Simultaneous, time-resolved measurements of OH and HO2 radicals by coupling of high repetition rate LIF and cw-CRDS techniques to a laser photolysis reactor and its application to the photolysis of H2O2

A new experimental set-up for the simultaneous, time-resolved measurement of OH and HO2 radicals by coupling high repetition rate Laser Induced Fluorescence (LIF) and cw-Cavity Ring-Down Spectroscopy (cw-CRDS) detection techniques to a laser photolysis reactor has been installed. The first experiments concern the well-known photolysis of H2O2: the absorption cross sections of H2O2 lines in the near-infrared at 6636.75 and 6639.90 cm(-1) have been determined by combined results of spectroscopic and kinetic measurements of OH and HO2 radicals produced by the photolysis of H2O2 at 248 nm. These experiments will enable the measurement of absolute H2O2 concentrations in future experiments with the same set-up.