Car-Parrinello Simulation of the Reaction of Aluminium with Oxygen

TL;DR

This paper uses Car-Parrinello molecular dynamics to simulate the initial oxidation process of aluminium, revealing rapid oxygen dissociation and oxide layer formation at the atomic level.

Contribution

It provides detailed insights into the reaction mechanism and atomic structure development of aluminium oxidation, which was previously not well understood.

Findings

Oxygen molecules dissociate within femtoseconds upon adsorption.

Chemisorbed oxygen atoms form a threefold coordinated oxide layer.

Higher oxygen pressure accelerates oxide layer formation.

Abstract

We present Car-Parrinello molecular dynamics simulations of the initial reaction steps leading to an inert oxide layer on aluminium. The mechanism of the reaction of the aluminium surface with single oxygen molecules is analysed. After adsorption at the surface the oxygen molecules dissociate at a femtosecond timescale and the atoms are chemisorbed at the surface at a distance of several angstrom. When the aluminium surface is exposed to higher oxygen pressure, a surface layer essentially consisting of threefold coordinated oxygen atoms starts to form.