Experimentally Constrained Molecular Relaxation: The Case of Glassy GeSe2

TL;DR

This paper introduces a hybrid modeling approach combining reverse Monte Carlo and first principles molecular dynamics to create atomistic models of disordered materials that agree with experiments and force fields, demonstrated on glassy GeSe2.

Contribution

The paper presents a novel hybrid method that jointly satisfies experimental data and theoretical force fields for modeling disordered materials.

Findings

Achieved a 647-atom model of glassy GeSe2 consistent with experiments.

Successfully reproduced the first sharp diffraction peak in the structure factor.

Computed electronic densities aligning with photoelectron spectroscopy data.

Abstract

An ideal atomistic model of a disordered material should contradict no experiments,and should also be consistent with accurate force fields (either {\it ab initio}or empirical). We make significant progress toward jointly satisfying {\it both} of these criteria using a hybrid reverse Monte Carlo approach in conjunction with approximate first principles molecular dynamics. We illustrate the method by studying the complex binary glassy material g-GeSe$_2$. By constraining the model to agree with partial structure factors and {\it ab initio} simulation, we obtain a 647-atom model in close agreement with experiment, including the first sharp diffraction peak in the static structure factor. We compute the electronic state densities and compare to photoelectron spectroscopies. The approach is general and flexible.