from data recorded around 3000 cm-1 showing the relative intensity of the lines starting from the J″ = 2 para and ortho levels. Spectra recorded around 4300 cm-1 are used to validate existing rovibrational parameters. Spectra recorded around 6000 cm-1 allow new rovibrational assignments to be performed in the N = 4 polyad. In particular, lines in the V1 + V3 band are identified for the first time. © 1998 Academic Press.
BibTeX: @article{Georges199813, author = {Georges, Robert and Herman, Michel and Hilico, Jean-Claude and Robert, Olivier}, title = {High-resolution FTIR spectroscopy using a jet: Sampling the rovibrational spectrum of 12CH4}, journal = {Journal of Molecular Spectroscopy}, year = {1998}, volume = {187}, number = {1}, pages = {13 – 20}, doi = {10.1006/jmsp.1997.7462} }
Godefroid MR, Jönsson P and Fischer CF (1998), "Atomic structure variational calculations in spectroscopy", Physica Scripta T. Vol. 78, pp. 33 – 46. [Abstract] [BibTeX]
Abstract: Recent ab initio variational calculations of radiative transition probabilities, isotope shifts and hyperfine structures are described in the spirit of the EGAS tradition for plenary talks. A few simple cases are selected to make the exposé at a level accessible to non-specialists in the field and to illustrate how computational atomic structure can be used in atomic spectroscopy for testing theoretical models or experimental results, predicting properties or interpreting them in terms of electron correlation. The effects inherent in the multiconfiguration Hartree-Fock method due to its variational nature are emphasized through some simple analysis of the wave function spatial distribution in correlation with the model used. © Physica Scripta 1998.
BibTeX: @conference{Godefroid199833, author = {Godefroid, Michel R. and Jönsson, Per and Fischer, Charlotte Froese}, title = {Atomic structure variational calculations in spectroscopy}, journal = {Physica Scripta T}, year = {1998}, volume = {78}, pages = {33 – 46} }
Henry A, Hurtmans D, Valentin A and Camy-Peyret C (1998), "Analysis of line profiles taking into account the intensity distribution within a TDL emission mode and precise concentration measurements of atmospheric air samples", VDI Berichte. (1366), pp. 223 – 232. [Abstract] [BibTeX]
Abstract: Careful measurements of the pressure effect on spectral line profiles is a powerful technique to probe intermolecular forces at work during close molecular encounters. But parameters derived from laboratory line profile studies (intensity, broadening coefficients, detailed line shape ) are also of major practical importance for many atmospheric applications based on high resolution quantitative spectroscopy in the infrared region. The final precision on the determination of spectroscopic line parameters using infrared tunable diode laser (TDL) spectrometers is limited by the exact knowledge of the emission intensity distribution of the diode. An illustration of the problem and an appropriate technique to take this TDL emission function into account are presented for two different lead salt diodes With this technique and with proper consideration of the zero transmission offset, the precise determination of line intensities, line broadening coefficients and non Voigt line shape parameters will be discussed. An interesting application of our technique to the measurement of the N2O concentration in stratospheric air samples (brought back to the laboratory) will be presented.
BibTeX: @article{Henry1998223, author = {Henry, A. and Hurtmans, D. and Valentin, A. and Camy-Peyret, C.}, title = {Analysis of line profiles taking into account the intensity distribution within a TDL emission mode and precise concentration measurements of atmospheric air samples}, journal = {VDI Berichte}, year = {1998}, number = {1366}, pages = {223 – 232} }
Hepp M and Herman M (1998), "The jet cooled spectrum of ethane between 4000 and 4500 CM-1", Molecular Physics. Vol. 94(5), pp. 829 – 838. [Abstract] [BibTeX] [DOI]
Abstract: The jet cooled infrared absorption spectrum of ethane was recorded from 4000 to 4500 cm-1 using a high resolution Fourier transform interferometer (Bruker IFS120HR). The instrument resolution was 0.01 cm-1, the rotational temperature obtained was around 40 K. Ten combination bands were identified. Rovibrational assignments were performed, for the first time, concerning over 770 rovibrational lines. Band origins were obtained. Numerous perturbations are reported. © 1998 Taylor & Francis Ltd.
BibTeX: @article{Hepp1998829, author = {Hepp, M. and Herman, M.}, title = {The jet cooled spectrum of ethane between 4000 and 4500 CM-1}, journal = {Molecular Physics}, year = {1998}, volume = {94}, number = {5}, pages = {829 – 838}, doi = {10.1080/002689798167674} }
Hepp M, Herregodts F and Herman M (1998), "Fourier transform infrared jet spectroscopy using a heated slit source", Chemical Physics Letters. Vol. 294(6), pp. 528 – 532. [Abstract] [BibTeX] [DOI]
Abstract: A supersonic slit-jet apparatus with a large heated slit nozzle apparatus used in combination with a high-resolution Fourier transform infrared spectrometer is described. The production of stable and reproducible expansions of samples, liquid under STP conditions, is demonstrated. The selective observation of vibrational hot bands is also achieved, with gas-phase species. The optimal available spectral resolution of the apparatus is illustrated.
BibTeX: @article{Hepp1998528, author = {Hepp, M. and Herregodts, F. and Herman, M.}, title = {Fourier transform infrared jet spectroscopy using a heated slit source}, journal = {Chemical Physics Letters}, year = {1998}, volume = {294}, number = {6}, pages = {528 – 532}, doi = {10.1016/S0009-2614(98)00888-4} }
Herman M, El Idrissi M, Pisarchik A, Campargue A, Gaillot A-C, Biennier L, Di Lonardo G and Fusina L (1998), "The vibrational energy levels in acetylene. III. 12C2D2", Journal of Chemical Physics. Vol. 108(4), pp. 1377 – 1389. [Abstract] [BibTeX] [DOI]
Abstract: We have performed the rovibrational analysis of the absorption spectrum of 12C2D2 between 5150 and 8000 cm-1, recorded by Fourier transform absorption spectroscopy, and between 12 800 and 16 600 cm-1, recorded by intracavity laser absorption spectroscopy. Respectively 10 and 9 bands are reported for the first time in each range. Improved or new rovibrational parameters were obtained for 34 vibrational levels altogether. The vibrational energies we obtained, together with those reported in the literature, were taken into account to model the vibrational energy pattern in 12C2D2(X̃ 1Σ+g). The analysis was performed in successive steps, inferring each time suitable parameters. The 44/55, 11/33, 12/33, and 1/244 quartic order anharmonic resonances were introduced during the procedure. They altogether define vibrational clusters which are characterized by only two dynamical constants of motion, Ns = V1 + V2 + V3 and k = l4 + l5. © 1998 American Institute of Physics.
BibTeX: @article{Herman19981377, author = {Herman, M. and El Idrissi, M.I. and Pisarchik, A. and Campargue, A. and Gaillot, A.-C. and Biennier, L. and Di Lonardo, G. and Fusina, L.}, title = {The vibrational energy levels in acetylene. III. 12C2D2}, journal = {Journal of Chemical Physics}, year = {1998}, volume = {108}, number = {4}, pages = {1377 – 1389}, doi = {10.1063/1.475352} }
Liévin J, Delon A and Jost R (1998), "Absorption cross section of NO2 by the reflection method from ab initio calculations involving the three low lying electronic states", Journal of Chemical Physics. Vol. 108(21), pp. 8931 – 8943. [Abstract] [BibTeX] [DOI]
Abstract: The potential energy surfaces of the three low lying electronic states of NO2, namely the X̃ 2A1, Ã 2B2, and B̃ 2B1 states, and the transition dipole moment surfaces between the ground state and both excited states have been calculated at two levels of ab initio theory; complete active space self-consistent field (CASSCF) and internally contracted multireference configuration interaction (CMRCI). Only 9 points of these surfaces, located around the equilibrium geometry of X̃ 2A1 and corresponding to C2v geometries, have been found sufficient for calculating the cross section, in the 10000-45000 cm-1 energy range, by means of a 2D version of the reflection method. The agreement between the experimental low resolution data and the ab initio absorption cross section is satisfactory, mainly at the CMRCI level, at which the energy at maximum amplitude, the width, the maximum amplitude and the effective transition dipole moment describing both involved electronic transitions are predicted within 4%, 6%, 20%, and 11%, respectively. The sources of errors coming from the reflection approximation and from the level of ab initio approximation are analyzed on the basis of test calculations. The relative importance of the different contributions to the total cross section (both electronic transitions, cold and hot bands) is also discussed. In addition, quantum calculations based on Franck-Condon factors have been performed in order to improve the description of the low energy part of the cross section and to interpret the observed radiative lifetimes. © 1998 American Institute of Physics.
BibTeX: @article{Liévin19988931, author = {Liévin, J. and Delon, A. and Jost, R.}, title = {Absorption cross section of NO2 by the reflection method from ab initio calculations involving the three low lying electronic states}, journal = {Journal of Chemical Physics}, year = {1998}, volume = {108}, number = {21}, pages = {8931 – 8943}, doi = {10.1063/1.475351} }
Ram R, Liévin J and Bernath P (1998), "Fourier transform infrared emission spectroscopy and ab initio calculations on RuN", Journal of Chemical Physics. Vol. 109(15), pp. 6329 – 6337. [Abstract] [BibTeX] [DOI]
Abstract: The emission spectrum of RuN has been observed in the near infrared using a Fourier transform spectrometer. RuN molecules were excited in a hollow cathode lamp operated with neon gas and a trace of nitrogen. Two bands with 0-0 Q heads near 7354 and 8079 cm-1 and a common lower state have been assigned as 2Π1/2-2Σ+ and 2Π3/2-2Σ+ subbands, respectively, of a C2Π-X2Σ+ transition. A rotational analysis of these bands has been performed and molecular constants have been extracted. The principal molecular constants for the ground X2Σ+ state of the most abundant 102RuN isotopomer are: B0=0.5527829(70)cm-1, D0=5.515(13)×10-7cm-1, γ0 =-0.044432(22)cm-1 and r0=1.573869(10)Å. The excited C2Π state has the following molecular constants: T00=7714.34260(53)cm-1, A0=725.8064(11)cm-1, B0=0.5168434(80)cm-1, D0=5.685(16)×10-7cm-1, p0=5.467(36)×10-3cm-1 and r0=1.627670(13)Å. Ab initio calculations have been carried out on RuN to ascertain the nature of the experimentally observed states and to predict the spectroscopic properties of the low-lying electronic states. Our electronic assignment is supported by these calculations and is also consistent with the observations for the isoelectronic RhC molecule [Kaving and Scullman, J. Mol. Spectrosc. 32, 475-500 (1969)]. The valence electron configuration 1σ22σ21π41δ 43σ1 is proposed for the X2Σ+ ground state of RuN and the configurations for the excited states have been discussed. There is no previous experimental or theoretical work on RuN. © 1998 American Institute of Physics.
BibTeX: @article{Ram19986329, author = {Ram, R.S. and Liévin, J. and Bernath, P.F.}, title = {Fourier transform infrared emission spectroscopy and ab initio calculations on RuN}, journal = {Journal of Chemical Physics}, year = {1998}, volume = {109}, number = {15}, pages = {6329 – 6337}, doi = {10.1063/1.477275} }
Rbaihi E, Belafhal A, Vander Auwera J, Naïm S and Fayt A (1998), "Fourier transform spectroscopy of carbonyl sulfide from 4800 to 8000 cm-1 and new global analysis of 16O12C32S", Journal of Molecular Spectroscopy. Vol. 191(1), pp. 32 – 44. [Abstract] [BibTeX] [DOI]
Abstract: We have measured the FT spectrum of natural OCS from 4800 to 8000 cm-1 with a near Doppler resolution and a line-position accuracy between 2 and 8 × 10-4 cm-1. For the normal isotopic species 16O12C32S, 37 vibrational transitions have been analyzed for both frequencies and intensities. We also report six bands of 16O13C34S, five bands of 16O13C32S, two bands of 16O12C33S, and two bands of 18O12C32S. Important effective Herman-Wallis terms are explained by the anharmonic resonances between closely spaced states. As those results complete the study of the Fourier transform spectra of natural carbonyl sulfide from 1800 to 8000 cm-1, a new global rovibrational analysis of 16O12C32S has been performed. We have determined a set of 148 molecular parameters, and a statistical agreement is obtained with all the available experimental data. © 1998 Academic Press.
BibTeX: @article{Rbaihi199832, author = {Rbaihi, E. and Belafhal, A. and Vander Auwera, J. and Naïm, S. and Fayt, A.}, title = {Fourier transform spectroscopy of carbonyl sulfide from 4800 to 8000 cm-1 and new global analysis of 16O12C32S}, journal = {Journal of Molecular Spectroscopy}, year = {1998}, volume = {191}, number = {1}, pages = {32 – 44}, doi = {10.1006/jmsp.1998.7616} }
Sutcliffe B (1998), "Quantum Systems in Chemistry and Physics: Some Hopes and Fears", Advances in Quantum Chemistry. Vol. 31(C), pp. 1 – 13. [Abstract] [BibTeX] [DOI]
Abstract: The topics to be discussed at this meeting are surveyed in an attempt to place them in the context of the considerations of our last meeting and of developments since then. © 1999 Academic Press Inc.
BibTeX: @article{Sutcliffe19981, author = {Sutcliffe, B.T.}, title = {Quantum Systems in Chemistry and Physics: Some Hopes and Fears}, journal = {Advances in Quantum Chemistry}, year = {1998}, volume = {31}, number = {C}, pages = {1 – 13}, doi = {10.1016/S0065-3276(08)60180-X} }
Vandaele A, Hermans C, Simon P, Carleer M, Colin R, Fally S, Mérienne M, Jenouvrier A and Coquart B (1998), "Measurements of the NO2 absorption cross-section from 42 000 cm-1 to 10 000 cm-1 (238-1000 nm) at 220 K and 294 K", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 59(3-5), pp. 171 – 184. [Abstract] [BibTeX] [DOI]
Abstract: The NO2 absorption cross-section has been measured from 42 000 to 10 000 cm-1 (238-1000 nm) with a Fourier transform spectrometer (at the resolution of 2 cm-1, 0.01 nm at 240 nm to 0.2 nm at 1000 nm) and a 5 m temperature controlled multiple reflection cell. The uncertainty on the cross-section is estimated to be less than 3% below 40 000 cm-1 (λ > 250 nm) at 294 K, 3% below 30 000 cm-1 (λ > 333 nm) at 220 K, but reaches 10% for higher wavenumbers. Temperature and pressure effects have been observed. Comparison with data from the literature generally shows a good agreement for wavenumbers between 37 500 and 20 000 cm-1 (267-500 nm). Outside these limits, the difference can reach several percent. © 1998 Elsevier Science Ltd. All rights reserved.
BibTeX: @article{Vandaele1998171, author = {Vandaele, A.C. and Hermans, C. and Simon, P.C. and Carleer, M. and Colin, R. and Fally, S. and Mérienne, M.F. and Jenouvrier, A. and Coquart, B.}, title = {Measurements of the NO2 absorption cross-section from 42 000 cm-1 to 10 000 cm-1 (238-1000 nm) at 220 K and 294 K}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {1998}, volume = {59}, number = {3-5}, pages = {171 – 184}, doi = {10.1016/S0022-4073(97)00168-4} }
Youssoufi Y, Lievin J, Vander Auwera J, Herman M, Fedorov A and Snavely D (1998), "The ground electronic state of 1,-dichloroethane II. Experimental investigation of the fundamental and overtone vibrations", Molecular Physics. Vol. 94(3), pp. 473 – 484. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of 1,-dichloroethane has been recorded under various experimental-conditions, between 50cm−1 and 10000cm−1 using Fourier transform spectroscopy, and-between 10800cm−1 and 17400cm−1 using optoacoustic laser spectroscopy. The assignment of the fundamental bands of the trans and gauche isomers was confirmed using in particular the results of recent ab initio calculations (El Youssoufi et al., 1998, Molec. Phys.,). The first overtone and combination bands were assigned for the first time using a variety of criteria including the band type and, in some cases, the spacing between clumps of rotational lines. Emphasis is placed on the CH progression of bands. Most of the results concern bands from the more abundant trans isomer, up to the near infrared range. Bands are tentatively assigned to the gauche species in the mid and near infrared regions and to the trans rotamer in the visible range. Vibrational frequencies and anharmonic parameters are obtained. © 1998 Taylor & Francis Group, LLC.
BibTeX: @article{Youssoufi1998473, author = {Youssoufi, Y.E. and Lievin, J. and Vander Auwera, J. and Herman, M. and Fedorov, A. and Snavely, D.L.}, title = {The ground electronic state of 1,-dichloroethane II. Experimental investigation of the fundamental and overtone vibrations}, journal = {Molecular Physics}, year = {1998}, volume = {94}, number = {3}, pages = {473 – 484}, doi = {10.1080/002689798167980} }
Youssoufi YE, Herman YE and Lievin J (1998), "The ground electronic state of 1,-dichloroethane I. Ab initio investigation of the geometrical, vibrational and torsional structure", Molecular Physics. Vol. 94(3), pp. 461 – 472. [Abstract] [BibTeX] [DOI]
Abstract: The trans and gauche isomers of 1,-dichloroethane are characterized using ab initio calculations at the MP4(SDQ) level of theory with the full double zeta polarized D95** basis set. The molecular geometry parameters, the torsion potential and the harmonic frequency of the normal modes of vibrations are calculated. The integrated intensity and the rotational type of the infrared fundamental bands also are determined. New labelling of the normal modes of vibration is introduced for the gauche isomer. The relative abundance and stability of both isomers are discussed. The torsional motion is investigated by means of an effective model taking the geometrical relaxation into account and leading to a theoretical torsional spectrum. © 1998 Taylor & Francis Group, LLC.
BibTeX: @article{Youssoufi1998461, author = {Youssoufi, Y. El and Herman, Y. El and Lievin, J.}, title = {The ground electronic state of 1,-dichloroethane I. Ab initio investigation of the geometrical, vibrational and torsional structure}, journal = {Molecular Physics}, year = {1998}, volume = {94}, number = {3}, pages = {461 – 472}, doi = {10.1080/002689798167971} }
Barry J, Locke G, Scollard D, Sidebottom H, Treacy J, Clerbaux C, Colin R and Franklin J (1997), "1,1,1,3,3,-pentafluorobutane (HFC-365mfc): Atmospheric degradation and contribution to radiative forcing", International Journal of Chemical Kinetics. Vol. 29(8), pp. 607 – 617. [Abstract] [BibTeX] [DOI]
Abstract: The rate constant for the reaction of the hydroxyl radical with 1,1,1,3,3-pentafluorobutane (HFC-365mfc) has been determined over the temperature range 278-323 K using a relative rate technique. The results provide a value of k(OH + CF3CH2CF2CH3) = 2.0 × 10-12 exp(- 1750 ± 400/T) cm3 molecule-1 s-1 based on k(OH + CH3CCl3) = 1.8 × 10-12 exp (- 1550 ± 150/T) cm3 molecule-1 s-1 for the rate constant of the reference reaction. Assuming the major atmospheric removal process is via reaction with OH in the troposphere, the rate constant data from this work gives an estimate of 10.8 years for the tropospheric lifetime of HFC-365mfc. The overall atmospheric lifetime obtained by taking into account a minor contribution from degradation in the stratosphere, is estimated to be 10.2 years. The rate constant for the reaction of Cl atoms with 1,1,1,3,3-pentafluorobutane was also determined at 298 ± 2 K using the relative rate method, k(Cl + CF3CH2CF2CH3) = (1.1 ± 0.3) × 10-15 cm3 molecule-1 s-1. The chlorine initiated photooxidation of CF3CH2CF2CH3 was investigated from 273-330 K and as a function of O2 pressure at 1 atmosphere total pressure using Fourier transform infrared spectroscopy. Under all conditions the major carbon-containing products were CF2O and CO2, with smaller amounts of CF3O3CF3. In order to ascertain the relative importance of hydrogen abstraction from the - CH2 - and - CH3 groups in CF3CH2CF2CH3, rate constants for the reaction of OH radicals and Cl atoms with the structurally similar compounds CF3CH2CCl2F and CF3CH2CF3 were also determined at 298 K k(OH + CF3CH2CCl2F) = (8 ± 3) × 10-16 cm3 molecule-1 s-1; k(OH + CF3CH2CF3) = (3.5 ± 1.5) × 10-16 cm3 molecule-1 s-1; k(Cl + CF3CH2CCl2F) = (3.5 ± 1.5) × 10-17 cm3 molecule-1 s-1; k(C; + CF3CH2F3) < 1 × 10-17 cm3 molecule-1 s-1. The results indicate that the most probable site for H-atom abstraction from CF3CH2CF2CH3 is the methyl group and that the formation of carbonyl compounds containing more than a single carbon atom will be negligible under atmospheric conditions, carbonyl difluoride and carbon dioxide being the main degradation products. Finally, accurate infrared absorption cross-sections have been measured for CF3CH2CF2CH3, and jointly used with the calculated overall atmospheric lifetime of 10.2 years, in the NCAR chemical-radiative model, to determine the radiative forcing of climate by this CFC alternative. The steady-state Halocarbon Global Warming Potential, relative to CFC-11, is 0.17. The Global Warming Potentials relative to CO2 are found to be 2210, 790, and 250, for integration time-horizons of 20, 100, and 500 years, respectively. © 1997 John Wiley & Sons, Inc.
BibTeX: @article{Barry1997607, author = {Barry, John and Locke, Garrett and Scollard, Donncha and Sidebottom, Howard and Treacy, Jack and Clerbaux, Cathy and Colin, Reginald and Franklin, James}, title = {1,1,1,3,3,-pentafluorobutane (HFC-365mfc): Atmospheric degradation and contribution to radiative forcing}, journal = {International Journal of Chemical Kinetics}, year = {1997}, volume = {29}, number = {8}, pages = {607 – 617}, note = {All Open Access, Bronze Open Access}, doi = {10.1002/(SICI)1097-4601(1997)29:8<607::AID-KIN6>3.0.CO;2-Y} }
Coxon JA and Colin R (1997), "Born-Oppenheimer breakdown effects from rotational analysis of the A1Σ+-x1Σ+ band system of BeH+, BeD+, and BeT+", Journal of Molecular Spectroscopy. Vol. 181(1), pp. 215 – 223. [Abstract] [BibTeX] [DOI]
Abstract: The A1Σ+-X1Σ+ band system of BeH+, BeD+, and BeT+ has been photographed at high resolution and rotationally analyzed. Together with literature data (W. W. Watson and R. F. Humphreys, Phys. Rev. 52, 318-321 (1937)) for υ″ = 7-10 of BeH+, the data set samples vibrational levels that extend up to ≈2/3 and ≈1/2 of the well depths of the X and A states, respectively. The measured line positions were employed in a global least-squares fit of the molecular Hamiltonians for the two states that take account of Born-Oppenheimer breakdown effects and in which a modified Lennard-Jones (MLJ) function is employed for the potential energy. The fit reproduces the measurements to within the estimated accuracy (≈0.05 cm-1). © 1997 Academic Press, Inc.
BibTeX: @article{Coxon1997215, author = {Coxon, John A. and Colin, R.}, title = {Born-Oppenheimer breakdown effects from rotational analysis of the A1Σ+-x1Σ+ band system of BeH+, BeD+, and BeT+}, journal = {Journal of Molecular Spectroscopy}, year = {1997}, volume = {181}, number = {1}, pages = {215 – 223}, doi = {10.1006/jmsp.1996.7153} }
De Maré GR, Panchenko YN and Auwera JV (1997), "Structure of the high-energy conformer of 1,3-butadiene", Journal of Physical Chemistry A. Vol. 101(22), pp. 3998 – 4004. [Abstract] [BibTeX] [DOI]
Abstract: The experimental vibrational frequencies of s-trans-1,3-butadiene, for which the assignments are well-established, are used to determine the scale factors for its quantum mechanical force field obtained at the MP2/6-31G//MP2/6-31G level of theory. The scale factors are then transferred to the MP2/6-31G//MP2/ 6-31G force fields of the s-cis and s-gauche rotamers and their theoretical frequencies calculated. Comparison of the vibrational frequencies of these three species indicates a special region of the IR spectrum of 1,3-butadiene in the gas phase (720-790 cm-1) in which only a band attributable to the s-gauche rotamer should be present; i.e., it should be free both of the observed IR bands of the s-trans and of the calculated vibrational frequencies of the s-cis conformer. Investigation of the medium- and high-resolution IR spectra of 1,3-butadiene in the gas phase reveals the presence of a band at 749.22(20) cm-1 possessing the typical B contour (consistent with A symmetry, C2 group). Rotational analysis of the medium-resolution spectrum of this band yields the rotational constants A″ - B″ = 0.4478(27) cm-1 and A′ - B̄′ = 0.4455(25) cm1, only about one-third of the experimental values for s-trans-1,3-butadiene. This identifies the band as belonging to the high-energy conformer of 1,3-butadiene. The agreement between the experimental and theoretical values of the band center (749 vs 735 cm-1), the clear B type contour, and the extremely complicated character of the high-resolution spectrum of the band at 749.22 cm-1 strongly suggest that the geometry of the high-energy conformer of 1,3-butadiene in the gas phase is nonplanar s-gauche and not planar s-cis.
BibTeX: @article{DeMaré19973998, author = {De Maré, George R. and Panchenko, Yurii N. and Auwera, Jean Vander}, title = {Structure of the high-energy conformer of 1,3-butadiene}, journal = {Journal of Physical Chemistry A}, year = {1997}, volume = {101}, number = {22}, pages = {3998 – 4004}, doi = {10.1021/jp970478y} }
Desouter-Lecomte M and Liévin J (1997), "Memory kernels and effective Hamiltonians from time dependent methods. I. Predissociation with a curve crossing", Journal of Chemical Physics. Vol. 107(5), pp. 1428 – 1440. [Abstract] [BibTeX] [DOI]
Abstract: Non-Hermitian complex effective Hamiltonians resulting from bound-continuous partitioning techniques are built from time dependent methods. We treat predissociation processes with a curve crossing. The energy dependent shift and half-width matrices are obtained simultaneously by a generalization of the wave packet Golden Rule treatment, as the real and imaginary parts of the Fourier transform of a memory kernel matrix. The latter contains auto- and cross-correlation functions. They are overlap integrals among the projections on the continuum of bound states multiplied by the interchannel coupling function responsible for the predissociation. These wave packets are propagated by the propagator of the sole continuous subspace. An approximate analytical expression of this correlation matrix is established for the harmonic/linear model. The numerical method is applied to the electronic predissociation of the MgCl A 2Π state, to a Morse/ exponential model and to a predissociation with two coupled repulsive decay channels. The comparison between the correlation time scales and the Golden Rule lifetimes is decisive so as to justify whether the memory kernel can be considered as an impulsive kernel. This Markovian approximation implies that the two time scales are well separated. In the energy domain, this corresponds to the introduction of a mean phenomenological effective Hamiltonian that neglects the energy variation of the discrete-continuous coupling elements. We observe that the separation of the time scales is effective for weakly open systems, but not for overlapping metastable states for which the perturbative-theory widths largely exceed the mean energy spacing. This confirms from a temporal viewpoint that a nonperturbative treatment should not neglect the energy dependence of the effective Hamiltonian, as currently assumed in the study of largely open systems. © 1997 American Institute of Physics.
BibTeX: @article{Desouter-Lecomte19971428, author = {Desouter-Lecomte, M. and Liévin, J.}, title = {Memory kernels and effective Hamiltonians from time dependent methods. I. Predissociation with a curve crossing}, journal = {Journal of Chemical Physics}, year = {1997}, volume = {107}, number = {5}, pages = {1428 – 1440}, doi = {10.1063/1.474497} }
El Youssoufi Y, Georges R, Liévin J and Herman M (1997), "High-Resolution Spectroscopic Investigation of v16 in trans-1,2-Dichloroethane", Journal of Molecular Spectroscopy. Vol. 186(2), pp. 239 – 245. [Abstract] [BibTeX] [DOI]
Abstract: We report on the first detailed rovibrational analysis in 1,2-dichloroethane. It concerns the a-type v16 absorption band of gaseous trans-1,2-dichloroethane at 1232 cm-1, which we have recorded using a Fourier transform interferometer, under room temperature and jet-cooled experimental conditions. The rotational analysis of the almost diatomic-like prominent R and P structures in v16 is performed for trans-1,2-12C2H435Cl2 and trans-1,2-12C2H435Cl37Cl. The nuclear spin statistics is discussed for various isotopomers and isomers of 1,2-dichloroethane. The complex absorption pattern observed at the band center is tentatively assigned in terms of overlapping Q branches, arising from fundamental bands involving different isotopomers in natural abundance (with 35Cl and 37Cl), and from related hot bands involving the three lowest vibrational modes in the molecule, v6, v10, and v18. © 1997 Academic Press.
BibTeX: @article{ElYoussoufi1997239, author = {El Youssoufi, Y. and Georges, R. and Liévin, J. and Herman, M.}, title = {High-Resolution Spectroscopic Investigation of v16 in trans-1,2-Dichloroethane}, journal = {Journal of Molecular Spectroscopy}, year = {1997}, volume = {186}, number = {2}, pages = {239 – 245}, doi = {10.1006/jmsp.1997.7445} }
Elyoussoufi Y, Herman M, Liévin J and Kleiner I (1997), "Ab initio and experimental investigation of the vibrational energy pattern in N2O4: The mid and near infrared ranges", Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy. Vol. 53(6), pp. 881 – 894. [Abstract] [BibTeX] [DOI]
Abstract: Extensive ab initio calculations are performed concerning N2O4 in the ground electronic state, at the MP4 and CMRCI levels of theory, using the 6-31G* and cc-pVTZ basis sets. Special care is devoted to internal degrees of freedom characterizing the quasi van der Waals NN bond, namely the torsion and the NN stretch vibrational modes. The role of the methodology is investigated with the help of previous literature results. It is shown that most properties are significantly better described by MP4 than by MP2, but that a variational multireference method, like CMRCI, is however required for all properties linked to the NN bond. The ab initio vibrational analysis is merged with the one of absorption spectra recorded at medium resolution between 700 and 7000 cm-1, using a Fourier transform interferometer. The resulting set of effective vibrational frequencies and anharmonicities is provided. The height of the torsional potential energy barrier is calculated to be 2000 cm-1, at the best level of theory (CMRCI/cc-pVTZ), in agreement with the highest experimental value available. © 1997 Elsevier Science B.V.
BibTeX: @article{Elyoussoufi1997881, author = {Elyoussoufi, Y. and Herman, M. and Liévin, J. and Kleiner, I.}, title = {Ab initio and experimental investigation of the vibrational energy pattern in N2O4: The mid and near infrared ranges}, journal = {Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy}, year = {1997}, volume = {53}, number = {6}, pages = {881 – 894}, doi = {10.1016/S1386-1425(96)01774-X} }
Firth S, Coheur PF, Mitzner R, Carleer M, Campbell EEB, Colin R and Kroto HW (1997), "The dispersed laser-induced fluorescence spectrum of gas-phase C60 at 308 nm", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 30(11), pp. L393–L400. [Abstract] [BibTeX] [DOI]
Abstract: We have recorded the dispersed laser-induced fluorescence spectrum of gas-phase C60 ablated from a rotating copper cylinder by 308 nm radiation from a XeCl excimer laser. At vibrational energies below 7000 cm-1 the spectrum consists of three progressions of transitions to the electronic ground state ending on the odd vibrational levels of the lowest frequency t2u mode, with the lowest hu and gu modes as additional origins or on the vibrational levels of the third hg mode with two quanta of the lowest gu mode and the combination hu(1)+gu(1) as the additional origins. At higher vibrational energies, the observed bands become more complex and have yet to be analysed.
BibTeX: @article{Firth1997L393, author = {Firth, Steven and Coheur, Pierce F. and Mitzner, Rolf and Carleer, Michel and Campbell, Eleanor E. B. and Colin, Reginald and Kroto, Harold W.}, title = {The dispersed laser-induced fluorescence spectrum of gas-phase C60 at 308 nm}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1997}, volume = {30}, number = {11}, pages = {L393–L400}, doi = {10.1088/0953-4075/30/11/003} }
Froese Fischer C, Gaigalas G and Godefroid M (1997), "The 2s2 1S0-2s3p 3P01 intercombination line in the Be-like sequence", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 30(15), pp. 3333 – 3342. [Abstract] [BibTeX] [DOI]
Abstract: Results from systematic multiconfiguration Hartree-Fock studies of the 2s2 1S0-2s3p 3Po1 transitions in the Be-like sequence in the range of Z = 4-10 are reported for valence and core-valence models of correlation. The inclusion of core-valence correlation was essential for obtaining good agreement for the fine-structure splitting. The most accurate transition rates are in good agreement with the rates predicted from a semi-empirical analysis of experimental data.
BibTeX: @article{FroeseFischer19973333, author = {Froese Fischer, C. and Gaigalas, G. and Godefroid, M.}, title = {The 2s2 1S0-2s3p 3P01 intercombination line in the Be-like sequence}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1997}, volume = {30}, number = {15}, pages = {3333 – 3342}, doi = {10.1088/0953-4075/30/15/006} }
Froese Fischer C, Godefroid M and Olsen J (1997), "Systematic studies of the 2s2 1S0-2s3p1Po1 transition in the Be-like sequence", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 30(5), pp. 1163 – 1172. [Abstract] [BibTeX] [DOI]
Abstract: Results from systematic multiconfiguration Hartree-Fock studies of the 2s2 1S-2s3p1Po transition in the Be-like sequence in the range of 7 = 4-10 are reported for several models. The inclusion of core-valence correlation is essential for obtaining good agreement in the length and velocity form of the oscillator strength, the agreement improving with Z and reaching one part in 4000 for neon. In the case of Be, extensive cancellation occurs in the calculation of the dipole matrix element and correlation in the 1s2 core already plays a role at the 1% level of accuracy. The orbitals obtained from the core correlation model were used in a Breit-Pauli calculation mixing 1,3 Po states. The effect on the allowed transition data is included. The present calculations are generally in better agreement with semi-empirical values predicted from experiment than from experiment itself.
BibTeX: @article{FroeseFischer19971163, author = {Froese Fischer, C. and Godefroid, M. and Olsen, J.}, title = {Systematic studies of the 2s2 1S0-2s3p1Po1 transition in the Be-like sequence}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1997}, volume = {30}, number = {5}, pages = {1163 – 1172}, doi = {10.1088/0953-4075/30/5/011} }
Georges BR, Bach M and Herman M (1997), "High resolution FTIR spectroscopy using a slit jet: Sampling the overtone spectrum of 12C2H4", Molecular Physics. Vol. 90(3), pp. 381 – 388. [Abstract] [BibTeX] [DOI]
Abstract: A Fourier transform interferometer was used to record the slit-jet cooled overtone absorption spectrum of 12C2H4 between 3800 cm−1 and 7900 cm−1, at a spectral resolution of 0·02 cm−1. The experimental set-up and its technical performance are described. The spectral data are exemplified with the help of six selected bands, at 4288·40, 4312·63, 4321·77, 4328·65, 4514·657 and 6150·978 cm−1, whose rotational analysis is performed for the first time. The two lower energy bands, both b type, were not previously reported at all. They are tentatively assigned to the anharmonically resonant pair υ2 + υ6 + υ12 and υ6 + 2υ10 + υ12. © 1997 Taylor & Francis Group, LLC.
BibTeX: @article{Georges1997381, author = {Georges, By R. and Bach, M. and Herman, M.}, title = {High resolution FTIR spectroscopy using a slit jet: Sampling the overtone spectrum of 12C2H4}, journal = {Molecular Physics}, year = {1997}, volume = {90}, number = {3}, pages = {381 – 388}, doi = {10.1080/002689797172499} }
Georges R, Van Der Vorst D, Herman M and Hurtmans D (1997), "Ar and Self-Pressure Broadening Coefficient of the R(11), 5v3 Line of 12C2H2", Journal of Molecular Spectroscopy. Vol. 185(1), pp. 187 – 188. [BibTeX] [DOI]
BibTeX: @article{Georges1997187, author = {Georges, R. and Van Der Vorst, D. and Herman, M. and Hurtmans, D.}, title = {Ar and Self-Pressure Broadening Coefficient of the R(11), 5v3 Line of 12C2H2}, journal = {Journal of Molecular Spectroscopy}, year = {1997}, volume = {185}, number = {1}, pages = {187 – 188}, doi = {10.1006/jmsp.1997.7372} }
Godefroid M, Van Meulebeke G, Jönsson P and Froese Fischer C (1997), "Large-scale MCHF calculations of hyperfine structures in nitrogen and oxygen", Zeitschrift fur Physik D-Atoms Molecules and Clusters. Vol. 42(3), pp. 193 – 201. [Abstract] [BibTeX] [DOI]
Abstract: The hyperfine structure constants for the 1s22s22p3 -4S ground state in nitrogen and the 1s22s22p33s 5So excited state in oxygen are calculated using the MCHF Atomic Structure Package. The single excitation picture is explored through the use of compact wave functions allowing radial non-orthogonalities. Electron correlation is described through numerical multiconfiguration Hartree-Fock calculations for configuration expansions obtained by allowing all single and double excitations from the reference configuration to an active set of orbitals. The latter is increased in a systematic way allowing the convergence of the hyperfine parameters to be studied. Three- and four-particle effects are shown to be important and are taken into account in a sequence of large configuration interaction calculations. The final results are in good agreement with experiment. © Springer-Verlag 1997.
BibTeX: @article{Godefroid1997193, author = {Godefroid, M.R. and Van Meulebeke, G. and Jönsson, P. and Froese Fischer, C.}, title = {Large-scale MCHF calculations of hyperfine structures in nitrogen and oxygen}, journal = {Zeitschrift fur Physik D-Atoms Molecules and Clusters}, year = {1997}, volume = {42}, number = {3}, pages = {193 – 201}, doi = {10.1007/s004600050354} }
Hepp M, Georges R and Herman M (1997), "The ν6 + ν10 band of ethane", Chemical Physics Letters. Vol. 275(5-6), pp. 513 – 518. [Abstract] [BibTeX] [DOI]
Abstract: A Fourier transform interferometer was used to record the slit-jet cooled overtone absorption spectrum of ethane around 2.3 μm, at a spectral resolution of 0.01 cm-1. The rotational temperature was determined to be 35 Κ. A band observed around 4343 cm-1, of perpendicular type, was analysed. 139 lines were assigned to 7 different subbands. One of these subbands, Κ'ΔΚ = -2, shows torsional splittings. Effective rotational parameters were obtained for each subband. A strong perturbation obscures the Κ'ΔΚ = +1 subband, which thus could not be assigned. The vibrational band was assigned to the ν6 + ν10 combination band on the basis of the Coriolis ξ constant, which was found to be ξ6+ 10 = 0.26(3). The band origin was determined to be ν06+ 10 = 4342.56(25) cm-1. © 1997 Published by Elsevier Science B.V.
BibTeX: @article{Hepp1997513, author = {Hepp, M. and Georges, R. and Herman, M.}, title = {The ν6 + ν10 band of ethane}, journal = {Chemical Physics Letters}, year = {1997}, volume = {275}, number = {5-6}, pages = {513 – 518}, doi = {10.1016/S0009-2614(97)00778-1} }
Liévin J and Vaeck N (1997), "Use of symmetry-adapted Brillouin theorem to analyze the variational content of molecular wave functions along potential energy surfaces: Application to BH2 and PO2", International Journal of Quantum Chemistry. Vol. 62(5), pp. 521 – 541. [Abstract] [BibTeX] [DOI]
Abstract: The analysis of the Brillouin conditions in a chain of groups is used to explain why self-consistent field (SCF), multiconfigurationai SCF (MCSCFX or configuration interaction (CI) methods can lead to an unbalanced description of the potential energy hypersurfaces along symmetry-broken pathways. A Wigner-Racah formulation of the generalized Brillouin theorem is the appropriate theoretical tool for performing such an analysis. We apply this procedure to a Renner-Teller splitting in BH2 and to a pseudo-Jahn-Teller conical intersection in PO2. A systematic ab initio study of both systems leads to the definition of compact CASSCF wave functions which ensure a balanced description of the ground Born-Oppenheimer potential enerev surfaces. © 1997 John Wiley & Sons, Inc.
BibTeX: @article{Liévin1997521, author = {Liévin, Jacques and Vaeck, Nathalie}, title = {Use of symmetry-adapted Brillouin theorem to analyze the variational content of molecular wave functions along potential energy surfaces: Application to BH2 and PO2}, journal = {International Journal of Quantum Chemistry}, year = {1997}, volume = {62}, number = {5}, pages = {521 – 541}, doi = {10.1002/(SICI)1097-461X(1997)62:5<521::AID-QUA9>3.0.CO;2-Y} }
Mellouki A, Georges R, Herman M, Snavely DL and Leytner S (1997), "Spectroscopic investigation of ground state pyrrole (12C4H5N): The N-H stretch", Chemical Physics. Vol. 220(3), pp. 311 – 322. [Abstract] [BibTeX] [DOI]
Abstract: We have recorded the infrared absorption spectrum of pyrrole at 0.005 cm-1 spectral resolution using a Fourier transform interferometer. The rotational analysis of the fundamental N-H stretch (110) at 3530.811343(82) cm-1 was performed. A set of 13 upper state rovibrational parameters was determined, allowing the 2715 assigned rovibrational lines to be reproduced with a standard deviation of 1.3 10-3 cm-1. An attempt to record the fundamental band under slit-jet conditions is reported. The role of hot bands accompanying the series of the N-H stretch excitation is investigated. Effective vibrational parameters - ω01, X011, Y111, X1,24 - are obtained. The lower level in the hot band series is unambiguously identified as the V24 = 1 level, by retrieving X1,24 independently, from other spectral data. The observation of the complex band pattern accompanying the N-H series in the higher overtone range is discussed with the help of new data, recorded around the 150 band at different temperatures using intracavity laser optoacoustic spectroscopy. © 1997 Elsevier Science B.V.
BibTeX: @article{Mellouki1997311, author = {Mellouki, Abdeloihid and Georges, Robert and Herman, Michel and Snavely, Deanne L. and Leytner, Svetlana}, title = {Spectroscopic investigation of ground state pyrrole (12C4H5N): The N-H stretch}, journal = {Chemical Physics}, year = {1997}, volume = {220}, number = {3}, pages = {311 – 322}, doi = {10.1016/S0301-0104(97)00136-5} }
Smith SJ and Sutcliffe BT (1997), "The Development of Computational Chemistry in the United Kingdom", Reviews in Computational Chemistry. Vol. 10, pp. 271 – 316. [BibTeX]
BibTeX: @article{Smith1997271, author = {Smith, Stephen J. and Sutcliffe, Brian T.}, title = {The Development of Computational Chemistry in the United Kingdom}, journal = {Reviews in Computational Chemistry}, year = {1997}, volume = {10}, pages = {271 – 316} }
Sutcliffe B (1997), "The Nuclear Motion Problem in Molecular Physics", Advances in Quantum Chemistry. Vol. 28(C), pp. 65 – 80. [Abstract] [BibTeX] [DOI]
Abstract: Modern highly accurate electronic structure calculations are undertaken with a view to elucidating molecular structure. For this to be possible the relationship of nuclear motion to electronic structure must be specified. An outline of how this specification might be made and some of the problems encountered in making it are discussed. © 1997 Academic Press Inc.
BibTeX: @article{Sutcliffe199765, author = {Sutcliffe, B.T.}, title = {The Nuclear Motion Problem in Molecular Physics}, journal = {Advances in Quantum Chemistry}, year = {1997}, volume = {28}, number = {C}, pages = {65 – 80}, doi = {10.1016/S0065-3276(08)60207-5} }
Vaeck N, Fleming J, Bell K, Hibbert A and Godefroid M (1997), "The 2s22p3s 1,3PJo→2s22p2 and 2s22p3p LSJ oscillator strengths in N II", Physica Scripta. Vol. 56(6), pp. 603 – 608. [Abstract] [BibTeX] [DOI]
Abstract: A comparison between the recent measurements [Musielok et al., Phys. Rev. A53, 3122 (1996)] of the relative oscillator strengths for all lines in the three multiplets comprising the 2p3s-2p3p transition array in N II, and theoretical configuration interaction calculations performed with the CIV3 code [Bell et al., Physica Scripta 52, 240 (1995)] shows that, although the agreement between the experimental data and the theoretical results is good for allowed transitions, some unexpected deviations occur for the intersystem lines. In this work, we show that the previous theoretical work can be improved and some significant discrepancies with experiment eliminated by increasing the accuracy of the calculated energy difference between the 2p3s 3P1o and 1P1o states. This is achieved by the inclusion of additional orbitals and configurations together with adjustment of the diagonal matrix elements of the Hamiltonian. The new theoretical results for the transitions 2p3s 1,2PJo→2p2 and 2p3p LSJ are compared with other theoretical work and with the experimental data.
BibTeX: @article{Vaeck1997603, author = {Vaeck, N. and Fleming, J. and Bell, K.L. and Hibbert, A. and Godefroid, M.R.}, title = {The 2s22p3s 1,3PJo→2s22p2 and 2s22p3p LSJ oscillator strengths in N II}, journal = {Physica Scripta}, year = {1997}, volume = {56}, number = {6}, pages = {603 – 608}, doi = {10.1088/0031-8949/56/6/012} }
Vander Auwera J and Kleiner I (1997), "The far infrared spectrum of 3,3,3-trifluoropropene", Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy. Vol. 53(11), pp. 1701 – 1703. [Abstract] [BibTeX] [DOI]
Abstract: The far infrared absorption spectrum of 3,3,3-trifluoropropene has been recorded using Fourier transform spectroscopy allowing to measure the position of the torsional fundamental band ν21 to 81 ± 5 cm-1 and thus to reduce its uncertainty resulting from the previously reported measurements. © 1997 Elsevier Science B.V.
BibTeX: @article{VanderAuwera19971701, author = {Vander Auwera, J. and Kleiner, I.}, title = {The far infrared spectrum of 3,3,3-trifluoropropene}, journal = {Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy}, year = {1997}, volume = {53}, number = {11}, pages = {1701 – 1703}, doi = {10.1016/s1386-1425(97)00049-8} }
Wauters L, Vaeck N, Godefroid M, Van Der Hart H and Demeur M (1997), "Recoil-induced electronic excitation and ionization in one-and two-electron ions", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 30(20), pp. 4569 – 4589. [Abstract] [BibTeX] [DOI]
Abstract: The electronic redistribution of an ion or atom induced by a sudden recoil of the nucleus occurring during the emission or capture of a neutral particle is theoretically investigated. For one-electron systems, analytical expressions are derived for the electronic transition probabilities to bound and continuum states. The quality of a B-spline basis set approach is evaluated from a detailed comparison with the analytical results. This numerical approach is then used Io study the dynamics of two-electron systems (neutral He and Ne 8+) using correlated wavefunctions for both the target and daughter ions. The total transition probabilities to discrete states, autoionizing states and direct single- and double-ionization probabilities are calculated from the pseudospectra. Sum rules for transition probabilities involving an initial bound state and a complete final series are discussed.
BibTeX: @article{Wauters19974569, author = {Wauters, L. and Vaeck, N. and Godefroid, M. and Van Der Hart, H.W. and Demeur, M.}, title = {Recoil-induced electronic excitation and ionization in one-and two-electron ions}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1997}, volume = {30}, number = {20}, pages = {4569 – 4589}, doi = {10.1088/0953-4075/30/20/018} }
Winand R, Van Ham P, Colin R and Milojevic D (1997), "An attempt to quantify electrodeposit metallographic growth structures", Journal of the Electrochemical Society. Vol. 144(2), pp. 428 – 436. [Abstract] [BibTeX] [DOI]
Abstract: A method is proposed to characterize quantitatively metallographic cross-sectional structures of electrodeposits pertaining to the BR, FT, FT-UD, and UD types in Fischer's classification which makes use of only three parameters to evaluate in three zones parallel to the substrate. The method is manual, but research is in progress to make it automatic on the basis of a specific image analysis program. The method should also be useful to characterize any structured deposit obtained by methods other than electrodeposition.
BibTeX: @article{Winand1997428, author = {Winand, René and Van Ham, Philippe and Colin, Renaud and Milojevic, Dragomir}, title = {An attempt to quantify electrodeposit metallographic growth structures}, journal = {Journal of the Electrochemical Society}, year = {1997}, volume = {144}, number = {2}, pages = {428 – 436}, doi = {10.1149/1.1837427} }
Xu L-H and Hurtmans D (1997), "Review of optically pumped FIR laser observations and FT-spectra-assisted FIR laser assignments for 13CD3OH", Infrared Physics and Technology. Vol. 38(6), pp. 357 – 372. [Abstract] [BibTeX] [DOI]
Abstract: The 13CD3OH methanol isotopomer is known to be an efficient FIR lasing molecule when optically pumped by a CO2 laser. One hundred and eighty-nine (189) FIR laser lines have been detected in laboratories to date and the frequencies of 80 of these have been accurately measured by heterodyne techniques. They include the third most efficient FIR laser line at 127 μm (the first and second most efficient FIR laser lines are at 123.5 μm and 118.8 μm for CH3OH) and a very long wavelength line at 2615 μm. The present work extends the identification of IR-pump/FIR-laser line systems with assistance from high-resolution FT-spectra. New assignments with full quantum numbers have been made for 44 FIR laser lines and partial J-assignments for 7 additional lines. This brings to 100 the total of FIR laser lines spectroscopically assigned to date for 13CD3OH. In the course of this work, we have compiled and updated all known information on the IR-pump/FIR-laser observations and spectroscopic assignments for CD3OH, and have made some substantial corrections to the existing literature on assignments. Very close FIR laser doublets reported for one system are associated with asymmetry splitting for K= 8 A levels in the excited 13CO-stretching state, representing the highest K state for which asymmetry doubling has been resolved for methanol and suggesting the presence of interesting vibrational perturbation and mode coupling. © 1997 Elsevier Science B.V.
BibTeX: @article{Xu1997357, author = {Xu, Li-Hong and Hurtmans, Daniel}, title = {Review of optically pumped FIR laser observations and FT-spectra-assisted FIR laser assignments for 13CD3OH}, journal = {Infrared Physics and Technology}, year = {1997}, volume = {38}, number = {6}, pages = {357 – 372}, doi = {10.1016/S1350-4495(97)00030-3} }
Abbouti Temsamani M and Herman M (1996), "Anharmonic resonances in monodeuteroacetylene (12C2HD)", Chemical Physics Letters. Vol. 260(1-2), pp. 253 – 256. [Abstract] [BibTeX] [DOI]
Abstract: Published data on the Fourier transform spectrum of 12C2HD in the overtone range, from Liévin et al. [Chem. Phys. 10 (1995) 419] and Abbouti Temsamani and Herman [Mol. Phys. 79 (1993) 359], are revisited by taking into account the (1/255) anharmonic resonance. A dedicated Hamiltonian is used to build interacting clusters. New vibrational parameters are obtained which account for previously reported anomalous spectral features.
