Thermal rate coefficients and kinetic isotope effects of the reaction HO + H2O → H2O + OH

Abstract

Hydrogen-transfer reactions take place in a wide range of chemically active environments. In this work, thermal rate coefficients of the prototypical hydrogen-transfer reaction HO + H2O → H2O + OH and its various isotopologues are computed using both tunneling-corrected transition state and quasi-classical trajectory methods on a recently developed global potential energy surface. On the one hand, the calculated rate coefficients and kinetic isotope effects agree well with available experimental results, indicating the high fidelity of the potential energy surface. On the other hand, the observed normal primary and inverse secondary kinetic isotope effects appear to be prevalent in hydrogen abstraction reactions, which are rationalized by the change of classical and adiabatic minimum energy paths. In addition, there exists strong non-Arrhenius behavior at low temperatures due to the significant quantum tunneling effect.