Rotation and dissociation dynamics of a single O2 molecule on the Pt(111) surface determined from a first principles study

TL;DR

This study uses first principles calculations and a new statistical model to elucidate the rotation and dissociation mechanisms of a single O2 molecule on Pt(111), resolving longstanding questions about these processes.

Contribution

It introduces a novel combined computational and statistical approach to accurately describe O2 dynamics on Pt(111), explaining low energy barriers and non-integer power-law behaviors.

Findings

Low energy barrier for O2 rotation explained by a specific pathway

Metastable site occupation due to surface accommodation dynamics

Non-integer power-law dependence of rotation rate on current clarified

Abstract

The STM induced rotation and dissociation dynamics of a single oxygen molecule on the Pt(111) surface have been finally determined by first principles calculations together with a newly developed statistical model for inelastic electron tunneling. Several long-standing puzzles associated with these dynamic processes in this classic system have been fully resolved. It is found that the unexpected low energy barrier of the O2 rotation is originated from an ingenious pathway, while the prior occupation of the metastable hcp-hollow site after the O2 dissociation can be attributed to a dynamic process of surface accommodation. The experimentally observed non-integer power-law dependence of the rotation rate as a function of the current can be perfectly explained by taking into account the randomness of multi-electron inelastic tunneling processes.