BibTeX: @article{AbboutiTemsamani1996253, author = {Abbouti Temsamani, M. and Herman, M.}, title = {Anharmonic resonances in monodeuteroacetylene (12C2HD)}, journal = {Chemical Physics Letters}, year = {1996}, volume = {260}, number = {1-2}, pages = {253 – 256}, doi = {10.1016/0009-2614(96)00880-9} }
Aboussaïd A, Carleer M, Hurtmans D, Biémont E and Godefroid M (1996), "Hyperfine structure of Sc I by infrared fourier transform spectroscopy", Physica Scripta. Vol. 53(1), pp. 28 – 32. [Abstract] [BibTeX] [DOI]
Abstract: The spectrum of scandium was recorded in the infrared region using a high resolution Fourier transform spectrometer and a hollow-cathode discharge. Hyperfine structures of the lines connecting the 3d24s and 3d4s4p level systems of Sc45I were observed between 4000 and 5000cm-1. The structures were not completely resolved but the individual line contributions to the complex profiles were simulated using the 3d24s 4FJ hyperfine structure constants previously measured with a high precision by laser techniques. We investigate the possibility of extracting the hyperfine constants of the 3d4s4p levels from a least-squares fit of the line profiles, assuming a Doppler lineshape and theoretical relative intensities. New results are presented for 12 levels.
BibTeX: @article{Aboussaïd199628, author = {Aboussaïd, A. and Carleer, M. and Hurtmans, D. and Biémont, E. and Godefroid, M.R.}, title = {Hyperfine structure of Sc I by infrared fourier transform spectroscopy}, journal = {Physica Scripta}, year = {1996}, volume = {53}, number = {1}, pages = {28 – 32}, doi = {10.1088/0031-8949/53/1/004} }
Anderson N and Sutcliffe BT (1996), "The nuclear motion Hamiltonian for a tetratomic molecule considered as a combination of an atom and a triatom", International Journal of Quantum Chemistry. Vol. 60(1), pp. 37 – 46. [Abstract] [BibTeX] [DOI]
Abstract: The body-fixed Hamiltonian developed here is expressed in terms of the atom's distance from and orientation with respect to the plane defined by the triatomic. © 1996 John Wiley & Sons, Inc.
BibTeX: @article{Anderson199637, author = {Anderson, Norman and Sutcliffe, Brian T.}, title = {The nuclear motion Hamiltonian for a tetratomic molecule considered as a combination of an atom and a triatom}, journal = {International Journal of Quantum Chemistry}, year = {1996}, volume = {60}, number = {1}, pages = {37 – 46}, doi = {10.1002/(SICI)1097-461X(1996)60:1<37::AID-QUA4>3.0.CO;2-6} }
Brems V, Desouter-Lecomte M and Liévin J (1996), "Avoided resonance overlapping beyond the energy independent formalism. II. Electronic predissociation", Journal of Chemical Physics. Vol. 104(6), pp. 2222 – 2236. [Abstract] [BibTeX] [DOI]
Abstract: The transition between the diabatic and the adiabatic zero order representation when the electronic potential coupling increases, is studied in the partitioning method (PM) and in the complex coordinate method (CCM) implemented in a discrete variable representation (DVR). The model is a C+ type predissociation in a diatomic system with a crossing between a Morse potential energy curve and an exponentially repulsive curve. In the weak coupling regime (isolated diabatic metastable states), both methods confirm the linear variation of the resonance widths with the strength of the electronic interaction, as expected in a perturbative treatment. When the coupling is large in the diabatic representation (strong overlap regime), the formation of narrow resonances supported by the upper adiabatic potential can be related, in PM, to the process of avoided resonance overlapping among interfering states. The complete change of representation can be described in the initial diabatic basis set in PM. However, the full energy dependence of the discrete-continuous matrix elements must then be taken into account. The deformation and the final splitting of a diffuse spectral line .with increasing coupling is re-examined in terms of these energy dependent eigenvalues of the effective Hamiltonian. The use of the appropriate representation, either diabatic or adiabatic, according to the strength of the electronic coupling, has been found decisive in CCM so as to observe the correct migration of the resonance positions towards the zero order adiabatic states, and the decrease of their widths. No relevant results have been obtained for the intermediate strength of the coupling in CCM. Analytical expressions for the derivative coupling matrix elements (∂/∂R) in the fixed node DVR (corresponding to the particle-in-a-box wave functions) have been established. © 1996 American Institute of Physics.
BibTeX: @article{Brems19962222, author = {Brems, V. and Desouter-Lecomte, M. and Liévin, J.}, title = {Avoided resonance overlapping beyond the energy independent formalism. II. Electronic predissociation}, journal = {Journal of Chemical Physics}, year = {1996}, volume = {104}, number = {6}, pages = {2222 – 2236}, doi = {10.1063/1.470919} }
Camy-Peyret C, Bergqvist B, Galle B, Carleer M, Clerbaux C, Colin R, Fayt C, Goutail F, Nunes-Pinharanda M, Pommereau J, Hausmann M, Platt U, Pundt I, Rudolph T, Hermans C, Simon P, Vandaele A, Plane J and Smith N (1996), "Intercomparison of instruments for tropospheric measurements using differential optical absorption spectroscopy", Journal of Atmospheric Chemistry. Vol. 23(1), pp. 51 – 80. [Abstract] [BibTeX] [DOI]
Abstract: The results of an intercomparison campaign of eight different long path UV-visible DOAS instruments measuring NO2, O3 and SO2 concentrations in a moderately polluted urban site are presented. For effective optical path lengths of 230 and 780 m the overall spread of these measurements (± 1 σ) are 5 x 1010, 6 x 1010 and 1 x 1010 molec·cm-3 (2.0, 2.4, and 0.4 ppb) for these molecules respectively when all instruments used a common set of absorption cross sections. The remaining differences are not completely random and the systematic differences are attributed to the different retrieval methods used for each instrument.
BibTeX: @article{Camy-Peyret199651, author = {Camy-Peyret, C. and Bergqvist, B. and Galle, B. and Carleer, M. and Clerbaux, C. and Colin, R. and Fayt, C. and Goutail, F. and Nunes-Pinharanda, M. and Pommereau, J.P. and Hausmann, M. and Platt, U. and Pundt, I. and Rudolph, T. and Hermans, C. and Simon, P.C. and Vandaele, A.C. and Plane, J.M.C. and Smith, N.}, title = {Intercomparison of instruments for tropospheric measurements using differential optical absorption spectroscopy}, journal = {Journal of Atmospheric Chemistry}, year = {1996}, volume = {23}, number = {1}, pages = {51 – 80}, doi = {10.1007/BF00058704} }
Coheur P, Carleer M and Colin R (1996), "The absorption cross sections of C60 and C70 in the visible-UV region", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 29(21), pp. 4987 – 4995. [Abstract] [BibTeX] [DOI]
Abstract: Absorption cross sections of gas phase C60 and C70 in the 40 000 to 16 000 cm-1 region have been determined. The results are based on the combination of absorbance measurements of fullerene vapour, produced by the sublimation of samples in quartz double cells, and the vapour pressure measurements of the literature for solvent-free solid fullerenes. The gas phase cross sections are compared to those derived from molar extinction coefficients of C60 and C70 in hexane solutions and highlight the problems associated with the evaporation of solvent-containing fullerenes.
BibTeX: @article{Coheur19964987, author = {Coheur, P.F. and Carleer, M. and Colin, R.}, title = {The absorption cross sections of C60 and C70 in the visible-UV region}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1996}, volume = {29}, number = {21}, pages = {4987 – 4995}, doi = {10.1088/0953-4075/29/21/013} }
Cox H, Sinclair PE, Smith SJ and Sutcliffe BT (1996), "Some calculations on the ground 1S state of the positronium negative ion", Molecular Physics. Vol. 87(2), pp. 399 – 406. [Abstract] [BibTeX] [DOI]
Abstract: The series solution method used by H. Cox, S. J. Smith and B. T. Sutcliffe (1994, Phys. Rev. A, 49, 4520, 4533) to obtain extremely accurate eigenvalues and eigenvectors for the lowest singlet and triplet states of low Z helium-like systems has been applied to the ground 1S state of the positronium negative ion. Secular determinatnts of up to size 2847 × 2847 have been solved to give a ground state energy of 0·262 005 070 231 742 au. This agrees to 12 decimal places with the most accurate literature value reported by Y. K. Ho (1993, Phys. Rev. A, 48, 4780). Various expectation values involving the interparticle distances have also been evaluated. We estimate the positron-electron annihilation rate Г as 2·086 1223 ns-1. This is in agreement with the most accurate literature value of 2·086 1222 ± 5 × 10-7 (Ho, 1993, Phys. Rev. A, 48, 4780) and the experimental value of 2·09 ± 9 × 10-2 (Mills, 1983, Phys. Rev. Lett., 50, 671). © 1996 Taylor & Francis Group, LLC.
BibTeX: @article{Cox1996399, author = {Cox, Hazel and Sinclair, Phillip E. and Smith, Stephen J. and Sutcliffe, Brian T.}, title = {Some calculations on the ground 1S state of the positronium negative ion}, journal = {Molecular Physics}, year = {1996}, volume = {87}, number = {2}, pages = {399 – 406}, doi = {10.1080/00268979600100261} }
Fleming J, Bell K, Hibbert A, Vaeck N and Godefroid M (1996), "Forbidden transitions in B II, C III, O V, Ne VII and Mg IX", Monthly Notices of the Royal Astronomical Society. Vol. 279(4), pp. 1289 – 1293. [Abstract] [BibTeX] [DOI]
Abstract: Intercombination line transition rates between n = 2 levels of B II, O V, Ne VII and Mg IX have been calculated using the configuration interaction code CIV3. The recommended A-values for the 2s2p 3P1o-2s2 1S0 intercombination lines are 9.73 s-1 for B II, 2280 s-1 for O V, 19 204 s-1 for Ne VII and 97 242 s-1 for Mg IX. We estimate that the accuracy of these values is better than 2 per cent. Calculations of the M2, E2 and M1 transitions have also been carried out for these ions and for C III.
BibTeX: @article{Fleming19961289, author = {Fleming, J. and Bell, K.L. and Hibbert, A. and Vaeck, N. and Godefroid, M.R.}, title = {Forbidden transitions in B II, C III, O V, Ne VII and Mg IX}, journal = {Monthly Notices of the Royal Astronomical Society}, year = {1996}, volume = {279}, number = {4}, pages = {1289 – 1293}, note = {All Open Access, Bronze Open Access}, doi = {10.1093/mnras/279.4.1289} }
Fleming J, Godefroid M, Bell K, Hibbert A, Vaeck N, Olsen J, Jönsson P and Froese Fischer C (1996), "The 2s2 1S-2s2p 1Po resonance line in neutral beryllium", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 29(19), pp. 4347 – 4363. [Abstract] [BibTeX] [DOI]
Abstract: The oscillator strength of the resonance transition 2s2 1S0-2s2p 1Po1 in neutral beryllium is evaluated using two independent codes: CIV3 and MCHF. Two separate approaches are executed using the code CIV3, which uses a common set of orbitals, the inclusion of valence, core-valence and core-core correlation being approached in different ways. In the MCHF scheme the wavefunctions of the two states are optimized independently. The convergence of the MCHF results with respect to the addition of orbital functions is considered in some detail. This convergence, together with the results of the CIV3 calculates, lead us to recommend a value of 1.375 for the oscillator strength, with an estimated uncertainty of less than 0.5%. This agrees closely with other recent extensive calculations but is 2.5% higher than the value derived from beam-foil experiments.
BibTeX: @article{Fleming19964347, author = {Fleming, J. and Godefroid, M.R. and Bell, K.L. and Hibbert, A. and Vaeck, N. and Olsen, J. and Jönsson, P. and Froese Fischer, C.}, title = {The 2s2 1S-2s2p 1Po resonance line in neutral beryllium}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1996}, volume = {29}, number = {19}, pages = {4347 – 4363}, doi = {10.1088/0953-4075/29/19/009} }
Fleming J, Vaeck N, Hibbert A, Bell K and Godefroid M (1996), "Oscillator strengths for the resonance line of ions in the beryllium isoelectronic sequence", Physica Scripta. Vol. 53(4), pp. 446 – 453. [Abstract] [BibTeX] [DOI]
Abstract: Extensive configuration-interaction calculations have been performed to obtain oscillator strengths for the resonance line of the ions of the beryllium isoelectronic sequence up to nuclear charge Z = 12. Valence, corevalence and core-core correlation effects are taken into account and relativistic effects are incorporated using the Breit-Pauli scheme. The present results are believed to be accurate to better than 1%.
BibTeX: @article{Fleming1996446, author = {Fleming, J. and Vaeck, N. and Hibbert, A. and Bell, K.L. and Godefroid, M.R.}, title = {Oscillator strengths for the resonance line of ions in the beryllium isoelectronic sequence}, journal = {Physica Scripta}, year = {1996}, volume = {53}, number = {4}, pages = {446 – 453}, doi = {10.1088/0031-8949/53/4/006} }
Georges R, Liévin J, Herman M and Perrin A (1996), "The v1 band in N2O3", Chemical Physics Letters. Vol. 256(6), pp. 675 – 678. [Abstract] [BibTeX] [DOI]
Abstract: The v1 fundamental band in N2O3 was recorded in absorption at high spectral resolution with a Fourier Transform interferometer, under jet cooled experimental conditions. The rotational structure, corresponding to 44 K rotational temperature, could be analysed, leading to a set of precise upper state parameters. The absence of b-type lines in the spectrum, expected to occur from the direction of the Q1 normal coordinate with respect to the principal axes of inertia, is fully justified by ab initio calculations performed at the MP2/6-31G * level, confirming the decisive role of the polarizing NO2 chromophore in tilting the corresponding induced dipole moment towards the direction of the a axis. The calculations also provide equilibrium geometry parameters.
BibTeX: @article{Georges1996675, author = {Georges, R. and Liévin, J. and Herman, M. and Perrin, A.}, title = {The v1 band in N2O3}, journal = {Chemical Physics Letters}, year = {1996}, volume = {256}, number = {6}, pages = {675 – 678}, doi = {10.1016/0009-2614(96)00510-6} }
Godefroid MR, Fischer CF and Jönsson P (1996), "Multiconfiguration Hartree-Fock calculations of atomic properties in light atoms", Physica Scripta T. Vol. 65, pp. 70 – 83. [Abstract] [BibTeX] [DOI]
Abstract: The progress achieved over the last few years in variational Multiconfiguration Hartree-Fock and Configuration Interaction calculations is reviewed. The high level of accuracy which can be reached in the ab initio calculation of atomic properties of light systems is illustrated through the results of calculations of isotope shifts, hyperfine structures and transition probabilities. The active space method and associated restricted active space methods allowing systematic calculations from which the accuracy of the studied property can be estimated will be discussed. We exemplify quality checks through results in small systems for which spectroscopic accuracy is often required. For transition probabilities, recent progress derived from new algorithm developments allowing independent optimization of the states is emphasized.
BibTeX: @conference{Godefroid199670, author = {Godefroid, Michel R. and Fischer, Charlotte Froese and Jönsson, Per}, title = {Multiconfiguration Hartree-Fock calculations of atomic properties in light atoms}, journal = {Physica Scripta T}, year = {1996}, volume = {65}, pages = {70 – 83}, doi = {10.1088/0031-8949/1996/t65/010} }
Henry A, Hurtmans D, Margottin-Maclou M and Valentin A (1996), "Confinement narrowing and absorber speed dependent broadening effects on CO lines in the fundamental band perturbed by Xe, Ar, Ne, He and N2", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 56(5), pp. 647 – 671. [Abstract] [BibTeX] [DOI]
Abstract: Lines of the CO fundamental band are studied at low concentration in He, Ne, Ar, Xe or N2 as buffer gas from 10 to 600 torr. The coefficient β0 associated with the Dicke narrowing effect is determined for each of the five mixtures. To obtain the proper value of this coefficient, when the pressure increases, the absorber speed dependence of the pressure broadening γ0 must be taken into account. Pressure shifts are also measured, and a faint asymmetry is observed for the CO-Xe mixture. The line scanning is done with a TDL tightly controlled by a Michelson interferometer. A precision better than one-thousandth for absorbed intensity and a wavenumber precision of a few 10-5 is reached. These precisions were found necessary for the needed parameter measurements. Copyright © 1996 Elsevier Science Ltd.
BibTeX: @article{Henry1996647, author = {Henry, A. and Hurtmans, D. and Margottin-Maclou, M. and Valentin, A.}, title = {Confinement narrowing and absorber speed dependent broadening effects on CO lines in the fundamental band perturbed by Xe, Ar, Ne, He and N2}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {1996}, volume = {56}, number = {5}, pages = {647 – 671}, doi = {10.1016/S0022-4073(96)00118-5} }
Jönsson P, Froese Fischer C and Godefroid M (1996), "Accurate calculations of transition probabilities, isotope shifts and hyperfine structures for some allowed 2s22pn-2s2pn+1 transitions in B I, C II and C I", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 29(12), pp. 2393 – 2412. [Abstract] [BibTeX] [DOI]
Abstract: Results from systematic multiconfiguration Hartree-Fock calculations of transition probabilities, isotope shifts and hyperfine structures of the 1s22s22p 2Po-1s22s23s 2S and 1s22s22p 2Po-1s22s2p2 2D transitions in B I, the 1s22s22p 2Po-1s22s2p2 2(S, P, D) transitions in C II and the 1s22s22p2 3P-1s22s2p3 3Do transition in C I are reported. Higher-order correlation effects beyond the pair-correlation approximation are shown to be important for the transition probabilities, and are included in large configuration interaction calculations. For all the transitions except one, the agreement between the length and velocity forms of the weighted oscillator strength is better than 0.4%. The present results are believed to be substantially more accurate than those of other theories.
BibTeX: @article{Jönsson19962393, author = {Jönsson, P. and Froese Fischer, C. and Godefroid, M.R.}, title = {Accurate calculations of transition probabilities, isotope shifts and hyperfine structures for some allowed 2s22pn-2s2pn+1 transitions in B I, C II and C I}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1996}, volume = {29}, number = {12}, pages = {2393 – 2412}, doi = {10.1088/0953-4075/29/12/007} }
Jönsson P, Ynnerman A, Froese Fischer C, Godefroid MR and Olsen J (1996), "Large-scale multiconfiguration Hartree-Fock and configuration-interaction calculations of the transition probability and hyperfine structures in the sodium resonance transition", Physical Review A - Atomic, Molecular, and Optical Physics. Vol. 53(6), pp. 4021 – 4030. [Abstract] [BibTeX] [DOI]
Abstract: Results from large-scale multiconfiguration Hartree-Fock (MCHF) and configuration-interaction (CI) calculations of the transition probability and hyperfine structures in the sodium 3s[Formula Presented]S-3p[Formula Presented]P resonance transition are presented. In the calculations the orbital sets of the initial and final state wave functions were not restricted to be the same, but were optimized independently. The evaluation of the transition matrix elements was done using a technique where the two orbital sets are transformed so as to become biorthonormal, in which case standard Racah algebra can be used. Three-particle effects were taken into account in the CI calculations and were found to be important for the hyperfine structures, but less important for the transition probability. The calculated transition probability is in perfect agreement with the most recent experimental values, thus resolving the long-standing disagreement between theory and experiment. Also the 3s[Formula Presented] and 3p[Formula Presented] hyperfine interaction constants are in very good agreement with available experimental values. © 1996 The American Physical Society.
BibTeX: @article{Jönsson19964021, author = {Jönsson, Per and Ynnerman, Anders and Froese Fischer, Charlotte and Godefroid, Michel R. and Olsen, Jeppe}, title = {Large-scale multiconfiguration Hartree-Fock and configuration-interaction calculations of the transition probability and hyperfine structures in the sodium resonance transition}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, year = {1996}, volume = {53}, number = {6}, pages = {4021 – 4030}, doi = {10.1103/PhysRevA.53.4021} }
Kleiner I, Lovas F and Godefroid M (1996), "Microwave spectra of molecules of astrophysical interest. XXIII. Acetaldehyde", Journal of Physical and Chemical Reference Data. Vol. 25(4), pp. 1113 – 1116. [Abstract] [BibTeX] [DOI]
Abstract: The microwave spectrum of acetaldehyde is critically reviewed and supplemented with spectral frequency calculations derived from the rotation-internal rotation analysis. A simultaneous analysis of the torsional ground state, vt = 0, and first and second torsionally excited states, vt = 1 and 2, was carried out. The primary objective of this review is to provide radio astronomers with complete spectral coverage over the range of 900 MHz to 500 GHz for the ground state and covering rotational quantum number, J, from 0 to 26. © 1996 American Institute of Physics and American Chemical Society.
BibTeX: @article{Kleiner19961113, author = {Kleiner, I. and Lovas, F.J. and Godefroid, M.}, title = {Microwave spectra of molecules of astrophysical interest. XXIII. Acetaldehyde}, journal = {Journal of Physical and Chemical Reference Data}, year = {1996}, volume = {25}, number = {4}, pages = {1113 – 1116}, doi = {10.1063/1.555983} }
Modugno G, De Natale P, Bellini M, Inguscio M, Di Lonardo G, Fusina L and Vander Auwera J (1996), "Precise measurement of molecular dipole moments with a tunable far-infrared Stark spectrometer: Application to HOCl", Journal of the Optical Society of America B: Optical Physics. Vol. 13(8), pp. 1645 – 1649. [Abstract] [BibTeX] [DOI]
Abstract: Stark measurement of the electric dipole moment components of H16O35Cl is performed with a tunable far-infrared spectrometer at the European Laboratory for Nonlinear Spectroscopy, Firenze, Italy. Two pure rotational transitions are analyzed, namely, the 11,1-00,0 at approximately 628 GHz and the asymmetry doublet 43,2-32,1, 43,1-32,2 at approximately 3.1 THz. The values obtained for μa and μb represent the first reported measurement of dipole moments from far-infrared transitions with an accuracy up to several parts in 104. © 1996 Optical Society of America.
BibTeX: @article{Modugno19961645, author = {Modugno, G. and De Natale, P. and Bellini, M. and Inguscio, M. and Di Lonardo, G. and Fusina, L. and Vander Auwera, J.}, title = {Precise measurement of molecular dipole moments with a tunable far-infrared Stark spectrometer: Application to HOCl}, journal = {Journal of the Optical Society of America B: Optical Physics}, year = {1996}, volume = {13}, number = {8}, pages = {1645 – 1649}, doi = {10.1364/JOSAB.13.001645} }
Perrin A, Flaud J-M, Camy-Peyret C, Hurtmans D and Herman M (1996), "The 2ν3, 4ν2, 2ν2 + ν3 and 2ν3 - ν3 bands of 14N16O2: Line positions and intensities", Journal of Molecular Spectroscopy. Vol. 177(1), pp. 58 – 65. [Abstract] [BibTeX] [DOI]
Abstract: High resolution Fourier transform absorption spectra of the 14N16O2 molecule recorded in the 3000-3400 cm-1 and 1520-1600 cm-1 spectral regions have been analyzed. In this way lines of the 2ν3, 4ν2, 2ν2 + ν3, and 2ν3 - ν3 bands of 14N16O2 have been assigned with Ka values ranging from O to 8 and N values up to 60. The spin-rotation energy levels were very satisfactorily reproduced using a theoretical model which takes explicitly into account both the Coriolis interaction between the spin-rotation levels of the (021) vibrational state and those of (040) and of (002), and the spin-rotation resonances within (021), (040), and (002). As a consequence, precise vibrational band centers and rotational, spin-rotation, and coupling constants were obtained for the triad (040), (002), (021) of interacting states of 14N16O2. In addition, using a large set of individual 2ν3, 4ν2, and 2ν2 + ν3 experimental line intensities at 3.2 μm, we have determined precisely the 2ν2 + ν3 and 2ν3 transition moment constants of 14N16O2. On the other hand, the transition moment constants of the 2ν3 - ν3 and 2ν2 + ν3 - 2ν2 bands were derived from those of the corresponding ν3 cold band. Finally, a comprehensive list of line positions and intensities of the interacting 4ν2, 2ν3, 2ν2 + ν3, and 2ν3 - ν3 bands of 14N16O2 has been generated at 3.2 μm and 6.2 μm, respectively, © 1996 Academic Press, Inc.
BibTeX: @article{Perrin199658, author = {Perrin, A. and Flaud, J.-M. and Camy-Peyret, C. and Hurtmans, D. and Herman, M.}, title = {The 2ν3, 4ν2, 2ν2 + ν3 and 2ν3 - ν3 bands of 14N16O2: Line positions and intensities}, journal = {Journal of Molecular Spectroscopy}, year = {1996}, volume = {177}, number = {1}, pages = {58 – 65}, doi = {10.1006/jmsp.1996.0117} }
Ram R, Morbi Z, Guo B, Zhang K-Q, Bernath P, Auwera JV, Johns J and Davis S (1996), "Infrared spectra of hot HF and DF", Astrophysical Journal, Supplement Series. Vol. 103(1), pp. 247 – 254. [Abstract] [BibTeX] [DOI]
Abstract: New Fourier transform emission measurements were obtained for HF and DF at a temperature of 2300°C. Both pure rotation and vibration-rotation lines were measured with a precision of about 0.0005 cm-1. These new lines were combined with previously measured data to give improved rotational constants for the vibrational levels υ = 0-5. The HF molecule is the most convenient monitor of 19F abundances in cool stars.
BibTeX: @article{Ram1996247, author = {Ram, R.S. and Morbi, Z. and Guo, B. and Zhang, K.-Q. and Bernath, P.F. and Auwera, J. Vander and Johns, J.W.C. and Davis, S.P.}, title = {Infrared spectra of hot HF and DF}, journal = {Astrophysical Journal, Supplement Series}, year = {1996}, volume = {103}, number = {1}, pages = {247 – 254}, note = {All Open Access, Bronze Open Access}, doi = {10.1086/192277} }
Sutcliffe BT (1996), "The development of the idea of a chemical bond", International Journal of Quantum Chemistry. Vol. 58(6), pp. 645 – 655. [Abstract] [BibTeX] [DOI]
Abstract: The development of the idea of a chemical bond is traced from Frankland to Heitler and London and beyond with emphasis on how electrons came to be considered essential to explaining the bond. © 1996 John Wiley & Sons, Inc.
BibTeX: @article{Sutcliffe1996645, author = {Sutcliffe, Brian T.}, title = {The development of the idea of a chemical bond}, journal = {International Journal of Quantum Chemistry}, year = {1996}, volume = {58}, number = {6}, pages = {645 – 655}, doi = {10.1002/(SICI)1097-461X(1996)58:6<645::AID-QUA7>3.0.CO;2-Y} }
Temsamani MA and Herman M (1996), "The vibrational energy pattern in 12C2H2(II): Vibrational clustering and rotational structure", Journal of Chemical Physics. Vol. 105(4), pp. 1355 – 1362. [Abstract] [BibTeX] [DOI]
Abstract: We achieve a systematic modeling of all rovibrational levels in the 12C2H2 (X̃1Σg+) molecule, which is tested up to the near infrared range. It is based on the cluster picture, which was demonstrated to block diagonalize the full vibrational energy matrix, and to allow unraveling the vibrational energy pattern in 12C2H2, up to 12 000 cm-1 [see M. Abbouti Temsamani and M. Herman, J. Chem. Phys. 102, 6371 (1995)]. Each of those clusters, which are called here V-clusters, is made of pure vibrational type diagonal and off-diagonal matrix elements. That model is extended to take care of the rotational structure, defining the V/l/C-cluster model. In a first step J-dependent terms are included in the diagonal elements of the V-clusters, and rotational l resonance off-diagonal matrix elements are included, leading to couple specific V-cluster matrices, resulting into so-called V/l-clusters. This extension is quantitatively demonstrated to reproduce the reported effective principal rotational constant and effective higher order distortion constants, for four selected clusters of levels: those containing V1+V3, V1+V2+V3, 3V3 and V2+3V3. In the case of the 3ν3 range, new FTIR spectra recorded around 9700 cm-1 are used. The related experimental conditions and new observed spectral features are briefly presented. A further extension of the model is then accomplished to include Coriolis-type interaction, by coupling V/l-clusters using a systematic mechanism. That step, defining the model of V/l/C-clusters, allows to suggest assignment for extra rovibrational lines observed around 3ν3. Those various steps are supported by a consistent picture involving constants of the motion, starting with three pseudoquantum numbers in the case of V-cluster, ns,nr,k, from which two, ns,nr and then one nr remain when defining respectively the V/l-cluster and V/l/C-cluster matrices. © 1996 American Institute of Physics.
BibTeX: @article{Temsamani19961355, author = {Temsamani, Mohammed Abbouti and Herman, Michel}, title = {The vibrational energy pattern in 12C2H2(II): Vibrational clustering and rotational structure}, journal = {Journal of Chemical Physics}, year = {1996}, volume = {105}, number = {4}, pages = {1355 – 1362}, doi = {10.1063/1.472989} }
Vandaele A, Hermans C, Simon P, Van Roozendael M, Guilmot J, Carleer M and Colin R (1996), "Fourier transform measurement of NO2 absorption cross-section in the visible range at room temperature", Journal of Atmospheric Chemistry. Vol. 25(3), pp. 289 – 305. [Abstract] [BibTeX] [DOI]
Abstract: New laboratory measurements of NO2 absorption cross-section were performed using a Fourier transform spectrometer at 2 and 16 cm-1 (0.03 and 0.26 nm at 400 nm) in the visible range (380-830 nm) and at room temperature. The use of a Fourier transform spectrometer leads to a very accurate wavenumber scale (0.005 cm-1, 8 x 10-5 nm at 400 nm). The uncertainty on the new measurements is better than 4%. Absolute and differential cross-sections are compared with published data, giving an agreement ranging from 2 to 5% for the absolute values. The discrepancies in the differential cross-sections can however reach 18%. The influence of the cross-sections on the ground-based measurement of the stratospheric NO2 total amount is also investigated.
BibTeX: @article{Vandaele1996289, author = {Vandaele, A.C. and Hermans, C. and Simon, P.C. and Van Roozendael, M. and Guilmot, J.M. and Carleer, M. and Colin, R.}, title = {Fourier transform measurement of NO2 absorption cross-section in the visible range at room temperature}, journal = {Journal of Atmospheric Chemistry}, year = {1996}, volume = {25}, number = {3}, pages = {289 – 305}, doi = {10.1007/BF00053797} }
Wauters L and Vaeck N (1996), "Study of the electronic rearrangement induced by nuclear transmutations: A B-spline approach applied to the β decay of 6He", Physical Review C - Nuclear Physics. Vol. 53(1), pp. 497 – 500. [Abstract] [BibTeX] [DOI]
Abstract: The electronic rearrangement resulting from the β decay of 6He has been calculated in the framework of the sudden approximation using a numerical B-spline basis set approach. We have calculated the excitation probabilities to the final discrete states of 6Li+ (including to the doubly excited autoionizing states) as well as the total probabilities for single and double ionization. The correct treatment of electronic correlation in the framework of the sudden approximation is shown to modify the PK value (the probability that an atomic K vacancy is created) by more than 2%.
BibTeX: @article{Wauters1996497, author = {Wauters, L. and Vaeck, N.}, title = {Study of the electronic rearrangement induced by nuclear transmutations: A B-spline approach applied to the β decay of 6He}, journal = {Physical Review C - Nuclear Physics}, year = {1996}, volume = {53}, number = {1}, pages = {497 – 500}, doi = {10.1103/PhysRevC.53.497} }
Aboussaïd A, Godefroid M, Jönsson P and Froese Fischer C (1995), "Multiconfigurational Hartree-Fock calculations of hyperfine-induced transitions in heliumlike ions", Physical Review A. Vol. 51(3), pp. 2031 – 2039. [Abstract] [BibTeX] [DOI]
Abstract: We are investigating the hyperfine quenching of 1s2p 3P0o for the three heliumlike ions F7+19, Na9+23, and Al11+27 in the multiconfigurational Hartree-Fock-Breit-Pauli scheme. The configuration expansions are generated with the active-space method and are increased in a systematic way, allowing the convergence of the calculated parameters to be studied. A careful comparison is done with the pioneering work of Mohr using a perturbation approach [Beam-Foil Spectroscopy, Atomic Structure and Lifetimes, edited by I. Sellin and D. Pegg (Plenum, New York, 1976), Vol. 1, pp. 97-103]. In the present calculations the orbital and spin-dipole magnetic contributions, which were previously neglected, are added to the dominant Fermi contact interaction term and a detailed analysis of the hyperfine induced transition rate is done in order to learn how to get an accurate description of the property in the multiconfiguration Hartree-Fock-Breit-Pauli approximation. © 1995 The American Physical Society.
BibTeX: @article{Aboussaïd19952031, author = {Aboussaïd, A. and Godefroid, M.R. and Jönsson, P. and Froese Fischer, C.}, title = {Multiconfigurational Hartree-Fock calculations of hyperfine-induced transitions in heliumlike ions}, journal = {Physical Review A}, year = {1995}, volume = {51}, number = {3}, pages = {2031 – 2039}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.51.2031} }
Campargue A, Abbouti Temsamani M and Herman M (1995), "The absorption spectrum of acetylene in the 2ν2 + 3ν3 region. A test of the cluster model", Chemical Physics Letters. Vol. 242(1-2), pp. 101 – 105. [Abstract] [BibTeX] [DOI]
Abstract: Three new weak bands of 12C2H2 at 13473.69, 13493.87 and 13787.97 cm-1 have been recorded by intracavity laser absorption spectroscopy and rotationally analyzed. Their presence was anticipated, on the basis of the cluster model recently presented by Abbouti Temsamani and Herman. The band energies and upper rotational parameters are well reproduced. The comparison between predicted and observed relative band intensities, including those previously reported in the literature in the range investigated, is briefly discussed. © 1995.
BibTeX: @article{Campargue1995101, author = {Campargue, Alain and Abbouti Temsamani, Mohammed and Herman, Michel}, title = {The absorption spectrum of acetylene in the 2ν2 + 3ν3 region. A test of the cluster model}, journal = {Chemical Physics Letters}, year = {1995}, volume = {242}, number = {1-2}, pages = {101 – 105}, doi = {10.1016/0009-2614(95)00711-C} }
Campargue A, Permogorov D, Bach M, Temsamani MA, Auwera JV, Herman M and Fujii M (1995), "Overtone spectroscopy in nitrous oxide", The Journal of Chemical Physics. Vol. 103(14), pp. 5931 – 5938. [Abstract] [BibTeX] [DOI]
Abstract: The near infrared and visible absorption spectrum of nitrous oxide 14N216O has been recorded by Fourier transform absorption spectroscopy, between 6500 and 11 000 cm-1, and by Intracavity Laser Absorption Spectroscopy, between 11700 and 15 000 cm -1. Nineteen new bands are observed and, altogether, 34 cold and 10 hot bands are rotationally analyzed. The related upper term values, vibrational assignments, and principal rotational constants, as well as the relative band intensities are quantitatively discussed in terms of the formation of vibrational clusters, on the basis of the effective Hamiltonian developed by J. L. Teffo, V. I. Perevalov and O. M. Lyulin [J. Mol. Spectrosc. 168, 390 (1994)]. © 1995 American Institute of Physics.
BibTeX: @article{Campargue19955931, author = {Campargue, Alain and Permogorov, Dmitri and Bach, Mohamed and Temsamani, Mohammed Abbouti and Auwera, Jean Vander and Herman, Michel and Fujii, Masaaki}, title = {Overtone spectroscopy in nitrous oxide}, journal = {The Journal of Chemical Physics}, year = {1995}, volume = {103}, number = {14}, pages = {5931 – 5938}, doi = {10.1063/1.470473} }
Carlsson J, Jonsson P, Godefroid M and Fischer CF (1995), "Accurate multiconfiguration hartree-fock calculations of isotope shifts in c i and c iv", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 28(17), pp. 3729 – 3740. [Abstract] [BibTeX] [DOI]
Abstract: A flew isotope shift program, part of the mchf atomic structure package, has recently been written. The program calculates the isotope shift of an atomic level from multiconfiguration Hartree-Fock (mchf) or configuration interaction (Ci) wavefunctions and is specially designed to be used with very large ci expansions, for which angular data cannot be stored on disk. To explore the capacity of the program, large-scale isotope shift calculations have been performed for the 1s22s2S and Is22p2P levels in C tv and for the ls22s22p2 S, ls22s22p3s ‘P, ls22s22p2 3P and ls22s2p3 5S levels in C t. From the isotope shifts of these levels theMC-i2C isotope shifts were calculated for the Is22s2S-ls22p2P transition in C iv and for the Is22s22p2 1 S-ls22s22p3sJP and ls22s22p2 3P-!s22s2p3 5S transitions in C i. The calculated transition isotope shifts are in very good agreement with experimental values, available for the C i transitions. As a check on the overall quality of the wavefunctions, the hyperfine structure interaction constants were calculated for the levels in C tv. © 1995 IOP Publishing Ltd.
BibTeX: @article{Carlsson19953729, author = {Carlsson, J. and Jonsson, P. and Godefroid, M.R. and Fischer, C. Froese}, title = {Accurate multiconfiguration hartree-fock calculations of isotope shifts in c i and c iv}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1995}, volume = {28}, number = {17}, pages = {3729 – 3740}, doi = {10.1088/0953-4075/28/17/012} }
Clerbaux C, Chazette P and Megie GJ (1995), "Tropospheric concentrations of infrared absorbing molecules using a nadir-looking Fourier transform spectrometer", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 2578, pp. 148 – 153. [Abstract] [BibTeX] [DOI]
Abstract: Atmospheric spectra to be recorded in the infrared spectral range by a spaceborne Fourier transform spectrometer using a nadir view have been simulated. Relevant spectral domains have been selected for the retrieval of carbon monoxide, methane, ozone and nitrous oxide. A new inversion algorithm using neural networks techniques is proposed to retrieve integrated contents and low resolution vertical profiles.
BibTeX: @conference{Clerbaux1995148, author = {Clerbaux, Cathy and Chazette, Patrick and Megie, Gerard J.}, title = {Tropospheric concentrations of infrared absorbing molecules using a nadir-looking Fourier transform spectrometer}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {1995}, volume = {2578}, pages = {148 – 153}, doi = {10.1117/12.228935} }
Culot F, Laruelle F and Liévin J (1995), "A vibrational CASSCF study of stretch-bend interactions and their influence on infrared intensities in the water molecule", Theoretica Chimica Acta. Vol. 92(4), pp. 211 – 226. [Abstract] [BibTeX] [DOI]
Abstract: An extension of the multiconfigurational SCF approach for the resolution of the vibrational problem is presented; it follows the philosophy of the CASSCF method developed in Quantum Chemistry. The new method allows a more complete treatment of anharmonic mode couplings, converges much faster and gives a clearer physical insight of vibrational interactions. This is exemplified by the calculation of infrared transition moments in the H2O and D2O isotopomers of the water molecule. It is shown how this property varies with the quality of the wave function when vibrational resonances occur. A detailed analysis by means of this new VCASSCF method demonstrates the crucial importance of excited bending oscillators in the intensity of some pure stretching transitions. © 1995 Springer-Verlag.
BibTeX: @article{Culot1995211, author = {Culot, F. and Laruelle, F. and Liévin, J.}, title = {A vibrational CASSCF study of stretch-bend interactions and their influence on infrared intensities in the water molecule}, journal = {Theoretica Chimica Acta}, year = {1995}, volume = {92}, number = {4}, pages = {211 – 226}, doi = {10.1007/BF01125947} }
Desouter-Lecomte M, Liévin J and Brems V (1995), "Avoided resonance overlapping beyond the energy independent formalism. I. Vibrational predissociation", The Journal of Chemical Physics. Vol. 103(11), pp. 4524 – 4537. [Abstract] [BibTeX] [DOI]
Abstract: The interaction of overlapping resonances is studied in the case of a vibrational predissociation in a linear molecule. The energy independent approach rests on the neglect of the variation of the coupling elements with the energy in the continuum. It predicts the formation of trapped and short-lived decay modes when resonances overlap. The relevance of this prediction is discussed on the basis of results obtained from two different methods going beyond this energy independent formalism. The first one consists in searching the solutions of the implicit equation derived from the Feshbach partitioning method, taking into account the full energy dependence of the local effective Hamiltonian Heff(E). The second one is the variational complex coordinate method (CCM), implemented in a discrete variable representation (DVR). The results demonstrate that the energy dependency enhances the trapping effect. The distribution of the resonance energies in the complex plane is different from the prediction of the energy independent formalism. The fast modes are found to be slower than expected. Their position is also completely shifted. The mean width is not constrained by a sum rule which is characteristic of the energy independent approximation. © 1995 American Institute of Physics.
BibTeX: @article{Desouter-Lecomte19954524, author = {Desouter-Lecomte, M. and Liévin, J. and Brems, V.}, title = {Avoided resonance overlapping beyond the energy independent formalism. I. Vibrational predissociation}, journal = {The Journal of Chemical Physics}, year = {1995}, volume = {103}, number = {11}, pages = {4524 – 4537}, doi = {10.1063/1.470641} }
Errera Q, Vanderauwera J, Belafhal A and Fayt A (1995), "Absolute intensities in 16o12c32s: The 2500-3100 cm-1", Journal of Molecular Spectroscopy. Vol. 173(2), pp. 347 – 369. [Abstract] [BibTeX] [DOI]
Abstract: About 400 absolute intensities have been measured for six bands(5 Σ-Σ and 1 Π-Σ bands) of 16O12C32S in the region of the ν1 + ν3 band near 3.4 μm. The majority of these bands exhibit weak to very strong Herman-Wallis behavior as a result of various anharmonic and l-type resonances between the upper levels involved. The individual line intensities were treated in two different ways. First, they were fitted to usual effective formulae, leading to the band strengths and Herman-Wallis factors. Second, the line intensities in the five Σ-Σ bands were fitted to a model taking explicitly into account the various anharmonic and I-type resonances between the upper levels. This treatment showed that these resonances quantitatively explain to a large extent the Herman-Wallis behavior observed. © 1995 Academic Press, Inc.
BibTeX: @article{Errera1995347, author = {Errera, Q. and Vanderauwera, J. and Belafhal, A. and Fayt, A.}, title = {Absolute intensities in 16o12c32s: The 2500-3100 cm-1}, journal = {Journal of Molecular Spectroscopy}, year = {1995}, volume = {173}, number = {2}, pages = {347 – 369}, doi = {10.1006/jmsp.1995.1240} }
Fleming J, Brage T, Bell K, Vaeck N, Hibbert A, Godefroid M and Froese Fischer C (1995), "Systematic studies of N IV transitions of astrophysical importance", Astrophysical Journal. Vol. 455(2), pp. 758 – 768. [Abstract] [BibTeX] [DOI]
Abstract: E1, M2, M1 and E2 rates of transitions between n = 2 levels of N IV have been calculated using the two independent codes CIV3 and MCHF. Convergence of each of the approaches has been studied and comparisons made as the complexity of the calculations increases to include valence, core-valence and core-core correlation. The agreement between the two methods is sufficiently good to allow us to set quite narrow uncertainty bars. For the 1S-1P0 resonance line, our recommended f-value is 0.609 with an estimated uncertainty of 0.002, while our recommended A-value for the 1S0-3P01 intercombination line is 580 s-1 with an estimated uncertainty of 10 s-1.
BibTeX: @article{Fleming1995758, author = {Fleming, J. and Brage, T. and Bell, K.L. and Vaeck, N. and Hibbert, A. and Godefroid, M.R. and Froese Fischer, C.}, title = {Systematic studies of N IV transitions of astrophysical importance}, journal = {Astrophysical Journal}, year = {1995}, volume = {455}, number = {2}, pages = {758 – 768}, note = {All Open Access, Bronze Open Access}, doi = {10.1086/176621} }
Georges R, Durry G, Bach M, Pétrisse R, Jost R and Herman M (1995), "Multinozzle supersonic expansion for Fourier transform absorption spectroscopy", Chemical Physics Letters. Vol. 246(6), pp. 601 – 606. [Abstract] [BibTeX] [DOI]
Abstract: A new supersonic expansion made of several, up to 31 aligned nozzles, on top of a set of powerful Roots blowers has been built. Adequate optics allowed the recording of infrared absorption spectra in a cell with a Fourier transform interferometer, at high spectral resolution. The system was tested with N2O, between 2000 and 4800 cm-1. The ν1 + 2ν2 + ν3 combination band, estimated to be some 10000 times weaker than the ν2 fundamental, could be observed among all the other expected bands, thus setting a limit for the sensitivity of the system. The formation of large N2O clusters was observed. © 1995.
BibTeX: @article{Georges1995601, author = {Georges, R. and Durry, G. and Bach, M. and Pétrisse, R. and Jost, R. and Herman, M.}, title = {Multinozzle supersonic expansion for Fourier transform absorption spectroscopy}, journal = {Chemical Physics Letters}, year = {1995}, volume = {246}, number = {6}, pages = {601 – 606}, doi = {10.1016/0009-2614(95)01161-4} }
Godefroid M, Olsen J, Jönsson P and Fischer CF (1995), "Accurate multiconfiguration Hartree-Fock calculations of oscillator strengths in light atoms: The boron (B II) line at 1362 Å", Astrophysical Journal. Vol. 450(1), pp. 473 – 476. [Abstract] [BibTeX] [DOI]
Abstract: A new method to deal with nonorthogonalities in transition calculations has been implemented and tested. Large-scale transition calculations using the multiconfiguration Hartree-Fock (MCHF) method have been performed for the resonance line of B II at 1362 Å. In these calculations the orbital sets of the initial and final-state wavefunctions have not been assumed to be equal but have been optimized independently. The calculated weighted multiplet oscillator strength gf = 0.999 has an estimated uncertainty of less than 0.5%. Together with the previously calculated isotope shift and hyperfine structure (Jönsson, Johansson, & Froese Fischer 1994), all the important atomic parameters needed for a detailed modeling of the B II resonance line in high-resolution astrophysical spectra are now available with high accuracy.
BibTeX: @article{Godefroid1995473, author = {Godefroid, Michel and Olsen, Jeppe and Jönsson, Per and Fischer, Charlotte Froese}, title = {Accurate multiconfiguration Hartree-Fock calculations of oscillator strengths in light atoms: The boron (B II) line at 1362 Å}, journal = {Astrophysical Journal}, year = {1995}, volume = {450}, number = {1}, pages = {473 – 476}, note = {All Open Access, Green Open Access}, doi = {10.1086/176157} }
Held A and Herman M (1995), "High resolution spectroscopic study of the first overtone of the NH stretch and of the fundamentals of the CH stretches in pyrrole", Chemical Physics. Vol. 190(2-3), pp. 407 – 417. [Abstract] [BibTeX] [DOI]
Abstract: We have examined the first overtone NH stretching region and the fundamental CH stretching region of gas phase pyrrole (C4H5N), using high resolution Fourier transform spectra. The first overtone NH stretch has been rotationally analysed using an asymmetric top model and was found to exhibit two separate perturbations. These perturbations produce line splittings and anomalous intensity patterns in the spectrum which are briefly discussed. Hot band transitions, one of them red-shifted and others likely to overlap the main cold transition are also discussed. Three bands observed around 3100 cm-1 were also rotationally analysed, using a symmetric top Hamiltonian, and assigbed to three of the four closely overlapping fundamentals of the CH stretch vibrations. Evidence was obtained for the fourth expected CH fundamental. © 1995.
BibTeX: @article{Held1995407, author = {Held, A. and Herman, M.}, title = {High resolution spectroscopic study of the first overtone of the NH stretch and of the fundamentals of the CH stretches in pyrrole}, journal = {Chemical Physics}, year = {1995}, volume = {190}, number = {2-3}, pages = {407 – 417}, doi = {10.1016/0301-0104(94)00377-M} }
Lehmann K, Herman M and Mills I (1995), "Preface", Chemical Physics. Vol. 190(2-3), pp. 157 – 158. [BibTeX] [DOI]
BibTeX: @article{Lehmann1995157, author = {Lehmann, K.K. and Herman, M. and Mills, I.M.}, title = {Preface}, journal = {Chemical Physics}, year = {1995}, volume = {190}, number = {2-3}, pages = {157 – 158}, doi = {10.1016/0301-0104(95)90029-2} }
Liévin J, Abbouti Temsamani M, Gaspard P and Herman M (1995), "Overtone spectroscopy and dynamics in monodeuteroacetylene (C2HD)", Chemical Physics. Vol. 190(2-3), pp. 419 – 445. [Abstract] [BibTeX] [DOI]
Abstract: Complementary experimental, ab initio and dynamical investigations are reported on monodeuteroacetylene, C2HD (X̃1Σ+). All experimental spectroscopic results previously reported in the literature on C2HD, i.e. from 500 to 16000 cm-1 are gathered. New results are included, which are obtained from the analysis of absorption data recorded with a Fourier transform interferometer at high resolution between 4600 and 9000 cm-1. The presence of numerous weak bands along the whole spectral range is analysed in terms of systematic anharmonic couplings. The entire set of energy data is then used to produce thirty-five vibrational frequencies and anharmonicities from a fit of the vibrational energies to a Dunham-type expansion, and the vibrational level density is extrapolated, up to higher energy. One- and two-dimensional potential energy and dipole moment surfaces refined from new ab initio results are fitted to a selected set among those experimental data, associated to the stretch overtones. The iterative procedure involving an original package of computer programs is described. The evolution of the overtone intensities of the CH and CD stretches, up to η = 4, is interpreted on that basis in terms of electric and mechanical anharmonicity contributions. Eventually, dynamical aspects are studied thanks to the newly introduced vibrograms, which allow to obtain the time recurrences of the vibrational dynamics. Using the Gutzwiller and Berry-Tabor trace formulas, these vibrational recurrences are semiclassically assigned to periodic orbits of the classical Hamiltonian given by the Dunham expansion. © 1995.
