Atomic resonance fluorescence for rate constants of rapid bimolecular reactions. Part 6.—Hydrogen atom reactions: H + Cl2from 300 to 730 K and H + NO2at 298 K

Abstract

Detection of H ²S atoms in a flow system using resonance fluorescence has been used to determine the rate constant k₁/cm³ molecule^–1 s^–1 for reaction (1), H + Cl₂[graphic omitted] HCl + Cl (1), Pseudo first-order kinetic conditions were used, with [Cl₂]₀/[H]₀ 1. Measurements of k₁ from 300 to 750 K gave the following Arrhenius expression: log₁₀k₁=(–9.851 ± 0.074)–(250 ± 28)/T(2σ); with k₁=(2.19 ± 0.32)× 10^–11(2σ) at 300 K. A similar technique has been used to determine k₂ at 298 K: H + NO₂[graphic omitted] OH + NO (2) the value was k₂=(1.1₃± 0.2₂)× 10^–10(2σ), in good agreement with other recent work.