Two-Dimensional Quantum Dynamics of O$_2$ Dissociative Adsorption on Ag(111)

TL;DR

This study explores the quantum dynamics of O2 dissociative adsorption on Ag(111), revealing tunneling effects, vibrational-translational energy transfer, and vibrationally assisted sticking, which influence adsorption probabilities at low energies.

Contribution

It provides a detailed quantum mechanical analysis of O2 adsorption on Ag(111), highlighting the role of tunneling and vibrational energy in the process, which was not previously well understood.

Findings

Dissociative adsorption occurs below the expected activation barrier.

Tunneling effects significantly influence adsorption probabilities.

Vibrational energy enhances adsorption via vibrationally assisted sticking.

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 increasing 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.