BibTeX: @article{Liévin1995419, author = {Liévin, J. and Abbouti Temsamani, M. and Gaspard, P. and Herman, M.}, title = {Overtone spectroscopy and dynamics in monodeuteroacetylene (C2HD)}, journal = {Chemical Physics}, year = {1995}, volume = {190}, number = {2-3}, pages = {419 – 445}, doi = {10.1016/0301-0104(94)00378-N} }
Olsen J, Godefroid MR, Jönsson P, Malmqvist PA and Fischer CF (1995), "Transition probability calculations for atoms using nonorthogonal orbitals", Physical Review E. Vol. 52(4), pp. 4499 – 4508. [Abstract] [BibTeX] [DOI]
Abstract: Individual orbital optimization of wave functions for the initial and final states produces the most accurate wave functions for given expansions, but complicates the calculation of transition-matrix elements since the two sets of orbitals will be nonorthogonal. The orbital sets can be transformed to become biorthonormal, in which case the evaluation of any matrix element can proceed as in the orthonormal case. The transformation of the wave-function expansion to the new basis imposes certain requirements on the wave function, depending on the type of transformation. An efficient and general method was found a few years ago for expansions in determinants, spin-coupled configurations, or configuration state functions for molecules belonging to the D2h point group or its subgroups. The method requires only that the expansions are closed under deexcitation and thus applies to restricted active space wave functions. This type of expansion is efficient for correlation studies and includes many types of expansions as special cases. The above technique has been generalized to the atomic, symmetry adapted case requiring the treatment of degenerate shells nlN, with arbitrary occupation numbers 0≤N≤4l+2. A computer implementation of the algorithm in the multiconfiguration Hartree-Fock atomic-structure package for atoms allows the calculation of transition moments for individually optimized states. An application is presented for the B i 1s22s22p 2Po→1s22s2p2 2D electric dipole transition probability, which is highly sensitive to core-polarization effects. © 1995 The American Physical Society.
BibTeX: @article{Olsen19954499, author = {Olsen, Jeppe and Godefroid, Michel R. and Jönsson, Per and Malmqvist, Per Ake and Fischer, Charlotte Froese}, title = {Transition probability calculations for atoms using nonorthogonal orbitals}, journal = {Physical Review E}, year = {1995}, volume = {52}, number = {4}, pages = {4499 – 4508}, doi = {10.1103/PhysRevE.52.4499} }
Palmeri P, Biémont E, Aboussaid A and Godefroid M (1995), "Hyperfine structure of infrared vanadium lines", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 28(17), pp. 3741 – 3752. [Abstract] [BibTeX] [DOI]
Abstract: High resolution profiles of neutral vanadium lines have been recorded in the infrared region (1800-9000 cm-1) by Fourier transform spectroscopy. 106 transitions showing resolvedor partially resolved hyperfine profiles have been analysed. An investigation of these structureshas allowed the deduction of magnetic dipole constants for 101 levels. For 69 levels the resultsobtained are new. The results of the present work have been compared with the few datapreviously published in the literature and they are generally in good agreement. © 1995 IOP Publishing Ltd.
BibTeX: @article{Palmeri19953741, author = {Palmeri, P. and Biémont, E. and Aboussaid, A. and Godefroid, M.}, title = {Hyperfine structure of infrared vanadium lines}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1995}, volume = {28}, number = {17}, pages = {3741 – 3752}, doi = {10.1088/0953-4075/28/17/013} }
Sutcliffe BT (1995), "The idea of a potential energy surface", Journal of Molecular Structure: THEOCHEM. Vol. 341(1-3), pp. 217 – 235. [Abstract] [BibTeX] [DOI]
Abstract: The development of the idea of a potential energy surface is examined in the context of solutions to the full quantum mechanical problem specified by the Schrödinger Hamiltonian expressed in laboratory-fixed coordinates. © 1995 Elsevier Science B.V. All rights reserved.
BibTeX: @article{Sutcliffe1995217, author = {Sutcliffe, Brian T.}, title = {The idea of a potential energy surface}, journal = {Journal of Molecular Structure: THEOCHEM}, year = {1995}, volume = {341}, number = {1-3}, pages = {217 – 235}, doi = {10.1016/0166-1280(95)04125-P} }
Temsamani MA and Herman M (1995), "The vibrational energy levels in acetylene 12C2H 2: Towards a regular pattern at higher energies", The Journal of Chemical Physics. Vol. 102(16), pp. 6371 – 6384. [Abstract] [BibTeX] [DOI]
Abstract: We have gathered 122 known experimental data concerning the vibrational energy levels of acetylene, C2H2, up to 12 000 cm -1. We have fitted the data simultaneously to a model based on the clustering of the levels induced by a set of eight anharmonic resonances. That set is carefully built from the literature information on various isotopomers of acetylene. The model takes full advantage of the anharmonic pattern and systematically block diagonalizes the entire vibrational energy matrix. The 122 input energies are reproduced within a standard deviation of 0.74 cm -1 with 35 fitted parameters. Decisive support to the model is brought by using the resulting vibrational parameters and matrix eigenvectors to reproduce energies, principal rotational parameters, and relative intensity features. The cluster picture is discussed, in terms of the 7 normal modes of vibration in acetylene, according to the theoretical model developed by Kellman [M. E. Kellman and G. Chen, J. Chem. Phys. 95, 8671 (1991)]. © 1995 American Institute of Physics.
BibTeX: @article{Temsamani19956371, author = {Temsamani, Mohammed Abbouti and Herman, Michel}, title = {The vibrational energy levels in acetylene 12C2H 2: Towards a regular pattern at higher energies}, journal = {The Journal of Chemical Physics}, year = {1995}, volume = {102}, number = {16}, pages = {6371 – 6384}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.469353} }
Vaeck N and Hansen JE (1995), "Auger decay of hollow nitrogen atoms", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 28(16), pp. 3523 – 3543. [Abstract] [BibTeX] [DOI]
Abstract: We present calculations of autoionization lifetimes for ‘hollow’ nitrogen atoms with and without a core of one or two Is electrons. We have observed a very similar patternin theNdependence of the lifetimes for all lsnp configurations withM= 0, 1 and 2, n 2, 3, 4.5, 6, 7 and 10 andN =2, 3, 4, 5 and 6. Also some IsntNconfigurations witht 1have been considered as well as configurations with mixed values ofn.For configurations withall the electrons in the samenshell we have found that the average lifetime inneutralsystemsis very short, typically of the order of 3-5 x 10-16 for n = 3 to 7. The same applies toconfigurations with mixed values ofn(of the order of 1-6 x 10-16s for n = 3 to 7). Wefind that the importance of electron correlation increases dramatically withnandNbut that theaverage autoionization decay rates do not change. The configurations studied are of interest, forexample, in the study of processes that occur during neutralization of highly charged nitrogenions at surfaces. © 1995 IOP Publishing Ltd.
BibTeX: @article{Vaeck19953523, author = {Vaeck, Nathalie and Hansen, Jørgen E.}, title = {Auger decay of hollow nitrogen atoms}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1995}, volume = {28}, number = {16}, pages = {3523 – 3543}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/28/16/008} }
Van Der Hart HW, Vaeck N and Hansen JE (1995), "Radiative stabilization of the doubly-excited 4l4l' and 4l5l' singlet terms in ne8+", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 28(24), pp. 5207 – 5228. [Abstract] [BibTeX] [DOI]
Abstract: Calculations concerning the competition between radiative and non-radiative decay for doubly-excited 4lnl' (n = 4.5) singlet states in Ne8+ are reported. Recent coincidence experiments have been interpreted as showing that for the 414/' states in Ne8+, as well as in the isoelectronic N5+ and O6+ systems, radiation contributes more than 50% to the total decay. The 4l4l' states in Ne8+ are, as in N5+ and O6+, degenerate with the 3ln!' Rydberg states and a considerable mixing exists between the two, which leads to an increase in the radiative decay probability. In the free Ne8+ ion we find that radiative decay accounts for 29% of the total decay for the singlet terms assuming a statistical population distribution. The results vary considerably between terms and the total radiative yield is strongly dependent on the initial population distribution. The branching ratio is similar to the ratio obtained under similar conditions for O6+. The similarity is ascribed to two competing effects: the lowering of the 4/41' states relative to the 3Ini' series with increasing Z, which favours decay through autoionization, and the Z4 behaviour of the radiative decay rates, which has the opposite effect. The free ion results are compared to results including the auto-transfer to Rydberg states (atr) mechanism. In N5+ we have shown that this effect leads to an appreciable reduction in the radiative yield. For Ne8+, the ATR mechanism is less important but we conclude that also here the effect on average is a (small) reduction in radiative yield. This is because the atr mechanism is usually so effective that the 4l4l' population is transferred to low Rydberg states. These autoionize in light ions while they have a larger probability for radiative decay with increasing Z. This seems to account for a large part of the difference between the atr results in N5+ and Ne8+. We report the results of an alternative approach in which part of the collision dynamics is included and we find that the atr model is rather sensitive to a number of parameters, which at the moment are not known very well. For the 4l5l' states, which are located above the N = 3 threshold, radiative decay accounts for 6% of the total decay, much less than for the 4l4l' states, due to the opening of autoionization channels to the N = 3 thresholds for the 4l5l' states. Assuming a statistical population distribution, the theoretical results are in clear disagreement with recent observations for both 4l4l' and 4l5l' manifolds. However, we conclude that it is necessary to obtain a more definite idea about the real population distribution before it is possible to make meaningful comparisons with the observed radiative yields. © 1995 IOP Publishing Ltd.
BibTeX: @article{VanDerHart19955207, author = {Van Der Hart, Hugo W. and Vaeck, Nathalie and Hansen, Jørgen E.}, title = {Radiative stabilization of the doubly-excited 4l4l' and 4l5l' singlet terms in ne8+}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1995}, volume = {28}, number = {24}, pages = {5207 – 5228}, note = {All Open Access, Green Open Access}, doi = {10.1088/0953-4075/28/24/007} }
Xantheas SS and Sutcliffe BT (1995), "The Hamiltonian for a weakly interacting trimer of polyatomic monomers", The Journal of Chemical Physics. Vol. 103(18), pp. 8022 – 8030. [Abstract] [BibTeX] [DOI]
Abstract: The body-fixed Hamiltonian for a trimer of polyatomic monomers is expressed in terms of the distances between the monomer centers of mass and of the orientation angles of the monomers relative to the body-fixed frame. The particular case where the monomers are water molecules is considered in some detail. In this work we attempt to assess the possibility of using a computer algebra system to aid in the evaluation of the angular matrix elements. © 1995 American Institute of Physics.
BibTeX: @article{Xantheas19958022, author = {Xantheas, Sotiris S. and Sutcliffe, Brian T.}, title = {The Hamiltonian for a weakly interacting trimer of polyatomic monomers}, journal = {The Journal of Chemical Physics}, year = {1995}, volume = {103}, number = {18}, pages = {8022 – 8030}, doi = {10.1063/1.470713} }
Auwera JV, Holland J, Jensen P and Johns J (1994), "The ν6 band system of c3o2 near 540 cm-11", Journal of Molecular Spectroscopy. Vol. 163(2), pp. 529 – 540. [Abstract] [BibTeX] [DOI]
Abstract: The infrared spectrum of the ν6 band system of carbon suboxide, C3O2, has been recorded between 500 and 600 cm-1 at a resolution of 0.002 cm-1. Altogether 23 bands have been assigned. They correspond to transitions ν6 + nν7 ← nν7, n ≤ 9, where ν6 is the asymmetric CCO bending mode and ν7 is the very anharmonic CCC bending mode. Among these bands, 20 have been rotationally analyzed and 1220 lines assigned. The line positions were fitted to effective parameters which characterize these 20 vibrational levels in the ν6 state. The results of the fits were then fitted so a semirigid bender model in order to determine the effective CCC bending potential function in the ν6 state. © 1994 Academic Press, Inc.
BibTeX: @article{Auwera1994529, author = {Auwera, J. Vander and Holland, J.K. and Jensen, P. and Johns, J.W.C.}, title = {The ν6 band system of c3o2 near 540 cm-11}, journal = {Journal of Molecular Spectroscopy}, year = {1994}, volume = {163}, number = {2}, pages = {529 – 540}, doi = {10.1006/jmsp.1994.1045} }
Clerbaux C and Colin R (1994), "A reinvestigation of the b3Σ--x3Σ- transition of the so radical", Journal of Molecular Spectroscopy. Vol. 165(2), pp. 334 – 348. [Abstract] [BibTeX] [DOI]
Abstract: The B3Σ--X3Σ- transition of the SO radical has been reinvestigated at high resolution for two isotopomers (32SO16O) and 32SO18O rotational analysis of several bands has led to a reassignment of the branches and to a new set of molecular constants for the v′ = 0 and v′ = 1 levels of the B state. A limiting curve of predissociation of the B3Σ- state by a shallow C3Π state has been obtained, which yields a precise value of the dissociation energy of the X3Σ- state: D″e = 43 680 ± 5 cm-1. Many new rotational perturbations were observed in the B3Σ- state, but a complete understanding of these was not possible. © 1994 Academic Press, Inc.
BibTeX: @article{Clerbaux1994334, author = {Clerbaux, C. and Colin, R.}, title = {A reinvestigation of the b3Σ--x3Σ- transition of the so radical}, journal = {Journal of Molecular Spectroscopy}, year = {1994}, volume = {165}, number = {2}, pages = {334 – 348}, doi = {10.1006/jmsp.1994.1137} }
Clerbaux C and Colin R (1994), "Determination of the infrared cross sections and global warming potentials of 1,1,2‐trifluoroethane (HFC‐143)", Geophysical Research Letters. Vol. 21(22), pp. 2377 – 2380. [Abstract] [BibTeX] [DOI]
Abstract: The Global Warming Potentials (GWPs) of CH2F‐CHF2 (HFC‐143) have been estimated for different time horizons. Radiative forcings associated with this CFC alternative have been derived relative to CFC‐11 and CO2 by introducing laboratory measured absorption cross sections into a coupled chemical‐radiative model. Copyright 1994 by the American Geophysical Union.
BibTeX: @article{Clerbaux19942377, author = {Clerbaux, C. and Colin, R.}, title = {Determination of the infrared cross sections and global warming potentials of 1,1,2‐trifluoroethane (HFC‐143)}, journal = {Geophysical Research Letters}, year = {1994}, volume = {21}, number = {22}, pages = {2377 – 2380}, note = {All Open Access, Green Open Access}, doi = {10.1029/94GL02365} }
Cox H, Smith SJ and Sutcliffe BT (1994), "An application of the computer algebra system Maple for calculations on atomic and molecular systems", Computer Physics Communications. Vol. 84(1-3), pp. 186 – 200. [Abstract] [BibTeX] [DOI]
Abstract: This paper presents a discussion of some programs written in the computer algebra language Maple and in the C language for solving the body-fixed Schrödinger equation for three particles with Coulomb interaction in perimetric coordinates by means of a series solution. © 1994.
BibTeX: @article{Cox1994186, author = {Cox, Hazel and Smith, Stephen J. and Sutcliffe, Brian T.}, title = {An application of the computer algebra system Maple for calculations on atomic and molecular systems}, journal = {Computer Physics Communications}, year = {1994}, volume = {84}, number = {1-3}, pages = {186 – 200}, doi = {10.1016/0010-4655(94)90211-9} }
Cox H, Smith SJ and Sutcliffe BT (1994), "Some calculations on the ground and lowest-triplet state of helium in the fixed-nucleus approximation", Physical Review A. Vol. 49(6), pp. 4520 – 4532. [Abstract] [BibTeX] [DOI]
Abstract: The series solution method developed by Pekeris [Phys. Rev. 112, 1649 (1958); 115, 1216 (1959)] for the Schrödinger equation for two-electron atoms, as generalized by Frost et al. [J. Chem. Phys. 41, 482 (1964)] to handle any three particles with a Coulomb interaction, has been used. The wave function is expanded in triple orthogonal set in three perimetric coordinates. From the Schrödinger equation an explicit recursion relation for the coefficients in the expansion is obtained, and the vanishing of the determinant of these coefficients provides the condition for the energy eigenvalues and for the eigenvectors. The Schrödinger equation is solved and the matrix elements are produced algebraically by using the computer algebra system maple. The substitutions for a particular atom and diagonalization were performed by a program written in the c language. Since the determinant is sparse, it is possible to go to the order of 1078 as Pekeris did without using excessive memory or computer CPU time. By using a nonlinear variational parameter in the expression used to remove the energy, nonrelativistic energies, within the fixed-nucleus approximation, have been obtained. For the ground-state singlet 1 1S state, this is of the accuracy claimed by Frankowski and Pekeris [Phys. Rev. 146, 46 (1966); 150, 366(E) (1966)] using logarithmic terms for Z from 1 to 10, and for the triplet 2 3S state, energies have been obtained to 12 decimal places of accuracy, which, with the exception of Z=2, are lower than any previously published, for all Z from 3 to 10. © 1994 The American Physical Society.
BibTeX: @article{Cox19944520, author = {Cox, Hazel and Smith, Stephen J. and Sutcliffe, Brian T.}, title = {Some calculations on the ground and lowest-triplet state of helium in the fixed-nucleus approximation}, journal = {Physical Review A}, year = {1994}, volume = {49}, number = {6}, pages = {4520 – 4532}, doi = {10.1103/PhysRevA.49.4520} }
Cox H, Smith SJ and Sutcliffe BT (1994), "Some calculations on the ground and lowest-triplet state of the helium isoelectronic sequence with the nucleus in motion", Physical Review A. Vol. 49(6), pp. 4533 – 4539. [Abstract] [BibTeX] [DOI]
Abstract: The method described in the preceding paper for the solution of two-electron atoms, which was used to calculate the 1 1S and 2 3S states of helium and heliumlike atoms within the fixed-nucleus approximation, has been applied to the case where all three particles are in relative motion. The solutions in the present case automatically include the effects of the mass polarization term and are compared with the results obtained for the term by using first-order perturbation theory with the fixed-nucleus wave functions. The input data for a particular atom consist of the atomic number, as before, but now the corresponding mass of the nucleus must be given also. Nonrelativistic energies with the nuclear mass included in the calculation have been obtained for the 1 1S and 2 3S states for Z ranging from 1 to 10. The energy with the nucleus in motion can be expressed only to eight significant figures (SF's) given the accuracy with which the relevant physical constants are known at present. All the results given here are computed as if these constants were known to ten SF's so that errors not incurred due to rounding. Convergence of the energies to ten SF's for both the singlet and triplet state was reached with a matrix of size 444 for Z values from 2 to 10. Convergence for the H- ion was a little slower. © 1994 The American Physical Society.
BibTeX: @article{Cox19944533, author = {Cox, Hazel and Smith, Stephen J. and Sutcliffe, Brian T.}, title = {Some calculations on the ground and lowest-triplet state of the helium isoelectronic sequence with the nucleus in motion}, journal = {Physical Review A}, year = {1994}, volume = {49}, number = {6}, pages = {4533 – 4539}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.49.4533} }
Culot F and Liévin J (1994), "A multiconfigurational SCF computational method for the resolution of the vibrational Schrödinger equation in polyatomic molecules", Theoretica Chimica Acta. Vol. 89(4), pp. 227 – 250. [Abstract] [BibTeX] [DOI]
Abstract: A new variational method for solving the molecular vibration problem is proposed. The so-called VMCSCF method (vibrational multiconfigurational self-consistent field) is based on the super-CI algorithm, previously developed in the framework of electronic ab initio calculations. This approach makes direct use of the generalised Brillouin theorem to ensure self-consistency. The method is dedicated to the study of strongly interacting states (vibrational resonances), which are one of the main sources of perturbation in vibrational spectra. The interest of the method to tackle resonance interactions is illustrated by means of test calculations performed on the water and formaldehyde molecules. © 1994 Springer-Verlag.
BibTeX: @article{Culot1994227, author = {Culot, F. and Liévin, J.}, title = {A multiconfigurational SCF computational method for the resolution of the vibrational Schrödinger equation in polyatomic molecules}, journal = {Theoretica Chimica Acta}, year = {1994}, volume = {89}, number = {4}, pages = {227 – 250}, doi = {10.1007/BF01225116} }
Demeur M, Heenen P-H and Godefroid M (1994), "Hartree-Fock study of molecules in very intense magnetic fields", Physical Review A. Vol. 49(1), pp. 176 – 183. [Abstract] [BibTeX] [DOI]
Abstract: We investigate the stability of homonuclear diatomic molecules from H2 up to C2 and of the finite chains Hn (n≤5) and Hen (n≤4) immersed in very intense magnetic fields (B108 T). The atomic and molecular total energies are calculated within the one-dimensional Hartree-Fock approximation, using a Lagrange basis set associated with a Cartesian mesh. The stability of the molecules decreases beyond Li2 although all the studied molecules are found stable. The energy per atom of H and He finite chains stabilizes already for the small chain sizes that we have investigated. © 1994 The American Physical Society.
BibTeX: @article{Demeur1994176, author = {Demeur, M. and Heenen, P.-H. and Godefroid, M.}, title = {Hartree-Fock study of molecules in very intense magnetic fields}, journal = {Physical Review A}, year = {1994}, volume = {49}, number = {1}, pages = {176 – 183}, doi = {10.1103/PhysRevA.49.176} }
Godefroid M, Judd B and Vaeck N (1994), "Applying the quark model to the atomic d shell", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 27(16), pp. 3635 – 3652. [Abstract] [BibTeX] [DOI]
Abstract: The atomic d shell is explored from the perspective of the quark model of the atom. In this scheme, all the states are generated by four statistically independent fictitious particles (the quarks), each with angular momentum 3/2, augmented by two parity labels. The detailed quark expansions are given for the two 2D terms of d3, and the results are compared to the classic analysis of Condon and Shortley (1935). Matrix elements of single-electron tensor operators and of the Coulomb interaction are calculated in the quark scheme, and the connection to the conventional approach is made. The diagonal sum method of Slater is applied to the quark states and extensions to many-electron operators are discussed. The correspondence between the quark model and the traditional method implies relations between various n-j symbols, and this is illustrated by two special cases. © 1994 IOP Publishing Ltd.
BibTeX: @article{Godefroid19943635, author = {Godefroid, M.R. and Judd, B.R. and Vaeck, N.}, title = {Applying the quark model to the atomic d shell}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1994}, volume = {27}, number = {16}, pages = {3635 – 3652}, doi = {10.1088/0953-4075/27/16/011} }
Henderson JR, Tennyson J and Sutcliffe BT (1994), "The calculation of molecular spectra using finite-element methods", Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties. Vol. 69(5), pp. 1027 – 1036. [Abstract] [BibTeX] [DOI]
Abstract: The body-fixed Hamiltonian for a triatomic molecule as given by Sutcliffe and Tennyson in 1991 had the molecule define the x-z plane. Here the relationship between this Hamiltonian and those in which the molecule defines other planes is exhibited. It is shown that in the Sutcliffe-Tennyson approach the original embedding is preferred. In this embedding the relative effectiveness of the finite- basis representation and the discrete-variable representation as a means of approximate solution are considered for rotationally excited states of water. © 1994 Taylor & Francis Ltd.
BibTeX: @article{Henderson19941027, author = {Henderson, James R. and Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {The calculation of molecular spectra using finite-element methods}, journal = {Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties}, year = {1994}, volume = {69}, number = {5}, pages = {1027 – 1036}, doi = {10.1080/01418639408240171} }
Herman M and Pisarchik A (1994), "Spectroscopy of C2D2 in the 3ν3 Region", Journal of Molecular Spectroscopy. Vol. 164(1), pp. 210 – 218. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of C2D2 in the region of 3νCD is recorded at high resolution using a Fourier transform spectrometer. Sixteen bands have been observed, from which 14 are rotationally analyzed. Absolute intensities are provided for those with an upper state of Σ+u symmetry. Vibrational parameter are obtained for the stretching vibrations. © 1994 Academic Press, Inc.
BibTeX: @article{Herman1994210, author = {Herman, M. and Pisarchik, A.}, title = {Spectroscopy of C2D2 in the 3ν3 Region}, journal = {Journal of Molecular Spectroscopy}, year = {1994}, volume = {164}, number = {1}, pages = {210 – 218}, doi = {10.1006/jmsp.1994.1067} }
Hougen JT, Kleiner I and Godefroid M (1994), "Selection rules and intensity calculations for a cs asymmetric top molecule containing a methyl group internal rotor", Journal of Molecular Spectroscopy. Vol. 163(2), pp. 559 – 586. [Abstract] [BibTeX] [DOI]
Abstract: A detailed discussion is presented of the relationships between four different molecular symmetry groups. i.e. D2, Cs, C3v, and C(m)3v commonly used to discuss energy level symmetry species and electric-dipole selection rules for internal rotor problems in molecules with a symmetric rotor top and a frame with a plane of symmetry. paying particular attention to confusion arising from the fact that the smaller groups are not always subgroups of the larger, and the groups are applied to different parts of the internal rotation problem (i.e., D2 to pure rotation, Cs to vibration-rotation, C3v and C(m) 3v to torsion-rotation). The meaning in this context of the traditional Ka, Kc labels for rotational energy levels in molecules with internal rotation is examined in detail. A discussion is also given of the relationship between three different schemes for defining a molecule-fixed axis system in internal rotation problems. i.e., the principal axis method, the internal axis method, and a hybrid method referred to here as the “rho axis method,” paying particular attention to the meaning of a-type, b-type, and c-type transitions when using each of these axis systems. Some of the above ideas were helpful in adding intensity calculations to our earlier computer program treating internal rotation and overall rotation in acetaldehyde-like molecules, and these intensity calculations are also briefly discussed. © 1994 Academic Press, Inc.
BibTeX: @article{Hougen1994559, author = {Hougen, Jon T. and Kleiner, I. and Godefroid, M.}, title = {Selection rules and intensity calculations for a cs asymmetric top molecule containing a methyl group internal rotor}, journal = {Journal of Molecular Spectroscopy}, year = {1994}, volume = {163}, number = {2}, pages = {559 – 586}, note = {All Open Access, Green Open Access}, doi = {10.1006/jmsp.1994.1047} }
Hurtmans D, Auwera J and Herman M (1994), "The ν1 + ν3 - ν3 hot band of BrNO", Chemical Physics Letters. Vol. 227(6), pp. 588 – 592. [Abstract] [BibTeX] [DOI]
Abstract: A line-removal method is used to artificially retrieve some information on weak overlapped bands in dense high-resolution spectra. This method consists of dividing the data - recorded with a Fourier transform spectrometer - by the computed spectrum of the main overlapping band. It is first demonstrated on N2O. It is then applied to the ν1 + ν3 - ν3 band of BrNO, in the region of the strong ν1 fundamental, leading to the following results: A′=2.82506(3) cm-1, B′=0.12596(2) cm-1 and ν0=1798.622(1) cm-1. © 1994.
BibTeX: @article{Hurtmans1994588, author = {Hurtmans, D. and Auwera, J.Vander and Herman, M.}, title = {The ν1 + ν3 - ν3 hot band of BrNO}, journal = {Chemical Physics Letters}, year = {1994}, volume = {227}, number = {6}, pages = {588 – 592}, doi = {10.1016/0009-2614(94)00869-8} }
Kleiner I and Herman M (1994), "The fundamental ν14 band of acetaldehyde", Journal of Molecular Spectroscopy. Vol. 167(2), pp. 300 – 313. [Abstract] [BibTeX] [DOI]
Abstract: The room temperature absorption spectrum of the ν14 CCH bending fundamental band of acetaldehyde (CH3CHO) has been recorded with a Fourier transform interferometer at a resolution of 0.00186 cm-1. The spectrum exhibits c-type transitions which have been assigned up to values of J′ ≤ 20 and K′a ≤ 9 for the A-type transitions and of J′ ≤ 15 and K′a < 7 for the E-type transitions. All data could not be fitted simultaneously to measurement precision. A partial fit, gathering some 277 lines of A-type and 75 of E-type, could be achieved with a RMS deviation of 0.000594 cm-1, i.e., about twice the measurement precision. © 1994 Academic Press, Inc.
BibTeX: @article{Kleiner1994300, author = {Kleiner, I. and Herman, M.}, title = {The fundamental ν14 band of acetaldehyde}, journal = {Journal of Molecular Spectroscopy}, year = {1994}, volume = {167}, number = {2}, pages = {300 – 313}, doi = {10.1006/jmsp.1994.1237} }
Kou Q, Guelachvili G, Abbouti Temsamani M and Herman M (1994), "The absorption spectrum of C2H2 around v+ vy. energy standards in the 1.5 jj-m region and vibrational clustering", Canadian Journal of Physics. Vol. 72(11-12), pp. 1241 – 1250. [Abstract] [BibTeX] [DOI]
Abstract: We have recorded the Fourier transform absorption spectrum of acetylene, C2H2, at high resolution, around 6500 cm"1. The positions of the strongest rovibrational lines are measured with respect to the rovibrational lines in 3-0 of CO. They provide secondary calibration standards in that range with an accuracy of 3 X 104 cm1. The rotational analysis of the data gives evidence of five vibrational levels of 2+ symmetry, in addition to the bright combination level (1010°0°). This is demonstrated to strictly fit the predicted anharmonic resonance pattern in that region, which permits the vibrational assignment of those extra transitions. Study of the relative intensities of the reported vibrational transitions suggests the need to include new quartic anharmonic couplings. This is supported by the rovibrational analysis of the cold bands around 8500 cm1, involving the (1110°0°) bright level, which is also presented. © 1994 Canadian Science Publishing. All rights reserved.
BibTeX: @article{Kou19941241, author = {Kou, Q. and Guelachvili, G. and Abbouti Temsamani, M. and Herman, M.}, title = {The absorption spectrum of C2H2 around v+ vy. energy standards in the 1.5 jj-m region and vibrational clustering}, journal = {Canadian Journal of Physics}, year = {1994}, volume = {72}, number = {11-12}, pages = {1241 – 1250}, doi = {10.1139/p94-160} }
Perrin A, Flaud J, Camy-Peyret C, Hurtmans D, Herman M and Guelachvili G (1994), "The ν2 + ν3 and ν2 + ν3 - ν2 bands of 14n16o2: Line positions and intensities", Journal of Molecular Spectroscopy. Vol. 168(1), pp. 54 – 66. [Abstract] [BibTeX] [DOI]
Abstract: High-resolution Fourier transform spectra recorded in the 2270-2400 cm-1 and 1520-1600 cm-1 spectral regions have been used to measure, up to very high N values, the positions of lines with Ka = 0-9 of the ν2 + ν3 and ν2 + ν3 - ν2 bands of 14N16O2 as well as their absolute intensities and a self broadening coefficient γ0 = 0.095 ± 0.032 cm-1 atm-1 (at 292 K). The spin-rotation energy levels were very satisfactorily reproduced using a theoretical model which explicitly takes into account both the Coriolis interaction between the spin-rotation levels of the (011) vibrational state and those of (030), and the spin-rotation resonances within (011) and (030). As a consequence, precise vibrational band centers and rotational, spin-rotation, and coupling constants were obtained for the diad (030), (011) of interacting states for 14N16O2. In addition, using a large set of individual ν2 + ν3 line intensities, we have determined precisely the ν2 + ν3 transition moments of 14N16O2. On the other hand, the transition moments of the ν2 + ν3 - ν2 and 3ν2 - ν2 bands were derived from those of the corresponding ν3 and 2ν2 cold bands. Finally, a comprehensive list of line positions and intensities of the interacting ν2 + ν3, 3ν2 and ν2 + ν3 - ν2, 3ν2 - ν2 bands of 14N16O2 has been generated at 4.2 and 6.2 μm, respectively. © 1994 Academic Press, Inc.
BibTeX: @article{Perrin199454, author = {Perrin, A. and Flaud, J.M. and Camy-Peyret, C. and Hurtmans, D. and Herman, M. and Guelachvili, G.}, title = {The ν2 + ν3 and ν2 + ν3 - ν2 bands of 14n16o2: Line positions and intensities}, journal = {Journal of Molecular Spectroscopy}, year = {1994}, volume = {168}, number = {1}, pages = {54 – 66}, doi = {10.1006/jmsp.1994.1259} }
Van der Hart HW, Vaeck N and Hansen J (1994), "Radiative stabilization in double-electron capture to 4l4l' and 4l5l' states in O6+", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 27(15), pp. 3489 – 3514. [Abstract] [BibTeX] [DOI]
Abstract: Following slow collisions between O8+ and Ar, double-electron capture into 4l4l' and 4l5l' states of O6+ has been reported. The experimental results show that in 25% of the events the two electrons are retained on the oxygen presumably due to radiative stabilization. In order to understand this high rate of stabilization, we have calculated for the first time the decay properties of all the 4l4l' and 4l5l' terms in the isolated atom using a truncated diagonalization method with B-spline basis sets. The 4l4l' states are lying in the same range of energy as the higher members of the 3lnl' Rydberg series and we have extended our B-spline approach to represent accurately the 3lnl' states with n up to 50. In this static approach, we obtain 30.8% radiative stabilization for the 4l4l' manifold and 2.6% for the 4l5l' manifold assuming in both cases a statistical population of the states. We conclude that these values, when combined with the experimentally determined initial populations of the two configurations, are too small to explain the experimental features assuming a statistical population distribution and we propose that in order to clarify the situation an experimental and/or theoretical study of the population distribution over the two configurations is necessary. © 1994 IOP Publishing Ltd.
BibTeX: @article{VanderHart19943489, author = {Van der Hart, Hugo W. and Vaeck, Nathalie and Hansen, Jørgen}, title = {Radiative stabilization in double-electron capture to 4l4l' and 4l5l' states in O6+}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1994}, volume = {27}, number = {15}, pages = {3489 – 3514}, doi = {10.1088/0953-4075/27/15/023} }
Biémont E, Hibbert A, Godefroid M and Vaeck N (1993), "New f-values in C I and the CNO abundances in the sun", Astrophysical Journal. Vol. 412(1), pp. 431 – 435. [Abstract] [BibTeX] [DOI]
Abstract: In an attempt to refine our knowledge of the solar abundances of the CNO elements, we discuss in this paper the implications of a new accurate set of oscillator strengths recently calculated in intermediate coupling for the 2p(2Po)nl-2p(2Po)n′l′ E1 transitions of astrophysical interest in C I and also for the forbidden transitions within the 2p2 ground configuration. As with previous analyses devoted to nitrogen and oxygen, configuration interaction effects have been considered in the calculations in a detailed way and empirical adjustments have been introduced in the diagonal Hamiltonian matrix elements in order to improve the agreement between theoretical eigenvalues and experimental energy differences. The new LTE result, based on a sample of 55 E1 transitions observed in the visible and in the near infrared regions, is AC = 8.60 ± 0.03 in the usual logarithmic scale. Taking departures from LTE into account leads, for a sample of 31 weak lines, to a mean result AC = 8.57 ± 0.03 in agreement with recent determinations.
BibTeX: @article{Biémont1993431, author = {Biémont, E. and Hibbert, A. and Godefroid, M. and Vaeck, N.}, title = {New f-values in C I and the CNO abundances in the sun}, journal = {Astrophysical Journal}, year = {1993}, volume = {412}, number = {1}, pages = {431 – 435}, note = {All Open Access, Bronze Open Access}, doi = {10.1086/172932} }
Brage I, Fischer CF and Vaeck N (1993), "Mchf calculations of autoionization widths in two- and three-electron systems", Journal of Physics D: Applied Physics. Vol. 26(4), pp. 621 – 640. [Abstract] [BibTeX] [DOI]
Abstract: We present calculations of autoionization widths using a fully numerical multiconfigurational Hartree-Fock method (mchf). Energy positions and autoionization rates are given for several doubly-excited states lying below the n = 2 threshold in He [and H˜. Particular attention is given to orthogonality considerations in the computation of the autoionization widths. The method is extended to the ls2p2 2D, ls2s(3S)3d 2D and ls2s(3S)4d 2D states of Li 1. To the authors’ knowledge, our MCHF value, 12.5 meV, is the first result obtained for the autoionization width of the ls2s(3S)4d 2D state. Comparison is made with other theoretical results and with experimental values and we point out several inconsistencies between the two sets of results. © 1993 IOP Publishing Ltd.
BibTeX: @article{Brage1993621, author = {Brage, Ibmas and Fischer, Charlotte Froese and Vaeck, Nathalie}, title = {Mchf calculations of autoionization widths in two- and three-electron systems}, journal = {Journal of Physics D: Applied Physics}, year = {1993}, volume = {26}, number = {4}, pages = {621 – 640}, doi = {10.1088/2015000624501X} }
Brage I, Fischer CF and Vaeck N (1993), "Mchf calculations of autoionization widths in two- and three-electron systems", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 26(4), pp. 621 – 640. [Abstract] [BibTeX] [DOI]
Abstract: We present calculations of autoionization widths using a fully numerical multiconfigurational Hartree-Fock method (mchf). Energy positions and autoionization rates are given for several doubly-excited states lying below the n = 2 threshold in He [and H-. Particular attention is given to orthogonality considerations in the computation of the autoionization widths. The method is extended to the ls2p2 2D, ls2s(3S)3d 2D and ls2s(3S)4d 2D states of Li 1. To the authors’ knowledge, our MCHF value, 12.5 meV, is the first result obtained for the autoionization width of the ls2s(3S)4d 2D state. Comparison is made with other theoretical results and with experimental values and we point out several inconsistencies between the two sets of results. © 1993 IOP Publishing Ltd.
BibTeX: @article{Brage1993621, author = {Brage, Ibmas and Fischer, Charlotte Froese and Vaeck, Nathalie}, title = {Mchf calculations of autoionization widths in two- and three-electron systems}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1993}, volume = {26}, number = {4}, pages = {621 – 640}, doi = {10.1088/0953-4075/26/4/006} }
Brage T, Fischer CF, Vaeck N, Godefroid M and Hibbert A (1993), "Core polarization in ca i and ca ii", Physica Scripta. Vol. 48(5), pp. 533 – 545. [Abstract] [BibTeX] [DOI]
Abstract: The effect of core polarization on binding energies, term splitting, fine structure, and transition probabilities is investigated for the low lying states 4s2S, 3d2D, 4p2P° in Ca II and 4s2‘S, 4s4p1'3P° in Ca I. Results from inclusions of core polarization in the form of model potentials are compared with explicit MCHF calculations, and the accuracy of the different approaches is discussed. © 1993 IOP Publishing Ltd.
BibTeX: @article{Brage1993533, author = {Brage, Tomas and Fischer, Charlotte Froese and Vaeck, Nathalie and Godefroid, Michel and Hibbert, Alan}, title = {Core polarization in ca i and ca ii}, journal = {Physica Scripta}, year = {1993}, volume = {48}, number = {5}, pages = {533 – 545}, doi = {10.1088/0031-8949/48/5/006} }
Bramley MJ, Henderson JR, Tennyson J and Sutcliffe BT (1993), "On the Meyer-Botschwina-Burton potential energy surface for H 3 + ", The Journal of Chemical Physics. Vol. 98(12), pp. 10104 – 10105. [BibTeX] [DOI]
BibTeX: @article{Bramley199310104, author = {Bramley, Matthew J. and Henderson, James R. and Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {On the Meyer-Botschwina-Burton potential energy surface for H 3 + }, journal = {The Journal of Chemical Physics}, year = {1993}, volume = {98}, number = {12}, pages = {10104 – 10105}, doi = {10.1063/1.464402} }
Burden FR and Sutcliffe BT (1993), "Three-body calculations in laboratory-fixed hyperspherical coordinates: Convergence properties using numerical wavefunctions as applied to the positronium ion e-3", Molecular Physics. Vol. 80(2), pp. 383 – 389. [Abstract] [BibTeX] [DOI]
Abstract: Non-adiabatic calculations on the positronium ion have been performed using laboratory-fixed hyperspherical coordinates and numerical wavefunctions. Convergence properties show that more than 98% of the true energy can be recovered using modest basis sets by truncating the radial domain and carrying out self-consistent field iterations solely on K = 0 levels. It seems likely that such procedures will enable more complex systems to be studied without recourse to extremely large basis sets. © 1993 Taylor & Francis Group, LLC.
BibTeX: @article{Burden1993383, author = {Burden, Frank R. and Sutcliffe, Brian T.}, title = {Three-body calculations in laboratory-fixed hyperspherical coordinates: Convergence properties using numerical wavefunctions as applied to the positronium ion e-3}, journal = {Molecular Physics}, year = {1993}, volume = {80}, number = {2}, pages = {383 – 389}, doi = {10.1080/00268979300102321} }
Dahl P, Andersen T, Jodal L, Kylstra N, Hansen J and Vaeck N (1993), "Angular distributions in autodetachment from doubly excited O- states", Physical Review A. Vol. 48(4), pp. 2844 – 2849. [Abstract] [BibTeX] [DOI]
Abstract: The angular distributions of electrons ejected from collisionally excited O- ions have been measured in order to test the previous assignments of excited states for this ion. The angular distributions support the interpretation that the two dominant peaks in the electron-energy spectrum represent the autodetachment of the 2p3(2D)3s2 2Do state, decaying to the 3P and 1D states of the oxygen ground-state configuration, with an experimental branching ratio of 1.58±0.08, and not that two different autodetaching states are populated, as previously assumed. Theoretical calculations are in good agreement with the experimental findings. © 1993 The American Physical Society.
BibTeX: @article{Dahl19932844, author = {Dahl, P. and Andersen, T. and Jodal, L. and Kylstra, N.J. and Hansen, J.E. and Vaeck, N.}, title = {Angular distributions in autodetachment from doubly excited O- states}, journal = {Physical Review A}, year = {1993}, volume = {48}, number = {4}, pages = {2844 – 2849}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.48.2844} }
Fischer CF, Smentek-Mielczarek L, Vaeck N and Miecznik G (1993), "A program to compute isotope shifts in atomic spectra", Computer Physics Communications. Vol. 74(3), pp. 415 – 431. [Abstract] [BibTeX] [DOI]
Abstract: The energy of a level of a specific isotope is affected both by the nuclear motion and the nuclear volume. This program treats the resulting energy shift as a small perturbation that can be separated into the normal and specific mass shift and field shift. Given an electronic wave function, generated either by the MCHF program (LS format) or the MCHF_CI (LSJ format), isotope independent parameters are computed and, from these, shifts between isotopes are predicted. © 1993.
BibTeX: @article{Fischer1993415, author = {Fischer, Charlotte Froese and Smentek-Mielczarek, Lidia and Vaeck, Nathalie and Miecznik, Gregory}, title = {A program to compute isotope shifts in atomic spectra}, journal = {Computer Physics Communications}, year = {1993}, volume = {74}, number = {3}, pages = {415 – 431}, doi = {10.1016/0010-4655(93)90023-6} }
Guilmot J, Mélen F and Herman M (1993), "Rovibrational Parameters for cis-Nitrous Acid", Journal of molecular spectroscopy. Vol. 160(2), pp. 401 – 410. [Abstract] [BibTeX] [DOI]
Abstract: We have recorded the spectrum of cis-HONO between 600 and 11 000 cm-1 using various experimental conditions. The full rovibrational analysis of the ν1, ν2, and ν4 bands and the vibrational analysis of the 2ν1, 2ν2, ν1 + ν4, and ν2 + ν4 bands are presented. The results have been combined with previous literature investigations to obtain a set of rovibrational parameters that is as complete as possible. © 1993 Academic Press, Inc.
BibTeX: @article{Guilmot1993401, author = {Guilmot, J.M. and Mélen, F. and Herman, M.}, title = {Rovibrational Parameters for cis-Nitrous Acid}, journal = {Journal of molecular spectroscopy}, year = {1993}, volume = {160}, number = {2}, pages = {401 – 410}, doi = {10.1006/jmsp.1993.1187} }
Guilmot J-M, Godefroid M and Herman M (1993), "Rovibrational Parameters for trans-Nitrous Acid", Journal of molecular spectroscopy. Vol. 160(2), pp. 387 – 400. [Abstract] [BibTeX] [DOI]
Abstract: The Fourier transform absorption spectrum of HONO was recorded at high resolution between 600 and 12 000 cm-1 using various experimental conditions. The results concerning the trans isomer are presented; i.e., the full rovibrational analysis of the ν1, ν2, ν3, ν4, and 2ν1 bands and the vibrational analysis and band contour simulation of the 2ν2, ν1 + ν4, ν1 + ν3, ν1 + 2ν3, and 3ν1 bands have been given. The results are combined with those of previous literature investigations to obtain a complete set of rovibrational parameters, including equilibrium rotational parameters, Ae = 3.122 cm-1, Be = 0.4230 cm-1, and Ce = 0.3724 cm-1. © 1993 Academic Press, Inc.
BibTeX: @article{Guilmot1993387, author = {Guilmot, J.-M. and Godefroid, M. and Herman, M.}, title = {Rovibrational Parameters for trans-Nitrous Acid}, journal = {Journal of molecular spectroscopy}, year = {1993}, volume = {160}, number = {2}, pages = {387 – 400}, doi = {10.1006/jmsp.1993.1186} }
Hansen J, Bentley M, Van Der Hart H, Landtman M, Lister G, Shen Y-T and Vaeck N (1993), "The introduction of b-spline basis sets in atomic structure calculations", Physica Scripta. Vol. 1993(T47), pp. 7 – 17. [Abstract] [BibTeX] [DOI]
Abstract: We review some of the progress which has been achieved in calculations of atomic structure over the last few years, especially connected with the introduction of B-spline basis sets. The most important property of these basis sets is that they are effectively complete even in the case of a rather small set of basis functions. The possibilities for systematic calculations are discussed and applications to configuration interaction calculations as well as to calculations based on many-body perturbation theory are reviewed. © 1993 IOP Publishing Ltd.
BibTeX: @article{Hansen19937, author = {Hansen, J.E. and Bentley, M. and Van Der Hart, H.W. and Landtman, M. and Lister, G.M.S. and Shen, Y.-T. and Vaeck, N.}, title = {The introduction of b-spline basis sets in atomic structure calculations}, journal = {Physica Scripta}, year = {1993}, volume = {1993}, number = {T47}, pages = {7 – 17}, doi = {10.1088/0031-8949/1993/T47/001} }
Henderson JR, Tennyson J and Sutcliffe BT (1993), "All the bound vibrational states of H3 +: A reappraisal", The Journal of Chemical Physics. Vol. 98(9), pp. 7191 – 7203. [Abstract] [BibTeX] [DOI]
Abstract: The 3D discrete variable representation (DVR) calculations of Henderson and Tennyson [Chem. Phys. Lett. 173, 133 (1990)] are reanalyzed to find the source of the nonvariational behavior highlighted by Carter and Meyer [J. Chem. Phys. 96, 2424 (1992)]. The discrepancy is found to be caused not by the use of incorrect boundary conditions, but by a failure of the quadrature approximation commonly used hi DVR calculations. Corrected DVR calculations show variational but slow convergence. Calculations using the same intermediate vectors as the nonvariational calculations and a corrected final Hamiltonian show greatly enhanced convergence. The vibrational band origins computed with this method are converged to within 2 cm-1 up to 35 000 cm-1. A complete list of these is presented and comparisons made with previous predictions. © 1993 American Institute of Physics.
BibTeX: @article{Henderson19937191, author = {Henderson, James R. and Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {All the bound vibrational states of H3 +: A reappraisal}, journal = {The Journal of Chemical Physics}, year = {1993}, volume = {98}, number = {9}, pages = {7191 – 7203}, doi = {10.1063/1.464711} }
Hurtmans D, Herman M and Vander Auwera J (1993), "Integrated band intensities in N2O4 in the infrared range", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 50(6), pp. 595 – 602. [Abstract] [BibTeX] [DOI]
Abstract: We have measured the integrated band intensities of the ν9 and ν11 bands of N2O4 which are observed around 1757 and 1261 cm-1, respectively. By varying temperature and pressure, we have obtained: Sband(ν9) = 9.60(130), 9.10(24), 8.80(66) and Sband(ν11)= 5.93(64), 5.70(21) and 5.33(46) (in 10-17 cm/molecule) at 293.15 (60), 277.25 (60) and 261.65 (60) K, respectively. © 1993.
BibTeX: @article{Hurtmans1993595, author = {Hurtmans, D. and Herman, M. and Vander Auwera, J.}, title = {Integrated band intensities in N2O4 in the infrared range}, journal = {Journal of Quantitative Spectroscopy and Radiative Transfer}, year = {1993}, volume = {50}, number = {6}, pages = {595 – 602}, doi = {10.1016/0022-4073(93)90027-F} }
Judd B, Lister G and Vaeck N (1993), "Overlaps between the irreducible representations of two SO(7) subgroups of SO(8) used in the quark model of the atomic f shell", Journal of Physics A: Mathematical and General. Vol. 26(19), pp. 4991 – 5005. [Abstract] [BibTeX] [DOI]
Abstract: In his studies of f electrons in atoms, Racah introduced the group SO(7) and its subgroup G2, with irreducible representations (irreps) W and U. By using a quarklike basis, these groups can be conveniently embedded in SO(8). This larger group, with irreps V, possesses two other SO(7) groups as subgroups that themselves contain G2 as a common subgroup. One of them, SO(7)' (with irreps W'), has been used to derive new selection rules on operators of physical interest. We describe methods for calculating the overlaps (VWU mod VW' U), the ultimate aim being to facilitate the transformations between SO(7) and SO(7)'. A table of relevant 6-U symbols (the G2 generalizations of 6-j symbols) is given. When V possesses null triality (that is, when the symbols labelling the open ends of the Dynkin diagram for SO(8) are equal), an undetermined phase in the overlaps can be used to generate matrix representations of S3, the permutation group on three objects. A brief table of zero overlaps is given. A remarkable factorization of the overlaps ((4310)W(40) I(4310)W'(40)) is noted, where (4310) is the irrep of SO(8) with dimension 25725.
BibTeX: @article{Judd19934991, author = {Judd, B.R. and Lister, G.M.S. and Vaeck, N.}, title = {Overlaps between the irreducible representations of two SO(7) subgroups of SO(8) used in the quark model of the atomic f shell}, journal = {Journal of Physics A: Mathematical and General}, year = {1993}, volume = {26}, number = {19}, pages = {4991 – 5005}, doi = {10.1088/0305-4470/26/19/028} }
Melen F, Herman M, Matti G and McNaughton D (1993), "Fourier Transform Jet Spectrum of the ν7 Band of C2H6", Journal of molecular spectroscopy. Vol. 160(2), pp. 601 – 603. [BibTeX] [DOI]
BibTeX: @article{Melen1993601, author = {Melen, F. and Herman, M. and Matti, G.Y. and McNaughton, D.M.}, title = {Fourier Transform Jet Spectrum of the ν7 Band of C2H6}, journal = {Journal of molecular spectroscopy}, year = {1993}, volume = {160}, number = {2}, pages = {601 – 603}, doi = {10.1006/jmsp.1993.1208} }
Pisarchik A, Abbouti Temsamani M, Vander Auwera J and Herman M (1993), "The Fourier transform spectrum of the coloured vibrations in mono- and dideuteroacetylene", Chemical Physics Letters. Vol. 206(1-4), pp. 343 – 348. [Abstract] [BibTeX] [DOI]
Abstract: The spectral ranges corresponding to 5vCH and 5vCD were recorded at high resolution in C2HD and C2D2 respectively, using a Fourier transform interferometer. The rovibrational analysis of the bands is presented, as well as the band strengths derived from the absolute rovibrational line intensities. © 1993.
