Pulsed Vacuum-uv Photochemical Study of Reactions of OH with H2, D2, and CO Using a Resonance-Fluorescent Detection Method

Resonance fluorescence (A 2Σ+; v′=0→ X 2Π; v″=0) was used to monitor OH radicals in the pulsed vacuum-uv photolysis of H2O. From the exponential decays of OH radicals in the presence of a large excess of added reactants, absolute rate constants of the following reactions were determined at 298°K: OH+CO→ CO2+H; k4=1.35 × 10−13cm3molecule−1· sec−1, OH+H2→ H2O+H; k5=7.1 × 10−15cm3molecule−1· sec−1, OH+D2→ DHO+D; k6=2.05 × 10−15cm3molecule−1· sec−1. The over-all uncertainty of these rate constants was estimated to be ±15%. The methods for production and detection of OH were discussed in detail.