OSSEIRAN Noureddin : Physico-chemical characterization of atmospheric pollutants - precursors of aerosols - by quantum chemistry calculations and microwave spectroscopy in a supersonic jet

Résumé de thèse : The Laboratory PhLAM has an internationally recognized activity in very high resolution molecular spectroscopy. The Spectroscopy and Applications team is using two impulse Fourier transform microwave spectrometers at the state-of-the art (very high resolution and sensitivity) – unique in France - to characterize the physico-chemical properties of astrophysical and atmospheric molecules. Within the Labex CaPPA and the CPER CLIMIBIO projects, the group is studying biogenic hydrocarbons, their oxidation products and the associated hydrates. These species are present in very weak concentration in the atmosphere but at the same time they are gas phase precursors of aerosols. As such they will have an impact on climate, on air quality and on health, namely in the Region Hauts-de-France. The objective of this PhD is to understand at a molecular scale the physico-chemical processes leading to aerosols formation. In order to be able to use state-of-the-art quantum physics it is necessary to record broadband spectra of high quality. To this end the group will implement a broadband chirped-pulse technique. Two complementary investigations will be considered. The first one is the development of the new spectrometer, with the available new equipment. The second one is dedicated to the study of molecular complexes with water and sulfur. At first quantum chemistry calculations will be used to characterize the structure of the conformers and their relative energy. Then the theoretical predictions will be used in order to observe various complexes experimentally. At the end we are aiming to a better knowledge of the hydrogen bonding associated with oxygen and sulfur atoms, of interest to explain the aerosols formation.

OSSEIRAN Noureddin - noureddin.osseiran[chez]gmail[point].com 

Directeur(s) de thèse : HUET Thérèse - DREAN Pascal et GOUBET Manuel