BibTeX: @article{Pisarchik1993343, author = {Pisarchik, A. and Abbouti Temsamani, M. and Vander Auwera, J. and Herman, M.}, title = {The Fourier transform spectrum of the coloured vibrations in mono- and dideuteroacetylene}, journal = {Chemical Physics Letters}, year = {1993}, volume = {206}, number = {1-4}, pages = {343 – 348}, doi = {10.1016/0009-2614(93)85562-3} }
Sundholm D, Olsen J, Godefroid M and Van Meulebeke G (1993), "Core-valence correlation on the low-lying 1,3Fo terms of Ca i", Physical Review A. Vol. 48(5), pp. 3606 – 3610. [Abstract] [BibTeX] [DOI]
Abstract: The excitation energies of the 3d4p 3Fo, 4s4f 3Fo, 3d4p 1Fo, and 4s4f 1Fo states relative to the ground state 4s2 1S and the ground-state ionization potential of neutral calcium (Ca i) are calculated using a finite-element multiconfiguration Hartree-Fock method, through the use of a systematic sequence of active spaces of increasing size. It is confirmed, through large-scale ab initio calculations, that a wrong position of the 3d4p perturber in the 1Fo series, found in valence multiconfiguration Hartree-Fock calculations, is due to the missing core-valence correlation. Some interference effects between core-valence and core-core correlation effects are also analyzed. © 1993 The American Physical Society.
BibTeX: @article{Sundholm19933606, author = {Sundholm, Dage and Olsen, Jeppe and Godefroid, Michel and Van Meulebeke, Guy}, title = {Core-valence correlation on the low-lying 1,3Fo terms of Ca i}, journal = {Physical Review A}, year = {1993}, volume = {48}, number = {5}, pages = {3606 – 3610}, doi = {10.1103/PhysRevA.48.3606} }
Sutcliffe BT (1993), "The coupling of nuclear and electronic motions in molecules", Journal of the Chemical Society, Faraday Transactions. Vol. 89(14), pp. 2321 – 2335. [Abstract] [BibTeX] [DOI]
Abstract: The usual quantum mechanical approach to the separation of electronic and nuclear motions is reformulated in a precise manner and re-examined. The coupling terms between the two kinds of motions prove to be rather elusive and their theoretical status often problematic. The problem areas are identified and suggestions are made about the ways in which the field might in future be developed. This Lennard-Jones memorial lecture was given on 21st September, 1992 at the Quantum Theory Conference in York.
BibTeX: @article{Sutcliffe19932321, author = {Sutcliffe, Brian T.}, title = {The coupling of nuclear and electronic motions in molecules}, journal = {Journal of the Chemical Society, Faraday Transactions}, year = {1993}, volume = {89}, number = {14}, pages = {2321 – 2335}, doi = {10.1039/FT9938902321} }
Temsamani MA, Auwera JV and Herman M (1993), "The absorption spectrum of C2HD between 9 000 and 13 000 cm-1", Molecular Physics. Vol. 79(2), pp. 359 – 371. [Abstract] [BibTeX] [DOI]
Abstract: Twenty-nine bands of the Fourier transform spectrum of C2HD between 9 100 and 12 800 cm-1 are observed at high resolution. Rotational parameters are derived for 25 excited vibrational levels and absolute intensities are determined for 27 of the observed transitions. The vibrational assignments are discussed, as well as the origin of reported rovibrational perturbations. © 1993 Taylor and Francis Ltd.
BibTeX: @article{Temsamani1993359, author = {Temsamani, M. Abbouti and Auwera, J. Vander and Herman, M.}, title = {The absorption spectrum of C2HD between 9 000 and 13 000 cm-1}, journal = {Molecular Physics}, year = {1993}, volume = {79}, number = {2}, pages = {359 – 371}, doi = {10.1080/00268979300101271} }
Vaeck N and Hansen JE (1993), "Comment on ‘stabilization of autoionizing states during ion-atom collisions’", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 26(17), pp. 2977 – 2980. [Abstract] [BibTeX] [DOI]
Abstract: In a recent tetter Bachau, Roncdn and Hare! have proposed an ingenious method based on the PCI effect to obtain stabilization of certain classes of autoionizing states during ion-atom collisions. In this comment we argue that although the effect as such is possible we find several difficulties with its application to cases for which stabilization has been observed. © 1993 IOP Publishing Ltd.
BibTeX: @article{Vaeck19932977, author = {Vaeck, Nathalie and Hansen, JØrgen E.}, title = {Comment on ‘stabilization of autoionizing states during ion-atom collisions’}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1993}, volume = {26}, number = {17}, pages = {2977 – 2980}, doi = {10.1088/0953-4075/26/17/028} }
Vandaele AC, Carleer M, Colin R and Simon PC (1993), "Detection of urban O3, NO2, H2CO, and SO2 using Fourier transform spectroscopy", Proceedings of SPIE - The International Society for Optical Engineering. Vol. 1715, pp. 288 – 292. [Abstract] [BibTeX]
Abstract: Concentrations of SO2, NO2, H2CO, and O3 have been measured regularly since October 1990 at the urban site of the Campus of the Universite Libre de Bruxelles, using the differential optical absorption spectroscopy (DOAS) technique associated with a Fourier Transform Spectrometer. The experimental set up has already been described elsewhere (Vandaele et al., 1992). It consists of a source (either a high pressure xenon lamp or a tungsten filament) and an 800 m long path system. The spectra are recorded in the 26,000 - 38,000 cm-1 and 14,000 - 30,000 cm-1 spectral regions, at the dispersion of 7.7 cm-1. The analytical method of the DOAS technique is based on the fact that in atmospheric measurements, it is impossible to obtain an experimental blank spectrum. Therefore, the Beer-Lambert law has to be rewritten as: I = I′oenΔσd where I is the measured intensity, Io the measured intensity from which all absorption structures have been removed, n the concentration, d the optical path length, and Δσ the differential absorption cross section of the molecule. Numerous methods for determining I′o exist. Fourier transform filtering has been used in this work. This method defines I′o as the inverse Fourier transform of the lower frequencies portion of the power spectrum of the experimental data. A least squares procedure is then applied in order to determine the concentration of the desired molecules.
BibTeX: @conference{Vandaele1993288, author = {Vandaele, Ann Carine and Carleer, M. and Colin, R. and Simon, Paul C.}, title = {Detection of urban O3, NO2, H2CO, and SO2 using Fourier transform spectroscopy}, journal = {Proceedings of SPIE - The International Society for Optical Engineering}, year = {1993}, volume = {1715}, pages = {288 – 292} }
Vanderauwera J, Hurtmans D, Carleer M and Herman M (1993), "The ν3 Fundamental in C2H2", Journal of molecular spectroscopy. Vol. 157(2), pp. 337 – 357. [Abstract] [BibTeX] [DOI]
Abstract: Absolute line positions and intensities are provided for the ν3 fundamental in C2H2 with an accuracy estimated to respectively 6 × 10-4 cm-1 and 0.05 cm-2 atm-1. Unperturbed values are derived for the energy and intensity parameters by treating the Fermi-type resonance and k-doubling effects involved through the interaction with the ν2 + ν4 + ν5 level. The complete set of k-components is included in the procedure. Fitting procedures are carried our on the line energies, the line intensities, and both sets of information simultaneously. The main results are, for the deperturbed values: E(ν3) = 3288.58075(13) cm-1, E(ν2 + ν4 + ν5) = 3296.79650(9)cm-1, k2345 = 25.86749(13) cm-1, and the transition moments Rv(ν3) = ±0.08907(3) D and Rv(ν2 + ν4 + ν5) = ∓2.63(3) × 10-3 D. with the errors (1σ) quoted on the last digits. The mixing between the various levels is quantitatively discussed. © 1993 Academic Press, Inc.
BibTeX: @article{Vanderauwera1993337, author = {Vanderauwera, J. and Hurtmans, D. and Carleer, M. and Herman, M.}, title = {The ν3 Fundamental in C2H2}, journal = {Journal of molecular spectroscopy}, year = {1993}, volume = {157}, number = {2}, pages = {337 – 357}, doi = {10.1006/jmsp.1993.1027} }
Cantarella E, Culott F and Lievin J (1992), "Ab initio calculation of vibrational dipole moment matrix elements.I.methods of calculation and diatomic test systems", Physica Scripta. Vol. 46(6), pp. 489 – 501. [Abstract] [BibTeX] [DOI]
Abstract: This paper is the first part of a series devoted to the ab initio calculation of some vibrational properties helpful in the interpretation of high resolution spectroscopy, atmospherical and astrophysical data.An ab initio method of calculation of the vibrational transition energies and dipole moment matrix elements is described and analyzed.The main features of this method are the resolution of both electronic and vibrational problems by analytical variational techniques and the representation of the potential energy and dipole moment hypersurfaces as Taylor’s series expansions in normal coordinates up to the fourth order.The dipole moment matrix elements are then evaluated by simple analytical formulae.In this first paper, some of the approximations inherent to the methodology are systematically analyzed on the basis of results obtained for diatomic molecules (BeH, HF, NH and NO) with a comparison to experimental and other theoretical results found in the literature.The dependence on the results of the effects of electrical and mechanical anharmonicities, electron correlation and basis set dependencies are investigated.The applicability of the method to small polyatomic systems is discussed in the second paper of this series, on the basis of test calculations on the water molecule. © 1992 IOP Publishing Ltd.
BibTeX: @article{Cantarella1992489, author = {Cantarella, E. and Culott, F. and Lievin, J.}, title = {Ab initio calculation of vibrational dipole moment matrix elements.I.methods of calculation and diatomic test systems}, journal = {Physica Scripta}, year = {1992}, volume = {46}, number = {6}, pages = {489 – 501}, doi = {10.1088/0031-8949/46/6/003} }
Culot F and Lievin J (1992), "Ab initio calculation of vibrational dipole moment matrix elements.Ii.the water molecule as a polyatomic test case", Physica Scripta. Vol. 46(6), pp. 502 – 517. [Abstract] [BibTeX] [DOI]
Abstract: This paper is the second part of a series devoted to the ab initio calculation of vibrational properties, like transition energies, dipole moment matrix elements and infrared intensities.The method of calculation has been detailed in the first paper, where test calculations on diatomic systems were also analyzed.The present paper applies the method to a simple polyatomic system, the water molecule in its ground electronic state.The purely polyatomic features of the method are discussed, as the determination of the potential energy and dipole moment surfaces and the description of vibrational mode couplings.The results concern vibrational energies of levels in the range 0 < v1+ v2+ v3< 3 and vibrational transition moments and intensities of cold and hot bands.Many methodological tests and comparisons to the experimental and theoretical literature are reported, showing that theoretical values of transition energies and dipole moments converge to the experimental ones; at the highest level of approximation (TZ + 2P/SD-CI; vibrational SCF/CI and FCI) the precision obtained is sufficient to provide useful complementary spectroscopical data.This convergence is however not achieved for diagonal dipole moment matrix elements, which are shown to be very sensitive to the mechanical and electrical anharmonicities. © 1992 IOP Publishing Ltd.
BibTeX: @article{Culot1992502, author = {Culot, F. and Lievin, J.}, title = {Ab initio calculation of vibrational dipole moment matrix elements.Ii.the water molecule as a polyatomic test case}, journal = {Physica Scripta}, year = {1992}, volume = {46}, number = {6}, pages = {502 – 517}, doi = {10.1088/0031-8949/46/6/004} }
Hansen JE, Schraa O and Vaeck N (1992), "Calculations of auger energies and autoionisation rates for KLL and LMM transitions involved in the neutralisation of nitrogen ions at surfaces", Physica Scripta. Vol. 1992(T41), pp. 41 – 44. [Abstract] [BibTeX] [DOI]
Abstract: Calculations of KLL and LMM transition energies and autoionisation transition probabilities for KLL transitions are reported for nitrogen ions with different L-shell populations. These quantities are of interest for the understanding of the process of neutralisation of ions at surfaces. A number of experiments have been carried out recently in which KLL and LMM Auger electrons have been observed. The observed energies have been used to obtain information about the number of L (M) electrons present when the KLL (LMM) transitions occur and about the population of the outer shells at this point. The spread in the quantities we report show that only very limited conclusions can be drawn from the observed energies about these two aspects of the neutralisation process. © 1992 IOP Publishing Ltd.
BibTeX: @article{Hansen199241, author = {Hansen, Jergen E. and Schraa, Olaf and Vaeck, Nathalie}, title = {Calculations of auger energies and autoionisation rates for KLL and LMM transitions involved in the neutralisation of nitrogen ions at surfaces}, journal = {Physica Scripta}, year = {1992}, volume = {1992}, number = {T41}, pages = {41 – 44}, doi = {10.1088/0031-8949/1992/T41/007} }
Hassan KH, Hollas J, Vanhorenbeke F and Herman M (1992), "Hybrid character of the 000 band of the S1-S0 269-nm absorption spectrum of 1,2,4-trifluorobenzene by rotational band contour analysis", Journal of Molecular Spectroscopy. Vol. 151(2), pp. 522 – 528. [Abstract] [BibTeX] [DOI]
Abstract: A rotational contour analysis of the 000 band of the 269-nm S1-S0 band system of 1,2,4-trifluorobenzene has been carried out by computer simulation. The band is a type A B hybrid which shows that the electronic transition is of the π*-π type polarized in the plane of the molecule. The fact that there is 75 ± 5% type B character shows that the transition moment is at 60 ± 4° to the a inertial axis, probably inclined toward the fluorine atom in position 4. © 1992.
BibTeX: @article{Hassan1992522, author = {Hassan, Karim H. and Hollas, J.Michael and Vanhorenbeke, Fabienne and Herman, Michel}, title = {Hybrid character of the 000 band of the S1-S0 269-nm absorption spectrum of 1,2,4-trifluorobenzene by rotational band contour analysis}, journal = {Journal of Molecular Spectroscopy}, year = {1992}, volume = {151}, number = {2}, pages = {522 – 528}, doi = {10.1016/0022-2852(92)90584-B} }
Henderson JR, Tennyson J and Sutcliffe BT (1992), "Reply to Comment on: Discrepancies between variationally calculated vibrational energies of H3 + ", Journal of Chemical Physics. Vol. 96(3), pp. 2426 – 2427. [BibTeX] [DOI]
BibTeX: @article{Henderson19922426, author = {Henderson, James R. and Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {Reply to Comment on: Discrepancies between variationally calculated vibrational energies of H3 + }, journal = {Journal of Chemical Physics}, year = {1992}, volume = {96}, number = {3}, pages = {2426 – 2427}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.462045} }
Holland J, Carleer M, Petrisse R and Herman M (1992), "Supersonic molecular jet Fourier transform interferometry applied to nitric oxides", Chemical Physics Letters. Vol. 194(3), pp. 175 – 180. [Abstract] [BibTeX] [DOI]
Abstract: A supersonic molecular jet has been located inside the sample chamber of a Bruker IFS120HR Fourier transform interferometer. Infrared bands of NO, NO2 and N2O4 are presented. Test spectra with CO2 are also discussed. © 1992.
BibTeX: @article{Holland1992175, author = {Holland, J.K. and Carleer, M. and Petrisse, R. and Herman, M.}, title = {Supersonic molecular jet Fourier transform interferometry applied to nitric oxides}, journal = {Chemical Physics Letters}, year = {1992}, volume = {194}, number = {3}, pages = {175 – 180}, doi = {10.1016/0009-2614(92)85530-N} }
Holland J, Newnham D, Mills I and Herman M (1992), "Vibration-rotation spectra of monofluoroacetylene: 1700 to 7500 cm-1", Journal of Molecular Spectroscopy. Vol. 151(2), pp. 346 – 368. [Abstract] [BibTeX] [DOI]
Abstract: High-resolution vibration-rotation spectra of monofluoroacetylene are reported for many bands in the region 1700 to 7500 cm-1. The spectra were observed on Nicolet 7199 and Bruker IFS 120 Fourier spectrometers, with resolutions of about 0.06 and 0.003 cm-1, respectively. About 130 bands have been observed in this region, of which about 80 have been rotationally analyzed. The assignment of vibrational labels to the higher energy levels is complicated by the effects of strong Fermi resonances, and many weak localized rotational resonances are observed. © 1992.
BibTeX: @article{Holland1992346, author = {Holland, J.K. and Newnham, D.A. and Mills, I.M. and Herman, M.}, title = {Vibration-rotation spectra of monofluoroacetylene: 1700 to 7500 cm-1}, journal = {Journal of Molecular Spectroscopy}, year = {1992}, volume = {151}, number = {2}, pages = {346 – 368}, doi = {10.1016/0022-2852(92)90571-5} }
Kleiner I, Hougen J, Suenram R, Lovas F and Godefroid M (1992), "The ground and first torsional states of acetaldehyde", Journal of Molecular Spectroscopy. Vol. 153(1-2), pp. 578 – 586. [Abstract] [BibTeX] [DOI]
Abstract: We have fitted to within experimental accuracy a data set for acetaldehyde consisting of 423 vt = 0 microwave lines, 270 vt = 1 microwave lines, and 214 vt = 1 ← 0 far-infrared lines, using a global model from the earlier literature. The vt = 1 microwave data set was extended and corrected by 76 new measurements from NIST; the theoretical model was extended by inclusion of higher order terms from the literature. The final fit requires only 34 parameters to achieve a unitless weighted standard deviation for the whole fit of 1.15, demonstrating both the power of the model and the internal consistency of the data. © 1992.
BibTeX: @article{Kleiner1992578, author = {Kleiner, I. and Hougen, J.T. and Suenram, R.D. and Lovas, F.J. and Godefroid, M.}, title = {The ground and first torsional states of acetaldehyde}, journal = {Journal of Molecular Spectroscopy}, year = {1992}, volume = {153}, number = {1-2}, pages = {578 – 586}, doi = {10.1016/0022-2852(92)90494-9} }
Lievin J (1992), "Ab initio characterization of the C ̃′1Ag state of the acetylene molecule", Journal of Molecular Spectroscopy. Vol. 156(1), pp. 123 – 146. [Abstract] [BibTeX] [DOI]
Abstract: Ab initio calculations on the few lowest 1Ag states of trans-bent acetylene have been performed at different levels of theory (SCF, CASSCF, SD-CI, and SO-CI) and with basis sets of increasing flexibilities (3-21G + pol, TZ + 2P, TZ + 2P + diff). The results predict the existence of an equilibrium structure (RCC = 1.621 A ̊, RCH = 1.096 A ̊, and θHCC = 104.5°) on the second potential energy surface of 1Ag symmetry, corresponding to the valence configuration 1ag21bu22ag2 2bu23ag23bu 24ag2 arising from a double Π → Π* excitation applied to the ground state configuration. The calculated parameters for this state, labeled C ̃′ (A = 8.71, B = 0.912, C = 0.825 cm-1; ν1 = 3126, ν2 = 934, ν3 = 1386 cm-1; Te = 7.53 eV), strictly confirm the recent findings of UVODR experiments. The analysis of the wavefunctions allows an interpretation of some of the features of this state, namely, its valence nature, its geometry (strong bending and enlarged CC bond), and the occurrence of multiple avoided crossings, leading to a potential energy barrier, along the pathway linking the C ̃′ minimum to the linear ground state geometry. The reason why previous ab initio calculations did not report the existence of this state is also discussed. © 1992.
BibTeX: @article{Lievin1992123, author = {Lievin, Jacques}, title = {Ab initio characterization of the C ̃′1Ag state of the acetylene molecule}, journal = {Journal of Molecular Spectroscopy}, year = {1992}, volume = {156}, number = {1}, pages = {123 – 146}, doi = {10.1016/0022-2852(92)90098-9} }
Mélen F, Carleer M and Herman M (1992), "Fourier transform jet spectrum of the ν9 band of N2O4", Chemical Physics Letters. Vol. 199(1-2), pp. 124 – 130. [Abstract] [BibTeX] [DOI]
Abstract: The rotational structure of the ν9 band of N2O4, recently recorded in a supersonic expansion using a Fourier transform interferometer by Holland, Carleer, Pétrisse and Herman, is analyzed, leading to the spectroscopic determination of rotational parameters for that species. © 1992.
BibTeX: @article{Mélen1992124, author = {Mélen, F. and Carleer, M. and Herman, M.}, title = {Fourier transform jet spectrum of the ν9 band of N2O4}, journal = {Chemical Physics Letters}, year = {1992}, volume = {199}, number = {1-2}, pages = {124 – 130}, doi = {10.1016/0009-2614(92)80058-J} }
Mélen F and Herman M (1992), "Vibrational Bands of HxNyOz Molecules", Journal of Physical and Chemical Reference Data. Vol. 21(4), pp. 831 – 881. [Abstract] [BibTeX] [DOI]
Abstract: A compilation of experimental data is presented which covers all known molecular species fitting the 1Hx14Ny16Oz ( y,z, 0) chemical formula. The vibrational bands of these compounds in gas, liquid, solid, and matrix are listed together with their assignments and the relevant references. Most of the literature before October 1991 is covered. © 1992, American Institute of Physics for the National Institute of Standards and Technology. All rights reserved.
BibTeX: @article{Mélen1992831, author = {Mélen, F. and Herman, M.}, title = {Vibrational Bands of HxNyOz Molecules}, journal = {Journal of Physical and Chemical Reference Data}, year = {1992}, volume = {21}, number = {4}, pages = {831 – 881}, doi = {10.1063/1.555916} }
Mélen F, Pokorni F and Herman M (1992), "Vibrational band analysis of N2O4", Chemical Physics Letters. Vol. 194(3), pp. 181 – 186. [Abstract] [BibTeX] [DOI]
Abstract: The Fourier transform absorption spectrum of N2O4 was recorded in the gas phase at medium resolution between 650 and 7000 cm-1 under various temperature conditions. A complete set of band identifications has been derived. © 1992.
BibTeX: @article{Mélen1992181, author = {Mélen, F. and Pokorni, F. and Herman, M.}, title = {Vibrational band analysis of N2O4}, journal = {Chemical Physics Letters}, year = {1992}, volume = {194}, number = {3}, pages = {181 – 186}, doi = {10.1016/0009-2614(92)85531-E} }
Ruth Le Sueur C, Miller S, Tennyson J and Sutcliffe BT (1992), "On the use of variational wavefunctions in calculating vibrational band intensities", Molecular Physics. Vol. 76(5), pp. 1147 – 1156. [Abstract] [BibTeX] [DOI]
Abstract: It is shown that vibrational band intensities calculated using variational wavefunctions and dipole surfaces give results which depend on how the Cartesian axes of the dipole surface are defined. It is suggested that the most consistent definition of these axes uses the rules proposed by Eckart for separating rovibrational motion. The consequences of this choice of axis system for the calculated band intensities of H2S, LiNC and H3+, and the apparent validity of Hönl-London factors are discussed. Computed band intensities are presented for H2S, HDS and D2S which correct previous literature values. © 1992 Taylor and Francis Group, LLC.
BibTeX: @article{RuthLeSueur19921147, author = {Ruth Le Sueur, C. and Miller, Steven and Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {On the use of variational wavefunctions in calculating vibrational band intensities}, journal = {Molecular Physics}, year = {1992}, volume = {76}, number = {5}, pages = {1147 – 1156}, doi = {10.1080/00268979200101941} }
Sutcliffe B, Smith S and Duffey GH (1992), "Computing the tetrahedral angle [3] (multiple letters)", Journal of Chemical Education. Vol. 69(2), pp. 171. [BibTeX] [DOI]
BibTeX: @article{Sutcliffe1992171, author = {Sutcliffe, B.T. and Smith, S.J. and Duffey, George H.}, title = {Computing the tetrahedral angle [3] (multiple letters)}, journal = {Journal of Chemical Education}, year = {1992}, volume = {69}, number = {2}, pages = {171}, doi = {10.1021/ed069p171.1} }
Sutcliffe BT (1992), "The chemical bond and molecular structure", Journal of Molecular Structure: THEOCHEM. Vol. 259(C), pp. 29 – 58. [Abstract] [BibTeX] [DOI]
Abstract: Since Coulson's Tilden Lecture in 1951 there have been many developments in ideas about the chemical bond and about molecular structure. One aspect of those developments is considered here from a quantum mechanical standpoint. The conclusion reached is one of qualified pessimism about the extent to which it is possible to account for bonding and molecular structure (as perceived by the working chemist) from a quantum mechanical point of view. © 1992.
BibTeX: @article{Sutcliffe199229, author = {Sutcliffe, Brian T.}, title = {The chemical bond and molecular structure}, journal = {Journal of Molecular Structure: THEOCHEM}, year = {1992}, volume = {259}, number = {C}, pages = {29 – 58}, doi = {10.1016/0166-1280(92)87004-J} }
Sutcliffe BT (1992), "The use of perimetric coordinates in the vibration-rotation hamiltonian for triatomic molecules", Molecular Physics. Vol. 75(6), pp. 1233 – 1236. [Abstract] [BibTeX] [DOI]
Abstract: That part of the vibration-rotation Hamiltonian for a triatomic molecule which is independent of the rotational motion, is expressed in generalized distance and generalized perimetric coordinates which, in special cases, are the interparticle coordinates and the standard perimetric coordinates. © 1992 Taylor & Francis Ltd.
BibTeX: @article{Sutcliffe19921233, author = {Sutcliffe, Brian T.}, title = {The use of perimetric coordinates in the vibration-rotation hamiltonian for triatomic molecules}, journal = {Molecular Physics}, year = {1992}, volume = {75}, number = {6}, pages = {1233 – 1236}, doi = {10.1080/00268979200100941} }
Tennyson J and Sutcliffe BT (1992), "Dicretization to avoid singularities in vibration–rotation Hamiltonians: A bisector embedding for AB2 triatomics", International Journal of Quantum Chemistry. Vol. 42(4), pp. 941 – 952. [Abstract] [BibTeX] [DOI]
Abstract: A previously proposed [Sutcliffe and Tennyson, Int. J. Quantum Chem. 29, 183 (1991)] body‐fixed Hamiltonian is applied to AB2 systems in Radau coordinates with the x‐axis embedded along the bisector of the angle. It is shown that by using a discrete variable representation for the angular coordinate it is possible to avoid singular regions of the Hamiltonian. A two‐step variational procedure is used to obtain rotationally excited states of the system. The results of test calculations H2S and D2S with J = 0, 1, 5, and 10 are discussed along with computer‐usage characteristics. Copyright © 1992 John Wiley & Sons, Inc.
BibTeX: @article{Tennyson1992941, author = {Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {Dicretization to avoid singularities in vibration–rotation Hamiltonians: A bisector embedding for AB2 triatomics}, journal = {International Journal of Quantum Chemistry}, year = {1992}, volume = {42}, number = {4}, pages = {941 – 952}, doi = {10.1002/qua.560420429} }
Vaeck N, Godefroid M and Froese Fischer C (1992), "Core-valence correlation effects on E1 and E2 decay rates in Ca+", Physical Review A. Vol. 46(7), pp. 3704 – 3716. [Abstract] [BibTeX] [DOI]
Abstract: Elaborate multiconfiguration Hartree-Fock wave functions have been obtained for the 4s 2S, 3d 2D, and 4p 2P°states in Ca+ in order to investigate the core-valence correlation effects on the transition probabilities of the electric dipole (E1) and quadrupole (E2) processes involving these levels. In parallel, model-potential calculations using a core-polarization potential have been performed. They support the large reduction of the oscillator strengths found in the ab initio approach for both the E1 and E2 processes. The agreement between the two sets of results is satisfactory only if the polarization term is included in the Hartree-Fock variational procedure. The present theoretical 2P°1/2,3/2 lifetime values differ by 3.5% from the most recent fast-beam laser measurements with an estimated single-standard-deviation uncertainty of about 1%. © 1992 The American Physical Society.
BibTeX: @article{Vaeck19923704, author = {Vaeck, N. and Godefroid, M. and Froese Fischer, C.}, title = {Core-valence correlation effects on E1 and E2 decay rates in Ca+}, journal = {Physical Review A}, year = {1992}, volume = {46}, number = {7}, pages = {3704 – 3716}, doi = {10.1103/PhysRevA.46.3704} }
Vaeck N and Hansen JE (1992), "Auger decay of slow highly-ionised ions neutralised at surfaces", Surface Science. Vol. 269-270(C), pp. 596 – 600. [Abstract] [BibTeX] [DOI]
Abstract: We present results of calculations of decay rates for hollow atoms which could be formed when an ion approaches a surface and we discuss the implications of these results for the interpretation of recent experiements concerned with the neutralisation of slow highly charged ions at surfaces. We find that multiply excited states in neutral atoms have lifetimes considerably shorter than those in the corresponding ions and point out that this property can explain the large number of low-energy electrons, which have been observed experimentally. In addition, the lifetimes appear to be of the right order of magnitude to explain the observed time development of the neutralisation process. We consider also the implications for the high-energy spectrum. © 1992.
BibTeX: @article{Vaeck1992596, author = {Vaeck, Nathalie and Hansen, Jørgen E.}, title = {Auger decay of slow highly-ionised ions neutralised at surfaces}, journal = {Surface Science}, year = {1992}, volume = {269-270}, number = {C}, pages = {596 – 600}, doi = {10.1016/0039-6028(92)91316-4} }
Vaeck N and Hansen JE (1992), "Calculations of autoionization rates for double-auger decay of multiply-excited states in nitrogen", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 25(17), pp. 3613 – 3619. [Abstract] [BibTeX] [DOI]
Abstract: We consider the probability for double-Auger decay of multiply-excited states in Nn+ with two Is vacancies. We have calculated the branching ratio R3 between the double-Auger decay filling both holes in the Is shell and the normal Auger decay for initial 2pN, 2s2pN-l and 2s22pN-2 configurations with N = 3, 4, 5 and 6. We show that R3 depends more strongly on the number of 2s electrons than on the total number of electrons in the n = 2 shells. We find that the ‘shake-down’ of a 2s electron due to the non-orthogonality between the initial 2s and the final is electron is the most important effect. Comparison with the result of recent studies of neutralization of slow highly-excited ions at surfaces suggests the presence of one or two 2s electrons in the ion at the time of the double-Auger decay. © 1992 IOP Publishing Ltd.
BibTeX: @article{Vaeck19923613, author = {Vaeck, Nathalie and Hansen, Jørgen E.}, title = {Calculations of autoionization rates for double-auger decay of multiply-excited states in nitrogen}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1992}, volume = {25}, number = {17}, pages = {3613 – 3619}, doi = {10.1088/0953-4075/25/17/013} }
Vaeck N and Hansen JE (1992), "Calculations of Energies, Radiative and Non-Radiative Decay Rates of Triply-Excited States in Li-Like and B-Like Nitrogen", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 25(5), pp. 883 – 905. [Abstract] [BibTeX] [DOI]
Abstract: We report calculations of energies and decay rates for triply-excited 3l3l’3l” configurations in Li-like N, N4+, and in B-like N, N2+, using a configuration interaction approach. Triply-excited configurations can be obtained in charge-exchange experiments and might be important in the process of neutralization of slow highly-ionized ions at surfaces but nearly no spectroscopic information is available for such states. They have found that there is a very strong configuration mixing in these systems which makes it difficult to give single-particle labels to the terms. This suggests that a molecular (collective) description might be useful in analogy with the molecular model of the doubly-excited nlnl’ configurations in He-like spectra. Watanabe and Lin (1987) have considered a molecular description of the 3l3l’3l” configurations in He−. We have considered whether this model is useful in the present case where the nuclear attraction is much stronger compared to the interelectronic repulsion but they do not find any compelling evidence for such a description. One of the motivations for the introduction of the collective model in the case of the doubly-excited states was the large difference between non-radiative decay rates for different states in these systems. However, we have not found evidence from the decay rates in the 3131’31” configurations far a collective behaviour of the atomic shell. The 3131’31” configurations have many levels and can be difficult to resolve experimentally so average values are often more useful for comparison with experiment than rates for individual levels. We show that the average values of the decay rates, calculated assuming that there is no configuration interaction between the 3131’31” configurations, are in very good agreement with the correct average values even though configuration interaction is very strong. Since doublyexcited states of the type 3131’ have a rather long lifetime we have suggested that multiply-excited states might be formed in the neutralization of slow highly-ionized ions at surfaces. We have found that triply-excited states have a considerably shorter lifetime and if additional electrons are added the lifetime seems to be reduced further so that this type of configuration can be responsible for the large number of low-energy electrons which are produced during a neutralization process. © 1992 IOP Publishing Ltd.
BibTeX: @article{Vaeck1992883, author = {Vaeck, Nathalie and Hansen, Jørgen E.}, title = {Calculations of Energies, Radiative and Non-Radiative Decay Rates of Triply-Excited States in Li-Like and B-Like Nitrogen}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1992}, volume = {25}, number = {5}, pages = {883 – 905}, doi = {10.1088/0953-4075/25/5/005} }
Vaeck N and Hansen JE (1992), "Competition between radiative and non-radiative decay processes in triply-excited 3l3l′ nlʺ and doubly-excited 2 lnl′ states in nitrogen ions", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 25(15), pp. 3267 – 3282. [Abstract] [BibTeX] [DOI]
Abstract: Results are presented for radiative and non-radiative decay rates for 3l3l′ nlʺ states in N4+and 2lnlʹ states in N5+in a single configuration as well as in a CI approximation. It is found that while radiative stabilization is negligible for the triply-excited states it is important for the doubly-excited states with n > 6. These results are used to interpret multiple charge-exchange experiments in nitrogen by Benoit-Cattin et al. The reasons for the difference between the doubly-and triply-excited states are discussed. © 1992 IOP Publication Ltd.
BibTeX: @article{Vaeck19923267, author = {Vaeck, Nathalie and Hansen, Jørgen E.}, title = {Competition between radiative and non-radiative decay processes in triply-excited 3l3l′ nlʺ and doubly-excited 2 lnl′ states in nitrogen ions}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1992}, volume = {25}, number = {15}, pages = {3267 – 3282}, doi = {10.1088/0953-4075/25/15/009} }
Vander Auwera J (1992), "High-resolution investigation of the far-infrared spectrum of formic acid", Journal of Molecular Spectroscopy. Vol. 155(1), pp. 136 – 142. [Abstract] [BibTeX] [DOI]
Abstract: We have analyzed the pure rotation spectrum of formic acid, recorded in the far infrared in the range from 20 to 130 cm-1 using a Bruker IFS120HR Fourier transform spectrometer. A list of calculated lines positions from 10 to 100 cm-1 and of corresponding predicted absolute intensities has been created. © 1992.
BibTeX: @article{VanderAuwera1992136, author = {Vander Auwera, J.}, title = {High-resolution investigation of the far-infrared spectrum of formic acid}, journal = {Journal of Molecular Spectroscopy}, year = {1992}, volume = {155}, number = {1}, pages = {136 – 142}, doi = {10.1016/0022-2852(92)90553-Z} }
Aspectt A, Bauchei J, Godefroid M, Grangier P, Hansen J and Vaeck N (1991), "Experimental and mchf isotope shifts of strongly perturbed levels in ca i and sr i", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 24(18), pp. 4077 – 4099. [Abstract] [BibTeX] [DOI]
Abstract: Theoretical and experimental isotope shifts for Ca l and Sr i levels are presented. The isotope shifts of the levels 4s6s1S0 4p2 ‘So and 4p21D2 of calcium have been measured between the isotopes 40, 42, 43, 44 and 48 in two-photon transitions from the Ca ground state using two lasers with different wavelengths. Results of ab inilio mass and field shift calculations are presented for these levels as well as for a number of other strongly perturbed low-lying levels in calcium and strontium using the multiconfigutation Hartree-Fock method. The ‘gradient’ and the alternative ‘Slater’ forms of the specific mass shift operator have been tested; the latter is found to be unreliable with our mchf expansions which are limited to valence correlation effects. The agreement between theory and experiment is systematically better in strontium than in calcium for the specific mass shifts. The ab inilio field shift values agree well with the trend of the observations for both atoms, although they are systematically too small. A semiempirical calibration procedure leads to very good agreement for both atoms. Core-relaxation effects are shown to be large particularly for the mass shift. © 1991 IOP Publishing Ltd.
BibTeX: @article{Aspectt19914077, author = {Aspectt, A. and Bauchei, J. and Godefroid, M. and Grangier, P. and Hansen, J.E. and Vaeck, N.}, title = {Experimental and mchf isotope shifts of strongly perturbed levels in ca i and sr i}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1991}, volume = {24}, number = {18}, pages = {4077 – 4099}, doi = {10.1088/0953-4075/24/18/019} }
Biémont E, Hibbert A, Godefroid M, Vaeck N and Fawcett B (1991), "Accurate oscillator strengths of astrophysical interest for neutral oxygen", Astrophysical Journal. Vol. 375(2), pp. 818 – 822. [Abstract] [BibTeX] [DOI]
Abstract: Knowledge of accurate oscillator strengths in neutral oxygen is of crucial importance in astrophysics. The accurate determination of the solar abundance of O I, which remains the primary source for the entry in cosmic abundance tables, requires the use of E1 transitions appearing in the solar photospheric spectrum. A new accurate scale of oscillator strengths has therefore been obtained for the 2p3(4S)nl-2p3(4S)n′l′ transitions of O I of astrophysical interest. Configuration interaction effects have been considered in a detailed way. The results have been used to improve the solar abundance determination for oxygen. The new result is A(O) = 8.86 ± 0.04 (in the usual logarithmic scale).
BibTeX: @article{Biémont1991818, author = {Biémont, E. and Hibbert, A. and Godefroid, M. and Vaeck, N. and Fawcett, B.C.}, title = {Accurate oscillator strengths of astrophysical interest for neutral oxygen}, journal = {Astrophysical Journal}, year = {1991}, volume = {375}, number = {2}, pages = {818 – 822}, doi = {10.1086/170245} }
Clerbaux C and Colin R (1991), "The 3d rydberg state of the beh molecule", Molecular Physics. Vol. 72(2), pp. 471 – 486. [Abstract] [BibTeX] [DOI]
Abstract: The absorption and the emission spectra of the BeH and BeD molecules in the region of 1850 Å are rotationally analysed. The features observed are shown to correspond to a transition between thèZ+ ground state and a 3d molecular complex that is strongly predissociated by thè C2Z+ state. Rotational constants for the v = 0 and v = 1 levels of the 3d state are derived by matrix X2Σ+diagonalization techniques, assuming interaction with the F(4pσ)2Σ+state. A tentative assignaient of previously observed absorption bands to transitions involving the v = 2 level of the 3d state is given. The 2-0 band of the B2∏-X2Σ++ transition of BeH and BeD is also identified in this region. The predissociation by the C2Σ+state is discussed. © 1991 Taylor & Francis Ltd.
BibTeX: @article{Clerbaux1991471, author = {Clerbaux, C. and Colin, R.}, title = {The 3d rydberg state of the beh molecule}, journal = {Molecular Physics}, year = {1991}, volume = {72}, number = {2}, pages = {471 – 486}, doi = {10.1080/00268979100100361} }
Froese Fischer C and Godefroid MR (1991), "Programs for computing LS and LSJ transitions from MCHF wave functions", Computer Physics Communications. Vol. 64(3), pp. 501 – 519. [Abstract] [BibTeX] [DOI]
Abstract: Given wave-function expansions for the initial and final state along with expressions for the transition matrix elements, the programs evaluate oscillator strengths and transition probabilities. The MCHF_LSTR program assumes wave functions are represented in the non-relativistic formalism and computers E1 and E2 transition data. The MCHF_LSJTR program requires wave-function expansions from a Breit-Pauli CI calculation and evaluates transition data for E1, E2, ..., or M1, M2, ..., transitions between a series of initial and final states. This program could be used for the study of transitions between multiplets. © 1991.
BibTeX: @article{FroeseFischer1991501, author = {Froese Fischer, Charlotte and Godefroid, Michel R.}, title = {Programs for computing LS and LSJ transitions from MCHF wave functions}, journal = {Computer Physics Communications}, year = {1991}, volume = {64}, number = {3}, pages = {501 – 519}, doi = {10.1016/0010-4655(91)90141-7} }
Froese Fischer C, Godefroid MR and Hibbert A (1991), "A program for performing angular integrations for transition operators", Computer Physics Communications. Vol. 64(3), pp. 486 – 500. [Abstract] [BibTeX] [DOI]
Abstract: The MCHF_MLTPOL program performs the angular integrations necessary for expressing the matrix elements of transition operators, E1, E2, ..., or M1, M2, ..., as linear combinations of radial integrals. All matrix elements for transitions between two lists of configuration states will be evaluated. A limited amount of non-orthogonality is allowed between orbitals of the initial and final state. © 1991.
BibTeX: @article{FroeseFischer1991486, author = {Froese Fischer, Charlotte and Godefroid, Michel R. and Hibbert, Alan}, title = {A program for performing angular integrations for transition operators}, journal = {Computer Physics Communications}, year = {1991}, volume = {64}, number = {3}, pages = {486 – 500}, doi = {10.1016/0010-4655(91)90140-G} }
Gaardsted J, Andersent T, Haugen H, Hansen J and Vaeck N (1991), "Multiphoton spectroscopy of doubly excited autoionizing states of ca", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 24(20), pp. 4363 – 4377. [Abstract] [BibTeX] [DOI]
Abstract: The autoionizing spectrum of Ca has been studied in the wavelength ranges of 490-540 nm and 555-590 nm through multiphoton absorption and the subsequent decay to excited Ca+(4p2P3/2, 1/2) states. The fluorescence signal of Ca+(4p) exhibits resonances attributed to the 3d6p and 3dnf (n=4-7) doubly excited autoionizing 3 = 1, 3 states (three-photon absorption) together with resonances due to excited bound states (two- photon absorption) of the neutral atom. Sufficient atomic density was obtained utilizing a vapour in a moderate pressure regime (2-5 mTorr) such that collisional excitation was stilt negligible. The pulsed -8 ns duration (fwhm) laser radiation was used in linear as well as in circular polarization. The observed 3 = 3 states has been interpreted with the help of theoretical results obtained by a configuration interaction approach. © 1991 IOP Publishing Ltd.
BibTeX: @article{Gaardsted19914363, author = {Gaardsted, J.O. and Andersent, T. and Haugen, H.K. and Hansen, J.E. and Vaeck, N.}, title = {Multiphoton spectroscopy of doubly excited autoionizing states of ca}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1991}, volume = {24}, number = {20}, pages = {4363 – 4377}, doi = {10.1088/0953-4075/24/20/008} }
Godefroid M, Lievin J and Metz J (1991), "Symmetry adapted formulation of the generalized Brillouin theorem", International Journal of Quantum Chemistry. Vol. 40(2), pp. 243 – 264. [Abstract] [BibTeX] [DOI]
Abstract: The singly excited functions satisfying Brillouin theorem are expressed as linear combinations of configuration‐state functions for any spin and spatial symmetries (atomic or molecular) and for any reference wave function. The generality of the formulation is ensured by the use of the irreducible tensor method that can be adapted to any symmetry point group of interest. The expansion coefficients are simply written as products of fractional parentage coefficients, spin‐ and orbit‐recoupling coefficients, and phase factors. The formalism is illustrated for some atomic (Kh) and molecular (C∞v, C3v, and Td) configurations. Group theoretical techniques are also used to correlate the Brillouin conditions within a chain of groups. Copyright © 1991 John Wiley & Sons, Inc.
BibTeX: @article{Godefroid1991243, author = {Godefroid, M. and Lievin, J. and Metz, J.‐Y.}, title = {Symmetry adapted formulation of the generalized Brillouin theorem}, journal = {International Journal of Quantum Chemistry}, year = {1991}, volume = {40}, number = {2}, pages = {243 – 264}, doi = {10.1002/qua.560400207} }
Hansen J, van der Hart H, Landtman M, Shen Y-T and Vaeck N (1991), "Calculations for doubly-excited states populated in two-electron processes", Zeitschrift für Physik D Atoms, Molecules and Clusters. Vol. 21(1 Supplement), pp. S87–S91. [Abstract] [BibTeX] [DOI]
Abstract: Recent calculations of doubly-excited states for two and four-electron states in neutral atoms and ions are described. In particular the radiative properties of these states are considered. It is pointed out that some of these states live so long that triply-excited states perhaps can be formed in neutralisation processes at surfaces. © 1991 Springer-Verlag.
BibTeX: @article{Hansen1991S87, author = {Hansen, J.E. and van der Hart, H. and Landtman, M. and Shen, Y.-T. and Vaeck, N.}, title = {Calculations for doubly-excited states populated in two-electron processes}, journal = {Zeitschrift für Physik D Atoms, Molecules and Clusters}, year = {1991}, volume = {21}, number = {1 Supplement}, pages = {S87–S91}, doi = {10.1007/BF01426256} }
Herman M, Abbouti Temsamani M, Lemaitre D and Vander Auwera J (1991), "The Fourier-transform vibrational spectrum of acetylene in the visible range", Chemical Physics Letters. Vol. 185(3-4), pp. 220 – 224. [Abstract] [BibTeX] [DOI]
Abstract: We have used a Fourier-transform spectrometer to record the pure vibrational absorption spectra of C2H2 at high resolution in the visible range, up to 21000 cm-1. The various observed bands are collected and some of the involved upper vibrational levels, reported for the first time, are characterised by rovibrational parameters. © 1991.
BibTeX: @article{Herman1991220, author = {Herman, M. and Abbouti Temsamani, M. and Lemaitre, D. and Vander Auwera, J.}, title = {The Fourier-transform vibrational spectrum of acetylene in the visible range}, journal = {Chemical Physics Letters}, year = {1991}, volume = {185}, number = {3-4}, pages = {220 – 224}, doi = {10.1016/S0009-2614(91)85051-W} }
Herman M, Abbouti Temsamani M, Vander Auwera J and Ottinger R (1991), "Near-infrared absorption spectroscopy: the n = 4 polyad of C2HD", Chemical Physics Letters. Vol. 185(3-4), pp. 215 – 219. [Abstract] [BibTeX] [DOI]
Abstract: We report the observation of absorption bands of C2HD in the near-infrared range leading to four out of five vibrational levels of the n = 4 polyad. Rovibrational parameters and absolute band strengths are obtained. © 1991.
BibTeX: @article{Herman1991215, author = {Herman, M. and Abbouti Temsamani, M. and Vander Auwera, J. and Ottinger, R.}, title = {Near-infrared absorption spectroscopy: the n = 4 polyad of C2HD}, journal = {Chemical Physics Letters}, year = {1991}, volume = {185}, number = {3-4}, pages = {215 – 219}, doi = {10.1016/S0009-2614(91)85050-7} }
Herman M, Huet T, Kabbadj Y and Auwera JV (1991), "L-type resonances in C2H2", Molecular Physics. Vol. 72(1), pp. 75 – 88. [Abstract] [BibTeX] [DOI]
Abstract: A full Hamiltonian matrix coherent with a phase convention leading to e/f labellings and to positive l-doubling q parameters is constructed to describe the rovibrational energy levels in a linear polyatomic molecule with two bending vibrations. This model is used to investigate quantitatively the effect of the rotational and vibrational l resonances on level mixings and intensity features in C2H2. © 1991 Taylor & Francis Group, LLC.
BibTeX: @article{Herman199175, author = {Herman, M. and Huet, T.R. and Kabbadj, Y. and Auwera, J. Vander}, title = {L-type resonances in C2H2}, journal = {Molecular Physics}, year = {1991}, volume = {72}, number = {1}, pages = {75 – 88}, doi = {10.1080/00268979100100031} }
Herman M, Hurtmans D, Vander Auwera J and Vervloet M (1991), "Lack of intensity alternation in C2H2", Journal of Molecular Spectroscopy. Vol. 150(1), pp. 293 – 295. [BibTeX] [DOI]
BibTeX: @article{Herman1991293, author = {Herman, M. and Hurtmans, D. and Vander Auwera, J. and Vervloet, M.}, title = {Lack of intensity alternation in C2H2}, journal = {Journal of Molecular Spectroscopy}, year = {1991}, volume = {150}, number = {1}, pages = {293 – 295}, doi = {10.1016/0022-2852(91)90215-V} }
Hibbertt A, Biémont E, Godefroid M and Vaeck N (1991), "El transitions of astrophysical interest in neutral oxygen", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 24(18), pp. 3943 – 3958. [Abstract] [BibTeX] [DOI]
Abstract: Atomic transition rates and f values have been calculated in the triplet and quintet systems and for some intercombination lines of neutral oxygen. Configuration interaction was included in tbs calculations performed with the CiV3 code of Hibbcrt for all the transitions connecting the n =3 and n =4 energy levels. In order to reproduce the observed energy splittings between the energy states, small empirical adjustments were introduced to the diagonal matrix elements. Comparisons with previously published f values and radiative lifetimes are discussed and the subsequent astrophysical applications of the results are briefly mentioned. © 1991 IOP Publishing Ltd.
BibTeX: @article{Hibbertt19913943, author = {Hibbertt, A. and Biémont, E. and Godefroid, M. and Vaeck, N.}, title = {El transitions of astrophysical interest in neutral oxygen}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1991}, volume = {24}, number = {18}, pages = {3943 – 3958}, doi = {10.1088/0953-4075/24/18/010} }
Huet T, Herman M and Johns J (1991), "The bending vibrational levels in C2D2 (X̃ 1Σg+)", The Journal of Chemical Physics. Vol. 94(5), pp. 3407 – 3414. [Abstract] [BibTeX] [DOI]
Abstract: Improved sets of data have been recorded and analyzed in order to study the bending rovibrational energy levels of C2D2, in the regions of the ν5-ν4 difference band (FIR) and of the ν5 fundamental band (IR). A matrix model is setup to deal with a Darling-Dennison coupling between sets of bending levels as well as with the usual l-type resonances. A simultaneous fit of the new data together with earlier microwave measurements produces an extended set of very accurate parameters, including for the first time in C2D2 s 45 and qtk. © 1991 American Institute of Physics.
