Dissociative chemisorption of methane on Ni(100): Threshold energy from CH4(2ν3) eigenstate-resolved sticking measurements

A three-parameter microcanonical theory of gas-surface reactivity is used to model the dissociative sticking of vibrationally excited methane with two quanta of energy in the ν3 antisymmetric C–H stretch. An apparent threshold energy for C–H bond cleavage of CH4 incident on Ni(100) of 65 kJ/mol is found, in quantitative agreement with ab initio quantum chemistry calculations but 38 kJ/mol less than GGA-DFT calculations. Successful microcanonical analysis and prediction of recent thermal equilibrium and various nonequilibrium dissociative chemisorption experiments for methane on Ni(100) provide no evidence for mode-specific reactivity.