Effective interaction potential for amorphous silica from ab initio simulations

TL;DR

This paper introduces a new method to derive effective interaction potentials from ab initio simulations, demonstrating improved accuracy for amorphous silica compared to existing models and analyzing the limitations of force matching techniques.

Contribution

A novel approach for deriving effective potentials from ab initio data, validated on amorphous silica, outperforming traditional models and highlighting limitations of force matching.

Findings

New effective potential better matches structural properties

Force matching approach was unreliable for silica

Method provides improved thermodynamic descriptions

Abstract

We discuss a novel approach that allows to obtain effective potentials from ab initio trajectories. Our method consists in fitting the weighted radial distribution functions obtained from the ab initio data with the ones obtained from simulations with the effective potential, and using the parameters of the latter as fitting variables. As a case study, we consider the example of amorphous silica, a material that is highly relevant in the field of glass science as well as in geology. Our approach is able to obtain an effective potential that gives a better description with respect to structural and thermodynamic properties than the potential proposed by van Beest, Kramer, and van Santen, and that has been very frequently used as a model for amorphous silica. In parallel, we have also used the so-called "force matching" approach proposed by Ercolessi and Adams to obtain an effective potential. We demonstrate that for the case of silica this method does not yield a reliable potential and discuss the likely origin for this failure.