BibTeX: @article{Huet19913407, author = {Huet, T.R. and Herman, M. and Johns, J.W.C.}, title = {The bending vibrational levels in C2D2 (X̃ 1Σg+)}, journal = {The Journal of Chemical Physics}, year = {1991}, volume = {94}, number = {5}, pages = {3407 – 3414}, doi = {10.1063/1.459763} }
Kabbadj Y, Herman M, Di Lonardo G, Fusina L and Johns J (1991), "The bending energy levels of C2H2", Journal of Molecular Spectroscopy. Vol. 150(2), pp. 535 – 565. [Abstract] [BibTeX] [DOI]
Abstract: Absorption spectra of C2H2 have been recorded between 50 and 1450 cm-1, with a resolution always better than 0.005 cm-1, using two different Fourier transform spectrometers. Analysis of the data provided two sets of results. First, the bending levels with Σt Vt(t = 4, 5) ≤ 2 were characterized by a coherent set of 34 parameters derived from the simultaneous analysis of 15 bands, performed using a matrix Hamiltonian. The following main parameters were obtained (in cm-1): ω40 = 608.985196(14), ω50 = 729.157564(10); B0 = 1.17664632(18), α4 = -1.353535(86) × 10-3, α5 = -2.232075(40) × 10-3; q40 = 5.24858(12) × 10-3, and q50 = 4.66044(12) × 10-3, with the errors (1σ) on the last quoted digit. Second, a more complete set of bending levels with Σt Vt ≤ 4, some of which have never previously been reported, and also including V2 = 1 have been fitted to 80 parameters. This simultaneous fit involved 43 bands and used the same full Hamiltonian matrix. Some perturbations which affect the higher excited levels are discussed. © 1991.
BibTeX: @article{Kabbadj1991535, author = {Kabbadj, Y. and Herman, M. and Di Lonardo, G. and Fusina, L. and Johns, J.W.C.}, title = {The bending energy levels of C2H2}, journal = {Journal of Molecular Spectroscopy}, year = {1991}, volume = {150}, number = {2}, pages = {535 – 565}, doi = {10.1016/0022-2852(91)90248-9} }
Kleiner I, Guilmot J, Carleer M and Herman M (1991), "The ν4 fundamental bands of trans- and cis-HNO2", Journal of Molecular Spectroscopy. Vol. 149(2), pp. 341 – 347. [Abstract] [BibTeX] [DOI]
Abstract: The spectra of trans- and cis-HNO2 have been recorded at an apodized resolution of 1.86 × 10-3 cm-1 in the region of 600 to 1000 cm-1. Some 1950 lines of a-type are assigned to the ν4 fundamental band of trans-HNO2 and over 3100 lines of a- and of b-types to the ν4 fundamental band of cis-HNO2. Relative intensity information is discussed. © 1991.
BibTeX: @article{Kleiner1991341, author = {Kleiner, I. and Guilmot, J.M. and Carleer, M. and Herman, M.}, title = {The ν4 fundamental bands of trans- and cis-HNO2}, journal = {Journal of Molecular Spectroscopy}, year = {1991}, volume = {149}, number = {2}, pages = {341 – 347}, doi = {10.1016/0022-2852(91)90290-Q} }
Kleiner I, Hougen J, Suenram R, Lovas F and Godefroid M (1991), "The ground torsional state of acetaldehyde", Journal of Molecular Spectroscopy. Vol. 148(1), pp. 38 – 49. [Abstract] [BibTeX] [DOI]
Abstract: New microwave measurements on the ground state of acetaldehyde have been carried out using a Fourier transform spectrometer in the region from 7 to 26 GHz (typical measurement uncertainty 4 kHz), and a conventional Stark spectrometer in the region from 45 to 116 GHz (typical measurement uncertainty 40 kHz). These new ground state measurements and remeasurements have permitted a much better fit to two theoretical models of a data set containing far-infrared combination differences from the literature, microwave transitions from the literature, and the new microwave transitions. Root-mean-square residuals obtained here for all these data (which come from a large number of sources) are only slightly larger (for either model) than the estimated measurement uncertainties. The first theoretical model is essentially a high-barrier effective Hamiltonian for one vibrational state only, based on Fourier expansions in terms of the form cos( 2πn 3)(ρK - σ). The second model is based on calculation using the internal-rotation potential function, and is in principle much more powerful than the first. The present successful fits using either model indicate that earlier fitting difficulties using the second model and a combined infrared and microwave data set were caused by problems in the microwave data set, rather than problems in the model. It is hoped that similar success can be achieved with the more powerful second model when data from higher excited torsional states are considered. © 1991.
BibTeX: @article{Kleiner199138, author = {Kleiner, I and Hougen, J.T and Suenram, R.D and Lovas, F.J and Godefroid, M}, title = {The ground torsional state of acetaldehyde}, journal = {Journal of Molecular Spectroscopy}, year = {1991}, volume = {148}, number = {1}, pages = {38 – 49}, doi = {10.1016/0022-2852(91)90032-6} }
Ramsay D, Vervloet M, Vanhorenbeke F, Godefroid M and Herman M (1991), "Rotational analysis of the 0-0 band of the a ̃3Au- X ̃1Ag system of trans-glyoxal", Journal of Molecular Spectroscopy. Vol. 149(2), pp. 348 – 355. [Abstract] [BibTeX] [DOI]
Abstract: The 0-0 band of the a ̃3Au- X ̃1Ag system of trans-glyoxal has been recorded in absorption using a Bomem DA3.002 Fourier-transform spectrometer. Rotational analysis reveals that the dominant structure consists of branches obeying the selection rules ΔJ = 0, ±1, ΔN = 0, ±1, ±2, and ΔKa = 0. The following molecular constants were obtained for the excited state (in cm-1): A = 1.9681(7), B = 0.15699(3), C = 0.14543(4), a0 = 0.025(3), a = -0.008(3), α = -0.08(3), T0 = 19 198.63(2), where the error limits are 3σ. © 1991.
BibTeX: @article{Ramsay1991348, author = {Ramsay, D.A and Vervloet, M and Vanhorenbeke, F and Godefroid, M and Herman, M}, title = {Rotational analysis of the 0-0 band of the a ̃3Au- X ̃1Ag system of trans-glyoxal}, journal = {Journal of Molecular Spectroscopy}, year = {1991}, volume = {149}, number = {2}, pages = {348 – 355}, doi = {10.1016/0022-2852(91)90291-H} }
Sutcliffe BT and Tennyson J (1991), "A general treatment of vibration‐rotation coordinates for triatomic molecules", International Journal of Quantum Chemistry. Vol. 39(2), pp. 183 – 196. [Abstract] [BibTeX] [DOI]
Abstract: An exact, within the Born–Oppenheimer approximation, body‐fixed Hamiltonian for the nuclear motions of a triatomic system is presented. This Hamiltonian is expressed in terms of two arbitrarily defined internal distances and the angle between them. The body‐fixed axis system is related to these coordinates in a general fashion. Problems with singularities and the domain of the Hamiltonian are discussed using specific examples of axis embedding. A number of commonly used coordinate systems including Jacobi, bond‐length‐bond‐angle, and Radau coordinates are special cases of this Hamiltonian. Sample calculations on the H2S molecule are presented using all these and other coordinate systems. The possibility of using this Hamiltonian for reactive scattering calculations is also discussed. Copyright © 1991 John Wiley & Sons, Inc.
BibTeX: @article{Sutcliffe1991183, author = {Sutcliffe, Brian T. and Tennyson, Jonathan}, title = {A general treatment of vibration‐rotation coordinates for triatomic molecules}, journal = {International Journal of Quantum Chemistry}, year = {1991}, volume = {39}, number = {2}, pages = {183 – 196}, doi = {10.1002/qua.560390208} }
Vaeck N, Godefroid M and Hansen J (1991), "Mchf oscillator strength and lifetime calculations in neutral calcium", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 24(2), pp. 361 – 381. [Abstract] [BibTeX] [DOI]
Abstract: We report extensive multiconfiguration Hartree-Fock (MCHF) calculations, taking into account valence correlation and core-relaxation effects, of energy levels, eigenvector compositions, electric dipole and quadrupole oscillator strengths involving the nS (n = 1-4), n1P° (n = 1, 2), n1D (n = 1—3) and n1F° (n = 1, 2) states in Ca I. On the whole, the agreement between theory and observation has been improved by our set of MCHF results. The theoretical transition probabilities allow the evaluation of the lifetimes for the levels 4s4p, 4s5p IP°; 4s4d, 4p2 D and 3d4p, 4s4f 1F° which are compared with the most recent measurements. The differences between MCHF calculations for series perturbed by doubly-exdted states in Ca and Sr are discussed. It is concluded that core-polarization effects are of about the same importance in the two atoms but that the effects on the 3d (Ca) and 4d (Sr) orbitals are such that the total core-polarization effects for series and perturbers are of the same magnitude in Sr while large differences exist in Ca. © 1991 IOP Publishing Ltd.
BibTeX: @article{Vaeck1991361, author = {Vaeck, N. and Godefroid, M. and Hansen, J.E.}, title = {Mchf oscillator strength and lifetime calculations in neutral calcium}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1991}, volume = {24}, number = {2}, pages = {361 – 381}, doi = {10.1088/0953-4075/24/2/006} }
Vaeck N and Hansen J (1991), "Calculations of decay rates for triply-excited states in N2+", Zeitschrift für Physik D Atoms, Molecules and Clusters. Vol. 21(1 Supplement), pp. S221–S223. [Abstract] [BibTeX] [DOI]
Abstract: We report here calculations of energy level values and autoionization decay rates for all the terms belonging to the 1s23 l3 l'3 l'' configuration in N2+. Comparison are made with previous calculations for 1s23 l3 l' terms in N3+. The properties of the triply-excited states and in particular the fast autoionization decay rates found in the present calculations can perhaps help in understanding the mechanism responsible for neutralisation of ions at surfaces. © 1991 Springer-Verlag.
BibTeX: @article{Vaeck1991S221, author = {Vaeck, N. and Hansen, J.E.}, title = {Calculations of decay rates for triply-excited states in N2+}, journal = {Zeitschrift für Physik D Atoms, Molecules and Clusters}, year = {1991}, volume = {21}, number = {1 Supplement}, pages = {S221–S223}, doi = {10.1007/BF01426298} }
Vaeck N and Hansen JE (1991), "Lifetimes of multiply-excited states in nitrogen", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 24(19), pp. L469 – L475. [Abstract] [BibTeX] [DOI]
Abstract: It has been observed experimentally that slow highly-ionized atoms are already neutralized on impact with a metal surface due to the strong potential which can 'puli’ electrons out of the surface into high-lying multiply-excited atomic states. We present quantitative results for decay rates of such multiply-excited states and show that the lifetimes for such states, when the electrons have large values of n, appear to be significantly different in neutral atoms and in the corresponding ions. © 1991 IOP Publishing Ltd.
BibTeX: @article{Vaeck1991L469, author = {Vaeck, Nathalie and Hansen, Jørgen E.}, title = {Lifetimes of multiply-excited states in nitrogen}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1991}, volume = {24}, number = {19}, pages = {L469 – L475}, doi = {10.1088/0953-4075/24/19/001} }
Vander Auwera J, Huet T, Temsamani M and Herman M (1991), "Rotational parameters for acetylene C2HD in the A ̃1A″ electronic state", Journal of Molecular Spectroscopy. Vol. 148(1), pp. 93 – 99. [Abstract] [BibTeX] [DOI]
Abstract: The rotational analysis of the conventional absorption spectrum of C2HD was attempted between 42 600 and 47 000 cm-1. Despite a very high spectral line density, rotational parameters could be obtained for the nν′3 (n = 1, 2, 4), ν′2 + nν′3 (n = 2, 3), ν′6 + nν′3 (n = 1-3) vibrational levels of the A ̃1A″ electronic state. © 1991.
BibTeX: @article{VanderAuwera199193, author = {Vander Auwera, J and Huet, T.R and Temsamani, M.Abbouti and Herman, M}, title = {Rotational parameters for acetylene C2HD in the A ̃1A″ electronic state}, journal = {Journal of Molecular Spectroscopy}, year = {1991}, volume = {148}, number = {1}, pages = {93 – 99}, doi = {10.1016/0022-2852(91)90038-C} }
Vander Auwera J, Johns J and Polyansky O (1991), "The far infrared spectrum of C3O2", The Journal of Chemical Physics. Vol. 95(4), pp. 2299 – 2316. [Abstract] [BibTeX] [DOI]
Abstract: The far infrared spectrum of carbon suboxide, 12C 316O2, has been recorded at a resolution of 0.003 cm-1 in the region from 15 to 130 cm-1 with a Bomem interferometer. Altogether 18 bands involving the excitation of up to 8 quanta in the low frequency quasilinear bending mode v7 were analyzed rotationally. A total of 1320 far infrared lines together with 231 microwave lines taken from Karyakin et al. [J. Mol. Spectrosc. 94, 283 (1982)] have been fitted to an effective model. Improved effective constants have been obtained for all the l sublevels of v7=0 to 4 and for l=1 of v7=5. Constants have been obtained for the first time for the levels 53 and 55 and some of the l sublevels of v7=6, 7, and 8. Data for the lower lying levels were fitted to a realistic linear model and some data were also fitted to a bent model. © 1991 American Institute of Physics.
BibTeX: @article{VanderAuwera19912299, author = {Vander Auwera, J. and Johns, J.W.C. and Polyansky, O.L.}, title = {The far infrared spectrum of C3O2}, journal = {The Journal of Chemical Physics}, year = {1991}, volume = {95}, number = {4}, pages = {2299 – 2316}, doi = {10.1063/1.460938} }
Guilmot J, Carleer M, Godefroid M and Herman M (1990), "The ν1 fundamental band of trans-HNO2", Journal of Molecular Spectroscopy. Vol. 143(1), pp. 81 – 90. [Abstract] [BibTeX] [DOI]
Abstract: The spectrum of trans-nitrous acid has been recorded at a resolution of about 2.5 × 10-3 cm-1 in the region from 3200 to 3800 cm-1. Over 500 lines are assigned to the ν1 fundamental band (OH stretching). Rovibrational constants are obtained for ν1. Systematic perturbations affecting some of the levels are attributed to a b-type Coriolis interaction involving the 2ν3 + ν5 + ν6 level. © 1990.
BibTeX: @article{Guilmot199081, author = {Guilmot, J.M. and Carleer, M. and Godefroid, M. and Herman, M.}, title = {The ν1 fundamental band of trans-HNO2}, journal = {Journal of Molecular Spectroscopy}, year = {1990}, volume = {143}, number = {1}, pages = {81 – 90}, doi = {10.1016/0022-2852(90)90262-O} }
Huet T, Godefroid M and Herman M (1990), "The A ̃ electronic state of acetylene: Geometry and axis-switching effects", Journal of Molecular Spectroscopy. Vol. 144(1), pp. 32 – 44. [Abstract] [BibTeX] [DOI]
Abstract: The geometrical parameters concerning acetylene in the A ̃ state are derived: rCC = 1.375 A ̊, rCH = 1.097 A ̊, and HCH = 122.48°. New rovibrational parameters of acetylene in the A ̃ state are provided or predicted. Axis-switching intensities are discussed on the basis of an extended formulation using the tensor algebra. © 1990.
BibTeX: @article{Huet199032, author = {Huet, T.R and Godefroid, M and Herman, M}, title = {The A ̃ electronic state of acetylene: Geometry and axis-switching effects}, journal = {Journal of Molecular Spectroscopy}, year = {1990}, volume = {144}, number = {1}, pages = {32 – 44}, doi = {10.1016/0022-2852(90)90306-B} }
Johns J and Auwera J (1990), "Absolute intensities in CO2: The ν2 fundamental near 15 μm", Journal of Molecular Spectroscopy. Vol. 140(1), pp. 71 – 102. [Abstract] [BibTeX] [DOI]
Abstract: About 925 absolute intensities have been measured in 18 bands of CO2 in the region of the ν2 fundamental near 15 μm. In addition to the band intensities many Herman-Wallis factors have also been determined. The results for the fundamental and the three strongest hot bands of the main isotope are summarized below: v2 \|R\|2 = 0.03294(5)[1+0.00096(2)m]2 (P,R)v1(l=0)-v2 \|R\|2 = 0.01505(4)[1+0.00107(7)m]2 (P,R)= 0.01505(4)[1+0.000022(2)J(J+1)]2 (Q)2v2(l=2)-v2 \|R\|2 = 0.0641(1)[1+0.00096(3)m]2 (P,R)2v2(l=0)-v2 \|R\|2 = 0.01722(3)[1+0.00096(5)m]2 (P,R)= 0.01721(3)[1+0.000031(2)J(J+1)]2 (Q). © 1990.
BibTeX: @article{Johns199071, author = {Johns, J.W.C. and Auwera, J.Vander}, title = {Absolute intensities in CO2: The ν2 fundamental near 15 μm}, journal = {Journal of Molecular Spectroscopy}, year = {1990}, volume = {140}, number = {1}, pages = {71 – 102}, doi = {10.1016/0022-2852(90)90008-E} }
Kleiner I, Godefroid M, Herman M and McKellar A (1990), "The fundamental torsion band in acetaldehyde", Journal of Molecular Spectroscopy. Vol. 142(2), pp. 238 – 253. [Abstract] [BibTeX] [DOI]
Abstract: High-resolution spectroscopy and low-temperature experimental conditions allowed us to carry out the rotational analysis of the ν15 fundamental band of acetaldehyde, observed around 150 cm-1. Some 1000 lines of A and E types have been assigned to the main band and some 90 A-type lines have been identified in the first overtone of the torsion mode. A simultaneous fit, using the nonrigid internal axis method, of a very severely selected set of unblended FIR data from the fundamental band (214 lines with J ≤ 10 and K <- 9), together with microwave data published in the literature, allowed us to obtain accurate molecular parameters describing describing internal and overall rotation in acetaldehyde. In particular, the Fourier coefficients V3 and V6 of the barrier for internal rotation as well as the rotationless origins of the ν15 fundamental band and its first overtone were determined with improved accuracy, compared to the data previously available in the literature. Some difficulties in treating vt = 1 microwave data led us to suspect problems in the theoretical model adopted or in the present vt = 1 microwave data set. Finally, a fit of selected unblended data from the first overtone of the torsion (29 A-type lines), together with the previously mentioned selected unblended data from the fundamental band, was carried out but resulted in a standard deviation somewhat higher than was obtained with the fundamental band alone. © 1990.
BibTeX: @article{Kleiner1990238, author = {Kleiner, I. and Godefroid, M. and Herman, M. and McKellar, A.R.W.}, title = {The fundamental torsion band in acetaldehyde}, journal = {Journal of Molecular Spectroscopy}, year = {1990}, volume = {142}, number = {2}, pages = {238 – 253}, doi = {10.1016/0022-2852(90)90181-O} }
Miller S, Tennyson J and Sutcliffe BT (1990), "Forbidden rotational and rovibrational transitions in H3+: First principles calculations", Journal of Molecular Spectroscopy. Vol. 141(1), pp. 104 – 117. [Abstract] [BibTeX] [DOI]
Abstract: Calculations of the linestrengths and transition frequencies of the forbidden pure rotational spectrum of H3+ in the vibrationally excited ν2 state are presented. These transitions occur in the far-infrared region, and their observation may be complicated by ν1 - ν2 difference transitions. Examples of these are also given. Forbidden rovibrational transition frequencies and linestrengths have also been calculated in the frequency range 2000-3000 cm-1. The bands (ν2 + ν1) - ν2 and (2ν2 (l = 0) + ν1) - 2ν2 (l = 2) are found to be particularly strong. Possible phenomenological explanations for the observed line intensities are discussed. Two routes to obtaining the energy levels of the ν1 manifold of H3+ are suggested. © 1990.
BibTeX: @article{Miller1990104, author = {Miller, Steven and Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {Forbidden rotational and rovibrational transitions in H3+: First principles calculations}, journal = {Journal of Molecular Spectroscopy}, year = {1990}, volume = {141}, number = {1}, pages = {104 – 117}, doi = {10.1016/0022-2852(90)90281-T} }
Ndikumana T, Carleer M and Colin R (1990), "Laser-induced fluorescence spectrum and radiative lifetimes of the gaseous PbSe molecule", Molecular Physics. Vol. 69(2), pp. 229 – 239. [Abstract] [BibTeX] [DOI]
Abstract: A molecular beam of PbSe molecules was excited by the 4965 Å line emitted by a cw Ar+ laser and the fluorescence spectrum was recorded. Five fluorescence series originating from the v'= 9 level and one series originating from the v'= 10 level of the A0+ state were observed and analysed to yield improved isotopic vibrational constants for the X0+ state. The observation of satellite lines due to inelastic collisions within the beam allowed also to determine the rotational B constant of the v'= 10 level of the A0+state. Using a pulsed dye laser, lifetimes of the v'= 9 and 10 levels of the A0+ state and of the v'= 1, 5, 6, 7 and 8 levels of the B1 state were measured. These lifetimes combined with calculated Franck-Condon factors allowed electronic transition moments for the A-X and B-X transitions to be determined. © 1990 Taylor & Francis Ltd.
BibTeX: @article{Ndikumana1990229, author = {Ndikumana, T. and Carleer, M. and Colin, R.}, title = {Laser-induced fluorescence spectrum and radiative lifetimes of the gaseous PbSe molecule}, journal = {Molecular Physics}, year = {1990}, volume = {69}, number = {2}, pages = {229 – 239}, doi = {10.1080/00268979000100161} }
Van Roozendael M and Herman M (1990), "Optoacoustic study of the NO2-N2O4 chemical system", Chemical Physics Letters. Vol. 166(3), pp. 233 – 239. [Abstract] [BibTeX] [DOI]
Abstract: The non-resonant optoacoustic technique is developed to characterize the response of the NO2/N2O4 chemical system to a temperature increase resulting from infrared laser absorption at low pressure. The role of the chemical equilibrium connecting the two species is investigated. © 1990.
BibTeX: @article{VanRoozendael1990233, author = {Van Roozendael, M. and Herman, M.}, title = {Optoacoustic study of the NO2-N2O4 chemical system}, journal = {Chemical Physics Letters}, year = {1990}, volume = {166}, number = {3}, pages = {233 – 239}, doi = {10.1016/0009-2614(90)80022-6} }
Carter S, Rosmus P, Handy NC, Miller S, Tennyson J and Sutcliffe BT (1989), "Benchmark calculations of first principles rotational and ro-vibrational line strenghts", Computer Physics Communications. Vol. 55(1), pp. 71 – 75. [Abstract] [BibTeX] [DOI]
Abstract: Benchmark first principles calculations of the pure rotational and ro-vibrational transition frequencies and line strengths are presented, using two independent program suites. Both sets of calculations were performed using the same potential energy and dipole surfaces. Our example calculations use recently calculated surfaces for H2S which have been shown to give good agreement with experimental data. The results, which show perfect agreement for the energy levels, transition frequencies and line strengths, are used as an external check on the two program suites. It is suggested they could provide a standard with which other groups working in this field can compare their calculations. © 1989.
BibTeX: @article{Carter198971, author = {Carter, Stuart and Rosmus, Pavel and Handy, Nicholas C. and Miller, Steven and Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {Benchmark calculations of first principles rotational and ro-vibrational line strenghts}, journal = {Computer Physics Communications}, year = {1989}, volume = {55}, number = {1}, pages = {71 – 75}, doi = {10.1016/0010-4655(89)90064-7} }
Colin R (1989), "Perturbations between the X2Π and a4Σ- states of the NH+ ion", Journal of Molecular Spectroscopy. Vol. 136(2), pp. 387 – 401. [Abstract] [BibTeX] [DOI]
Abstract: On the basis of previously published optical data (Colin and Douglas, Canad. J. Phys. 46, 61-73 (1968)) for three isotopes (14NH+, 15NH+ and 14ND+) of the NH+ ion, a study of the perturbations occurring between the X2Π and a4Σ- states has been carried out using matrix diagonalization techniques. This makes it possible to derive for both states equilibrium rotational and vibrational constants, from which RKR potential energy functions, vibrational overlap integrals, electronic interaction parameters, and a pure electronic term value for the a4Σ- state are deduced. © 1989.
BibTeX: @article{Colin1989387, author = {Colin, R.}, title = {Perturbations between the X2Π and a4Σ- states of the NH+ ion}, journal = {Journal of Molecular Spectroscopy}, year = {1989}, volume = {136}, number = {2}, pages = {387 – 401}, doi = {10.1016/0022-2852(89)90344-5} }
Godefroid M, Lievin J and Heenen P-H (1989), "Laguerre meshes in atomic structure calculations", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 22(20), pp. 3119 – 3136. [Abstract] [BibTeX] [DOI]
Abstract: A new method to discretise the Schrodinger equations has been described recently and applied successfully to simple quantum mechanical and nuclear Hartree-Fock problems. The method is based on an accurate approximation of a variational calculation. The authors apply this approach in atomic structure calculations by discretising on Laguerre meshes the Schrodinger equation for hydrogen and the Hartree-Fock and configuration interaction equations of two-electron systems. They investigate the accuracy of the method for the ground states and some of the excited states of H, He and H-. They illustrate the striking simplicity of the Hamiltonian matrix elements arising from the Lagrange functions properties when using the Gauss quadrature integration formula and test its accuracy as a function of the number of points defining the mesh. They also test the quality of the Lagrange function basis set by checking sum rules and by calculating the second-order energy of helium.
BibTeX: @article{Godefroid19893119, author = {Godefroid, M. and Lievin, J. and Heenen, P.-H.}, title = {Laguerre meshes in atomic structure calculations}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1989}, volume = {22}, number = {20}, pages = {3119 – 3136}, doi = {10.1088/0953-4075/22/20/006} }
Hamilton C, Field R, Huet T and Herman M (1989), "Low-energy vibrational levels in the A ̃1Au electronic state of C2D2 ", Journal of Molecular Spectroscopy. Vol. 137(2), pp. 427 – 429. [BibTeX] [DOI]
BibTeX: @article{Hamilton1989427, author = {Hamilton, C and Field, R.W and Huet, T.R and Herman, M}, title = {Low-energy vibrational levels in the A ̃1Au electronic state of C2D2 }, journal = {Journal of Molecular Spectroscopy}, year = {1989}, volume = {137}, number = {2}, pages = {427 – 429}, doi = {10.1016/0022-2852(89)90184-7} }
Herman M, Huet T and Vervloet M (1989), "Spectroscopy and vibrational couplings in the 3v3 region of acetylene", Molecular Physics. Vol. 66(2), pp. 333 – 353. [Abstract] [BibTeX] [DOI]
Abstract: 14 rovibrational bands are observed in the 1 micron region of the absorption spectrum of C2H2between 9300 and 10500 cm-1, and rotationally analysed. Transition induced dipole moments are estimated for all the cold bands involving upper levels of (Formula Presented)symmetry. Those various data are used to demonstrate the leading role of the 0030°0° level in the vibrational mixings and also to deal quantitatively with a possible picture of the couplings occurring among the cluster of levels in resonance with 0030°0°. © 1989 Taylor & Francis Ltd.
BibTeX: @article{Herman1989333, author = {Herman, M. and Huet, T.R. and Vervloet, M.}, title = {Spectroscopy and vibrational couplings in the 3v3 region of acetylene}, journal = {Molecular Physics}, year = {1989}, volume = {66}, number = {2}, pages = {333 – 353}, doi = {10.1080/00268978900100161} }
Huet T and Herman M (1989), "The A ̃- X ̃ band system of C2D2: Vibration-rotation constants for the A ̃1Au state", Journal of Molecular Spectroscopy. Vol. 137(2), pp. 396 – 419. [Abstract] [BibTeX] [DOI]
Abstract: The analysis of data arising from high-resolution absorption spectra of the A ̃- X ̃ band system in C2D2 leads to assignment of 130 out of 135 bands observed between 41 500 and 47 900 cm-1. New or improved results are obtained for 24 vibrational levels in the A ̃1Au electronic state. For the first time rotational constants are presented for the upper state, concerning 19 of those vibrational levels. The analysis of several axis-switching bands is also reported. Perturbations are tentatively assigned in terms of a close-by triplet electronic state. © 1989.
BibTeX: @article{Huet1989396, author = {Huet, T.R and Herman, M}, title = {The A ̃- X ̃ band system of C2D2: Vibration-rotation constants for the A ̃1Au state}, journal = {Journal of Molecular Spectroscopy}, year = {1989}, volume = {137}, number = {2}, pages = {396 – 419}, doi = {10.1016/0022-2852(89)90182-3} }
Kabbadj Y and Lievin J (1989), "Ab initio study of the electronic structure of the PO2radical", Physica Scripta. Vol. 40(3), pp. 259 – 269. [BibTeX] [DOI]
BibTeX: @article{Kabbadj1989259, author = {Kabbadj, Y. and Lievin, J.}, title = {Ab initio study of the electronic structure of the PO2radical}, journal = {Physica Scripta}, year = {1989}, volume = {40}, number = {3}, pages = {259 – 269}, doi = {10.1088/0031-8949/40/3/002} }
Miller S, Tennyson J and Sutcliffe BT (1989), "First principles calculation of rotational and ro-vibrational line strengths spectra for H2D+and D2H+", Molecular Physics. Vol. 66(2), pp. 429 – 456. [Abstract] [BibTeX] [DOI]
Abstract: Theory is developed for the calculation of dipole transition line strengths and frequencies for rotational and ro-vibrational transitions from wavefunc-tions expressed in the generalized body-fixed co-ordinates proposed by Sutcliffe and Tennyson (1986, Molec. Phys., 58, 1053). Computations using this theory produce calculated frequencies for the fundamental ro-vibrational transitions of H2D+and D2H+in very good agreement with experiment. These first principles calculations use the highly accurate ab initio electronic potential energy and dipole surface of Meyer, Botschwina and Burton, which has previously been shown by the authors to give ro-vibrational transition frequencies, rotational constants and vibrational fundamentals of spectroscopic accuracy. Three line reassignments are proposed on frequency considerations. Several transitions are proposed as candidates for observation on the grounds of computed relative intensities. Calculated pure rotational transitions in ground state for H2D+and D2H+ are in excellent agreement with limited data available, and the full rotational spectra of these molecules are predicted. © 1989 Taylor & Francis Ltd.
BibTeX: @article{Miller1989429, author = {Miller, Steven and Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {First principles calculation of rotational and ro-vibrational line strengths spectra for H2D+and D2H+}, journal = {Molecular Physics}, year = {1989}, volume = {66}, number = {2}, pages = {429 – 456}, doi = {10.1080/00268978900100211} }
Renneboog-Squilbin C, Nammour S, Coomans D, Barel A, Carleer M and Dourov N (1989), "Measurement of pulp temperature increase to externally applied heat (argon laser, hot water, drilling).", Journal de biologie buccale. Vol. 17(3), pp. 179 – 186. [Abstract] [BibTeX]
Abstract: In order to weld cracks in tooth enamel, it is necessary to bring the surface of the tooth to the fusion temperature of the enamel (greater than 1,000 degrees C). The study investigated whether this increase in surface temperature can cause damage to the vitality of the tooth by recording, using a thermocouple, the temperature in the pulp chamber of teeth exposed to argon laser irradiation (power density after focusing: 4000 W/cm2; duration of continuous irradiation: 1-5 seconds). These pulp temperature increases were compared with those considered safe for the tooth, i.e., contact with a hot drink, drilling of cavities with air + water cooling. It was shown that punctual irradiations with an argon laser for periods of 2 or 4 seconds generated temperature increases in the pulp chamber which were less than inferior to those caused by contact with water at 54-55 degrees C for 1 or 2 seconds, and were of the same order as those caused by the drilling of class III or V cavities of 1 mm in depth and 1 mm in diameter. These results suggest that it is worth continuing research into applying the technique in the mouth.
BibTeX: @article{Renneboog-Squilbin1989179, author = {Renneboog-Squilbin, C. and Nammour, S. and Coomans, D. and Barel, A. and Carleer, M. and Dourov, N.}, title = {Measurement of pulp temperature increase to externally applied heat (argon laser, hot water, drilling).}, journal = {Journal de biologie buccale}, year = {1989}, volume = {17}, number = {3}, pages = {179 – 186} }
van Roozendael M and Herman M (1989), "Mechanism of the response of the N2O4 ⇌ 2NO2 chemical equilibrium to an optical perturbation", Chemical Physics. Vol. 139(2-3), pp. 391 – 400. [Abstract] [BibTeX] [DOI]
Abstract: The variation of population on rotational levels in NO2, in N2O4, in their ground electronic states, induced at a few mbar pressure by an optical laser pumping in NO2 is monitored with the help of infrared probe laser lines. It is demonstrated that temperature jumps result from the chopped excitation, which drive the response of the system. A kinetic model is established to semi-quantitatively detail the role of the chemical equilibrium to that response. © 1989.
BibTeX: @article{vanRoozendael1989391, author = {van Roozendael, M. and Herman, M.}, title = {Mechanism of the response of the N2O4 ⇌ 2NO2 chemical equilibrium to an optical perturbation}, journal = {Chemical Physics}, year = {1989}, volume = {139}, number = {2-3}, pages = {391 – 400}, doi = {10.1016/0301-0104(89)80151-X} }
Vaeck N and Hansen J (1989), "Calculations for 1s23l3l' states in C2+, N 3+, O4+, Ne6+ and Xe50+", Journal of Physics B: Atomic, Molecular and Optical Physics. Vol. 22(20), pp. 3137 – 3153. [Abstract] [BibTeX] [DOI]
Abstract: Calculations are presented of energy level values, radiative transition probabilities and autoionisation rates for terms belonging to the 1s 23l3l' configurations for several ions in the Be I isoelectronic sequence (C2+, N3+, O4+, Ne6+ and Xe50+). The results of a CI calculation including the configurations of the complex (and the 3d4f configuration) are compared with experimental results obtained in collisions of highly stripped ions with He, H2 and Ar and with the results of theoretical calculations.
BibTeX: @article{Vaeck19893137, author = {Vaeck, N. and Hansen, J.E.}, title = {Calculations for 1s23l3l' states in C2+, N 3+, O4+, Ne6+ and Xe50+}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, year = {1989}, volume = {22}, number = {20}, pages = {3137 – 3153}, doi = {10.1088/0953-4075/22/20/007} }
Van Roozendael M, Miller P and Herman M (1989), "Optoacoustic experiments in the gas phase", Optics Communications. Vol. 72(1-2), pp. 71 – 75. [Abstract] [BibTeX] [DOI]
Abstract: A non-resonant spectrophone adapted for low pressure measurements in the gas phase is used to produce results concerning radiative and non radiative processes induced in NO, NH3 and NO2 using an infrared CO laser. © 1989.
BibTeX: @article{VanRoozendael198971, author = {Van Roozendael, M. and Miller, P. and Herman, M.}, title = {Optoacoustic experiments in the gas phase}, journal = {Optics Communications}, year = {1989}, volume = {72}, number = {1-2}, pages = {71 – 75}, doi = {10.1016/0030-4018(89)90258-7} }
Vander Auwera J, Huet T, Herman M, Hamilton C, Kinsey J and Field R (1989), "The A ̃1A″ electronic state of monodeuterated acetylene", Journal of Molecular Spectroscopy. Vol. 137(2), pp. 381 – 395. [Abstract] [BibTeX] [DOI]
Abstract: Eighty-six vibronic subbands of the A ̃- X ̃ system of C2HD are assigned, in the conventional high-resolution absorption spectrum and in the jet-cooled laser fluorescence excitation spectrum, between 42 200 and 47 000 cm-1. Transitions involving all six normal modes of vibration in the A ̃ state are assigned, leading to the determination of an extensive set of vibrational parameters. Isotopic comparisons are used to predict still unknown vibrational frequencies in the A ̃ state of C2H2 and C2D2. © 1989.
BibTeX: @article{VanderAuwera1989381, author = {Vander Auwera, J and Huet, T.R and Herman, M and Hamilton, C and Kinsey, J.L and Field, R.W}, title = {The A ̃1A″ electronic state of monodeuterated acetylene}, journal = {Journal of Molecular Spectroscopy}, year = {1989}, volume = {137}, number = {2}, pages = {381 – 395}, doi = {10.1016/0022-2852(89)90181-1} }
Botschwina P, Handy N, Halonen L, Gaw J, Ha T, Lewerenz M, Quack M, Sheppard N, Duncan J, Brodersen S, Baggott J, Law D, Lehmann K, Hutchinson J, Winnewisser M, Holme T, Carney G, Duxbury G, Tennyson J, Child M, Chambers A, Sutcliffe B, Jensen P, Marquardt R, Newnham D, Henry B, Mills I, Coy S, Caldow G, Smith A, Walsh R, Ashfold M, McKean D, Watts R, Carrasquillo E, Utz A, Crim F, Temps F, Santamaría J, Getino-Gonzalez C, Ezra G, Simons J, García-Ayllón A and Levine R (1988), "General discussion", Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics. Vol. 84(9), pp. 1555 – 1642. [BibTeX] [DOI]
BibTeX: @article{Botschwina19881555, author = {Botschwina, P. and Handy, N.C. and Halonen, L. and Gaw, J.F. and Ha, T.K. and Lewerenz, M. and Quack, M. and Sheppard, N. and Duncan, J.L. and Brodersen, S. and Baggott, J.E. and Law, D.W. and Lehmann, K.K. and Hutchinson, J.S. and Winnewisser, M. and Holme, T.A. and Carney, G.D. and Duxbury, G. and Tennyson, J. and Child, M.S. and Chambers, A.V. and Sutcliffe, B.T. and Jensen, P. and Marquardt, R. and Newnham, D.A. and Henry, B.R. and Mills, I.M. and Coy, S.L. and Caldow, G.L. and Smith, A.M. and Walsh, R. and Ashfold, M.N.R. and McKean, D.C. and Watts, R.O. and Carrasquillo, E. and Utz, A.L. and Crim, F.F. and Temps, F. and Santamaría, J. and Getino-Gonzalez, C. and Ezra, G.S. and Simons, J.P. and García-Ayllón, A. and Levine, R.D.}, title = {General discussion}, journal = {Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics}, year = {1988}, volume = {84}, number = {9}, pages = {1555 – 1642}, doi = {10.1039/F29888401555} }
Hibbert A, Froese Fischer C and Godefroid M (1988), "Non-orthogonal orbitals in MCHF or configuration interaction wave functions", Computer Physics Communications. Vol. 51(3), pp. 285 – 293. [Abstract] [BibTeX] [DOI]
Abstract: The method of calculating interaction matrix elements between multi-configurational wave functions, given by Fano (1965) for orthogonal orbitals, is extended to allow the use of non-orthogonal orbitals. We allow up to two subshells in each configuration function which contain spectator (non-interacting) electrons described by orbitals which are not orthogonal to orbitals in the other configuration function of the matrix element. A discussion of the effects of less restrictive conditions is presented. © 1988.
BibTeX: @article{Hibbert1988285, author = {Hibbert, A. and Froese Fischer, C. and Godefroid, M.R.}, title = {Non-orthogonal orbitals in MCHF or configuration interaction wave functions}, journal = {Computer Physics Communications}, year = {1988}, volume = {51}, number = {3}, pages = {285 – 293}, doi = {10.1016/0010-4655(88)90141-5} }
Huet T and Herman M (1988), "Levels of the transbending normal mode of vibration in C2D2", Journal of Molecular Spectroscopy. Vol. 132(2), pp. 361 – 368. [Abstract] [BibTeX] [DOI]
Abstract: The analysis of data arising from high-resolution absorption spectra of C2D2 in the ultraviolet range leads to results concerning the transbending levels in the ground electronic state. Original rovibrational constants are obtained for 2ν4 and 3ν4 and vibrational term values are derived for 4ν4. © 1988.
BibTeX: @article{Huet1988361, author = {Huet, T.R. and Herman, M.}, title = {Levels of the transbending normal mode of vibration in C2D2}, journal = {Journal of Molecular Spectroscopy}, year = {1988}, volume = {132}, number = {2}, pages = {361 – 368}, doi = {10.1016/0022-2852(88)90331-1} }
Sutcliffe B, Miller S and Tennyson J (1988), "An effective computational approach to the calculation of the vibration-rotation spectra of triatomic molecules", Computer Physics Communications. Vol. 51(1-2), pp. 73 – 82. [Abstract] [BibTeX] [DOI]
Abstract: The results of some highly accurate non-empirical ro-vibrational calculations on H2D+ are reported including some for J = 30 which are the first calculations to describe such a highly rotationally excited state. These results are obtained using an improved version of our algorithm. The method used is a variational one and is well adapted to execution on supercomputers. The computational characteristics of the performance the method on the CRAY 1s and the CRAY XMP 48 are given. © 1988.
BibTeX: @article{Sutcliffe198873, author = {Sutcliffe, B.T. and Miller, S. and Tennyson, J.}, title = {An effective computational approach to the calculation of the vibration-rotation spectra of triatomic molecules}, journal = {Computer Physics Communications}, year = {1988}, volume = {51}, number = {1-2}, pages = {73 – 82}, doi = {10.1016/0010-4655(88)90063-X} }
Tennyson J, Miller S and Sutcliffe BT (1988), "Beyond ro-vibrational separation", Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics. Vol. 84(9), pp. 1295 – 1303. [Abstract] [BibTeX] [DOI]
Abstract: Results are presented for nuclear motion calculations on D3+, H2D+ and the van der Waals complex ArCO in rotationally excited states. These calculations are performed using a two-step variational procedure which allows large ro-vibrational interactions (Coriolis couplings) to be treated accurately. The difficulty of assigning states in systems such as H2D+ where the Coriolis interactions are large is illustrated and the limitations of effective Hamiltonians derived from perturbation theory discussed.
BibTeX: @article{Tennyson19881295, author = {Tennyson, Jonathan and Miller, Steven and Sutcliffe, Brian T.}, title = {Beyond ro-vibrational separation}, journal = {Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics}, year = {1988}, volume = {84}, number = {9}, pages = {1295 – 1303}, doi = {10.1039/F29888401295} }
Urdaneta C, Largo-Cabrerizo A, Lievin J, Lie G and Clementi E (1988), "Gaussian functions in hylleraas-Cl calculations. I. Ground state energies for H2, HeH+, and H3+", The Journal of Chemical Physics. Vol. 88(3), pp. 2091 – 2093. [BibTeX] [DOI]
BibTeX: @article{Urdaneta19882091, author = {Urdaneta, C. and Largo-Cabrerizo, A. and Lievin, J. and Lie, G.C. and Clementi, E.}, title = {Gaussian functions in hylleraas-Cl calculations. I. Ground state energies for H2, HeH+, and H3+}, journal = {The Journal of Chemical Physics}, year = {1988}, volume = {88}, number = {3}, pages = {2091 – 2093}, doi = {10.1063/1.454090} }
Vaeck N, Godefroid M and Hansen JE (1988), "Multiconfiguration Hartree-Fock calculations for singlet terms in neutral strontium", Physical Review A. Vol. 38(6), pp. 2830 – 2845. [Abstract] [BibTeX] [DOI]
Abstract: Multiconfiguration Hartree-Fock (MCHF) calculations are presented for singlet terms in neutral strontium (Sr i) belonging to (perturbed) sp, sd, and sf Rydberg series. We discuss briefly some particularly difficult MCHF calculations and the steps taken to overcome the difficulties. The ab initio wave functions are used to calculate radiative lifetimes as well as individual transition rates for electric dipole and quadrupole radiation. The calculated lifetimes are compared to recent experimental results. The observed trends are well reproduced by the calculations. We compare our wave functions with wave functions obtained from multichannel quantum-defect theory (MQDT) in either of two different ways. One is based on semiempirical fitting to the observed energy levels and the other on a recent ab initio R-matrix calculation of MQDT parameters. We find good agreement with the wave functions obtained in the latter calculation, confirming earlier conjectures about the degree of reliability of semiempirical MQDT fits to perturbed Rydberg series [C. Froese Fischer and J. E. Hansen, Phys. Rev. A 24, 631 (1981)]. © 1988 The American Physical Society.
BibTeX: @article{Vaeck19882830, author = {Vaeck, N. and Godefroid, M. and Hansen, Jorgen E.}, title = {Multiconfiguration Hartree-Fock calculations for singlet terms in neutral strontium}, journal = {Physical Review A}, year = {1988}, volume = {38}, number = {6}, pages = {2830 – 2845}, note = {All Open Access, Green Open Access}, doi = {10.1103/PhysRevA.38.2830} }
Vervloet M and Herman M (1988), "Fourier transform emission spectroscopy of C2H", Chemical Physics Letters. Vol. 144(1), pp. 48 – 50. [Abstract] [BibTeX] [DOI]
Abstract: The C2H radical is produced by flowing C2H2 through a radiofrequency discharge and the resulting emission is recorded in the mid-infrared with a high resolution Fourier transform spectrophotometer. Five of the bands previously reported in absorption studies are observed for the first time in emission - the so-called "3600, 3702, 3772, 4012 and 4108 cm-1 bands". Two new bands connecting known vibronic levels of the molecule are also observed. © 1988.
BibTeX: @article{Vervloet198848, author = {Vervloet, Michel and Herman, Michel}, title = {Fourier transform emission spectroscopy of C2H}, journal = {Chemical Physics Letters}, year = {1988}, volume = {144}, number = {1}, pages = {48 – 50}, doi = {10.1016/0009-2614(88)87087-8} }
Auwera J and Herman M (1987), "Infrared optical double resonance signal in glyoxal (C2H2O2)", Chemical Physics Letters. Vol. 135(4-5), pp. 432 – 434. [Abstract] [BibTeX] [DOI]
Abstract: The prediction and observation of an infrared optical double resonance scheme in glyoxal is reported. © 1987.
BibTeX: @article{Auwera1987432, author = {Auwera, J.Vander and Herman, M.}, title = {Infrared optical double resonance signal in glyoxal (C2H2O2)}, journal = {Chemical Physics Letters}, year = {1987}, volume = {135}, number = {4-5}, pages = {432 – 434}, doi = {10.1016/0009-2614(87)85184-9} }
Godefroid M, Lievin J and Metz J (1987), "Brillouin's theorem for complex atomic configurations", Journal of Physics B: Atomic and Molecular Physics. Vol. 20(14), pp. 3283 – 3296. [Abstract] [BibTeX] [DOI]
Abstract: General mathematical expressions are derived for the weighting coefficients of the configuration state functions defining the singly excited function satisfying Brillouin's theorem for complex atomic configurations. The relations are illustrated for different cases and tested numerically by the cancellation of the Brillouin matrix elements using the Hartree-Fock solution for the reference function.
BibTeX: @article{Godefroid19873283, author = {Godefroid, M. and Lievin, J. and Metz, J.Y.}, title = {Brillouin's theorem for complex atomic configurations}, journal = {Journal of Physics B: Atomic and Molecular Physics}, year = {1987}, volume = {20}, number = {14}, pages = {3283 – 3296}, doi = {10.1088/0022-3700/20/14/004} }
Godefroid M, Lievin J and Metz J (1987), "Inversion of the fractional parentage matrix", Journal of Physics A: Mathematical and General. Vol. 20(7), pp. 1645 – 1653. [Abstract] [BibTeX] [DOI]
Abstract: The Racah fractional parentage coefficients (1943) used in atomic structure calculations contribute to a part of an ordinary unitary matrix transformation. In the present paper the authors describe three different approaches for completing this matrix using (i) projection operator techniques, (ii) the factorisation lemma of Racah and (iii) the spin-free formalism already used in theoretical studies of nuclear structures. The authors hope to give a deeper insight into the fractional parentage expansion and to its inverse transformation. © 1987, IOP Publishing Ltd.
BibTeX: @article{Godefroid19871645, author = {Godefroid, M. and Lievin, J. and Metz, J.Y.}, title = {Inversion of the fractional parentage matrix}, journal = {Journal of Physics A: Mathematical and General}, year = {1987}, volume = {20}, number = {7}, pages = {1645 – 1653}, doi = {10.1088/0305-4470/20/7/011} }
Kleiner I, Godefroid M, Herman M and Mc Kellar A (1987), "Infrared laser Stark spectrum of HNO3 at 6 μm", Journal of the Optical Society of America B: Optical Physics. Vol. 4(7), pp. 1159 – 1164. [Abstract] [BibTeX] [DOI]
Abstract: Intracavity laser Stark experiments were performed on the v2 fundamental band of nitric acid, HNO3, using a CO laser. Despite the high density of observed resonances in the spectra, it was possible to recognize and fit several transitions. Calculations were made using a theoretical approach describing the Stark effect in asymmetric-topped molecules in terms of tensorial elements. The main result of the analysis was the first reported determination of the a and b components of the electric-dipole moment in the v2 = 1 vibrational level. © 1987, Optical Society of America.
BibTeX: @article{Kleiner19871159, author = {Kleiner, I. and Godefroid, M. and Herman, M. and Mc Kellar, A.R.W.}, title = {Infrared laser Stark spectrum of HNO3 at 6 μm}, journal = {Journal of the Optical Society of America B: Optical Physics}, year = {1987}, volume = {4}, number = {7}, pages = {1159 – 1164}, doi = {10.1364/JOSAB.4.001159} }
Nammour S, Carleer M, Renneboog-Squilbin C and Dourov N (1987), "Use of the laser for welding cracks on the dental enamel.", Journal de biologie buccale. Vol. 15(1), pp. 37 – 43. [Abstract] [BibTeX]
Abstract: An all line argon laser beam of initial power 2W (4000W/cm2-800 J/cm2, after focusing), was used to weld enamel cracks on extracted human teeth. The welding, observed with the naked eye, caused a small heightening in the welded area which was whiter in color than the rest of the enamel. Examinations were performed on the outer surface of the welding with an inverted metallurgical microscope and using a microdurometer. Sections were then made and studied, on the one hand with a light microscope, and on the other using microradiographical methods. The welding was seen to reach across half the enamel thickness. The possibilities for therapeutic applications of this work are discussed.
BibTeX: @article{Nammour198737, author = {Nammour, S. and Carleer, M. and Renneboog-Squilbin, C. and Dourov, N.}, title = {Use of the laser for welding cracks on the dental enamel.}, journal = {Journal de biologie buccale}, year = {1987}, volume = {15}, number = {1}, pages = {37 – 43} }
Sutcliffe BT and Tennyson J (1987), "Variational methods for the calculation of rovibrational energy levels of small molecules", Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics. Vol. 83(9), pp. 1663 – 1674. [Abstract] [BibTeX] [DOI]
Abstract: Variational rovibrational calculations performed on the molecules H2O and CH+2 are discussed with a view to pin-pointing the best solution strategy for each system. While all the methods discussed appeared to be reliable for the low-lying levels of water, CH+2 has proved a more testing system. A recently proposed method for calculating highly rotationally excited states is applied to the J = 10 levels of CH+2. Comparison of these calculations with those of Carter and Handy suggests that at this level of rotational excitation it will be necessary to consider full rovibronic coupling effects in the characterisation of any spectra of this floppy system.
