Nuclear quantum effect on the elasticity of ice VII under pressure: A path-integral molecular dynamics study

TL;DR

This study uses path-integral molecular dynamics to show that nuclear quantum effects significantly influence the elastic properties and structural transition of ice VII under high pressure, with NQEs increasing elastic constants by about 20%.

Contribution

First ab initio PIMD study quantifying nuclear quantum effects on ice VII's elasticity under pressure.

Findings

NQEs cause a transition from static to dynamic disorder in ice VII above 40 GPa.

NQEs increase elastic constants of ice VII by approximately 20% at 70 GPa.

NQEs are crucial for accurately modeling the high-pressure elasticity of ice VII.

Abstract

We investigate the effect of nuclear quantum effects (NQEs) of hydrogen atoms on the elasticity of ice VII at high pressure and ambient temperature conditions using ab initio path-integral molecular dynamics (PIMD) calculations. We find that the NQEs of hydrogen contributes to the transition of ice VII from a static disordered structure to a dynamically disordered structure at pressures exceeding 40 GPa. This transition is marked by a discontinuous increase of the elastic constants. Comparison of ab initio molecular dynamics and PIMD calculations reveal that NQEs increase the elastic constants of ice by about 20% at 70 GPa and 300 K.