Structure and bonding of dense liquid oxygen from first principles simulations

TL;DR

This study uses first principles simulations to explore the structural and electronic changes in dense liquid oxygen under high pressure, revealing a gradual transition from semiconducting to metallic states and molecular dissociation around 80 GPa.

Contribution

It provides detailed insights into the pressure-induced electronic and structural transitions in dense liquid oxygen using first principles methods.

Findings

Band gap closure occurs in the molecular liquid.

A slow transition from semi-conducting to metallic state over a wide pressure range.

Molecular dissociation observed at approximately 80 GPa.

Abstract

Using first principles simulations we have investigated the structural and bonding properties of dense fluid oxygen up to 180 GPa. We have found that band gap closure occurs in the molecular liquid, with a "slow" transition from a semi-conducting to a poor metallic state occurring over a wide pressure range. At approximately 80 GPa, molecular dissociation is observed in the metallic fluid. Spin fluctuations play a key role in determining the electronic structure of the low pressure fluid, while they are suppressed at high pressure.