Reaction of hydrogen atoms with singlet delta oxygen (O2(a1Δg)). Is everything completely clear?

Abstract

In this paper, a comprehensive analysis of the reaction H + O2(a1Δg) → products and its channels, including available experimental data, theoretical estimations and kinetic studies, was carried out. A possible intrinsic mechanism of the reaction H + O2(a1Δg) → products, taking into account Renner–Teller coupling between the lowest doublet 2A′ and 2A″ states of a HO2 molecule was suggested. The proposed mechanism allows qualitative justification of the available data on the high probability for the quenching reaction: H + O2(a1Δg) → H + O2(3Σg). The effect of the reactions, including electronically excited molecules on the evaluation of temperature dependencies for the total and branching rate constants of the reaction H + O2(a1Δg) → products at low temperatures, was investigated. The value of the reaction H + O2(a1Δg)(+M) → HO2(2A′,2A″)(+M) rate constant was evaluated from shock tube experiments on O2(a1Δg) quenching in a lean H2–O2–O2(a1Δg) mixture. Based on the obtained results, temperature and pressure dependencies for the rate constants of the reaction H + O2(a1Δg) → product channels were recommended for the simulations, together with the proposed kinetic sub-mechanism for O2(a1Δg) chemistry in H2–O2 mixtures.