Two-dimensional quantum dynamics of O2 dissociative adsorption on Ag(111)

Abstract

We have investigated the quantum dynamics of O₂ dissociative adsorption on a Ag(111) surface. We performed the calculations with a Hamiltonian where the O₂ translational motion is perpendicular to the surface and for O₂ vibrational energy. We found that dissociative adsorption occurs with an incident translational energy below the expected activation barrier, while the translational-energy dependence for adsorption probabilities is a smooth sigmoid. Thus, there are non-negligible tunneling effects in the dissociative adsorption that are affected by the activation barrier width. Moreover, the incident translational energies at the inflection points of the adsorption probabilities shift lower with an increase in vibrational quantum numbers of the incident O₂. Thus, there is significant energy transfer and coupling from vibration to translational motion. The vibrational energy assists the O₂ dissociative adsorption via a vibrationally assisted sticking effect.