Molecular Orientation and Surface Site Dependence of the Dissociative Adsorption of O$_{2}$/Al(111)

TL;DR

This study combines density functional theory and quantum dynamics to analyze how molecular orientation and surface site influence the dissociative adsorption of O₂ on Al(111), revealing site-dependent activation barriers and the role of vibrational motion.

Contribution

It provides a detailed computational analysis of the surface site and orientation dependence of O₂ dissociation on Al(111), highlighting the importance of vibrational motion and surface site in adsorption.

Findings

Large activation barrier for top site dissociation

Vibrational motion facilitates dissociation via late barrier

Surface site and molecular orientation critically affect adsorption

Abstract

We reproduced the initial sticking probability of O$_{2}$/Al(111) by use of spin-polarized density functional theory and quantum dynamics calculations. We found a large activation barrier when the molecule is dissociatively adsorbed through $abstraction$ on the top site unlike on the hollow and bridge sites. This barrier is sensitive to the molecular orientation and surface site. The vibrational motion of the molecule facilitates the abstraction due to the $late barrier$. Finally, we suggest a possibility on how widely separated oxygen atoms adsorbed on the surface could be realized.