Ab initio based polarizable force field generation and application to liquid silica and magnesia

TL;DR

This paper extends the potfit program to generate polarizable force fields including electrostatics and induced dipoles, enabling large-scale molecular dynamics simulations of metal oxides like silica and magnesia.

Contribution

It introduces a new method for generating polarizable potentials from ab initio data with linear scaling, validated on liquid silica and magnesia.

Findings

Successfully generated potentials for SiO2 and MgO

Accurately modeled microstructural and thermodynamic properties

Enabled large-scale simulations with linear computational effort

Abstract

We extend the program potfit, which generates effective atomic interaction potentials from ab initio data, to electrostatic interactions and induced dipoles. The potential parametrization algorithm uses the Wolf direct, pairwise summation method with spherical truncation. The polarizability of oxygen atoms is modeled with the Tangney-Scandolo interatomic force field approach. Due to the Wolf summation, the computational effort in simulation scales linearly in the number of particles, despite the presence of electrostatic interactions. Thus, this model allows to perform large-scale molecular dynamics simulations of metal oxides with realistic potentials. Details of the implementation are given, and the generation of potentials for SiO2 and MgO is demonstrated. The approach is validated by simulations of microstructural, thermodynamic and vibrational properties of liquid silica and magnesia.