The mode specificity of the dissociative chemisorption of D2O on a rigid Cu(111) surface was investigated by calculating the approximate full-dimensional (9D) dissociation probabilities with the implementation of the seven-dimensional (7D) quantum dynamics calculations and site averaging approximations. The approximate 9D dissociation probabilities for D2O initially in various vibrational states were obtained by averaging the site-specific 7D results over 9 impact sites on an accurate 9D potential energy surface (PES). Strong mode specificity was observed for the title reaction, where vibrational excitations of the two stretching modes of D2O are more efficacious than increasing the translational energy in promoting the reaction, while the bending excitations with one and two quanta are less efficacious than the same amount of translational energy in enhancing the reactivity at low kinetic energies.
