# O2 Dissociative Adsorption on Mg(0001)Surface Oxidation, Peroxide Formation, and Oxide Layer Thickening

## TL;DR

This study explores how oxygen interacts with a magnesium surface, leading to oxidation and peroxide formation through computational methods.

## Contribution

The paper reveals the spontaneous dissociation of O2 on Mg(0001) and the formation of oxide islands and peroxides through DFT and AIMD simulations.

## Key findings

- O2 dissociates spontaneously on Mg(0001), forming oxide islands due to Mg–O interactions.
- Oxide islands grow with increased O2 exposure, forming two oxidized layers.
- Surface peroxides form through mixed adsorption of oxygen atoms and O2 molecules.

## Abstract

O2 exposure-dependent oxidation process on
the p(4 × 4) Mg(0001) surface has been systematically
studied
based on DFT computation and AIMD analysis. At initial exposure, O2 dissociates spontaneously, and the oxygen atoms penetrate
the subsurface layers, forming oxide islands due to the electrostatic
attractive Mg–O interaction. The oxide islands grow laterally
and vertically with an increase in the level of exposure to O2 and eventually, the first two stoichiometrically oxidized
layers (32 × O) are formed. The oxidized surface layer can further
uptake both oxygen atoms and molecular O2 and forms stable
mixed adsorption configurations (4O+xO2, x = 1–4),
which reveal the formation of surface peroxides, as proposed by an
XPS study. The AIMD analysis explains the experimentally observed
changes in the LEED patterns during the oxidation process upon the
increase of O2 exposure.