A Flash Photolysis Study of CH4–O2 Mixtures behind Shock Waves: Examination of Reaction of CH3+O2

Abstract

ArF laser photolysis in the mixtures of CH₄ and O₂ highly diluted in Ar has been conducted behind reflected shock waves, where O and H atoms have been monitored using the ARAS technique. The rate constant for the reaction CH₄ + O → CH₃ + OH (1) has been directly determined to be 10^{−8.95 ± 0.27} exp [−(15.4 ± 2.0)kcal mol⁻¹/RT] cm³ molecule⁻¹ s⁻¹ over the temperature range of 1365–1840 K. Also the consecutive reactions; CH₃ + O₂ → CH₃O + O (3a) and CH₃ + O₂ → CH₂O + OH (3b) have been examined more directly than in previous thermally initiated experiments, and the combinations of k_3a and k_3b have been evaluated at the temperature range from 1622 to 1840 K.