Discharge-flow studies of the kinetics of the reactions of CH3O with Cl, Br, I, ClO, BrO and IO using laser-induced fluorescence and resonance-fluorescence detection

Abstract

A low-pressure discharge-flow system employing LIF detection for CH₃O, and resonance-fluorescence detection for Cl, Br and I atoms, was used to investigate the kinetics of the reactions of CH₃O with X and XO (where X = Cl, Br and I) at T = 298 K. The rate constants obtained are k_Cl = (7.6 ± 1.4) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹, k_Br = (5.3 ± 0.9) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹, k_I = (8.5 ± 2.3) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹, k_ClO = (3.4 ± 0.7) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹, k_BrO = (5.5 ± 1.0) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ and k_IO = (4 ± 2) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹. It is likely that the major channel in the reaction of CH₃O with X yields HX and CH₂O, while, in the reaction with XO, the main products are HOX and CH₂O.