BibTeX: @article{Sutcliffe19871663, author = {Sutcliffe, Brian T. and Tennyson, Jonathan}, title = {Variational methods for the calculation of rovibrational energy levels of small molecules}, journal = {Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics}, year = {1987}, volume = {83}, number = {9}, pages = {1663 – 1674}, doi = {10.1039/F29878301663} }
Sutcliffe BT, Tennyson J and Miller S (1987), "The use of supercomputers for the variational calculation of ro-vibrationally excited states of floppy molecules", Theoretica Chimica Acta. Vol. 72(4), pp. 265 – 276. [Abstract] [BibTeX] [DOI]
Abstract: The advent of supercomputers has led to great advances in electronic structure calculations and to the ab initio calculation of molecular spectra. Recent theoretical developments have allowed us to develop a two-step variational algorithm for the calculation of rotationally highly excited states of floppy molecules. This algorithm allows highly accurate nuclear motion calculations to be performed on low-lying ro-vibrational states and greatly extends the range of states that can practicably be considered. The algorithm has been adapted to run efficiently on the Cray supercomputers. Analysis of the timings suggest that construction of the secular matrix is highly vectorised and that the special structure of secular matrix can be used to give rapid diagonalisation. The limiting factor on these calculations is the available fast storage, but analysis suggests that this bottleneck could be removed by use of a Solid State Device (SSD). Sample results are given for calculations involving a range of rotational excitation. An adaptation of the algorithm to a loop of parallel processors is also suggested. © 1987 Springer-Verlag.
BibTeX: @article{Sutcliffe1987265, author = {Sutcliffe, Brian T. and Tennyson, Jonathan and Miller, Steven}, title = {The use of supercomputers for the variational calculation of ro-vibrationally excited states of floppy molecules}, journal = {Theoretica Chimica Acta}, year = {1987}, volume = {72}, number = {4}, pages = {265 – 276}, doi = {10.1007/BF00529031} }
Vander Auwera J and Herman M (1987), "Spectroscopic investigation of the response of the NO2-N2O4 chemical system to optical laser pumping", Journal of Photochemistry. Vol. 38(C), pp. 15 – 33. [Abstract] [BibTeX] [DOI]
Abstract: An argon laser beam was used to perturb the NO2-N2O4 chemical system. The perturbation was monitored, in different experiments, with the laser-induced fluorescence and the IR optical double-resonance (IODR) techniques. The expected quantum perturbations which involve specific rotational levels in NO2, X 2A1 were observed. Unexpected chemical effects which involve the ground state concentration of both species and which are attributed to the response of the chemical equilibrium to the optical perturbation were also observed. The IODR results are discussed with the help of a model based on the Beer-Lambert law, which allows the role of the chemical response to be demonstrated. © 1987.
BibTeX: @article{VanderAuwera198715, author = {Vander Auwera, Jean and Herman, Michael}, title = {Spectroscopic investigation of the response of the NO2-N2O4 chemical system to optical laser pumping}, journal = {Journal of Photochemistry}, year = {1987}, volume = {38}, number = {C}, pages = {15 – 33}, doi = {10.1016/0047-2670(87)87002-8} }
Carleer M, Herman M, Auwera J and Van Roozendael M (1986), "Ar+ laser-induced fluorescence in NO2", Chemical Physics Letters. Vol. 127(1), pp. 13 – 18. [Abstract] [BibTeX] [DOI]
Abstract: The assignment of the resonant fluorescence induced by the AR+ laser lines in 14N16O2 is reported for the first time with the 4727 and 4765 Å laser lines and is further developed with the 4579 and 4965 Å laser lines. © 1986.
BibTeX: @article{Carleer198613, author = {Carleer, M. and Herman, M. and Auwera, J.Vander and Van Roozendael, M.}, title = {Ar+ laser-induced fluorescence in NO2}, journal = {Chemical Physics Letters}, year = {1986}, volume = {127}, number = {1}, pages = {13 – 18}, doi = {10.1016/S0009-2614(86)80201-9} }
Fischer CF and Godefroid M (1986), "Multi-configuration Hartree-Fock plus Breit-Pauli results for some forbidden transitions", Journal of Physics B: Atomic and Molecular Physics. Vol. 19(2), pp. 137 – 148. [Abstract] [BibTeX] [DOI]
Abstract: The multi-configuration Hartree-Fock method, extended to include relativistic effects in the Breit-Pauli approximation (MCHF+BP), has been applied to the study of some forbidden transitions between levels of the 3s 23p3 configuration in the phosphorus sequence. Term energy separations, fine-structure splittings, and E2 and M1 transition rates are reported for S II of interest in astrophysics and for several atomic systems with nuclear charge, Z, in the range 28
BibTeX: @article{Fischer1986137, author = {Fischer, Charlotte Froese and Godefroid, Michel}, title = {Multi-configuration Hartree-Fock plus Breit-Pauli results for some forbidden transitions}, journal = {Journal of Physics B: Atomic and Molecular Physics}, year = {1986}, volume = {19}, number = {2}, pages = {137 – 148}, doi = {10.1088/0022-3700/19/2/004} }
Henriet C and Verhaegen G (1986), "Accurate calculation of the excited states of the molecule beh", Physica Scripta. Vol. 33(4), pp. 299 – 309. [Abstract] [BibTeX] [DOI]
Abstract: The five lowest states of both2∑+ and2π symmetries were calculated with a large STO basis set (24σ, 13π, 55δ, including Rydberg orbitals on Be and on H), over a wide range of interatomic distances. A two-step Cl procedure (singles, doubles and triples over the valence shell) involving each 2899 and 4122 CSF’s for2∑+ and2π states respectively was used throughout the work. The results include term energies (also of dissociation products), dissociation energies, spectroscopic constants and dipole moments. The agreement between calculated results and available experimental data indicates a precision of 400cm-1 in the energies 0.005Å in the equilibrium internuclear distances and 15 cm-1 in the vibration frequencies. The states are analysed as a function of intemuclear distance by means of their natural orbitals, and semi-quantitive information is obtained concerning the validity of the Bom-Oppenheimer approximation for certain states at certain distances. Finally, experimental interpretations of observed anomalies are rationalized. © 1986 IOP Publishing Ltd.
BibTeX: @article{Henriet1986299, author = {Henriet, C. and Verhaegen, G.}, title = {Accurate calculation of the excited states of the molecule beh}, journal = {Physica Scripta}, year = {1986}, volume = {33}, number = {4}, pages = {299 – 309}, doi = {10.1088/0031-8949/33/4/004} }
Sutcliffe B and Tennyson J (1986), "The construction and fitting of molecular potential energy surfaces and their use in vibration‐rotation calculations", International Journal of Quantum Chemistry. Vol. 30(20 S), pp. 507 – 520. [Abstract] [BibTeX] [DOI]
Abstract: The state‐of‐the‐art in non‐empirical calculations of potential energy surfaces for small molecules is discussed, as is the present position with respect to the analytic fitting of such surfaces. The results of some nonempirical vibration‐rotation calculations performed on such analytic surfaces are presented and compared with experimental results. An attempt is made to assess the extent to which present methods of electronic structure calculation and present analytic fitting methods are adequate to produce surfaces for the interpretation of high‐resolution spectral data. Copyright © 1986 John Wiley & Sons, Inc.
BibTeX: @article{Sutcliffe1986507, author = {Sutcliffe, B.T. and Tennyson, J.}, title = {The construction and fitting of molecular potential energy surfaces and their use in vibration‐rotation calculations}, journal = {International Journal of Quantum Chemistry}, year = {1986}, volume = {30}, number = {20 S}, pages = {507 – 520}, doi = {10.1002/qua.560300744} }
Sutcliffe BT and Tennyson J (1986), "A generalized approach to the calculation of ro-vibrational spectra of triatomic molecules", Molecular Physics. Vol. 58(6), pp. 1053 – 1066. [Abstract] [BibTeX] [DOI]
Abstract: A generalization of the well known atom-diatom scattering hamiltonian to a coordinate system of two lengths and an angle is derived, another special case of which is a previously known bond angle-bond length hamiltonian. Different axis embeddings are also considered. The formalism is applied to the ro-vibrational levels of D2H+, CH2+ and HDHe (A1A’) and the advantage of a judicious choice of coordinates demonstrated. The vibrational band origins for HDHe*, the first predictions for this system for which previous calculations had failed, are obtained using a new geometrically defined coordinate system. It is suggested that these coordinates might be used to represent isotopically substituted van der Waals complexes. © 1986 Taylor & Francis Group, LLC.
BibTeX: @article{Sutcliffe19861053, author = {Sutcliffe, Brian T. and Tennyson, Jonathan}, title = {A generalized approach to the calculation of ro-vibrational spectra of triatomic molecules}, journal = {Molecular Physics}, year = {1986}, volume = {58}, number = {6}, pages = {1053 – 1066}, doi = {10.1080/00268978600101801} }
Tennyson J and Sutcliffe BT (1986), "Highly rotationally excited states of floppy molecules: H2D+ with j≤20", Molecular Physics. Vol. 58(6), pp. 1067 – 1085. [Abstract] [BibTeX] [DOI]
Abstract: A partitioning of the generalized triatomic hamiltonian of the preceding paper is developed which allows the calculation of highly-excited rotational states, without approximation, in a two-step variational procedure. Iterative diagonalization techniques are found to be particularly useful for the second variational step. The rotationally-excited states of H2D+ are studied with J≤20, well into the region where the ground and excited state manifolds overlap. Comparison of results for two different ab initio potentials and convergence considerations suggest that pure rotational transition frequencies obtained from our results should be accurate to about 1 cm-1 for J 15. © 1986 Taylor & Francis Group, LLC.
BibTeX: @article{Tennyson19861067, author = {Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {Highly rotationally excited states of floppy molecules: H2D+ with j≤20}, journal = {Molecular Physics}, year = {1986}, volume = {58}, number = {6}, pages = {1067 – 1085}, doi = {10.1080/00268978600101811} }
Tennyson J and Sutcliffe BT (1986), "The infrared spectrum of H3+ and its isotopomers. A challenge to theory and experiment", Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics. Vol. 82(8), pp. 1151 – 1162. [Abstract] [BibTeX] [DOI]
Abstract: H3+ and its isotopomers are seen as a benchmark for the comparison of theory and experiment. The stages of an ab initio calculation (electronic structure, potential fitting and nuclear motion) are discussed and the sources of error highlighted by consideration of recent results. Fitting of the electronic structure data is seen to be an area needing more development. New results are presented for the low-lying rovibrational states of D3+. While rovibrational properties can be calculated in the low-energy region to within ca. 0.1% accuracy, the high-energy region is still largely unexplored. New developments in the calculation of excited rotational states (J ≤ 20) are outlined and the possibility of quantum-mechanical calculations of vibrational levels in the near-dissociation region is discussed in the light of illustrative calculations.
BibTeX: @article{Tennyson19861151, author = {Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {The infrared spectrum of H3+ and its isotopomers. A challenge to theory and experiment}, journal = {Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics}, year = {1986}, volume = {82}, number = {8}, pages = {1151 – 1162}, doi = {10.1039/F29868201151} }
Van Craen J, Herman M, Colin R and Watson J (1986), "The A ̃- X ̃ band system of acetylene: Bands of the short-wavelength region", Journal of Molecular Spectroscopy. Vol. 119(1), pp. 137 – 143. [Abstract] [BibTeX] [DOI]
Abstract: The high-resolution study of the A ̃1Au(C2h)- X ̃1Σg +(D∞h) absorption system of C2H2 is extended to the region 2050-1930 Å. Bands involving the upper levels nν′3(n = 7, 8), ν′2 + nν′3(n = 6-8), and ν′1 + nν′3(n = 4, 5), and the lower levels mν″4(m = 0-3) are tentatively identified. The other observed bands have not been assigned. The various bands overlap strongly and many perturbations affect the upper state rovibrational energy levels, preventing rotational analyses of all but a few of the bands. Most of the bands can be characterized by features such as the temperature dependence and the presence or absence of an intensity alternation, and these are reported here. A general discussion of the analysis of the entire band system is also presented. © 1986.
BibTeX: @article{VanCraen1986137, author = {Van Craen, J.C and Herman, M and Colin, R and Watson, J.K.G}, title = {The A ̃- X ̃ band system of acetylene: Bands of the short-wavelength region}, journal = {Journal of Molecular Spectroscopy}, year = {1986}, volume = {119}, number = {1}, pages = {137 – 143}, doi = {10.1016/0022-2852(86)90208-0} }
Van Roozendael M, Hills G and Herman M (1986), "Optogalvanic studies with a CO laser", Optics Communications. Vol. 58(5), pp. 319 – 323. [Abstract] [BibTeX] [DOI]
Abstract: Optogalvanic signals are reported in low pressure, RF discharges in NO, NO2, H2O, HNO3, HCO2H, H2CO and C2H2O2, using an infrared, isotopic CO laser. The results illustrate the role of the OG technique in locating coincidences useful for other spectroscopic investigations and perhaps for optically pumped, far infrared lasers. The formation and simultaneous OG detection of the free radical NO, when using NO2, is also reported and quantified. © 1986.
BibTeX: @article{VanRoozendael1986319, author = {Van Roozendael, M. and Hills, G.W. and Herman, M.}, title = {Optogalvanic studies with a CO laser}, journal = {Optics Communications}, year = {1986}, volume = {58}, number = {5}, pages = {319 – 323}, doi = {10.1016/0030-4018(86)90235-X} }
Godefroid M and Froese Fischer C (1985), "Relativistic and correlation effects on the lifetimes of 3s4p3p°j levels in mg-like sulphur and chlorine", Physica Scripta. Vol. 31(4), pp. 237 – 245. [Abstract] [BibTeX] [DOI]
Abstract: Accurate multiconfiguration Hartree-Fock calculations were performed to investigate the J-dependence of the lifetimes of 3s4p3P°J (J = 2, 1, 0) in S V and Cl VI. The relativistic corrections have been included through the Breit-Pauli approximation. The variation with J, observed in S V but not in Cl VI [4], is explained by the selective opening of decay channels resulting from the triplet-singlet mixing and by the J-dependence found in the El spin-allowed transition decay rates where the coulomb and relativistic configuration interaction between 3s4p and 3p3d play a crucial role. The effects of the relativistic shift corrections on the wavefunction compositions and transition probabilities are discussed. New gf-values are reported for the singlet-singlet electric dipole transistions from 3s4p1P°1, taking into account the1P-character loss due to the inter-symmetry mixing. © 1985 IOP Publishing Ltd.
BibTeX: @article{Godefroid1985237, author = {Godefroid, M. and Froese Fischer, C.}, title = {Relativistic and correlation effects on the lifetimes of 3s4p3p°j levels in mg-like sulphur and chlorine}, journal = {Physica Scripta}, year = {1985}, volume = {31}, number = {4}, pages = {237 – 245}, doi = {10.1088/0031-8949/31/4/004} }
Godefroid M, Magnusson C, Zetterberg P and Joelsson I (1985), "Forbidden transitions in na− and mg-like spectra", Physica Scripta. Vol. 32(2), pp. 125 – 128. [Abstract] [BibTeX] [DOI]
Abstract: Quantitative comparisons between observed and theoretical wavelengths and intensity ratios are made to confirm the identification of some emission lines observed in the spectra of Na- and Mg-like ions as electric quadrupole (E2) transitions. The transition rates of these lines connecting D symmetry levels and the ground level are calculated using the multiconfiguration Hartree-Fock (MCHF) wavefunctions. © 1985 IOP Publishing Ltd.
BibTeX: @article{Godefroid1985125, author = {Godefroid, M. and Magnusson, C.E. and Zetterberg, P.O. and Joelsson, I.}, title = {Forbidden transitions in na− and mg-like spectra}, journal = {Physica Scripta}, year = {1985}, volume = {32}, number = {2}, pages = {125 – 128}, doi = {10.1088/0031-8949/32/2/006} }
Herman M, Van Craen J-C, Vander Auwera J and Hills G (1985), "Infrared-optical double resonance effects in the 2NO2 ⇌ N2O4 chemical equilibrium", Chemical Physics Letters. Vol. 115(4-5), pp. 445 – 449. [Abstract] [BibTeX] [DOI]
Abstract: Infrared absorptions of N2O4(ν9) at CO laser frequencies were monitored as an NO2/N2O4 sample was subjected to visible radiation from an argon laser. Double resonance signals corresponding to a two-molecule scheme involving the 2NO2 ⇌ N2O4 chemical equilibrium have been observed and interpreted. © 1985.
BibTeX: @article{Herman1985445, author = {Herman, M. and Van Craen, J.-C. and Vander Auwera, J. and Hills, G.W.}, title = {Infrared-optical double resonance effects in the 2NO2 ⇌ N2O4 chemical equilibrium}, journal = {Chemical Physics Letters}, year = {1985}, volume = {115}, number = {4-5}, pages = {445 – 449}, doi = {10.1016/0009-2614(85)85167-8} }
Lievin J and Metz J-Y (1985), "Extension of a simplified method for molecular correlation energy calculations to molecules containing third row atoms II. Application to HCl, HCl+, ClO and NCl molecules", Theoretica Chimica Acta. Vol. 67(5), pp. 391 – 407. [Abstract] [BibTeX] [DOI]
Abstract: A simplified method for molecular correlation energy calculations developed in I is applied to the determination of the potential curves of some diatomic chlorinated molecules HCl(1Σ+), HCl+(2II), ClO(2II) and NCl(X3Σ-, a1Δ, b1Σ+). Dissociation energies, vibrational frequencies and equilibrium internuclear distances are derived from these curves. The ionisation potential (Ip) of HCl, the proton affinity (PA) of Cl, and the term energies of the excited states of the NCl radical are also calculated. It is shown that the results are very sensitive to correlation effects and that the correlated results converge to the corresponding experimental values within 10% for PA, De, Te and ωe, 2% for Re and 0.3% for Ip. This agreement allows us to predict the following lower limits for the dissociation energies of the NCl radical: 2.14, 3.28 and 2.47 eV respectively for the X3Σ-, a1Δ and b1Σ+ states. Results on HF and HF+ are also discussed and compared with those obtained for HCl and HCl+. © 1985 Springer-Verlag.
BibTeX: @article{Lievin1985391, author = {Lievin, Jacques and Metz, Jean-Yves}, title = {Extension of a simplified method for molecular correlation energy calculations to molecules containing third row atoms II. Application to HCl, HCl+, ClO and NCl molecules}, journal = {Theoretica Chimica Acta}, year = {1985}, volume = {67}, number = {5}, pages = {391 – 407}, doi = {10.1007/BF00530089} }
McWeeny R and Sutcliffe B (1985), "Fundamentals of Self-Consistent-Field (SCF), Hartree-Fock (HF), Multi-Configuration (MC)SCF and Configuration Interaction (CI) schemes", Computer Physics Reports. Vol. 2(5), pp. 219 – 278. [Abstract] [BibTeX] [DOI]
Abstract: This report is concerned with the calculation of molecular wavefunctions and consist of two parts: the first provides an over-view of the development of various forms of self-consistent field (SCP) theory, from the early work of Hartee and collaborators (on atoms) up to the present day; while tehsecond turns to the systematic improvement of approximations at the Hartee-Fock (HF) level by the admission of configuration interaction (CI). The emphasis of the report is on the development of methodology, always in a form well adapted to computer implementation, but considerations of a purely computational nature are excluded. The aim is rather to provide a coherent review of one sector of a large and rapidly expanding area of computational physics - the calculation and use of high-precision electronic wavefunctions for molecules - and to provide a general introduction to other reports in this series. Part I deals first with the traditional approach to the problem of optimizing the orbitals in a one-determinant wavefunctions, as applied in the closed-shell, retricted and unrestricted forms of the HF approximation. This is followed by the introduction of second-quantization techniques and a more detailed discussion of solution methods. Part II is concerned with the general problem of constructing high-precision wavefunctions as truncated complete-set expansions containing thousands, sometimes millions, of terms. Recent progress is discussed, with emphasis on the exploitation of permutation and unitary group symmetries, the efficient evaluation of matrix elements, and the development of algorithms for solving very high order matrix eigenvalue equations. © 1984.
BibTeX: @article{McWeeny1985219, author = {McWeeny, R. and Sutcliffe, B.T.}, title = {Fundamentals of Self-Consistent-Field (SCF), Hartree-Fock (HF), Multi-Configuration (MC)SCF and Configuration Interaction (CI) schemes}, journal = {Computer Physics Reports}, year = {1985}, volume = {2}, number = {5}, pages = {219 – 278}, doi = {10.1016/0167-7977(85)90009-7} }
Metz J-Y and Lievin J (1985), "Extension of a simplified method for molecular correlation energy calculations to molecules containing third row atoms. I. Methodological developments", Theoretica Chimica Acta. Vol. 67(5), pp. 369 – 390. [Abstract] [BibTeX] [DOI]
Abstract: An extension of a simplified method for molecular correlation energy calculations to molecules containing third row atoms is presented. In addition to the use of pseudo-potentials in the calculations, the consequences of this extension on the different components of the energy partition which is the basic idea of the method, is analysed. Particular emphasis is placed on the specific role played by the 3 d orbitals in each of the energy components. First, at the zeroth order, the energy is found to be very sensitive to the optimization of the 3 d polarization functions. Secondly, the internal correlation energy, calculated by CI, requires the optimization of distinct 3 d correlation orbitals to describe adequately the strong near-degeneracy effects that occur within the valence space. Finally it is shown that the 3 d orbitals contribute partially to the non-internal correlation energy and that, the "atoms-in-molecule" structures corresponding typically to all-external contributions are negligible. The concept of error energy is introduced in place of the non-internal correlation energy: it includes the relativistic contributions within the semi-empirical tables. Such tables are presented for second row atoms and for the chlorine atom. From these tables, predicted values for some atomic term energies, experimentally undetermined, are derived. The methodological tests are limited here to the chlorine atom which is chosen for further applications in the next paper of this series. The conclusions concerning the applicability of the method to third row atoms are however quite general. © 1985 Springer-Verlag.
BibTeX: @article{Metz1985369, author = {Metz, Jean-Yves and Lievin, Jacques}, title = {Extension of a simplified method for molecular correlation energy calculations to molecules containing third row atoms. I. Methodological developments}, journal = {Theoretica Chimica Acta}, year = {1985}, volume = {67}, number = {5}, pages = {369 – 390}, doi = {10.1007/BF00530088} }
Tennyson J and Sutcliffe BT (1985), "A calculation of the rovibrational spectra of the H+3, H2D+ and D2H+ molecules", Molecular Physics. Vol. 56(5), pp. 1175 – 1183. [Abstract] [BibTeX] [DOI]
Abstract: Variationally exact rovibrational calculations are performed for the H3+, H2D+ and D2H+ molecules using two recent fits to the ab initio potential energy data of Burton et al. (1985, Molec. Phys., 55, 527). For the best surface, vibrational fundamentals are vA1 = 3175 cm-1 and νE = 2518 (2521) cm-1 for H3+ ; νl = 2989 (2992) cm-1, ν2= 2203 cm-1, and ν3 = 2332cm-1 for H2D+ , and νt = 2733 (2737), ν2 = 1965, ν3 = 2027 for D2H+ (where experimental results are given in parenthesis). Rotational constants, which agree well with the experimental constants, where available, are calculated for H3+ and D2H+ . Results are presented for the (0, 1, 0) and (0, 0, 1) states of D2H+ which are yet to be characterized experimentally. © 1985 Taylor & Francis Group, LLC.
BibTeX: @article{Tennyson19851175, author = {Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {A calculation of the rovibrational spectra of the H+3, H2D+ and D2H+ molecules}, journal = {Molecular Physics}, year = {1985}, volume = {56}, number = {5}, pages = {1175 – 1183}, doi = {10.1080/00268978500102981} }
Tennyson J and Sutcliffe BT (1985), "Calculated ro-vibrational spectrum of H2D+", Molecular Physics. Vol. 54(1), pp. 141 – 144. [Abstract] [BibTeX] [DOI]
Abstract: Ab initio data for the rotational levels of the (0, 0, 0), (0, 1, 0) and (0, 0, 1) states of H2D+ are fitted and assignments suggested for the spectrum of Shy, Farley and Wing (1981, Phys. Rev., A, 24, 1146). © 1985 Taylor and Francis Group, LLC.
BibTeX: @article{Tennyson1985141, author = {Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {Calculated ro-vibrational spectrum of H2D+}, journal = {Molecular Physics}, year = {1985}, volume = {54}, number = {1}, pages = {141 – 144}, doi = {10.1080/00268978500100111} }
Van Craen J, Herman M, Colin R and Watson J (1985), "The A ̃- X ̃ band system of acetylene: Analysis of medium-wavelength bands, and vibration-rotation constants for the levels nν′3 (n = 4-6), ν′2 + nν′3 (n = 3-5), and ν′1 + nν′3 (n = 2, 3)", Journal of Molecular Spectroscopy. Vol. 111(1), pp. 185 – 197. [Abstract] [BibTeX] [DOI]
Abstract: The previous study [J. Mol. Spectrosc.95, 101-132 (1982)] of the high-resolution absorption spectrum of the A ̃1Au(C2h)- X ̃1Σg+(D∞h) electronic transition of C2H2 is extended to the region 2190-2050 Å. The vibrational levels nν′3 (n = 4-6), ν′2 + nν′3 (n = 3-5), and ν′1 + nν′3 (n = 2-3) of the A ̃ state are assigned. These levels and another unidentified level are observed as upper states of vibrational progressions in the known ν″4(πg) vibrational mode of the ground state. Detailed rotational analyses of all these bands are performed. The rotational levels of each of these upper state vibrational levels are perturbed by interactions with unidentified vibronic levels, which probably also belong to the A ̃ electronic state. As a result, only approximate upper rovibrational constants are obtained. © 1985.
BibTeX: @article{VanCraen1985185, author = {Van Craen, J.C. and Herman, M. and Colin, R. and Watson, J.K.G.}, title = {The A ̃- X ̃ band system of acetylene: Analysis of medium-wavelength bands, and vibration-rotation constants for the levels nν′3 (n = 4-6), ν′2 + nν′3 (n = 3-5), and ν′1 + nν′3 (n = 2, 3)}, journal = {Journal of Molecular Spectroscopy}, year = {1985}, volume = {111}, number = {1}, pages = {185 – 197}, doi = {10.1016/0022-2852(85)90080-3} }
Godefroid M and Fischer C (1984), "MCHF-BP fine-structure splittings and transition rates for the ground configuration in the nitrogen sequence", Journal of Physics B: Atomic and Molecular Physics. Vol. 17(5), pp. 681 – 692. [Abstract] [BibTeX] [DOI]
Abstract: The multiconfiguration Hartree-Fock method extended to include relativistic effects in the Breit-Pauli approximation (MCHF-BP) is tested in the study of the ground configuration of nitrogen-like ions. Fine-structure splittings, E2 and M1 transition rates calculated with the classical (nonrelativistic) form of the magnetic transition operator are presented and compared with other theoretical and experimental results up to Zn XXIV. The astrophysical problem of the high-density limit of the intensity ratio I(2D5/2 to 4S3/2)/I(2D3/2 to 4S 3/2) is discussed on the basis of these new theoretical data.
BibTeX: @article{Godefroid1984681, author = {Godefroid, M. and Fischer, C.F.}, title = {MCHF-BP fine-structure splittings and transition rates for the ground configuration in the nitrogen sequence}, journal = {Journal of Physics B: Atomic and Molecular Physics}, year = {1984}, volume = {17}, number = {5}, pages = {681 – 692}, doi = {10.1088/0022-3700/17/5/008} }
Henriet C and Verhaegen G (1984), "Valence and Rydberg states of the BeH molecule", Journal of Molecular Structure: THEOCHEM. Vol. 107(C), pp. 63 – 73. [Abstract] [BibTeX] [DOI]
Abstract: Accurate ab initio LCAO-MO-SCF-CI calculations were performed at a series of internuclear distances in order to obtain the potential energy curves for the five lowest states of 2Σ+ symmetry and the four lowest of 2Π symmetry. A large STO basis set including Rydberg orbitals (RO) was used. The CI calculations were carried out in two steps, the first without including the RO's, the second including them together with the leading NO's of the first CI calculation. The results are in excellent agreement with available experimental values. Calculations were run with ALCHBXL (ref.1), an adapted version of ALCHEMY (ref.2) to CDC CYBER 170 computers. © 1984.
BibTeX: @article{Henriet198463, author = {Henriet, C. and Verhaegen, G.}, title = {Valence and Rydberg states of the BeH molecule}, journal = {Journal of Molecular Structure: THEOCHEM}, year = {1984}, volume = {107}, number = {C}, pages = {63 – 73}, doi = {10.1016/0166-1280(84)80038-X} }
Lievin J and Metz J (1984), "Semi-empirical calculation of the molecular correlation energy", Journal of Molecular Structure: THEOCHEM. Vol. 107(C), pp. 23 – 38. [Abstract] [BibTeX] [DOI]
Abstract: A simplified method for molecular correlation energy calculations has been recently proposed (ref. 1-2) on the basis of a partition into internal and non-internal contributions. The field of application of the method is discussed, some typical results are commented and recent developments are presented. The formalism of the "atoms-in-molecule" approach adopted for the non-internal correlation energy calculations is analyzed in order to optimize its programming. The extension of the method to molecules containing atoms of the third row is considered and particular emphasis is layed on the choice of semi-empirical atomic data. Finally, preliminar results obtained for the Chlorine atom are presented. © 1984.
BibTeX: @article{Lievin198423, author = {Lievin, J. and Metz, J.Y.}, title = {Semi-empirical calculation of the molecular correlation energy}, journal = {Journal of Molecular Structure: THEOCHEM}, year = {1984}, volume = {107}, number = {C}, pages = {23 – 38}, doi = {10.1016/0166-1280(84)80034-2} }
Moreau B, Sana M, Leroy G and Lievin J (1984), "Contribution to the semi-empirical calculation of electronic correlation hypersurfaces", Journal of Molecular Structure: THEOCHEM. Vol. 107(C), pp. 111 – 115. [Abstract] [BibTeX] [DOI]
Abstract: A semi-empirical method for electronic correlation energy calculations, recently proposed by Liévin and al. (refs.1,3), is discussed in regard to its domain of applicability. Although the economical version of this method was primarily limited to the calculation of reaction energies, it is proposed here to extend the use of this version to the study of potential surfaces associated with the fundamental state of a supermolecule. A few points of the potential surface of 2 CN are examined as an example. © 1984.
BibTeX: @article{Moreau1984111, author = {Moreau, B. and Sana, M. and Leroy, G. and Lievin, J.}, title = {Contribution to the semi-empirical calculation of electronic correlation hypersurfaces}, journal = {Journal of Molecular Structure: THEOCHEM}, year = {1984}, volume = {107}, number = {C}, pages = {111 – 115}, doi = {10.1016/0166-1280(84)80045-7} }
Tenyson J and Sutcliffe BT (1984), "On the rovibrational levels of the H3+ and H2D+ molecules", Molecular Physics. Vol. 51(4), pp. 887 – 906. [Abstract] [BibTeX] [DOI]
Abstract: Variationally exact rovibrational levels for the H3+ and H2D+ molecules are calculated using a recently published accurate potential. Vibrational fundamentals are vA1 = 3191 cm-1 and vE = 2494 (2521-6) cm-1 for H3+ and v1 = 3000 cm-1, v2 = 2184 cm-1 and v3 = 2310 cm-1 for H2D+. For H3+ calculated ground state rotational constants are B0 = 43-51 (43-57) cm-1, C„ = 20-59 (20-71) cm-1, Dj0 = 0-04 (0-05) cm-1, DJK0= -0-07 (-0-10) cm-1 and Dk = 0-04 (0-04) cm-1 (where experimental results are given in parenthesis). An attempt is made to stabilize many vibrational states. We thus reassess the results of Carney and Porter. The implications for astrophysics, the interpretation of the infrared spectrum of H3+ near its dissociation limit and the unassigned spectrum of H2D+ are discussed. © 1984 Taylor & Francis Group, LLc.
BibTeX: @article{Tenyson1984887, author = {Tenyson, Jonathan and Sutcliffe, Brain T.}, title = {On the rovibrational levels of the H3+ and H2D+ molecules}, journal = {Molecular Physics}, year = {1984}, volume = {51}, number = {4}, pages = {887 – 906}, doi = {10.1080/00268978400100591} }
Breuletx J and Lievin J (1983), "Study of correlation effects in the calculation of heats of reactions.", Journal of Molecular Structure: THEOCHEM. Vol. 93(C), pp. 341 – 345. [Abstract] [BibTeX] [DOI]
Abstract: A simplified method of correlation energy calculation has been recently proposed (ref. 1-2). This method, which was shown to give good reaction heats where H.F. calculation fails (dissociations) is tested here in the calculation of reaction heats for which the H.F. approximation gives good results. © 1983.
BibTeX: @article{Breuletx1983341, author = {Breuletx, J. and Lievin, J.}, title = {Study of correlation effects in the calculation of heats of reactions.}, journal = {Journal of Molecular Structure: THEOCHEM}, year = {1983}, volume = {93}, number = {C}, pages = {341 – 345}, doi = {10.1016/0166-1280(83)80123-7} }
Brocks G, Van Der Avoird A, Sutcliffe B and Tennyson J (1983), "Quantum dynamics of non-rigid systems comprising two polyatomic fragments", Molecular Physics. Vol. 50(5), pp. 1025 – 1043. [Abstract] [BibTeX] [DOI]
Abstract: We combine earlier treatments for the embedding of body-fixed coordinates in linear molecules with the close-coupling formalism developed for atom- diatom scattering and derive a hamiltonian which is most convenient for describing the nuclear motions in van der Waals complexes and other non-rigid Systems comprising two polyatomic fragments, A and B. This hamiltonian can stili be partitioned in the form Ha + Hb + HINT, just as the space-fixed hamiltonian. The body-fixed form, however, has several advantages. We discuss solution strategies for the rovibrational problem in non-rigid dimers, based on this partitioning of the hamiltonian. Finally, in view of the size of the generai polyatomic-polyatomic case, we suggest problems which should be currently practicable. © 1983 Taylor & Francis Group, LLC.
BibTeX: @article{Brocks19831025, author = {Brocks, G. and Van Der Avoird, A. and Sutcliffe, B.T. and Tennyson, J.}, title = {Quantum dynamics of non-rigid systems comprising two polyatomic fragments}, journal = {Molecular Physics}, year = {1983}, volume = {50}, number = {5}, pages = {1025 – 1043}, note = {All Open Access, Green Open Access}, doi = {10.1080/00268978300102831} }
Carter S, Handy N and Sutcliffe B (1983), "Preliminary communication: A variational method for the calculation of rovibrational levels of any triatomic molecule", Molecular Physics. Vol. 49(3), pp. 745 – 748. [BibTeX] [DOI]
BibTeX: @article{Carter1983745, author = {Carter, S. and Handy, N.C. and Sutcliffe, B.T.}, title = {Preliminary communication: A variational method for the calculation of rovibrational levels of any triatomic molecule}, journal = {Molecular Physics}, year = {1983}, volume = {49}, number = {3}, pages = {745 – 748}, doi = {10.1080/00268978300101521} }
Metz J-Y and Lievin J (1983), "Application of an economical method for the calculation of molecular correlation energies to the study of a potential energy surface: The HO2 radical dissociation process", Theoretica Chimica Acta. Vol. 62(3), pp. 195 – 207. [Abstract] [BibTeX] [DOI]
Abstract: A simplified method for the calculation of molecular correlation energies, developed previously, is applied to the study of the potential energy hypersurface related to the reaction O2+H→HO2→OH+O. The main parameters that characterize the topology of the surface have been determined: the equilibrium geometries and vibrational frequencies of HO2 and of its dissociation products, the dissociation energies, the energy gap between the dissociation limits, the geometry of an activated complex, and the corresponding potential barrier height. The particular importance of including the correlation energy is discussed for each of the calculated parameters. In spite of the minimal computational effort required, the results are in good agreement with the experimental data on the one hand, and with the results proceeding from elaborate variational calculations on the other hand. Moreover the controverted existence of a potential barrier (0.19 eV) along the O2+H→ HO2 recombination path is discussed. © 1983 Springer-Verlag.
BibTeX: @article{Metz1983195, author = {Metz, Jean-Yves and Lievin, Jacques}, title = {Application of an economical method for the calculation of molecular correlation energies to the study of a potential energy surface: The HO2 radical dissociation process}, journal = {Theoretica Chimica Acta}, year = {1983}, volume = {62}, number = {3}, pages = {195 – 207}, doi = {10.1007/BF00548834} }
Sutcliffe B (1983), "A comment on a recent proposal for the calculation of vibrational energies in the general triatomic molecule", Molecular Physics. Vol. 48(3), pp. 561 – 566. [Abstract] [BibTeX] [DOI]
Abstract: In a recent paper Carter and Handy recommended the use generally of a particular form of the vibration-rotation hamiltonian for a triatomic molecule. The grounds on which this recommendation is made are examined and shown to be inadequate. A detailed examination of the properties of the proposed hamiltonian is undertaken and some suggestions about its likely domain are made. © 1983 Taylor & Francis Group, LLC.
BibTeX: @article{Sutcliffe1983561, author = {Sutcliffe, B.T.}, title = {A comment on a recent proposal for the calculation of vibrational energies in the general triatomic molecule}, journal = {Molecular Physics}, year = {1983}, volume = {48}, number = {3}, pages = {561 – 566}, doi = {10.1080/00268978300100391} }
Tennyson J and Sutcliffe BT (1983), "Variationally exact ro-vibrational levels of the floppy CH2+ molecule", Journal of Molecular Spectroscopy. Vol. 101(1), pp. 71 – 82. [Abstract] [BibTeX] [DOI]
Abstract: Ro-vibrational calculations are performed on the CH2+ radical using a method recently developed for atom-diatom systems. The vibrational fundamentals obtained are 2998.8, 718.3, and 3270.7 cm-1, in good agreement with recent results. Band origins for several higher vibrational levels are also obtained. Calculations with J = 1 show that the Coriolis interaction play a significant role and two alternative embeddings are discussed. Use of correlation parameters confirms that CH2+ belongs to no idealized class of molecules in keeping with its "floppy" nature. © 1983.
BibTeX: @article{Tennyson198371, author = {Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {Variationally exact ro-vibrational levels of the floppy CH2+ molecule}, journal = {Journal of Molecular Spectroscopy}, year = {1983}, volume = {101}, number = {1}, pages = {71 – 82}, doi = {10.1016/0022-2852(83)90007-3} }
Tennyson J and Sutcliffe BT (1983), "Variationally exact rovibrational spectra of nonrigid triatomics: The HeHF van der Waals molecule", The Journal of Chemical Physics. Vol. 79(1), pp. 43 – 51. [Abstract] [BibTeX] [DOI]
Abstract: A variationally exact method of obtaining the rovibrational levels of triatomic potentials is presented. This LC-RAMP method derives from the close-coupling approach in body-fixed coordinates, but uses optimized Morse oscillator functions to give radial basis sets for both the diatomic and complex stretching coordinates. The method is suited to the nuclear dynamics of nonrigid molecules and atom-diatom van der Waals complexes. A recent full interaction surface for HeHF is fitted and used for dynamical calculations. The binding energy of the complex increases slowly with HF vibrational excitation. Correlation between the HF and complex vibrational modes is found to be negligible. © 1983 American Institute of Physics.
BibTeX: @article{Tennyson198343, author = {Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {Variationally exact rovibrational spectra of nonrigid triatomics: The HeHF van der Waals molecule}, journal = {The Journal of Chemical Physics}, year = {1983}, volume = {79}, number = {1}, pages = {43 – 51}, doi = {10.1063/1.445541} }
Breulet J and Lievin J (1982), "Comparative theoretical study of the dissociation process of the isoelectronic molecules BH3CO, CH2CO, HNCO, CO2 and BH3N2, CH2N2, HN3, N2O", Theoretica Chimica Acta. Vol. 61(1), pp. 59 – 72. [Abstract] [BibTeX] [DOI]
Abstract: An ab initio study of the electronic structure of several 22-electrons molecules is presented. The equilibrium geometries of their ground state are calculated at the SCF level using the 6-31G basis set and are found to be in good agreement with the experimental geometries. The dissociation process of these molecules leading to the isoelectronic products CO or N2 on the one hand and BH3, CH2, NH and O on the other hand is studied. The least-energy dissociation paths of the ground states determined at the SCF level are compared on the basis of electron density interactions. The dissociation energies corresponding to the two lowest dissociation channels are calculated. In these calculations, the correlation energy is taken into account using a non-variational method developed previously. The calculated values of dissociation energies are in good agreement with the existing experimental values. The results permit to predict values for HNCO, BH3CO and CH2N2 and to confirm the instability of BH3N2. © 1982 Springer-Verlag.
BibTeX: @article{Breulet198259, author = {Breulet, Jacques and Lievin, Jacques}, title = {Comparative theoretical study of the dissociation process of the isoelectronic molecules BH3CO, CH2CO, HNCO, CO2 and BH3N2, CH2N2, HN3, N2O}, journal = {Theoretica Chimica Acta}, year = {1982}, volume = {61}, number = {1}, pages = {59 – 72}, doi = {10.1007/BF00573865} }
Colin R (1982), "Spectrum of SO. Evidence for a new 3δ state", Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics. Vol. 78(8), pp. 1139 – 1147. [Abstract] [BibTeX] [DOI]
Abstract: A rotational analysis has been carried out on the 3Π 1 and 3Π0 sub-bands of the 1-0 band of the A 3Π-X3Σ spectrum of SO obtained previously. A perturbation present on the v′ = 1, J′ = 15 level of the F 2(3Π1) component of the A3Π state is shown to be consistent with that arising from interaction with a 3Δ state. Using calculations of Dixon et al., coupled with an empirical correction to the calculated term value of the 3Δ state, a crude potential is constructed which would cross the A state at v′ = 1.
BibTeX: @article{Colin19821139, author = {Colin, Reginald}, title = {Spectrum of SO. Evidence for a new 3δ state}, journal = {Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics}, year = {1982}, volume = {78}, number = {8}, pages = {1139 – 1147}, doi = {10.1039/F29827801139} }
Colin R, Herman M and Prevot F (1982), "The bO+X1O+ band system of the PI molecule", Chemical Physics Letters. Vol. 91(3), pp. 213 – 216. [Abstract] [BibTeX] [DOI]
Abstract: A new band system lying in the region 8500-8970 Å and composed of twelve single-headed violet-degraded bands has been photographed at medium resolution from a microwave discharge of He + PI3. The bands are assigned to the b 0+-X10+ transition of PI and vibrational analysis leads to ω′e = 426.30, ω′ex′c = 1.40, ω″e = 399.90, ω″ex″e = 1.35 and Te = 11532.28cm-1. © 1982.
BibTeX: @article{Colin1982213, author = {Colin, R. and Herman, M. and Prevot, F.}, title = {The bO+X1O+ band system of the PI molecule}, journal = {Chemical Physics Letters}, year = {1982}, volume = {91}, number = {3}, pages = {213 – 216}, doi = {10.1016/0009-2614(82)83644-0} }
Fischer C and Godefroid M (1982), "Lifetime trends for the n=3 singlet states in the Mg sequence", Nuclear Instruments and Methods In Physics Research. Vol. 202(1-2), pp. 307 – 322. [Abstract] [BibTeX] [DOI]
Abstract: Theoretical lifetime trends are reported for all bound singlet states in the n=3 complex of the Mg sequence for Z≤26. Calculations are based on MCHF wavefunctions and include only dipole allowed transitions in the LS scheme. For states that are entering the bound spectrum, the reported lifetime is an upper bound. At sufficiently high Z, all these states can decay only through Δn=0 transitions and several lifetime trends become similar. Implications for the cascade problem in beam-foil spectroscopy are discussed. © 1982.
BibTeX: @article{Fischer1982307, author = {Fischer, C.Froese and Godefroid, M.}, title = {Lifetime trends for the n=3 singlet states in the Mg sequence}, journal = {Nuclear Instruments and Methods In Physics Research}, year = {1982}, volume = {202}, number = {1-2}, pages = {307 – 322}, doi = {10.1016/0167-5087(82)90411-2} }
Godefroid M (1982), "Note on the mutual spin-orbit matrix elements", Journal of Physics B: Atomic and Molecular Physics. Vol. 15(20), pp. 3583 – 3586. [Abstract] [BibTeX] [DOI]
Abstract: Relations between magnetic radial integrals are derived and used in the discussion of symmetry properties of mutual spin-orbit matrix elements.
BibTeX: @article{Godefroid19823583, author = {Godefroid, M.}, title = {Note on the mutual spin-orbit matrix elements}, journal = {Journal of Physics B: Atomic and Molecular Physics}, year = {1982}, volume = {15}, number = {20}, pages = {3583 – 3586}, doi = {10.1088/0022-3700/15/20/008} }
Herman M, Johns J and McKellar A (1982), "High-resolution laser Stark and Fourier transform spectroscopy of DBr at 5.5 μm", Journal of Molecular Spectroscopy. Vol. 95(2), pp. 405 – 412. [Abstract] [BibTeX] [DOI]
Abstract: A very close coincidence between the P(1) transition of the 1-0 band of D79Br and a CO laser line has allowed the observation of a DBr laser Stark spectrum. The observed inverse Lamb dips resolve the Br hyperfine structure of the transition, and are used to determine the value of the dipole moment of DBr in the v = 1 state. A high-resolution Fourier transform spectrum of DBr in the region 1750 to 1900 cm-1 has also been recorded and accurately measured. These new data, together with the best previous microwave and infrared measurements, are used to determine molecular parameters for DBr, and also result in improved secondary wavenumber standards for the 5.5-μm region. © 1982.
BibTeX: @article{Herman1982405, author = {Herman, M. and Johns, J.W.C. and McKellar, A.R.W.}, title = {High-resolution laser Stark and Fourier transform spectroscopy of DBr at 5.5 μm}, journal = {Journal of Molecular Spectroscopy}, year = {1982}, volume = {95}, number = {2}, pages = {405 – 412}, doi = {10.1016/0022-2852(82)90139-4} }
Herman M and Lievin J (1982), "Acetylene from intensity alternation in spectra to ortho and para molecules", Journal of Chemical Education. Vol. 59(1), pp. 17 – 21. [BibTeX] [DOI]
BibTeX: @article{Herman198217, author = {Herman, Michel and Lievin, Jacques}, title = {Acetylene from intensity alternation in spectra to ortho and para molecules}, journal = {Journal of Chemical Education}, year = {1982}, volume = {59}, number = {1}, pages = {17 – 21}, doi = {10.1021/ed059p17} }
Lievin J (1982), "Plots of potential curves and vibritional levels", Journal of Chemical Education. Vol. 59(9), pp. 777 – 778. [BibTeX] [DOI]
BibTeX: @article{Lievin1982777, author = {Lievin, Jacques}, title = {Plots of potential curves and vibritional levels}, journal = {Journal of Chemical Education}, year = {1982}, volume = {59}, number = {9}, pages = {777 – 778}, doi = {10.1021/ed059p777} }
Lievin J, Breulet J, Clercq P and Metz JY (1982), "A simplified method for molecular correlation energy calculations by separation into internal and non-internal parts. Application to multiconfigurational zeroth-order wavefunctions", Theoretica chimica acta. Vol. 61(6), pp. 513 – 537. [Abstract] [BibTeX] [DOI]
Abstract: A simplified method of determining the molecular correlation energy by two separate calculations, one for the internal and one for the non-internal correlation energies, is extended to multiconfigurational zeroth-order wavefunctions. This extension offers the possibility of deriving correlated potential energy curves or surfaces for processes involving configurational changes. The internal correlation energy is shown to be correctly determined by an MC/CI procedure combining the use of minimal and extended basis sets. An original semi-empirical “atoms-in-molecules” method based on the L.C.A.O. expansion of the molecular wavefunction is proposed for the non-internal correlation energy calculations. This method is shown to be able to overcome some of the shortcomings of a previous populations analysis approach. Test calculations concern potential curve parameters (De, Te, Re, We) of the ground and some excited states of the NH, C2, HCN and CN molecules. The results are found to be in good agreement with corresponding experimental and large CI results. © 1982, Springer-Verlag. All rights reserved.
BibTeX: @article{Lievin1982513, author = {Lievin, Jacques and Breulet, Jacques and Clercq, Philippe and Metz, Jean -Yves}, title = {A simplified method for molecular correlation energy calculations by separation into internal and non-internal parts. Application to multiconfigurational zeroth-order wavefunctions}, journal = {Theoretica chimica acta}, year = {1982}, volume = {61}, number = {6}, pages = {513 – 537}, doi = {10.1007/BF02394731} }
Neisius D and Verhaegen G (1982), "Bond functions for AB initio calculations. MCSCF results for CH, NH, OH and FH", Chemical Physics Letters. Vol. 89(3), pp. 228 – 233. [Abstract] [BibTeX] [DOI]
Abstract: Separate optimized s and p bond functions (BFs) were added to the corresponding Dunning basis sets (11s,6p15s) → (5s,4p13s) for the four hydrides. Properties calculated with these basis sets are quasi-identical to those obtained with conventional polarization functions (dlp). The computer time ratios found are: t(BF)/t(dlp) = 1 2 for UHF calculations, and 2 3 for MC SCF calculations. © 1982.
BibTeX: @article{Neisius1982228, author = {Neisius, Daniel and Verhaegen, Georges}, title = {Bond functions for AB initio calculations. MCSCF results for CH, NH, OH and FH}, journal = {Chemical Physics Letters}, year = {1982}, volume = {89}, number = {3}, pages = {228 – 233}, doi = {10.1016/0009-2614(82)80047-X} }
Tennyson J and Sutcliffe BT (1982), "Ab initio vibrational-rotational spectrum of potassiumcyanide: Kcn", Molecular Physics. Vol. 46(1), pp. 109. [Abstract] [BibTeX] [DOI]
Abstract: Dynamical calculations are performed on an ab initio potential energy surface for KCN. Approximate variational solutions of the vibrational Eckart hamiltonian are presented for several states. Fundamental vibrations are found to lie at 302-7 cm-1 and 119-7 cm-1. An effective rotational hamiltonian is solved for several vibrational states allowing vibrational assignments to be made to the observed rotational spectrum. © 1982 Taylor & Francis Group, LLC.
