Dynamics of the H + O₂ → O + OH Chain-Branching Reaction:  Accurate Quantum Mechanical and Experimental Absolute Reaction Cross Sections

Abstract

The H + O 2 → O + OH chain-branching reaction, one of the most important elementary reactions in combustion chemistry, represents a challenging benchmark system for testing dynamical theories against experiments. The translational energy dependence of the total reaction cross section of the H + O 2 (vibrational quantum number ν = 0) reaction was investigated experimentally employing a pulsed laser pump−probe technique and theoretically by means of quantum mechanical scattering calculations. The present results indicate that there is no sharp increase in reactivity for translational energies E tr ≥ 1.4 eV as was suggested by earlier experiments and approximate dynamical calculations. Furthermore, our results indicate that the potential energy surface needs to be improved to achieve quantitative agreement between experiment and theory.