The photolysis of NO2 at 193 nm

Infrared kinetic spectroscopy has been used to investigate the photo-dissociation of NO2 at 193 nm. The O(1D)/(O(1D)+O(3P)) branching ratio was measured as 0.55±0.03 by adding a large excess of H2 to the system, and comparing the amount of NO2 removed during the photolysis to the amount of OH formed by the subsequent fast reaction between O(1D) and H2. The rate constant for the reaction between O(1D) and NO2 was measured as (1.5±0.3)×10−10 cm−3 s−1, and the 193 nm absorption cross-section for NO2 was estimated as (2.9±1.2)×10−19 cm2.