Tunnel effects in oxidative addition reaction of methane to bare Pd atom

Abstract

The potential-energy surface has been calculated for oxidative addition of methane to a bare Pd atom by the semiempirical LCAO MO SCF CNDO/S² technque. Quantum rate constants and values of the kinetic isotope effect have been computed for both the ground and vibrationally excited states of Pd–CH₄ and Pd–CD₄ reactions using the reaction path Hamiltonian approach with evaluation of the reaction path curvature. Quantum tunnelling has been shown to give the dominant contribution to the cumulative rate constant for the Pd–CH₄ reaction at temperatures below 200 K.