Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing
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Experimental Spectroscopy Atmospheric

Thibault Bertin


  • BA in chemistry, ULB (2014-2017)
  • MA in chemistry, ULB (2017-2019)
  • Master thesis "Spectroscopie à transformée de Fourier de l’ammoniac", ULB (2019)
  • PhD student in Sciences, ULB, FRIA grant (2019-2023)

PhD project

Collisional effects on spectra
Intermolecular collisions play a central role in the construction of the absorption spectrum of molecular species in the gas phase. They can lead to the broadening and shift of spectral lines and couple them, but also generate an absorption in spectral regions far from the line centres. The experimental and theoretical study of these effects is above all driven by their direct or possible applications in the understanding of dilute environments.
This project is centred around the study of the effects of pressures increasing up to about 25 bars on the infrared absorption spectrum of light molecules in the gas phase, by means of high-resolution Fourier transform spectroscopy.
This research will concern the infrared absorption spectrum of methane (in particular the 3 μm region) and water vapor (specifically the 2.7 μm region) perturbed by carbon dioxide, of direct interest for the study of various planetary atmospheres. It will be extended to the infrared absorption spectrum of methane perturbed by helium, also of planetological interest. Through the analysis of absorption spectra recorded for total pressures up to about 1 bar, we will measure the parameters (broadening, shift and line mixing) characterizing the effects of the pressure of carbon dioxide and helium on the spectral lines of methane observed near 3 μm.
This work will notably involve a study of the impact of the line profile model used on the retrieved parameters. We will also characterize the far wings absorption of CH4 (near 3 μm) and H2O (near 2.7 μm) perturbed by pressures of CO2 between about 5 and 25 bars.


See here.


Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES)( https://squares.ulb.be//),
Université Libre de Bruxelles, CP160/09
50 Av. F.D. Roosevelt, B-1050 Belgium

Université Libre de Bruxelles – Faculté des Sciences