BibTeX: @article{Tennyson1982109, author = {Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {Ab initio vibrational-rotational spectrum of potassiumcyanide: Kcn}, journal = {Molecular Physics}, year = {1982}, volume = {46}, number = {1}, pages = {109}, doi = {10.1080/00268978200101101} }
Tennyson J and Sutcliffe BT (1982), "The ab initio calculation of the vibrational-rotational spectrum of triatomic systems in the close-coupling approach, with KCN and H2Ne as examples", The Journal of Chemical Physics. Vol. 77(8), pp. 4061 – 4072. [Abstract] [BibTeX] [DOI]
Abstract: A Hamiltonian for the vibration-rotation motions of atom-diatom systems is derived in body-fixed coordinates and a method for its solution as a close-coupled secular problem is formulated. The radial coordinate is expanded in Morse oscillator functions. Calculations on KCN and H2Ne are presented. For KCN the neglect of Coriolis interactions is found to have little effect. Extensions of the method to problems in more dimensions are suggested. © 1982 American Institute of Physics.
BibTeX: @article{Tennyson19824061, author = {Tennyson, Jonathan and Sutcliffe, Brian T.}, title = {The ab initio calculation of the vibrational-rotational spectrum of triatomic systems in the close-coupling approach, with KCN and H2Ne as examples}, journal = {The Journal of Chemical Physics}, year = {1982}, volume = {77}, number = {8}, pages = {4061 – 4072}, doi = {10.1063/1.444316} }
Watson J, Herman M, Van Craen J and Colin R (1982), "The A ̃- X ̃ band system of acetylene. Analysis of long-wavelength bands, and vibration-rotation constants for the levels nν″4 (n = 0-4), nν′3 (n = 0-3), and ν′2 + nν′3 (n = 0-2)", Journal of Molecular Spectroscopy. Vol. 95(1), pp. 101 – 132. [Abstract] [BibTeX] [DOI]
Abstract: The A ̃- X ̃ band system of acetylene with origin near 2400 Å was photographed in absorption with higher resolution than in previous studies. A detailed rotational analysis of bands in the 2470-2150-Å region, involving the levels nν″4 (n = 0-4) of the X ̃1Σg+(D∞h) state and nν′3 (n = 0-3) and ν′2 + nν′3 (n = 0-2) of the A ̃1Au(C2h) state, is presented. Some of the previous assignments are modified. Both the principal subbands with ΔK = ± 1 and the satellite subbands with ΔK = 0, ±2 (due to axis-switching) and ΔK = ±3 (due to axis-switching, asymmetry, and l resonance) are included in a comprehensive least-squares fit. Rotational levels of all the l components of the levels of ν″4 are observed, and are consistent with the theory of l doubling and l resonance of a linear molecule. The rotational structures of the vibrational levels of the nonlinear A ̃ state are fitted with asymmetric top rotational constants Av, Bv, Cv and principal centrifugal constants DvJ, DvJK, DvK. A small perturbation of ν′2 + ν′3, together with the inertial defect Δ′v, are discussed in terms of the unobserved vibrational frequencies of the A ̃ state. © 1982.
BibTeX: @article{Watson1982101, author = {Watson, J.K.G and Herman, M and Van Craen, J.C and Colin, R}, title = {The A ̃- X ̃ band system of acetylene. Analysis of long-wavelength bands, and vibration-rotation constants for the levels nν″4 (n = 0-4), nν′3 (n = 0-3), and ν′2 + nν′3 (n = 0-2)}, journal = {Journal of Molecular Spectroscopy}, year = {1982}, volume = {95}, number = {1}, pages = {101 – 132}, doi = {10.1016/0022-2852(82)90242-9} }
Bartholomae R, Martin D and Sutcliffe B (1981), "A nonempirical calculation of the lowest vibrational band origins for the CH2+ radical using a novel vibrational wavefunction", Journal of Molecular Spectroscopy. Vol. 87(2), pp. 367 – 381. [Abstract] [BibTeX] [DOI]
Abstract: Nonempirical molecular structure calculations were performed to obtain an electronic potential energy surface for the CH2+ radical. The vibrational Eckart Hamiltonian was approximately solved on this surface using a variational method, with basis functions designed to allow for the singular behavior of the Eckart Hamiltonian as the radical becomes linear. © 1981.
BibTeX: @article{Bartholomae1981367, author = {Bartholomae, R. and Martin, D. and Sutcliffe, B.T.}, title = {A nonempirical calculation of the lowest vibrational band origins for the CH2+ radical using a novel vibrational wavefunction}, journal = {Journal of Molecular Spectroscopy}, year = {1981}, volume = {87}, number = {2}, pages = {367 – 381}, doi = {10.1016/0022-2852(81)90409-4} }
Herman M and Colin R (1981), "The absorption spectra of C2H2, C2D2, and C2HD in the region 1260 to 1370 Å", Journal of Molecular Spectroscopy. Vol. 85(2), pp. 449 – 461. [Abstract] [BibTeX] [DOI]
Abstract: The absorption spectrum of acetylene in the region of 1260 to 1370 Å has been reinvestigated with C2H2 and C2D2 isotopes and studied for the first time with the C2HD isotope. The analysis of the spectra of the asymmetric compound allows a choice to be made between previous contradictory interpretations: it confirms the presence of three excited electronic states, D ̃, E ̃, and F ̃ in this region. The geometry of the molecule in these states, their symmetry and Rydberg character are discussed. © 1981.
BibTeX: @article{Herman1981449, author = {Herman, M. and Colin, R.}, title = {The absorption spectra of C2H2, C2D2, and C2HD in the region 1260 to 1370 Å}, journal = {Journal of Molecular Spectroscopy}, year = {1981}, volume = {85}, number = {2}, pages = {449 – 461}, doi = {10.1016/0022-2852(81)90216-2} }
Lievin J, Breulet J and Verhaegen G (1981), "A method for molecular correlation energy calculations. Application to the determination of dissociation energies of diatomic and polyatomic molecules", Theoretica Chimica Acta. Vol. 60(4), pp. 339 – 353. [Abstract] [BibTeX] [DOI]
Abstract: A simple and economical method for molecular correlation energy calculations is developed. In this method, the internal part of the correlation energy is calculated by means of a CI in a minimal basis set and the non-internal part (semi-internal and all-external) is evaluated using an original "atoms-in-molecule" method. It is successfully applied to the determination of dissociation energies of some diatomic (H2, NH, C2, CN, N2, CO, NO, O2, F2) and polyatomic (H2O, N2O, CO2, N3H, CH2N2, CH2CO, C2N2) molecules. The results are compared to those obtained using very elaborate variational methods. © 1981 Springer-Verlag.
BibTeX: @article{Lievin1981339, author = {Lievin, Jacques and Breulet, Jacques and Verhaegen, Georges}, title = {A method for molecular correlation energy calculations. Application to the determination of dissociation energies of diatomic and polyatomic molecules}, journal = {Theoretica Chimica Acta}, year = {1981}, volume = {60}, number = {4}, pages = {339 – 353}, doi = {10.1007/BF00549277} }
Neisius D and Verhaegen G (1981), "Bond functions for ab initio calculations on polyatomic molecules. Molecules containing C, N, O and H", Chemical Physics Letters. Vol. 78(1), pp. 147 – 152. [Abstract] [BibTeX] [DOI]
Abstract: Parameters (exponent and position) have been optimized for bond functions and lone-pair functions to be added to basis sets 6-31G. Single average values are proposed for: C-H: N-H and O-H; C-C; C-N, C-O, N-N, N-O and O-O bonds; and all lone pairs on C, N and O. Test calculations favour this type of polarization function with respect to traditional d functions. © 1981.
BibTeX: @article{Neisius1981147, author = {Neisius, Daniel and Verhaegen, Georges}, title = {Bond functions for ab initio calculations on polyatomic molecules. Molecules containing C, N, O and H}, journal = {Chemical Physics Letters}, year = {1981}, volume = {78}, number = {1}, pages = {147 – 152}, doi = {10.1016/0009-2614(81)85573-X} }
Adamantides V, Neisius D and Verhaegen G (1980), "Ab initio study of the O4 molecule", Chemical Physics. Vol. 48(2), pp. 215 – 220. [Abstract] [BibTeX] [DOI]
Abstract: SCF-CI calculations were done on tetratomic oxygen complexes at various geometries. The results point to the existence of a metastable covalent molecule O4 completely different from the van der Waals structure (O2)2 detected experimentally. At its equilibrium geometry, the O4 molecule is a quasi-square (r(OO) ≈ 1.4 Å), slightly twisted out of plane, corresponding to the symmetry group D2d. The activation energy of the reaction O4(1Ag) → 202(X 3Σ-g) is found to be ≈ 15 kcal/mole, that of the inverse reaction, ≈ 75 kcal/mole. © 1980.
BibTeX: @article{Adamantides1980215, author = {Adamantides, V. and Neisius, D. and Verhaegen, G.}, title = {Ab initio study of the O4 molecule}, journal = {Chemical Physics}, year = {1980}, volume = {48}, number = {2}, pages = {215 – 220}, doi = {10.1016/0301-0104(80)80051-6} }
Biemont E and Godefroid M (1980), "Outer correlation MCHF wavefunctions and oscillator strengths along the zinc isoelectronic sequence", Physica Scripta. Vol. 22(3), pp. 231 – 239. [Abstract] [BibTeX] [DOI]
Abstract: Nonrelativistic multiconfiguration Hartree–Fock wavefunctions and oscillator strengths are reported for selected transitions of neutral zinc and of its isoelectronic sequence up to W XLV. Correlation among the outer electrons has been considered in a detailed way. The final values, when compared with the few experimental observations or theoretical calculations available at the neutral end of the sequence, agree well with the most recent and accurate results published for Zn I. © 1980 IOP Publishing Ltd.
BibTeX: @article{Biemont1980231, author = {Biemont, E. and Godefroid, M.}, title = {Outer correlation MCHF wavefunctions and oscillator strengths along the zinc isoelectronic sequence}, journal = {Physica Scripta}, year = {1980}, volume = {22}, number = {3}, pages = {231 – 239}, doi = {10.1088/0031-8949/22/3/009} }
Burtin B, Carleer M, Colin R, Dreze C and Ndikumana T (1980), "Laser-induced fluorescence of gaseous PbS", Journal of Physics B: Atomic and Molecular Physics. Vol. 13(19), pp. 3783 – 3795. [Abstract] [BibTeX] [DOI]
Abstract: A molecular beam of PbS molecules was excited by a CW Ar+ laser in single and multimode operation. Fluorescence spectra induced by the 4880 AA line were recorded and four fluorescence series originating from the nu =7, 8 and 9 levels of the A0+ state were analysed. Using a pulsed dye laser, lifetimes of the nu =4, 5, 6, 7 and 8 level of the A0+ state, the nu =0, 1, 2 and 3 levels of the B1 state and the nu =21 level of the a1 state were measured. The electronic transition moments of the a-X, A-X and B-X transitions were calculated and the lifetimes of the a, A and B states of PbS are compared with those of PbO.
BibTeX: @article{Burtin19803783, author = {Burtin, B. and Carleer, M. and Colin, R. and Dreze, C. and Ndikumana, T.}, title = {Laser-induced fluorescence of gaseous PbS}, journal = {Journal of Physics B: Atomic and Molecular Physics}, year = {1980}, volume = {13}, number = {19}, pages = {3783 – 3795}, doi = {10.1088/0022-3700/13/19/016} }
Godefroid M and Verhaegen G (1980), "MCHF calculations of electric dipole and quadrupole oscillator strengths along the helium isoelectronic sequence", Journal of Physics B: Atomic and Molecular Physics. Vol. 13(16), pp. 3081 – 3098. [Abstract] [BibTeX] [DOI]
Abstract: Accurate wavefunctions obtained by the MCHF method in its reduced form were used to compute the oscillator strengths for all possible electric dipole (E1) and electric quadrupole (E2) transitions between the states 11S, 21,3(S,P0), 31,3D and 41,3F 0 of helium-like systems ranging from He I to Ne IX. The length and velocity forms of the oscillator strengths are in close agreement in all cases; the correlation contributions to the gf values are discussed. The present results are the most accurate to date for E11,3(3D-4F0) and for all the E2 transitions.
BibTeX: @article{Godefroid19803081, author = {Godefroid, M. and Verhaegen, G.}, title = {MCHF calculations of electric dipole and quadrupole oscillator strengths along the helium isoelectronic sequence}, journal = {Journal of Physics B: Atomic and Molecular Physics}, year = {1980}, volume = {13}, number = {16}, pages = {3081 – 3098}, doi = {10.1088/0022-3700/13/16/007} }
Herman M and Colin R (1980), "The geometrical structure of the acetylene molecule in the X̃, G̃ and Ĩ states", Bulletin des Sociétés Chimiques Belges. Vol. 89(5), pp. 335 – 342. [Abstract] [BibTeX] [DOI]
Abstract: The ro and rs geometrical parameters of the acetylene molecule in the linear X̃, G̃ and Ĩ electronic states are determined from the Bo rotational constants of several isotopes. The comparison of the internuclear distances shows a lengthening of the C ‐ C and C ‐ H bonds in the excited states compared to the ground state. Copyright © 1980 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim
BibTeX: @article{Herman1980335, author = {Herman, M. and Colin, R.}, title = {The geometrical structure of the acetylene molecule in the X̃, G̃ and Ĩ states}, journal = {Bulletin des Sociétés Chimiques Belges}, year = {1980}, volume = {89}, number = {5}, pages = {335 – 342}, doi = {10.1002/bscb.19800890503} }
Le Blanc B, Carleer M, Demers Y and Gagné EJ-M (1980), "Déformations du profil du coefficient d’absorption de la raie 5915 å UI dans un generateur de vapeur à cathode creuse pulsee", Applied Optics. Vol. 19(3), pp. 463 – 468. [Abstract] [BibTeX] [DOI]
Abstract: During the development and study of a hollow cathode pulsed source of uranium vapor, we have observed that the absorption line shape changes considerably with time. This has been shown to be due to oscillatory collective displacement of the vapor in the cavity of the source. © 1980, Optical Society of America.
BibTeX: @article{LeBlanc1980463, author = {Le Blanc, B. and Carleer, M. and Demers, Y. and Gagné, Et J.-M.}, title = {Déformations du profil du coefficient d’absorption de la raie 5915 å UI dans un generateur de vapeur à cathode creuse pulsee}, journal = {Applied Optics}, year = {1980}, volume = {19}, number = {3}, pages = {463 – 468}, doi = {10.1364/AO.19.000463} }
Bell G, Herman M, Johns J and Peck E (1979), "The D2Σ+-X2Σ+band system of CaH", Physica Scripta. Vol. 20(5-6), pp. 609 – 616. [Abstract] [BibTeX] [DOI]
Abstract: The D2Σ+-X2Σ+band system of CaH has been reinvestigatedin emission and in absorption. Analysis shows that the previously accepted vibrational numbering must be changed with the result that the vibration frequency of the D state must be reduced by a factor of two. Anomalies in the rotational structure of the D state are explained by a strong homogeneous interaction with excited vibrational levels of B2Σ+. © 1979 IOP Publishing Ltd.
BibTeX: @article{Bell1979609, author = {Bell, G.D. and Herman, M. and Johns, J.W.C. and Peck, E.R.}, title = {The D2Σ+-X2Σ+band system of CaH}, journal = {Physica Scripta}, year = {1979}, volume = {20}, number = {5-6}, pages = {609 – 616}, doi = {10.1088/0031-8949/20/5-6/010} }
Colin R, Herman M and Kopp I (1979), "Renner-teller interactions in the acetylene molecule", Molecular Physics. Vol. 37(5), pp. 1397 – 1412. [Abstract] [BibTeX] [DOI]
Abstract: The analysis of high resolution absorption spectra of the C2H2, C2D213C2H2 and C2HD molecules in the region 1205-1255 A has been achieved. The results, combined with available theoretical relations, have led to a complete interpretation of the features observed in that region in terms of several Renner-Teller interactions involving two close-lying electronic states, G and H, and the two bending vibrations of the molecule. Upper state parameters ɛ and ω satisfying isotopic relations, are derived from the interpretation. © 1979 Taylor & Francis Group, LLC.
BibTeX: @article{Colin19791397, author = {Colin, R. and Herman, M. and Kopp, I.}, title = {Renner-teller interactions in the acetylene molecule}, journal = {Molecular Physics}, year = {1979}, volume = {37}, number = {5}, pages = {1397 – 1412}, doi = {10.1080/00268977900101031} }
Dale R, Herman M, Johns J, McKellar A, Nagler S and Strathy I (1979), "IMPROVED LASER FREQUENCIES AND DUNHAM COEFFICIENTS FOR ISOTOPICALLY SUBSTITUTED CARBON MONOXIDE.", Can J Phys. Vol. 57(5), pp. 677 – 686. [Abstract] [BibTeX] [DOI]
Abstract: New measurements of carbon monoxide laser frequencies in the 5. 3 to 7. 2 mu m region have been made using the techniques of infrared grating spectroscopy and heterodyne beat frequency detection. The observations concentrated on the rarer isotopic species 13C16O, 12C18O, and 13C18O, and on the lower frequency region of CO laser oscillation, where less data have previously been available. The new results have been combined with a large amount of previous data in a simultaneous least-squares fit involving all known isotopic species of CO. The resulting parameters are a set of 'reduced' Dunham coefficients and a set of mass-scaling factors which describe how their isotopic variation differs from the simple mass-dependence normally assumed. Laser frequencies calculated from the new Dunham coefficients are improved from those and they should prove useful in spectroscopic applications of the CO laser. Comprehensive tables of Dunham coefficients for all CO isotopes and of calculated laser frequencies for 12C16O, 13C16O, 12C18O, and 13C18O are given.
BibTeX: @article{Dale1979677, author = {Dale, R.M. and Herman, M. and Johns, J.W.C. and McKellar, A.R.W. and Nagler, S. and Strathy, I.K.M.}, title = {IMPROVED LASER FREQUENCIES AND DUNHAM COEFFICIENTS FOR ISOTOPICALLY SUBSTITUTED CARBON MONOXIDE.}, journal = {Can J Phys}, year = {1979}, volume = {57}, number = {5}, pages = {677 – 686}, doi = {10.1139/p79-096} }
Gagné J, Leblanc B, Mongeau B, Carleer M and Bertrand L (1979), "Study by absorbing a vapor of a laser beam d'238 U(5L06) obtained using a hollow cathode lamp", Applied Optics. Vol. 18(7), pp. 1084 – 1087. [Abstract] [BibTeX] [DOI]
Abstract: The density of U atoms in the (5L06) ground state present in a vapor of this element from a hollow cathode lamp has been measured using laser absorption spectroscopy.The influence of the carrier gases (Ar, Kr, Xe) on the density, the absorption coefficient profiles, and on the ratio of U atoms to the dissipated electrical power has been investigated.It has been found that, in our range of operating conditions, the xenon gas is the most efficient.With xenon, a density of 2.2 × 1012 cm−3 ground-state U atoms is obtained when the lamp dissipates 40 W of electrical power.© 1979 Optical Society of America.
BibTeX: @article{Gagné19791084, author = {Gagné, J.M. and Leblanc, B. and Mongeau, B. and Carleer, M. and Bertrand, L.}, title = {Study by absorbing a vapor of a laser beam d'238 U(5L06) obtained using a hollow cathode lamp}, journal = {Applied Optics}, year = {1979}, volume = {18}, number = {7}, pages = {1084 – 1087}, doi = {10.1364/AO.18.001084} }
Gagné J-M, Carleer M, Leblanc B, Demers Y and Mongeau B (1979), "Générateur de vapeur d’uranium: La lampe à cathode creuse pulsée", Applied Optics. Vol. 18(13), pp. 2107 – 2111. [Abstract] [BibTeX] [DOI]
Abstract: The production of uranium vapors has been studied in the 5L°6 ground state using a pulsed hollow cathode lamp. The evolution of the 238U (5L°6) concentration with time has been studied with Xe and Ar as buffer gases. A density of 2.7 × 1013 atoms cm-3 was obtained with Xe as a buffer gas. In addition, those measurements, obtained from the absorption of a laser beam tuned to the 5758.143 Å (5L°6-17, 3617L6) transition, lowed the determination of the transition probability A = 2.1 × 105 sec-1 and of the branching ratio BR = 0.08 for this transition. © 1979 Optical Society of America.
BibTeX: @article{Gagné19792107, author = {Gagné, J.-M. and Carleer, M. and Leblanc, B. and Demers, Y. and Mongeau, B.}, title = {Générateur de vapeur d’uranium: La lampe à cathode creuse pulsée}, journal = {Applied Optics}, year = {1979}, volume = {18}, number = {13}, pages = {2107 – 2111}, doi = {10.1364/AO.18.002107} }
Lievin J, Breulet J and Verhaegen G (1979), "Ab initio study of hydrazoic acid - I. The ground state: HN3(1 A′)", Theoretica Chimica Acta. Vol. 52(1), pp. 75 – 88. [Abstract] [BibTeX] [DOI]
Abstract: SCF and CI calculations were carried out on the ground1 A′ state of HN3. The equilibrium geometry and vibration frequencies were computed. The results point to a planar structure (group Cs) but to a non-linear (170 °) N-N-N conformation. The calculated vibration frequencies are in fair agreement with experimental assignments. The dissociation path of the molecule to NH and N2 products was investigated and compared to the isoelectronic reaction of diazomethane. The dissociation energy of hydrazoic acid is estimated to be about -8 kcal/mole, with a potential barrier to dissociation of about 30 kcal/mole. © 1979 Springer-Verlag.
BibTeX: @article{Lievin197975, author = {Lievin, Jacques and Breulet, Jacques and Verhaegen, Georges}, title = {Ab initio study of hydrazoic acid - I. The ground state: HN3(1 A′)}, journal = {Theoretica Chimica Acta}, year = {1979}, volume = {52}, number = {1}, pages = {75 – 88}, doi = {10.1007/BF00581703} }
Neisius D and Verhaegen G (1979), "Bond functions for AB initio calculations on polyatomic molecules hydrocarbons", Chemical Physics Letters. Vol. 66(2), pp. 358 – 362. [Abstract] [BibTeX] [DOI]
Abstract: Transferable gaussian CH and CC bond functions and a C lone-pair function were optimized and compared to conventional polarization functions. The exponents (α) and position (γ,β) of these functions are α = 0.9, γ = 0.27 for CH bonds; α = 1.2, γ = 0.50 for CC bonds; α = 0.3, β = 0.47 for C lone-pair. © 1979.
BibTeX: @article{Neisius1979358, author = {Neisius, Daniel and Verhaegen, Georges}, title = {Bond functions for AB initio calculations on polyatomic molecules hydrocarbons}, journal = {Chemical Physics Letters}, year = {1979}, volume = {66}, number = {2}, pages = {358 – 362}, doi = {10.1016/0009-2614(79)85034-4} }
Carleer M, Colin R and Jones W (1978), "Rotational analysis of the (f0+, e0-)-X21 transition of the antimony monofluoride molecule", Journal of Molecular Spectroscopy. Vol. 70(3), pp. 405 – 409. [Abstract] [BibTeX] [DOI]
Abstract: A rotational analysis is performed on the 0-0 band of the so called C2 band system of antimony monofluoride. The results show that the band actually consits of two transitions designated as the f0+-X21 and e0--X21 transitions. © 1978.
BibTeX: @article{Carleer1978405, author = {Carleer, M. and Colin, R. and Jones, W.E.}, title = {Rotational analysis of the (f0+, e0-)-X21 transition of the antimony monofluoride molecule}, journal = {Journal of Molecular Spectroscopy}, year = {1978}, volume = {70}, number = {3}, pages = {405 – 409}, doi = {10.1016/0022-2852(78)90178-9} }
Godefroid M (1978), "An adaptation of acrz to calculate electric quadrupole oscillator strengths", Computer Physics Communications. Vol. 15(3-4), pp. 275 – 282. [BibTeX] [DOI]
BibTeX: @article{Godefroid1978275, author = {Godefroid, M.}, title = {An adaptation of acrz to calculate electric quadrupole oscillator strengths}, journal = {Computer Physics Communications}, year = {1978}, volume = {15}, number = {3-4}, pages = {275 – 282}, doi = {10.1016/0010-4655(78)90097-8} }
Sutcliffe B and Gaze C (1978), "A theoretical study of the temperature dependence of isotropic hyperfine coupling constants for the ch3 and ch2oh radicals", Molecular Physics. Vol. 35(2), pp. 525 – 539. [Abstract] [BibTeX] [DOI]
Abstract: A theoretical model is described which is based on the assumption that the temperature dependence of hyperfine coupling constants (h.c.c.s) in the E.S.R. spectra of organic free radicals is due to nuclear vibrations. The model is tested on the α-proton h.c.c.s of the methyl and hydroxymethyl radicals and in each case it shows that, although only the lowest vibrational mode contributes to the temperature dependence of the h.c.c.s, other modes do contribute to the vibrationally averaged coupling constant. © 1978 Taylor & Francis Group, LLC.
BibTeX: @article{Sutcliffe1978525, author = {Sutcliffe, B.T. and Gaze, C.}, title = {A theoretical study of the temperature dependence of isotropic hyperfine coupling constants for the ch3 and ch2oh radicals}, journal = {Molecular Physics}, year = {1978}, volume = {35}, number = {2}, pages = {525 – 539}, doi = {10.1080/00268977800100381} }
Corvilain-Berger S and Verhaegen G (1977), "Theoretical determination of the ionization potentials of the 1σ and 2σ electrons of CO(1Σ+)", Chemical Physics Letters. Vol. 50(3), pp. 468 – 475. [Abstract] [BibTeX] [DOI]
Abstract: Large-basis-set calculations of near Hartree-Fock accuracy were performed on CO+(1σ-hole 2Σ+) and CO+)2σ-hole, 2Σ+); correlation energies for these systems and for CO were calculated using an atoms-in-molecule approach, relativistic energies and vibrational structure corrections were also considered. The results are: IP(CO, 1σ) = 542.4 (542.57) eV, IP(CO,2σ) = 297.0 (296.24) cV, Dc(CO, 1Σ+) = 10.8 (11.1) Ev, D3(CO+, 1σ, 2Σ+) = 11.9 eV, De(CO+, 2σ, 2Σ+) = 9.1 eV, where IP and De stand respectively for ionization potential and dissociation energy, and where the numbers in parentheses refer to the most recent experimental values. The electron transfers resulting from the ionization of inner-shell electrons are discussed. Finally a quantitative correlation is developed correlating absolute chemical shifts to charge densities. Agreement between the calculated values and those derived from the correlation is quite satisfactory. © 1977.
BibTeX: @article{Corvilain-Berger1977468, author = {Corvilain-Berger, S. and Verhaegen, G.}, title = {Theoretical determination of the ionization potentials of the 1σ and 2σ electrons of CO(1Σ+)}, journal = {Chemical Physics Letters}, year = {1977}, volume = {50}, number = {3}, pages = {468 – 475}, doi = {10.1016/0009-2614(77)80368-0} }
Gervy D and Verhaegen G (1977), "Simplified methods for ab initio calculations. The valence states of CH2 and CH 2+", International Journal of Quantum Chemistry. Vol. 12(1), pp. 115 – 131. [Abstract] [BibTeX] [DOI]
Abstract: Three simplifying methodds are discussed and applied to the four lowest valence states of CH2(3B1, 1A1, 1B1 and 1Σ g+(1A 1)) and to the two lowest of CH 2+(2A1 and 2∏u(2B1)). These methods concern: (1) the development of polarization functions for Gaussian‐lobe basis sets by least‐square fitting of numebrical multiconfigurational atomic fuinctions (this approach is tested also on (C2H2, (2) the use of intermediate Hamiltonians to calculate avoided crossings between potential hypersurfaces, and (3) thecalculation of correlation energies using an atoms‐in‐molecule approach. The calculated equilibrium geometries of the CH2 States are within 0.02 Å and 5° of available experimental data. The calculated term values and ionization potentials, Te(1A1 = 0.35 eV, Te (1B1) = 1.22 eV, Te (1Σ g+(1A 1)) 2.48 eV, I.P. (2A1) = 10.39 eV and I. P. (2∏u(2B1)) = 10.58 eV, are in agreement with some recent theoretical studies, and are very close to existing experimental information. Copyright © 1977 John Wiley & Sons, Inc.
BibTeX: @article{Gervy1977115, author = {Gervy, D. and Verhaegen, G.}, title = {Simplified methods for ab initio calculations. The valence states of CH2 and CH 2+}, journal = {International Journal of Quantum Chemistry}, year = {1977}, volume = {12}, number = {1}, pages = {115 – 131}, doi = {10.1002/qua.560120111} }
Godefroid M, Berger J and Verhaegen G (1977), "Multiconfigurational transition state calculations of atomic oscillator strengths. The resonance transition of beryllium", International Journal of Quantum Chemistry. Vol. 12(11 S), pp. 119 – 123. [Abstract] [BibTeX] [DOI]
Abstract: Transition state Hamiltonians are used at a multiconflgurational level of accuracy to calculate the oscillator strength (length and velocity forms) of the 1s22s2(1S) → 1s22s2p(1P0) transition of beryllium. Three distinct approximations of the formalism are developed and examined. Copyright © 1977 John Wiley & Sons, Inc.
BibTeX: @article{Godefroid1977119, author = {Godefroid, M. and Berger, J.J. and Verhaegen, G.}, title = {Multiconfigurational transition state calculations of atomic oscillator strengths. The resonance transition of beryllium}, journal = {International Journal of Quantum Chemistry}, year = {1977}, volume = {12}, number = {11 S}, pages = {119 – 123}, doi = {10.1002/qua.560120817} }
Herman M and Lievin J (1977), "Group theory: From common objects to molecules", Journal of Chemical Education. Vol. 54(10), pp. 596 – 598. [Abstract] [BibTeX] [DOI]
Abstract: In order to express precisely the abstract concept of symmetry, let us "work" on a common object-a tennis ball.
BibTeX: @article{Herman1977596, author = {Herman, Michel and Lievin, Jacques}, title = {Group theory: From common objects to molecules}, journal = {Journal of Chemical Education}, year = {1977}, volume = {54}, number = {10}, pages = {596 – 598}, doi = {10.1021/ed054p596} }
Lefebvre-Brion H and Colin R (1977), "Anomalous isotope effects in indirect predissociations. An example in the spectrum of BeH", Journal of Molecular Spectroscopy. Vol. 65(1), pp. 33 – 45. [Abstract] [BibTeX] [DOI]
Abstract: Measurements of the linewidths in the (3pπ) B2Π state of BeH and BeD which is predissociated by a 2Σ+ state show an anomalous isotope effect. Ab initio calculations of the five lowest excited 2Σ+ states of BeH show that the first excited 2Σ+ state is stable at a large inter-nuclear distance and is responsible for the observed predissociation. The anomalous isotope effect is explained by an indirect mechanism of predissociation involving this 2Σ+ state and the (3pσ) 2Σ+ state which is separated from the (3pπ) B2Π state by an energy of the order of magnitude of ωe. A new method to calculate the widths and the shifts of predissociated levels is presented and calculations in the case of BeH and BeD give good agreement with the experimental data. © 1977.
BibTeX: @article{Lefebvre-Brion197733, author = {Lefebvre-Brion, H. and Colin, R.}, title = {Anomalous isotope effects in indirect predissociations. An example in the spectrum of BeH}, journal = {Journal of Molecular Spectroscopy}, year = {1977}, volume = {65}, number = {1}, pages = {33 – 45}, doi = {10.1016/0022-2852(77)90356-3} }
Lievin J and Verhaegen G (1977), "Theoretical study of the electronic structure of diazomethane - II. Determination of the least-energy dissociation path to CH2 and N2 products", Theoretica Chimica Acta. Vol. 45(4), pp. 269 – 281. [Abstract] [BibTeX] [DOI]
Abstract: The least-energy dissociation path of the ground state of CH2N2 was determined from ab initio calculations using in a complementary way basis sets of minimal size (STO-3G) and double-zeta (DZ) quality. The results indicate that the least-energy point of attack of the N2 molecule on CH2 (1A1) is roughly perpendicular to the molecular plane (93 °), the C and N atoms being almost co-linear (angle C-N-N:203 ° with outermost N atom pointing away from CH2). The potential barrier of ∼ 1.2 eV found previously on the C2v dissociation path, disappears completely along the least-energy dissociation path (point group Cs (out-of-plane)). These findings corroborate the Woodward-Hoffman rules for this process since the outermost orbitals of the two intersecting states found in point group C2v (...2 b1 and ...8 a1) both correlate to the same irreducible representation (10 á) in point group Cs (out-of-plane). Larger basis set calculations (DZ + polarization functions on all centers, 3 dc and 3 dN developed here), were also carried out on CH2N2 (1A1,3A2 and1A2) at the1A1 equilibrium geometry and on CH2 (3B1) and N2 (1Σg+) at their respective equilibrium geometries. These calculations, together with consideration of correlation energy differences, yield D00 (CH2N2,1A1) = 19 kcal/mole and vertical excitation energies of 67 and 73 kcal/mole for the3A2 and1A2 states respectively. The latter value is in good agreement with the measured experimental value: 72.4 kcal/mole corresponding to the maximum of intensity in the1A2←1A1 absorption band. © 1977 Springer-Verlag.
BibTeX: @article{Lievin1977269, author = {Lievin, Jacques and Verhaegen, Georges}, title = {Theoretical study of the electronic structure of diazomethane - II. Determination of the least-energy dissociation path to CH2 and N2 products}, journal = {Theoretica Chimica Acta}, year = {1977}, volume = {45}, number = {4}, pages = {269 – 281}, doi = {10.1007/BF00554536} }
Woolley R and Sutcliffe B (1977), "Molecular structure and the born-Oppenheimer approximation", Chemical Physics Letters. Vol. 45(2), pp. 393 – 398. [Abstract] [BibTeX] [DOI]
Abstract: A discussion is attempted of the validity of the Born-Oppenheimer approximation which is characterized as an asymptotic analysis leading to a semiclassical theory of molecular structure. It is suggested that there are inherent defects in the resulting semiclassical theory which will limit its utility in the explanation of highly accurate experiments involving molecules. © 1977.
BibTeX: @article{Woolley1977393, author = {Woolley, R.G. and Sutcliffe, B.T.}, title = {Molecular structure and the born-Oppenheimer approximation}, journal = {Chemical Physics Letters}, year = {1977}, volume = {45}, number = {2}, pages = {393 – 398}, doi = {10.1016/0009-2614(77)80298-4} }
Godefroid M, Berger J and Verhaegen G (1976), "A priori calculation of atomic oscillator strengths using correlated transition states", Journal of Physics B: Atomic and Molecular Physics. Vol. 9(13), pp. 2181 – 2193. [Abstract] [BibTeX] [DOI]
Abstract: Atomic oscillator strengths (length and velocity forms) are calculated for a series of transitions using transition Hamiltonians within the Hartree-Fock (HF) approximation. Two methods are implemented: the first defines a transition configuration (TC) corresponding to an average over the occupation numbers of initial and final configurations of the transition considered; the second defines a transition state (TS) corresponding to an average over the energies of the states involved in the transition. In general the TS results agree well with the corresponding HF values, while the TC results show larger discrepancies due to nonphysical self-interactions described in the text. An original method is described for obtaining a multiconfigurational transition state wavefunction. This method (MCTS) is applied to the evaluation of the oscillator strength of the transition Be(1s22s2 1S to 1s 22s2p1P degrees ).
BibTeX: @article{Godefroid19762181, author = {Godefroid, M. and Berger, J.J. and Verhaegen, G.}, title = {A priori calculation of atomic oscillator strengths using correlated transition states}, journal = {Journal of Physics B: Atomic and Molecular Physics}, year = {1976}, volume = {9}, number = {13}, pages = {2181 – 2193}, doi = {10.1088/0022-3700/9/13/007} }
Lievin J and Verhaegen G (1976), "Theoretical study of the electronic structure of diazomethane - I. The dissociation process CH2N2→CH2 + N2 in point group C2 v Symmetry", Theoretica Chimica Acta. Vol. 42(1), pp. 47 – 65. [Abstract] [BibTeX] [DOI]
Abstract: Ab initio calculations of the dissociation process CH2N2 → CH2 + N2 are presented. Calculations were made on the ground 1A1 state as well as on the first few excited states (3B1, 1B1, 1A1*) necessary to the description of the dissociation mechanism in point group C2 v symmetry. The variation of energy was determined as a function of the parameters RCH-RNN and θHCH at several RCN values. Most results were obtained by using a basis set of Gaussian lobe functions contracted to "double-zeta" accuracy. A few calculations were made with the addition of polarization functions on all centers. The equilibrium geometry of the ground state, determined from coupled quadratic equations in the molecular parameters, is in satisfactory agreement with experimental values. The dissociation paths on the potential energy surfaces were determined. The locus of intersection points of the two 1A1 states is described; the avoided crossing of the two potential surfaces was determined from CI calculations based on an "intermediate" Hamiltonian. The geometric and electronic rearrangements due to dissociation as well as the bonding characteristics of the orbitals are discussed. The dissociation energy of the molecule (D00(CH2N2)) is calculated to be 0.91 eV. Finally, the term energy of the 1A1 state of CH2 is predicted to be 0.49 eV. © 1976 Springer-Verlag.
BibTeX: @article{Lievin197647, author = {Lievin, Jacques and Verhaegen, Georges}, title = {Theoretical study of the electronic structure of diazomethane - I. The dissociation process CH2N2→CH2 + N2 in point group C2 v Symmetry}, journal = {Theoretica Chimica Acta}, year = {1976}, volume = {42}, number = {1}, pages = {47 – 65}, doi = {10.1007/BF00548290} }
Scott JM and Sutcliffe BT (1976), "A configuration interaction study of phosphine using bonded functions", Theoretica Chimica Acta. Vol. 41(2), pp. 141 – 148. [Abstract] [BibTeX] [DOI]
Abstract: A computational study is made of the effect of basis set upon the energy, properties and inversion barrier of the phosphine molecule. The calculations are performed at both the SCF and CI level. The flexibility of the double zeta basis is discussed in the light of the results. © 1976 Springer-Verlag.
BibTeX: @article{Scott1976141, author = {Scott, James M. and Sutcliffe, Brian T.}, title = {A configuration interaction study of phosphine using bonded functions}, journal = {Theoretica Chimica Acta}, year = {1976}, volume = {41}, number = {2}, pages = {141 – 148}, doi = {10.1007/BF01178074} }
Prevot F, Colin R and Jones W (1975), "Rotational analysis of the ultraviolet bands of the antimony monofluoride molecule", Journal of Molecular Spectroscopy. Vol. 56(3), pp. 432 – 440. [Abstract] [BibTeX] [DOI]
Abstract: A rotational analysis is performed on several bands of the ultraviolet systems of the SbF molecule obtained at high resolution in emission and in absorption. The results confirm the electronic term value diagram proposed earlier [J. Mol. Spectrosc. 49, 377 (1974)] and yield molecular constants for the first excited state a2 and for the highly excited C31 state of the molecule. © 1975.
BibTeX: @article{Prevot1975432, author = {Prevot, F. and Colin, R. and Jones, W.E.}, title = {Rotational analysis of the ultraviolet bands of the antimony monofluoride molecule}, journal = {Journal of Molecular Spectroscopy}, year = {1975}, volume = {56}, number = {3}, pages = {432 – 440}, doi = {10.1016/0022-2852(75)90130-7} }
Scott JM and Sutcliffe BT (1975), "Direct formation of the CI Hamiltonian matrix from an expansion of Bonded Functions", Theoretica Chimica Acta. Vol. 39(4), pp. 289 – 300. [Abstract] [BibTeX] [DOI]
Abstract: A method of forming the CI Hamiltonian matrix directly from a list of Bonded Functions and the MO-SCF wavefunction is proposed. For small expansions (circa 500 members) this method is definitely more efficient than the normal symbolic techniques and can be more efficient than iterative energy construction techniques. © 1975 Springer-Verlag.
BibTeX: @article{Scott1975289, author = {Scott, James M. and Sutcliffe, Brian T.}, title = {Direct formation of the CI Hamiltonian matrix from an expansion of Bonded Functions}, journal = {Theoretica Chimica Acta}, year = {1975}, volume = {39}, number = {4}, pages = {289 – 300}, doi = {10.1007/BF00551540} }
Sutcliffe B (1975), "The convergence properties of direct energy minimisation with respect to linear coefficients in the MC-LCAO-MO-SCF approach", Theoretica Chimica Acta. Vol. 39(1), pp. 93 – 102. [Abstract] [BibTeX] [DOI]
Abstract: It is shown that in the LCAO-MO-MC-SCF problem, if the molecular orbital orthonormality constraints are introduced in the manner suggested by Kari and Sutcliffe or indeed by any similar method then the Hessian of the problem with respect to the linear coefficients is singular. The nature of this singularity is analysed and it is shown that in general it is possible to remove it in a level-shifting-like scheme, but that only in certain special cases is this procedure likely to be quickly convergent. © 1975 Springer-Verlag.
BibTeX: @article{Sutcliffe197593, author = {Sutcliffe, B.T.}, title = {The convergence properties of direct energy minimisation with respect to linear coefficients in the MC-LCAO-MO-SCF approach}, journal = {Theoretica Chimica Acta}, year = {1975}, volume = {39}, number = {1}, pages = {93 – 102}, doi = {10.1007/BF00547789} }
Colin R, de Greef D, Goethals P and Verhaegen G (1974), "The ionization potential of the BeH molecule", Chemical Physics Letters. Vol. 25(1), pp. 70 – 73. [Abstract] [BibTeX] [DOI]
Abstract: The ionization potential of the BeH molecule is derived from a few Rydberg states observed in the absorption spectrum and from "ab initio" calculations of the energies of the ground states of the BeH and BeH+ molecules at their equilibrium distances. The values are in agreement and yield PI(BeH, X2Σ+) = 66 100 ± 500 cm-1. © 1974.
BibTeX: @article{Colin197470, author = {Colin, R. and de Greef, D. and Goethals, P. and Verhaegen, G.}, title = {The ionization potential of the BeH molecule}, journal = {Chemical Physics Letters}, year = {1974}, volume = {25}, number = {1}, pages = {70 – 73}, doi = {10.1016/0009-2614(74)80334-9} }
De Greef D and Colin R (1974), "The electronic isotope shift in the A2Π-X2Σ+ bands of BeH, BeD and BeT", Journal of Molecular Spectroscopy. Vol. 53(3), pp. 455 – 465. [Abstract] [BibTeX] [DOI]
Abstract: The 0-0, 1-1, 2-2, and 3-3 bands of the A2Π-X2Σ+ transition of the tritiated beryllium monohydride molecule have been observed at 5000 Å in emission using a beryllium hollow-cathode discharge in a He + T2 mixture. The rotational analysis of these bands yields the following principal molecular constants. A2Π:Be = 4.192 cm-1; re = 1.333 A ̊X2Σ:Be = 4.142 cm-1; re = 1.341 A ̊ωe′ - ωe″ = 16.36 cm-1; ωe′Xe′ - ωe″Xe″ = 0.84 cm-1. From the pure electronic energy difference (EΠ - EΣ)BeT = 20 037.91 ± 1.5 cm-1 and the corresponding previously known values for BeH and BeD, the following electronic isotope shifts are derived ΔEei(BeH-BeT) = -4.7 ≠ 1.5cm1, ΔEei(BeH-BeT) = -1.8 ≠ 1.5cm1 and related to the theoretical approach given by Bunker to the problem of the breakdown of the Born-Oppenheimer approximation. © 1994.
BibTeX: @article{DeGreef1974455, author = {De Greef, D. and Colin, R.}, title = {The electronic isotope shift in the A2Π-X2Σ+ bands of BeH, BeD and BeT}, journal = {Journal of Molecular Spectroscopy}, year = {1974}, volume = {53}, number = {3}, pages = {455 – 465}, doi = {10.1016/0022-2852(74)90082-4} }
Diercksen GH and Sutcliffe B (1974), "Configuration interaction by the method of bonded functions, some preliminary calculations", Theoretica Chimica Acta. Vol. 34(2), pp. 105 – 114. [Abstract] [BibTeX] [DOI]
Abstract: A resumé of Boys' approach to configuration interaction calculations is presented, and a program suitable to perform such calculations is described in some detail. The results of a preliminary calculation on water, together with some timings are presented. © 1974 Springer-Verlag.
BibTeX: @article{Diercksen1974105, author = {Diercksen, Geerd H.F. and Sutcliffe, B.T.}, title = {Configuration interaction by the method of bonded functions, some preliminary calculations}, journal = {Theoretica Chimica Acta}, year = {1974}, volume = {34}, number = {2}, pages = {105 – 114}, doi = {10.1007/BF00551361} }
Sutcliffe B (1974), "The convergence properties of direct methods of energy minimization with respect to linear coefficients in the LCAO-MO-SCF approach", Theoretica Chimica Acta. Vol. 33(3), pp. 201 – 214. [Abstract] [BibTeX] [DOI]
Abstract: It is shown that in the LCAO-MO-SCF problem, if the molecular orbital orthonormality constraints are introduced in the manner first suggested by Fletcher, then the Hessian of the problem is singular. It is suggested that this singularity may well account for the slow convergence observed using direct energy minimization methods to solve the SCF problem. Ways of avoiding the consequences of this singularity are discussed. © 1974 Springer-Verlag.
BibTeX: @article{Sutcliffe1974201, author = {Sutcliffe, B.T.}, title = {The convergence properties of direct methods of energy minimization with respect to linear coefficients in the LCAO-MO-SCF approach}, journal = {Theoretica Chimica Acta}, year = {1974}, volume = {33}, number = {3}, pages = {201 – 214}, doi = {10.1007/BF00551255} }
Wang D, Jones W, Prevot F and Colin R (1974), "The b0+-X21 and b0+-X10+ bands of SbF", Journal of Molecular Spectroscopy. Vol. 49(3), pp. 377 – 387. [Abstract] [BibTeX] [DOI]
Abstract: In the emission spectrum of the SbF molecule a new band system is recorded in the near infrared. The rotational analysis of these new bands shows that they belong to the b0+-X21 and b0+-X1O+ transitions and yields molecular constants for the states involved. This new information, together with improved vibrational analyses of the B and C1 systems, permits the electronic energy diagram of the SbF molecule to be derived. © 1974.
BibTeX: @article{Wang1974377, author = {Wang, D.K.W. and Jones, W.E. and Prevot, F. and Colin, R.}, title = {The b0+-X21 and b0+-X10+ bands of SbF}, journal = {Journal of Molecular Spectroscopy}, year = {1974}, volume = {49}, number = {3}, pages = {377 – 387}, doi = {10.1016/0022-2852(74)90018-6} }
Bagus P, Moser C, Goethals P and Verhaegen G (1973), "Accurate ab initia calculation of the BeH molecule. I. the X 2Σ+ and A2∏ states", The Journal of Chemical Physics. Vol. 58(5), pp. 1886 – 1897. [Abstract] [BibTeX] [DOI]
Abstract: Results of calculations using a configuration interaction LCAO-MO method are presented for the X 2Σ+ and A 2∏ states of BeH. Apart from the 1s shell of Be, the correlation energy of the remaining three electrons is calculated quantitatively using an extended basis set and complete configuration interaction including all single, double and triple replacements. The calculated spectroscopic constants are in excellent agreement with available experimental data. The present calculations also predict a value of De(BeH, X 2Σ+) = 2.115 eV, and dismiss the possibility of a potential maximum in the ground state potential energy curve.
BibTeX: @article{Bagus19731886, author = {Bagus, P.S. and Moser, C.M. and Goethals, P. and Verhaegen, G.}, title = {Accurate ab initia calculation of the BeH molecule. I. the X 2Σ+ and A2∏ states}, journal = {The Journal of Chemical Physics}, year = {1973}, volume = {58}, number = {5}, pages = {1886 – 1897}, doi = {10.1063/1.1679448} }
Corvilain S and Verhaegen G (1973), "K‐shell binding energies in C and O", International Journal of Quantum Chemistry. Vol. 7(7 S), pp. 69 – 81. [Abstract] [BibTeX] [DOI]
Abstract: The 1s‐ionization potentials of carbon and oxygen atoms have been calculated. The effects due to the relaxation of the valence orbitals have been taken into account at all levels of the calculations (Hartree‐Fock, relativistic, and correlation energies). The results obtained are IP(1s, C3P) = 295.2 eV and IP (1s, O3P) = 543.5 eV. Exchange‐induced splittings have also been determined: ΔE(C+, 1s(4P – 2P)) = 3.34 eV and ΔE(O +, 1s(4P – 2P)) = 4.43 eV. These predictions are compared to analogous experimental results. Copyright © 1973 John Wiley & Sons, Inc.
BibTeX: @article{Corvilain197369, author = {Corvilain, S. and Verhaegen, G.}, title = {K‐shell binding energies in C and O}, journal = {International Journal of Quantum Chemistry}, year = {1973}, volume = {7}, number = {7 S}, pages = {69 – 81}, doi = {10.1002/qua.560070711} }
Kari R and Sutcliffe B (1973), "Direct minimization of the energy functional in LCAO–MO calculations", International Journal of Quantum Chemistry. Vol. 7(3), pp. 459 – 473. [Abstract] [BibTeX] [DOI]
Abstract: In this paper we obtain formulae useful in methods for the direct minimization of the energy functional in the LCAO‐MO‐MC‐SCF approach. The formulae are appropriate for dealing with variations in both the linear and nonlinear parameters. We include formulae for the usual closed‐ and open‐shell problems as special cases. Copyright © 1973 John Wiley & Sons, Inc.
BibTeX: @article{Kari1973459, author = {Kari, R. and Sutcliffe, B.T.}, title = {Direct minimization of the energy functional in LCAO–MO calculations}, journal = {International Journal of Quantum Chemistry}, year = {1973}, volume = {7}, number = {3}, pages = {459 – 473}, doi = {10.1002/qua.560070304} }
Chiu M, Gilbert B and Sutcliffe B (1972), "A Theoretical study of hyperfme coupling constants of some σ radicals based on the INDO method", Journal of Physical Chemistry. Vol. 76(4), pp. 553 – 564. [Abstract] [BibTeX] [DOI]
Abstract: A study based on the INDO method has been made of a variety of σ radicals. The desirability of minimizing the energy with respect to molecular geometry for a number of small radicals (e.g., ·CONH2, H2C=N ·, H2C= ĊH) is discussed. INDO calculations have also been performed for a series of iminoxy radicals (R2C=NO·), the appropriate geometry around the radical center being chosen as that which minimizes the energy for the smallest radical in the series. An alternative method of determining the proportionality constants for relating esr hyperfine splittings to spin density matrix elements is suggested. Spin density distributions in the space around some of the radicals studied are expressed in the form of spin density contour maps.
