Journal of Physical Chemistry A, Vol.122, No.10, 2645-2652, 2018
Thermal Rate Coefficients and Kinetic Isotope Effects for the Reaction OH + CH4 -> H2O + CH3 on an ab Initio-Based Potential Energy Surface
Thermal rate coefficients for the title reaction and its various isotopologues are computed using a tunneling-corrected transition-state theory on a global potential energy surface recently developed by fitting a large number of high-level ab initio points. The calculated rate coefficients are found to agree well with the measured ones in a wide temperature range, validating the accuracy of the potential energy surface. Strong non-Arrhenius effects are found at low temperatures. In addition, the calculations reproduced the primary and secondary kinetic isotope effects. These results confirm the strong influence of tunneling to this heavy-light-heavy hydrogen abstraction reaction.