Kinetic study of the OH + HO2 → H2O + O2 reaction using ring polymer molecular dynamics and quantum dynamics

Abstract

The reaction OH + HO₂ → H₂O + O₂ is a prototype of radical–radical reactions. It plays an important role in interstellar/atmospheric chemistry and combustion, and considerable attention has thus been dedicated to its kinetics. In our previous work, we reported an accurate full-dimensional potential energy surface for the title reaction on the ground triplet electronic state. The quasi-classical trajectory (QCT) approach was employed to investigate its kinetics. Although the QCT rate coefficients were in good agreement with some experimental and theoretical results, QCT cannot account for the quantum mechanical effects, such as zero-point vibrational energy, recrossing, and tunneling, which may significantly affect the rate coefficients, particularly at low temperatures. In this work, the reduced-dimensional quantum dynamics and ring polymer molecular dynamics calculations were carried out to examine these effects and their impact on rate coefficients over the temperature range of 300–1300 K.