BibTeX: @article{Chiu1972553, author = {Chiu, M.F. and Gilbert, B.C. and Sutcliffe, B.T.}, title = {A Theoretical study of hyperfme coupling constants of some σ radicals based on the INDO method}, journal = {Journal of Physical Chemistry}, year = {1972}, volume = {76}, number = {4}, pages = {553 – 564}, doi = {10.1021/j100648a018} }
Colin R, Devillers J and Prevot F (1972), "The b1Σ+-X3Σ- band system of PF", Journal of Molecular Spectroscopy. Vol. 44(2), pp. 230 – 235. [Abstract] [BibTeX] [DOI]
Abstract: The 0-0, 1-1, 2-2, 3-3 and 4-4 bands of the b1Σ+-X3Σ- transition of the PF molecule have been observed in the afterglow produced when PF5 + He (or Ar) is pumped rapidly through a microwave discharge. Measurements of the lines of the sR and oP branches of the strong 0-0 band, which lies at 7483 Å, allows the calculation of Te(b1Σ+) = 13 353.91 ± 0.05 cm-1 and the derivation of the position of all previously known singlet states of this molecule with respect to the triplet ground state. © 1972.
BibTeX: @article{Colin1972230, author = {Colin, R. and Devillers, J. and Prevot, F.}, title = {The b1Σ+-X3Σ- band system of PF}, journal = {Journal of Molecular Spectroscopy}, year = {1972}, volume = {44}, number = {2}, pages = {230 – 235}, doi = {10.1016/0022-2852(72)90102-6} }
Horne R and Colin R (1972), "The A2Π ‐ X2Σ+ band system of BeH and BeD in absorption", Bulletin des Sociétés Chimiques Belges. Vol. 81(1), pp. 93 – 107. [Abstract] [BibTeX] [DOI]
Abstract: A description is given of the absorption spectrum in the region between 6000 and 1700 Å of the BeH and BeD molecules obtained in a King furnace. The A2Π ‐ X2Σ+ bands near 5000 Å, observed previously in emission, have been obtained at high resolution in absorption and reanalysed. Improved vibrational and rotational constants are given. Pure electronic energy differences (EΠ ‐ EΣ)BeH = 20 033.19 and (EΠ‐EΣ)BeD = 20 036.11 cm−1 have been derived and show the existence of an electronic isotope shift Δ νe(BeH ‐ BeD) = ‐2.9 ± 1.0 cm−1 which cannot sofar be explained by existing theories. Precise A‐doubling constants of the A2Π sate are also derived. Copyright © 1972 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim
BibTeX: @article{Horne197293, author = {Horne, R. and Colin, R.}, title = {The A2Π ‐ X2Σ+ band system of BeH and BeD in absorption}, journal = {Bulletin des Sociétés Chimiques Belges}, year = {1972}, volume = {81}, number = {1}, pages = {93 – 107}, doi = {10.1002/bscb.19720810108} }
Liu H and Verhaegen G (1972), "Theoretical Calculation of the Electronic States of the Molecule LiO", Bulletin des Sociétés Chimiques Belges. Vol. 81(1), pp. 109 – 124. [Abstract] [BibTeX] [DOI]
Abstract: Ab initio calculations are performed on a serie of valence states of LiO. The calculations are carried out according to the LCAOMOSCF scheme with a basis set sufficiently large so as to furnish energies very close to the corresponding Hartree‐Fock limits. Correlation energies are calculated semi‐empirically using corresponding atomic data. The results are in good agreement with available experimental data concerning the equilibrium internuclear distance and vibration frequency of the ground state. A2 Π ‐ 2Σ+ electronic transition is predicted to lie in the infra‐red region of the spectrum at about 1750 cm−1. Copyright © 1972 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim
BibTeX: @article{Liu1972109, author = {Liu, H.P.D. and Verhaegen, G.}, title = {Theoretical Calculation of the Electronic States of the Molecule LiO}, journal = {Bulletin des Sociétés Chimiques Belges}, year = {1972}, volume = {81}, number = {1}, pages = {109 – 124}, doi = {10.1002/bscb.19720810109} }
Desclaux J, Moser C and Verhaegen G (1971), "Relativistic energies of excited states of atoms and ions of the second period", Journal of Physics B: Atomic and Molecular Physics. Vol. 4(3), pp. 296 – 310. [Abstract] [BibTeX] [DOI]
Abstract: Relativistic energies are computed for a series of j states corresponding to 1s22sm2pn (0?m?2; 0?n?6) configurations by solution of the hartree-fock-dirac equations. The j states calculated are those states whose eigenfunctions within a configuration correspond to a unique and maximum eigenvalue of the operator j2. In addition, average relativistic energies are obtained for all configurations considered. The two sets of results are compared, and in certain cases (for the 1s22p, 1s22p5, 1s22s22p, 1s 22s22p5 configurations) permit a determination of multiplet splittings (e(2p12/-2p 32/)). The results of these splittings are in excellent agreement with available experimental data. The present results also tend to confirm the assumption that the relativistic energy contributions for the j averaged ls states are the same for all states arising from the same configuration. This makes it possible to evaluate the relativistic energies of all states belonging to the configurations of interest to this paper. These in turn serve to re-evaluate more correctly recently obtained correlation energies for the same states.
BibTeX: @article{Desclaux1971296, author = {Desclaux, J.P. and Moser, C.M. and Verhaegen, G.}, title = {Relativistic energies of excited states of atoms and ions of the second period}, journal = {Journal of Physics B: Atomic and Molecular Physics}, year = {1971}, volume = {4}, number = {3}, pages = {296 – 310}, doi = {10.1088/0022-3700/4/3/003} }
Liu H and Verhaegen G (1971), "Electronic states of NH and OH+", International Journal of Quantum Chemistry. Vol. 5(5 S), pp. 103 – 118. [Abstract] [BibTeX] [DOI]
Abstract: Ab initio calculations (LCAO‐MO‐SCF) nearing Hartree‐Fock accuracy were made for a series of valence states of the molecules NH and OH+. The correlation energies of all states considered were calculated by a method used precedingly and described in this work. Good agreement with experimental data is found for a series of molecular properties such as equilibrium internuclear distances, term values, dissociation energies and ionization potentials; fair agreement is found for vibration frequencies and unharmonic constants. The precision of the present calculations allow definite predictions to be made concerning the relative energies of the singlet and triplet states in NH, and concerning the potential energy curves of unobserved singlets in OH+. Finally, the examination of the dissociation properties of the electronic states from calculations carried out at large internuclear distances, make it possible to reach conclusions concerning the eventual presence of potential maxima in their potential energy curves. Copyright © 1971 John Wiley & Sons, Inc.
BibTeX: @article{Liu1971103, author = {Liu, H.P.D. and Verhaegen, G.}, title = {Electronic states of NH and OH+}, journal = {International Journal of Quantum Chemistry}, year = {1971}, volume = {5}, number = {5 S}, pages = {103 – 118}, doi = {10.1002/qua.560050813} }
McWeeny R and Sutcliffe B (1971), "Methods of Molecular Quantum Mechanics", Physics Today. Vol. 24(5), pp. 50. [BibTeX] [DOI]
BibTeX: @article{McWeeny197150, author = {McWeeny, R. and Sutcliffe, B.T.}, title = {Methods of Molecular Quantum Mechanics}, journal = {Physics Today}, year = {1971}, volume = {24}, number = {5}, pages = {50}, doi = {10.1063/1.3022743} }
Moser C, Nesbet R and Verhaegen G (1971), "A correlation energy calculation of the 1s hole state in neon", Chemical Physics Letters. Vol. 12(2), pp. 230 – 232. [Abstract] [BibTeX] [DOI]
Abstract: The Bethe-Goldstone formalism for calculating correlation energy has been applied to the 1s hole state in neon. The binding energy of the 1s electron is computed to be 870.0 eV which is in excellent agreement with experiment. © 1971.
BibTeX: @article{Moser1971230, author = {Moser, C.M. and Nesbet, R.K. and Verhaegen, G.}, title = {A correlation energy calculation of the 1s hole state in neon}, journal = {Chemical Physics Letters}, year = {1971}, volume = {12}, number = {2}, pages = {230 – 232}, doi = {10.1016/0009-2614(71)85052-2} }
Verhaegen G, Berger J, Desclaux J and Moser C (1971), "A priori calculation of the 1s and 2s hole states in neon", Chemical Physics Letters. Vol. 9(5), pp. 479 – 481. [Abstract] [BibTeX] [DOI]
Abstract: The 1s and 2s electron binding energies in Ne are calculated from the Hartree-Fock and Fock-Dirac energies of Ne(1S0), Ne+(2S, 1s-hole) and Ne+ (2S, 2s-hole). Correlation energies are estimated from the work of Nesbet and of Oksüz and Sinanoǧlu. Close agreement with recent experimental data is found for both binding energies. © 1971.
BibTeX: @article{Verhaegen1971479, author = {Verhaegen, G. and Berger, J.J. and Desclaux, J.P. and Moser, C.M.}, title = {A priori calculation of the 1s and 2s hole states in neon}, journal = {Chemical Physics Letters}, year = {1971}, volume = {9}, number = {5}, pages = {479 – 481}, doi = {10.1016/0009-2614(71)80275-0} }
Carleer M and Colin R (1970), "The f1Δ u-a1Δ g band system of S2 in absorption", Journal of Physics B: Atomic and Molecular Physics. Vol. 3(12), pp. 1715 – 1723. [Abstract] [BibTeX] [DOI]
Abstract: Using flash photolysis and flash discharge techniques, 28 bands of the f1 Delta u-a1 Delta g transition of S2 were photographed at high resolution in absorption. Vibrational and rotational analysis of these bands was made. The observation of this system in absorption allows the a 1 Delta g state to be identified as arising from the ground state electronic configuration pi u4 pi g2. The predissociation occurring between the v=10 and v=11 levels of the f1 Delta u state is probably a c+ type predissociation caused by a repulsive 3 Delta u state.
BibTeX: @article{Carleer19701715, author = {Carleer, M. and Colin, R.}, title = {The f1Δ u-a1Δ g band system of S2 in absorption}, journal = {Journal of Physics B: Atomic and Molecular Physics}, year = {1970}, volume = {3}, number = {12}, pages = {1715 – 1723}, doi = {10.1088/0022-3700/3/12/015} }
Chiu M and Sutcliffe B (1970), "A semi-empirical approach to the estimation of ESR isotropic hyperfine coupling constants in aromatic radicals", Theoretica Chimica Acta. Vol. 16(5), pp. 331 – 345. [Abstract] [BibTeX] [DOI]
Abstract: Using a generalised product wave function, an expression is given for the isotropic hyperfine coupling constant at a given atom in an aromatic π-radical. By a consistent scheme of approximation the expression is cast in a form in which the coupling constant at a given atom in the radical can be evaluated from the results of a Hückel calculation, provided that certain integrals are known. A scheme for assigning and relating these integrals is given, coupling constants are calculated for 13C, 14N, 17O and 19F atoms, and the calculations compared with experiment. © 1970 Springer-Verlag.
BibTeX: @article{Chiu1970331, author = {Chiu, M.F. and Sutcliffe, B.T.}, title = {A semi-empirical approach to the estimation of ESR isotropic hyperfine coupling constants in aromatic radicals}, journal = {Theoretica Chimica Acta}, year = {1970}, volume = {16}, number = {5}, pages = {331 – 345}, doi = {10.1007/BF00527081} }
Kari R and Sutcliffe B (1970), "Direct minimisation of the energy functional in some open-shell LCAO calculations on atoms", Chemical Physics Letters. Vol. 7(1), pp. 149 – 152. [Abstract] [BibTeX] [DOI]
Abstract: In this paper we investigate the solution of the open-shell problem, in the LCAO approximation, for some first row atoms, by methods involving direct minimisation of the energy functional. We believe these methods to be applicable to the general multi-configuration SCF problem. © 1970.
BibTeX: @article{Kari1970149, author = {Kari, R. and Sutcliffe, B.T.}, title = {Direct minimisation of the energy functional in some open-shell LCAO calculations on atoms}, journal = {Chemical Physics Letters}, year = {1970}, volume = {7}, number = {1}, pages = {149 – 152}, doi = {10.1016/0009-2614(70)80271-8} }
Liu H and Verhaegen G (1970), "Electronic states of CH and NH+", The Journal of Chemical Physics. Vol. 53(2), pp. 735 – 745. [Abstract] [BibTeX] [DOI]
Abstract: Ab initio calculations (LCAO-MO-SCF) are performed on a series of valence levels of the molecules CH and NH+. Correlation energies are estimated semiempirically from corresponding atomic data. Close agreement with experiment is found for known states for a series of molecular properties such as equilibrium internuclear distances, vibration frequencies, term values, and dissociation energies. A low-lying 4∑- state in CH is calculated to lie 7500 cm-1 above the X 2∏ state. No observable quartet transition could be found for CH, while for NH+ a 4∏-4∑- transition should occur in the region of 1000 Å. Other qualitative differences in the observed spectra of the two molecules are discussed. Finally a value of D0 0(NH+)=3.4 eV is calculated.
BibTeX: @article{Liu1970735, author = {Liu, H.P.D. and Verhaegen, G.}, title = {Electronic states of CH and NH+}, journal = {The Journal of Chemical Physics}, year = {1970}, volume = {53}, number = {2}, pages = {735 – 745}, doi = {10.1063/1.1674051} }
Verhaegen G and Moser C (1970), "Hartree-Fock, correlation and term energies of valence excited states of atoms and ions of the second row of the periodic table", Journal of Physics B: Atomic and Molecular Physics. Vol. 3(4), pp. 478 – 492. [Abstract] [BibTeX] [DOI]
Abstract: Hartree-Fock energies have been calculated for 333 valence states of atoms and ions of the second row of the periodic table corresponding to 1s 22sm2pn (m=0.1; 0
BibTeX: @article{Verhaegen1970478, author = {Verhaegen, G. and Moser, C.M.}, title = {Hartree-Fock, correlation and term energies of valence excited states of atoms and ions of the second row of the periodic table}, journal = {Journal of Physics B: Atomic and Molecular Physics}, year = {1970}, volume = {3}, number = {4}, pages = {478 – 492}, doi = {10.1088/0022-3700/3/4/004} }
Goldfinger P and Verhaegen G (1969), "Stability of the gaseous ammonium chloride molecule", The Journal of Chemical Physics. Vol. 50(3), pp. 1467 – 1471. [Abstract] [BibTeX] [DOI]
Abstract: The equilibrium vapor effusing from a Knudsen cell, in which solid ND 4Cl was evaporated, was analyzed by a quadrupole mass spectrometer. In the temperature range considered (335°-485°K) the main vaporization process corresponds to the decomposition of the solid towards gaseous ND 3 and DCl; the measured enthalpy change ΔH°407 dec[ND4Cl(s)]=42.6±2.0 kcal mole-1 is very close to that measured for NE4Cl: ΔH°407 dec[NH4Cl(s)]=42.5 kcal mole-1. Apart from the main gaseous species, small proportions (5×10-5-2×10 -3) of ND4Cl molecules were also observed. The ND 4Cl molecule fragments (>99%) under electron impact and yields the ND4+(m/e=22) ion. From the observed ion intensity ratios, as well as their dependence on temperature, D0°(NH 4Cl⇌NH3+HCl)= 10.0±3.0 kcal mole -1 was obtained confirming Clementi's computed prediction <14.0 kcal mole-1.
BibTeX: @article{Goldfinger19691467, author = {Goldfinger, P. and Verhaegen, G.}, title = {Stability of the gaseous ammonium chloride molecule}, journal = {The Journal of Chemical Physics}, year = {1969}, volume = {50}, number = {3}, pages = {1467 – 1471}, doi = {10.1063/1.1671212} }
Colin R and Drowart J (1968), "Mass spectrometric determination of dissociation energies of gaseous indium sulphides, selenides and tellurides", Transactions of the Faraday Society. Vol. 64, pp. 2611 – 2621. [Abstract] [BibTeX] [DOI]
Abstract: The atomization energies: D°0(InS) = 67.9 ± 3.5; D°0(InSe) = 57.7 ± 3.5; D °0(InTe) = 50.6 ± 3.5; ΔH °0(In2S) = 148.2 ± 4.0; ΔH°0(In2Se) = 132.7 ± 4.0; ΔH°0(In2Te) = 110.8 ± 4.0; ΔH°0(In2S2) = 224.5 ± 10.0; ΔH°0(In2Se 2) = 200.5 ± 10.0; ΔH° 0(In2Te2) = 173.2 ± 10.0 and ΔH0(InTe2) = 107.4 ± 4.0 kcal/mole were determined. The heat of formation of In2S3(s) was deduced : ΔH°298, f(In2S3) = -82.8 ± 4.5 kcal/mole. The dissociation energies D° 0(Se2) = 73.6 ± 2.0 and D° 0(Te2) = 55.9 ± 2.0 kcal/mole were also measured.
BibTeX: @article{Colin19682611, author = {Colin, R. and Drowart, J.}, title = {Mass spectrometric determination of dissociation energies of gaseous indium sulphides, selenides and tellurides}, journal = {Transactions of the Faraday Society}, year = {1968}, volume = {64}, pages = {2611 – 2621}, doi = {10.1039/TF9686402611} }
Verhaegen G (1968), "Theoretical calculation of the electronic states of C2+", The Journal of Chemical Physics. Vol. 49(10), pp. 4674 – 4679. [Abstract] [BibTeX] [DOI]
Abstract: Results of ab initia calculations are presented for a series of valence levels of C2+ and for the two lowest states of Cs (x 1∑ g + and X′ IIu). Correlation energies of all the levels are estimated by a new scheme taking into account near-degeneracy effects in the molecule and in the constituent ion pairs. Results for C2 are in close agreement with experiment for equilibrium internuclear distances, vibration frequencies,, term energies and dissociation energies. For C 2+ the calculations show the ground state to be 4∑g- with relatively low-lying (∼0.6 eV)* δg and 2IIu levels. The electron-impact measurement for the appearance potential of C2+ is interpreted as C2 (3IIu, ν= 1)→ Cs+ (4∑-, ν=0). The quartet transition %→4∑- is predicted to lie at 60001. The major doublet transitions all lie in the infrared.
BibTeX: @article{Verhaegen19684674, author = {Verhaegen, G.}, title = {Theoretical calculation of the electronic states of C2+}, journal = {The Journal of Chemical Physics}, year = {1968}, volume = {49}, number = {10}, pages = {4674 – 4679}, doi = {10.1063/1.1669932} }
Csizmadia I, Harrison M, Moskowitz J and Sutcliffe B (1967), "Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Graussian type functions", Theoretica Chimica Acta. Vol. 7(2), pp. 156. [BibTeX] [DOI]
BibTeX: @article{Csizmadia1967156, author = {Csizmadia, I.G. and Harrison, M.C. and Moskowitz, J.W. and Sutcliffe, B.T.}, title = {Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Graussian type functions}, journal = {Theoretica Chimica Acta}, year = {1967}, volume = {7}, number = {2}, pages = {156}, note = {All Open Access, Bronze Open Access}, doi = {10.1007/BF01151918} }
Verhaegen G and Richards W (1967), "The ground state of the BeS molecule", Proceedings of the Physical Society. Vol. 90(2), pp. 579 – 581. [Abstract] [BibTeX] [DOI]
Abstract: Matrix Hartree-Fock wave functions are calculated for the low-lying configurations of the BeS molecule The energy of each state is computed variationally and estimates made of differences in correlation energy between the various levels The results indicate a 1Σ+ ground state.
BibTeX: @article{Verhaegen1967579, author = {Verhaegen, G. and Richards, W.G.}, title = {The ground state of the BeS molecule}, journal = {Proceedings of the Physical Society}, year = {1967}, volume = {90}, number = {2}, pages = {579 – 581}, doi = {10.1088/0370-1328/90/2/129} }
Verhaegen G, Richards W and Moser C (1967), "Ground state and main spectroscopic system of the nitrogen-molecule positive ion", The Journal of Chemical Physics. Vol. 47(8), pp. 2595 – 2598. [Abstract] [BibTeX] [DOI]
Abstract: The ground state and first excited state of the nitrogen-molecule positive ion are calculated using the matrix Hartree-Fock approximation, which results in a reversal of the observed spectroscopic order of states. The inclusion of estimates of correlation-energy differences between the levels corrects this and leads to a calculated term value of the excited state (1.17 eV) in extremely close agreement with experiment (1.16 eV).
BibTeX: @article{Verhaegen19672595, author = {Verhaegen, G. and Richards, W.G. and Moser, C.M.}, title = {Ground state and main spectroscopic system of the nitrogen-molecule positive ion}, journal = {The Journal of Chemical Physics}, year = {1967}, volume = {47}, number = {8}, pages = {2595 – 2598}, doi = {10.1063/1.1712275} }
Verhaegen G, Richards W and Moser C (1967), "Low-lying valence levels of BN and C2. The ground state of BN", The Journal of Chemical Physics. Vol. 46(1), pp. 160 – 164. [Abstract] [BibTeX] [DOI]
Abstract: Some low-lying valence levels of BN and C2 are calculated by the LCAO MO SCF method. Variational calculations are performed on three different configurations for BN and two for C2. Term values are obtained from the minima of the computed potential curves together with estimates of pair correlation energy differences between the various configurations. The results obtained for C2 are in reasonably good agreement (error∼0.2 eV) with experiment. For BN the calculations indicate a 3Π ground state with low-lying 3Σ+, 1Σ +, and 1Π states.
BibTeX: @article{Verhaegen1967160, author = {Verhaegen, G. and Richards, W.G. and Moser, C.M.}, title = {Low-lying valence levels of BN and C2. The ground state of BN}, journal = {The Journal of Chemical Physics}, year = {1967}, volume = {46}, number = {1}, pages = {160 – 164}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.1840367} }
Csizmadia I, Harrison M, Moskowitz J and Sutcliffe B (1966), "Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Gaussian type functions - Part I. Introductory review and mathematical formalism", Theoretica Chimica Acta. Vol. 6(3), pp. 191 – 216. [Abstract] [BibTeX]
Abstract: This paper (Part I) describes the theoretical and computational bases of some non-empirical calculations on small organic molecules to be reported in later papers (Parts II et seq). Approximate solutions for the usual fixed nucleus electronic Hamiltonian, in the term of wave functions composed of Slater determinants, are discussed, with particular emphasis on their computational utility. Possible choices of basis functions, from which to form the determinants are examined, and the advantages of Gaussian type functions (GTF) centered on the component atoms are pointed out. Some of the properties of molecules which can be calculated using such approximate wave functions are outlined. Finally an attempt is made to discuss the current limitations of non-empirical calculations of the type described here, and some guesses are made about their future. Brief outlines as a set of appendices are given of the mathematical formalism and computational details of the calculations. © 1966 Springer-Verlag.
BibTeX: @article{Csizmadia1966191, author = {Csizmadia, I.G. and Harrison, M.C. and Moskowitz, J.W. and Sutcliffe, B.T.}, title = {Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Gaussian type functions - Part I. Introductory review and mathematical formalism}, journal = {Theoretica Chimica Acta}, year = {1966}, volume = {6}, number = {3}, pages = {191 – 216} }
Csizmadia I, Harrison M and Sutcliffe B (1966), "Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Gaussian type functions - Part II. Preliminary investigations on formyl fluoride", Theoretica Chimica Acta. Vol. 6(3), pp. 217 – 239. [Abstract] [BibTeX]
Abstract: Non-empirical molecular quantum chemical calculations were performed on formyl fluoride (HCOF) in the LCAO-MO-SCF framework using Gaussian type functions as atomic orbitals. In the first half of this paper a quantitative correlation has been established between some of the calculable molecular properties of HCOF and the size of the basis set used. It is hoped that the basic conclusions are general enough to be applicable to calculations of similar type on different molecules. The second part consists of a preliminary SCF study of HCOF in its electronic ground state. © 1966 Springer-Verlag.
BibTeX: @article{Csizmadia1966217, author = {Csizmadia, I.G. and Harrison, M.C. and Sutcliffe, B.T.}, title = {Non-empirical LCAO-MO-SCF-CI calculations on organic molecules with Gaussian type functions - Part II. Preliminary investigations on formyl fluoride}, journal = {Theoretica Chimica Acta}, year = {1966}, volume = {6}, number = {3}, pages = {217 – 239} }
Gilbert B, Hanson P, Norman R and Sutcliffe B (1966), "The cation-radical and the neutral radical from phenothiazine", Chemical Communications (London). (6), pp. 161 – 164. [BibTeX] [DOI]
BibTeX: @article{Gilbert1966161, author = {Gilbert, B.C. and Hanson, P. and Norman, R.O.C. and Sutcliffe, B.T.}, title = {The cation-radical and the neutral radical from phenothiazine}, journal = {Chemical Communications (London)}, year = {1966}, number = {6}, pages = {161 – 164}, doi = {10.1039/C19660000161} }
Sutcliffe BT (1966), "Matrix elements between bonded functions", The Journal of Chemical Physics. Vol. 45(1), pp. 235 – 239. [Abstract] [BibTeX] [DOI]
Abstract: Formulas are given for the spinless one- and two-particle density matrices and for certain other density functions in terms of bonded function wavefunctions.
BibTeX: @article{Sutcliffe1966235, author = {Sutcliffe, Brian T.}, title = {Matrix elements between bonded functions}, journal = {The Journal of Chemical Physics}, year = {1966}, volume = {45}, number = {1}, pages = {235 – 239}, doi = {10.1063/1.1727316} }
Verhaegen G and Richards W (1966), "Valence levels of beryllium oxide", The Journal of Chemical Physics. Vol. 45(5), pp. 1828 – 1833. [Abstract] [BibTeX] [DOI]
Abstract: The low-lying valence levels of BeO, are calculated by the LCAO MO SCF method in order to ascertain the nature of the ground state of the molecule. Calculations of excited states using virtual orbitals are found to be inconclusive. Better results are found by doing variational calculations on three low-lying configurations for a series of internuclear distances, employing a large basis set and data on differences in molecular correlation energies between the various configurations. The calculations indicate a closed-shell 1∑+ ground state. Spectroscopic constants are derived for this and other valence states. An unobserved 3∑+- 3II transition is predicted to lie in the infrared region at about 9000 Å. The lowest-lying excited state is a 3II. This level is shown to lie sufficiently high with respect to the ground state so as not to require an alteration of the published dissociation energy.
BibTeX: @article{Verhaegen19661828, author = {Verhaegen, G. and Richards, W.G.}, title = {Valence levels of beryllium oxide}, journal = {The Journal of Chemical Physics}, year = {1966}, volume = {45}, number = {5}, pages = {1828 – 1833}, doi = {10.1063/1.1727840} }
Colin R, Drowart J and Verhaegen G (1965), "Mass-spectrometric study of the vaporization of tin oxides: Dissociation energy of SnO", Transactions of the Faraday Society. Vol. 61, pp. 1364 – 1371. [Abstract] [BibTeX] [DOI]
Abstract: The evaporation of tin oxide SnO2 and mixtures of tin and tin oxide was studied. The vaporization reactions are (Equation Presented) The dissociation energy of the molecule SnO was determined: D°0 = 126.5±2.0 kcal/mole; as well as the polymerization energies ΔH 298° = 66.8±4, 136.5±5, 207.6±5 kcal/mole for (SnO)2, (SnO)3 snd (SnO)4 respectively. A re-interpretation of the total vapour pressures given in the literature was made. The presence of the polymeric molecules is the cause of previously unexplained differences.
BibTeX: @article{Colin19651364, author = {Colin, R. and Drowart, J. and Verhaegen, G.}, title = {Mass-spectrometric study of the vaporization of tin oxides: Dissociation energy of SnO}, journal = {Transactions of the Faraday Society}, year = {1965}, volume = {61}, pages = {1364 – 1371}, doi = {10.1039/tf9656101364} }
Drowart J, Colin R and Exsteen G (1965), "Mass-spectrometric study of the vaporization of lead monoxide: Dissociation energy of PbO", Transactions of the Faraday Society. Vol. 61, pp. 1376 – 1383. [Abstract] [BibTeX] [DOI]
Abstract: The composition of the vapour in equilibrium with lead oxide (yellow rhombic form β) in the temperature interval 1000-1150°K was determined mass spectrometrically. The predominant species are PbO, Pb2O 2, Pb3O3 and Pb4O4. From the partial PbO pressures measured here as well as those based on a re-interpretation of the literature data, taking the presence of the polymers into account, the dissociation energy of the molecule PbO was calculated: D 0°(PbO) = 88.4±l-4 kcal/mole. The enthalpy ΔH 298° of the reactions: Pb2O2(g) →2 PbO(g), Pb3O3(g) →3 PbO(g), Pb4O 4(g) →4 PbO(g), is 63.4±4, 126.4±6.0 and 202.0±10.0 kcal/mole respectively.
BibTeX: @article{Drowart19651376, author = {Drowart, J. and Colin, R. and Exsteen, G.}, title = {Mass-spectrometric study of the vaporization of lead monoxide: Dissociation energy of PbO}, journal = {Transactions of the Faraday Society}, year = {1965}, volume = {61}, pages = {1376 – 1383}, doi = {10.1039/tf9656101376} }
Drowart J, Degreve F, Verhaegen G and Colin R (1965), "Thermochemical study of the germanium oxides using a mass spectrometer: Dissociation energy of the molecule GeO", Transactions of the Faraday Society. Vol. 61, pp. 1072 – 1085. [Abstract] [BibTeX] [DOI]
Abstract: The mass spectrometric study of the vaporization of the compounds GeO 2(hex) and GeO(am) and of the mixture GeO2(hex)+Ge(c) made it possible to establish their mode of vaporization: GeO2(hex) →GeO(g)+1/2O2 (I) n GeO(am)→(GwO)n(g) (n = 1,2,3), (II) (n/2)GeO2(hex) + (n/2)Ge(c)→(GeO)n(g) (n = 1,2,3). (III) The enthalpies of vaporization are ΔH298° (I) = 124.3±2.4 kcal/mole; ΔH298°(II, n = 1) = 53.1± 1.0 kcal/mole; ΔH298°(III, n = 1) = 57.5±1.0 kcal/mole. The polymerization energies are ΔH 298° (GeO-GeO) = 44.7±3.0 kcal/mole; ΔH 298°(GeO-GeO-GeO) = 88.5±5.0 kcal/mole. Total pressures given in the literature were re-interpreted taking the presence of the polymers into account. The heat of formation of the metastable compound GeO(am) is ΔHf°(GeO) = -60.8±1.4 kcal/mole. The dissociation energy of the gaseous molecule GeO is D0°(GeO) = 156.2±1.9 kcal/mole.
BibTeX: @article{Drowart19651072, author = {Drowart, J. and Degreve, F. and Verhaegen, G. and Colin, R.}, title = {Thermochemical study of the germanium oxides using a mass spectrometer: Dissociation energy of the molecule GeO}, journal = {Transactions of the Faraday Society}, year = {1965}, volume = {61}, pages = {1072 – 1085}, note = {All Open Access, Green Open Access}, doi = {10.1039/TF9656101072} }
Smoes S, Drowart J and Verhaegen G (1965), "Mass-Spectrometric Study of Gaseous Oxides and Suboxides of Scandium, Yttrium, and Lanthanum", The Journal of Chemical Physics. Vol. 43(2), pp. 732 – 736. [Abstract] [BibTeX] [DOI]
Abstract: The dissociation energy of the molecule ScO was determined: D 0°(ScO) = 160.9±3.5 kcal/mole. The dissociation energies of the molecules YO and LaO, D0°(YO) = 168.6±2.8 and D0°(LaO) = 191.0±2.5 kcal/mole, are discussed. The molecules SC2O, Y2O, Y2O2, La 2O, and La2O2 were identified. Their atomization energies are: D0°(Sc2O) = 245±11, D0° (Y2O) = 258±8, D0°(Y 2O2) = 445±12, D0° (La2O) = 266±8, D0° (La2O2) = 468±11 kcal/mole.
BibTeX: @article{Smoes1965732, author = {Smoes, S. and Drowart, J. and Verhaegen, G.}, title = {Mass-Spectrometric Study of Gaseous Oxides and Suboxides of Scandium, Yttrium, and Lanthanum}, journal = {The Journal of Chemical Physics}, year = {1965}, volume = {43}, number = {2}, pages = {732 – 736}, doi = {10.1063/1.1696798} }
Verhaegen G, Colln R, Exsteen G and Drowart J (1965), "Mass spectrometric determination of the stability of gaseous molybdites, tungstites, molybdates and tungstates of magnesium, calcium, strontium and tin", Transactions of the Faraday Society. Vol. 61, pp. 1372 – 1375. [Abstract] [BibTeX] [DOI]
Abstract: A number of gaseous ternary oxides have been identified by mass spectrometry, while vaporizing MgO, CaO, SrO and SnO2+Sn from Mo and W crucibles. The stabilities of the gaseous molecules SrMoO3, CaWO3, SrWO3, MgMoO4, CaMoO4, SrMoO4, MgWO4, CaWO4, SrWO4, SnWO4 and Sn2WO5, were deduced from the measurements.
BibTeX: @article{Verhaegen19651372, author = {Verhaegen, G. and Colln, R. and Exsteen, G. and Drowart, J.}, title = {Mass spectrometric determination of the stability of gaseous molybdites, tungstites, molybdates and tungstates of magnesium, calcium, strontium and tin}, journal = {Transactions of the Faraday Society}, year = {1965}, volume = {61}, pages = {1372 – 1375}, doi = {10.1039/tf9656101372} }
Colin R (1964), "Thermodynamic study of germanium monotelluride using a mass spectrometer", Journal of Physical Chemistry. Vol. 68(2), pp. 428 – 430. [BibTeX] [DOI]
BibTeX: @article{Colin1964428, author = {Colin, R.}, title = {Thermodynamic study of germanium monotelluride using a mass spectrometer}, journal = {Journal of Physical Chemistry}, year = {1964}, volume = {68}, number = {2}, pages = {428 – 430}, doi = {10.1021/j100784a512} }
Colin R and Drowart J (1964), "Thermodynamic study of tin selenide and tin telluride using a mass spectrometer", Transactions of the Faraday Society. Vol. 60, pp. 673 – 683. [Abstract] [BibTeX] [DOI]
Abstract: In a mass-spectrometric investigation of the vapour in equilibrium with solid SnSe and solid SnTe, a number of reaction enthalpies were measured, which, combined with known thermochemical data, yield: (Equation Presented) The dissociation energies are compared with spectroscopic data.
BibTeX: @article{Colin1964673, author = {Colin, R. and Drowart, J.}, title = {Thermodynamic study of tin selenide and tin telluride using a mass spectrometer}, journal = {Transactions of the Faraday Society}, year = {1964}, volume = {60}, pages = {673 – 683}, doi = {10.1039/tf9646000673} }
Colin R, Goldfinger P and Jeunehomme M (1964), "Mass-spectrometric studies of the vaporization of the sulphides of calcium, strontium and barium. The dissociation energy of S2 and SO", Transactions of the Faraday Society. Vol. 60, pp. 306 – 316. [Abstract] [BibTeX] [DOI]
Abstract: CaS, SrS and BaS have been evaporated from molybdenum Knudsen cells and the emerging molecular beam analyzed by mass spectrometry. From the composition of the vapour, the following thermodynamic properties of the gaseous species are obtained: D°0(S2) = 97±5 kcal mole-1 in agreement with a proposed value of D°0(S2) = 99.4±2.5 kcal mole-1 which takes into account data on dissociation energies of GeS, SnS, PbS, and spectroscopic data on D°0(S2). Further the values, D°0(CaS) = 73.7±4.5 kcal; D°0(SrS) = 74.1±4.5 kcal; D°0(BaS) = 94.7±4.5 kcal; ΔH(dim. BaS) = 113.9±5 kcal; ΔH°298 vap (CaS) = 14.0±5 kcal; ΔH°298 vap (SrS) = 143.0±5 kcal; ΔH°298 vap (BaS) = 122.5±5 kcal mole-1 were measured. Oxides in some of the samples permitted one to measure D°0(CaO) = 84.4±6 kcal; D°0(SrO) = 92.2±6 kcal; D°0(BaO) = 130.4±6 kcal from the equilibrium with SO; simultaneously the value D°0(SO) = 123.5 kcal mole-1 was confirmed.
BibTeX: @article{Colin1964306, author = {Colin, R. and Goldfinger, P. and Jeunehomme, M.}, title = {Mass-spectrometric studies of the vaporization of the sulphides of calcium, strontium and barium. The dissociation energy of S2 and SO}, journal = {Transactions of the Faraday Society}, year = {1964}, volume = {60}, pages = {306 – 316}, doi = {10.1039/tf9646000306} }
Drowart J, Exsteen G and Verhaegen G (1964), "Mass spectrometric determination of the dissociation energy of the molecules MgO, CaO, SrO and Sr2O", Transactions of the Faraday Society. Vol. 60, pp. 1920 – 1933. [Abstract] [BibTeX] [DOI]
Abstract: The dissociation energy of the molecules MgO, CaO, SrO was determined: D0°(MgO) = 86±5; D0°(CaO) = 93±5; D0(SrO) = 102±5 kcal/mole. The ground state was considered to be 1Σ. This choice is discussed. A discussion of the literature values for D0°(MgO, CaO, SrO) is made. The molecule Sr 2O was identified and its atomization energy determined: ΔH0°, at(Sr2O) = 194±6 kcal/mole.
BibTeX: @article{Drowart19641920, author = {Drowart, J. and Exsteen, G. and Verhaegen, G.}, title = {Mass spectrometric determination of the dissociation energy of the molecules MgO, CaO, SrO and Sr2O}, journal = {Transactions of the Faraday Society}, year = {1964}, volume = {60}, pages = {1920 – 1933}, doi = {10.1039/tf9646001920} }
Verhaegen G, Stafford F and Deowart J (1964), "Mass spectrometric study of the systems boron-carbon and boron-carbon-silicon", The Journal of Chemical Physics. Vol. 40(6), pp. 1622 – 1628. [Abstract] [BibTeX] [DOI]
Abstract: The vaporization behavior of the systems boron-carbon and boron-carbon-silicon has been studied with a mass spectrometer. In addition to the gaseous species characteristic of graphite, silicon carbide and boron, the molecules BC2, B2C, BCSi, BSi2, BC, and BSi were identified and their atomization energies measured. The values are: 294, 254, 247, 174, 106, and 68 kcal/mole, respectively. The atomization energies of SiC, Si2C, and SiC2 have been redetermined.
BibTeX: @article{Verhaegen19641622, author = {Verhaegen, G. and Stafford, F.E. and Deowart, J.}, title = {Mass spectrometric study of the systems boron-carbon and boron-carbon-silicon}, journal = {The Journal of Chemical Physics}, year = {1964}, volume = {40}, number = {6}, pages = {1622 – 1628}, doi = {10.1063/1.1725370} }
McWeeny R and Sutcliffe B (1963), "Spin polarization effects in paramagnetic molecules calculations on the nh2 radical", Molecular Physics. Vol. 6(5), pp. 493 – 502. [Abstract] [BibTeX] [DOI]
Abstract: The ‘ spin polarization ’ induced in one part of a molecule by the presence of unpaired spins in another part is investigated in a general way, using a density matrix formulation. The general theory is then applied in a non-empirical calculation of spin densities and hyperfine coupling constants in the NH2 radical. © 1963 Taylor & Francis Group, LLC.
BibTeX: @article{McWeeny1963493, author = {McWeeny, R. and Sutcliffe, B.T.}, title = {Spin polarization effects in paramagnetic molecules calculations on the nh2 radical}, journal = {Molecular Physics}, year = {1963}, volume = {6}, number = {5}, pages = {493 – 502}, doi = {10.1080/00268976300100551} }
Sutcliffe BT (1963), "Hyperfine electron spin resonance spectrum of the NH2 free radical", The Journal of Chemical Physics. Vol. 39(12), pp. 3322 – 3326. [Abstract] [BibTeX] [DOI]
Abstract: The unrestricted Hartree-Fock method in the LCAO-MO approximation is used to calculate the coupling constants for nitrogen and hydrogen in the NHa free radical. Both Slater and self-consistent field orbitals are used as basis functions. The effect of a spin annihilator after energy minimization, and the effects of "freezing" the nitrogen core are examined. The results are compared with those obtained in a recent configuration interaction calculation; and with the experimental results.
BibTeX: @article{Sutcliffe19633322, author = {Sutcliffe, Brian T.}, title = {Hyperfine electron spin resonance spectrum of the NH2 free radical}, journal = {The Journal of Chemical Physics}, year = {1963}, volume = {39}, number = {12}, pages = {3322 – 3326}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.1734196} }
Ackerman M, Drowart J, Stafford FE and Verhaegen G (1962), "Mass spectrometric study of the gaseous molecules above AgSn, AuSn, and CuSn alloys", The Journal of Chemical Physics. Vol. 36(6), pp. 1557 – 1560. [Abstract] [BibTeX] [DOI]
Abstract: Mass spectrometric technique has been employed to analyze the molecular beams effusing from mullite Knudsen cells containing Sn and alloys of Cu, Ag, and Au with Sn. From the experimental intensities of monatomic and diatomic species and the vapor pressure of Sn, the following dissociation energies are obtained: D0° (Sn2) = 45.8±4 kcal/mole, D 0° (AgSn) = 31.6±5 kcal/mole, D0° (AuSn) = 57.5±4 kcal/mole, D0° (CuSn) = 41.4±4 kcal/mole.
BibTeX: @article{Ackerman19621557, author = {Ackerman, Marcel and Drowart, Jean and Stafford, Fred E. and Verhaegen, Georges}, title = {Mass spectrometric study of the gaseous molecules above AgSn, AuSn, and CuSn alloys}, journal = {The Journal of Chemical Physics}, year = {1962}, volume = {36}, number = {6}, pages = {1557 – 1560}, doi = {10.1063/1.1732778} }
Ackerman M, Stafford FE and Verhaegen G (1962), "Studies of the vapors of the system Au-Cr and Au-Pd by mass spectrometry", The Journal of Chemical Physics. Vol. 36(6), pp. 1560 – 1562. [Abstract] [BibTeX] [DOI]
Abstract: The molecules AuCr and AuPd have been identified. From data for the reaction Au2+X=AuX+Au, and D0°(Au2) = 51.5 kcal/mole: D0°(AuCr) = 50.4±3.5 kcal/mole, D 0°(AuPd) = 33.3±5 kcal/mole.
BibTeX: @article{Ackerman19621560, author = {Ackerman, Marcel and Stafford, Fred E. and Verhaegen, Georges}, title = {Studies of the vapors of the system Au-Cr and Au-Pd by mass spectrometry}, journal = {The Journal of Chemical Physics}, year = {1962}, volume = {36}, number = {6}, pages = {1560 – 1562}, doi = {10.1063/1.1732779} }
Colin R and Drowart J (1962), "Thermodynamic study of tin sulfide and lead sulfide using a mass spectrometer", The Journal of Chemical Physics. Vol. 37(5), pp. 1120 – 1125. [Abstract] [BibTeX] [DOI]
Abstract: A mass-spectrometric investigation of the vapor in equilibrium with solid SnS, solid PbS, and a mixture of SnS and PbS has yielded the following reaction enthalpies: SnS(s)→SnS(g) ΔH2980 = 52.6±1.6 kcal/mole 2SnS(s)→Sn2S2(g) 56.5±5.0 PbS(s)→PbS(g) 55.7±1.6 2PbS(s)→Pb 2S2(g) 66.6±5.0 PbS(g)→Pb(g) + 1/2 S 2(g) 28.8±2.6 Sn2S2(g)→2SnS(g) 48.7±5.0 Pb2S2(g)→2PbS(g) 44.8±5.0 SnPbS2(g)→SnS(g)+PbS(g) 46.5±5.0. The dissociation energies of gaseous SnS and PbS were determined to be D00 (SnS) = 110.1±3.0 kcal/mole, D00(PbS) = 79.1±2.8 kcal/mole and are compared with the spectroscopically determined values.
BibTeX: @article{Colin19621120, author = {Colin, R. and Drowart, J.}, title = {Thermodynamic study of tin sulfide and lead sulfide using a mass spectrometer}, journal = {The Journal of Chemical Physics}, year = {1962}, volume = {37}, number = {5}, pages = {1120 – 1125}, note = {All Open Access, Bronze Open Access}, doi = {10.1063/1.1733223} }
Colin R, Goldfinger P and Jeunehomme M (1962), "Existence of gaseous sulphides of the transition elements: Dissociation energy of gaseous MnS", Nature. Vol. 194(4825), pp. 282 – 283. [Abstract] [BibTeX] [DOI]
Abstract: IT is of interest to obtain data on the lattice energy, ΔH 00[at.], of solids, and dissociation energies, D 00, of gaseous molecules of whole groups of compounds, such as homonuclear molecules1, oxides2, sulphides 2, etc., and to study the variation of these properties, or the ratio of these magnitudes, ΔH00[at.]/D0 0 = α, as a function of the electronic structure of the constituting atoms. An interesting case is that of the sulphides of transition elements. © 1962 Nature Publishing Group.
BibTeX: @article{Colin1962282, author = {Colin, R. and Goldfinger, P. and Jeunehomme, M.}, title = {Existence of gaseous sulphides of the transition elements: Dissociation energy of gaseous MnS}, journal = {Nature}, year = {1962}, volume = {194}, number = {4825}, pages = {282 – 283}, doi = {10.1038/194282a0} }
Verhaegen G and Drowart J (1962), "Mass spectrometric determination of the heat of sublimation of boron and of the dissociation energy of B2", The Journal of Chemical Physics. Vol. 37(6), pp. 1367 – 1368. [BibTeX] [DOI]
BibTeX: @article{Verhaegen19621367, author = {Verhaegen, G. and Drowart, J.}, title = {Mass spectrometric determination of the heat of sublimation of boron and of the dissociation energy of B2}, journal = {The Journal of Chemical Physics}, year = {1962}, volume = {37}, number = {6}, pages = {1367 – 1368}, doi = {10.1063/1.1733286} }
Verhaegen G, Stafford F, Ackerman M and Drowart J (1962), "Mass spectrometric investigation of gaseous species in the system boron-carbon", Nature. Vol. 193(4822), pp. 1280. [Abstract] [BibTeX] [DOI]
Abstract: MOLECULES of high stability are known to exist in the vapours in equilibrium, with boron1, carbon2-5. silicon carbide 6,7and several metallic carbides and metal-carbon systems 8,9. It was therefore of interest to examine the vapour in equilibrium with the boron-carbon system. © 1962 Nature Publishing Group.
BibTeX: @article{Verhaegen19621280, author = {Verhaegen, G. and Stafford, F.E. and Ackerman, M. and Drowart, J.}, title = {Mass spectrometric investigation of gaseous species in the system boron-carbon}, journal = {Nature}, year = {1962}, volume = {193}, number = {4822}, pages = {1280}, note = {All Open Access, Bronze Open Access}, doi = {10.1038/1931280a0} }
Verhaegen G, Stafford F, Goldfinger P and Ackerman M (1962), "Correlation of dissociation energies of gaseous molecules and of heats of vaporization of solids. Part 1. - Homonuclear diatomic molecules", Transactions of the Faraday Society. Vol. 58, pp. 1926 – 1938. [Abstract] [BibTeX] [DOI]
Abstract: In this paper two correlations are proposed. The first correlation classifies the forty odd known homonuclear diatomic molecules according to the ratio α = ΔH0o (vap. M)/D0 o(M2) (heat of vaporization of an atom/dissociation energy of the diatomic molecule). Values of α = 0.5 to 1, 1.2 to 2.5 and >5 correspond to three categories each consisting of several whole groups of elements. The significance of this classification is discussed qualitatively. The second correlation shows that ΔH0o(vap. M) can be closely represented by Λ-BΣiεi(M). Σiεi(M) is the energy necessary to excite the atoms to a promoted " configuration " composed of equal contributions of a well-defined set of low lying electronic states of the free atom. Λ and B are empirical parameters. One set of electronic states is taken for Ca to Ni, Sr to Pd, and Ba to Pt with B = 1/2 and Λ = 178, 206, 250 kcal/g atom respectively; another set of electronic levels and Λ = 131 kcal and B = 1/4 represent ΔH0o(vap. M) for Ni, Cu, Zn, Pd, Ag, Cd, Pt, Au, Hg. Using the first classification, the experimental conditions are estimated for observation of the yet unknown homonuclear diatomic molecules of the transition elements. For this purpose a self-consistent set of free energy functions has been calculated.
BibTeX: @article{Verhaegen19621926, author = {Verhaegen, G. and Stafford, F.E. and Goldfinger, P. and Ackerman, M.}, title = {Correlation of dissociation energies of gaseous molecules and of heats of vaporization of solids. Part 1. - Homonuclear diatomic molecules}, journal = {Transactions of the Faraday Society}, year = {1962}, volume = {58}, pages = {1926 – 1938}, doi = {10.1039/TF9625801926} }
Colin R, Goldfinger P and Jeunehomme M (1960), "Mass spectrometric investigation of the vaporization of sulphides and the dissociation energy of S2", Nature. Vol. 187(4735), pp. 408 – 409. [Abstract] [BibTeX] [DOI]
Abstract: THE disagreement between second- and third-law values of the dissociation energy of S2(D00(S2)) obtained from equilibrium measurements was emphasized many years ago1. A relationship was also pointed out between the heat of combustion of SO, D 00(O2), D00(SO) and D00(S2), which should permit one to choose one of the values allowed by observed predissociations for D0 0(S2) and D00(SO). Recent measurements2 do not seem to settle the question3. © 1960 Nature Publishing Group.
BibTeX: @article{Colin1960408, author = {Colin, R. and Goldfinger, P. and Jeunehomme, M.}, title = {Mass spectrometric investigation of the vaporization of sulphides and the dissociation energy of S2}, journal = {Nature}, year = {1960}, volume = {187}, number = {4735}, pages = {408 – 409}, doi = {10.1038/187408a0} }

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