Title: The Reaction of RO2 Radicals with OH and its Impact in Remote Environments
Time: 14:00 to 15:00, Wednesday, May.31, 2023
Place: F207, School of Mechanical Engineering
Speaker: Dr. Christa Fittschen（University Lille, France）
Host: QI Fei, Professor (Institute of Aerospace Propulsion)

Biography
Dr. Christa Fittschen is Research Director at CNRS and head of the Atmospheric Chemistry section at the laboratory “Physical Chemistry of Combustion and Atmospheric Chemistry Processes” at the University Lille, France. She has been recruited to a permanent position at CNRS in 1992 and is working since then on the development of laser-based techniques dedicated to the detection of radical species and their application to the kinetic of elementary reactions of atmospheric interest. Her special interest since more than a decade is on the chemistry of peroxy radicals.

Abstract
Peroxy radicals, RO2, are key species in the atmosphere. They are formed from a reaction of OH radicals with hydrocarbons. Recently, the rate constant for the reaction RO2 + OH  products has been measured for C1 to C4 peroxy radicals and it was shown to be fast enough to become competitive to other sinks. However, in order to evaluate the impact of this so far neglected sink for peroxy radicals on the composition of remote atmospheres, the reaction products must be known. 

Recent results obtained in my laboratory by using the technique of laser photolysis coupled to a detection of peroxy radicals by cw-Cavity Ring Down Spectroscopy (CRDS) and of OH radicals by Laser Induced Fluorecence (LIF) will be presented. Experiments have been devoted to the determination of the rate constant as well as of the yields of possible reaction products and on their impact in remote environments.