Semi-classical generalized Langevin equation for equilibrium and nonequilibrium molecular dynamics simulation

TL;DR

This paper reviews the extension of Langevin molecular dynamics to include nuclear quantum effects and their coupling to external fields, enabling more accurate simulations of light-element materials and surface phenomena.

Contribution

It introduces a semi-classical generalized Langevin equation framework that incorporates nuclear quantum effects into molecular dynamics simulations.

Findings

Enhanced modeling of adsorbate dynamics on metal surfaces.

Improved understanding of current-induced molecular behavior.

Insights into quantum thermal transport mechanisms.

Abstract

Molecular dynamics (MD) simulation based on Langevin equation has been widely used in the study of structural, thermal properties of matters in difference phases. Normally, the atomic dynamics are described by classical equations of motion and the effect of the environment is taken into account through the fluctuating and frictional forces. Generally, the nuclear quantum effects and their coupling to other degrees of freedom are difficult to include in an efficient way. This could be a serious limitation on its application to the study of dynamical properties of materials made from light elements, in the presence of external driving electrical or thermal fields. One example of such system is single molecular dynamics on metal surface, an important system that has received intense study in surface science. In this review, we summarize recent effort in extending the Langevin MD to include nuclear quantum effect and their coupling to flowing electrical current. We discuss its applications in the study of adsorbate dynamics on metal surface, current-induced dynamics in molecular junctions, and quantum thermal transport between different reservoirs.