UMR CNRS 5805 EPOC
Environnements et Paléoenvironnements
Océaniques et Continentaux

        

Consignes de Sécurité et Numéros d'Urgence
(à l'usage des personnels du laboratoire)

July 11, 2012

Pranay MORAJKAR

Christa Fittschen (Université de Lille 1) / Eric Villenave

OH and HO2 radicals play a vital role in many oxidation processes in the atmosphere. The degradation of volatile organic compounds under tropospheric conditions is induced by reaction with hydroxyl radicals followed by the subsequent chemistry of the initial OH oxidation products with O2. This thesis deals with the kinetic study of some of these atmospherically relevant reactions to better understand their oxidation mechanisms using experimental techniques such as laser photolysis coupled to detection by Laser Induced Fluorescence (LIF, for OH), continuous wave- Cavity Ring- down Spectroscopy (cw-CRDS, for HO2) and time resolved UV spectroscopy (UV, for Hexamethylbenzene-OH adduct).
Different chemical systems have been studied using the above techniques: 1) the reaction of HO2 radicals with formaldehyde, 2) the 248 nm photolysis of acetaldehyde and 3) the OH initiated oxidation of Hexamethyl benzene. In addition to this, the spectroscopic application of cw-CRDS technique and UV spectroscopy has been used for the measurement of absorption cross section of selected absorption lines of formaldehyde in the near infrared region and Hexamethylbenzene-OH adduct in the UV region respectively.

http://www.theses.fr/2012LIL10063