Incorporating Gibbs free energy into interatomic potential fitting

TL;DR

This paper introduces a novel method that integrates Gibbs free energy data into the fitting process of interatomic potentials, improving accuracy for high-temperature atomic systems.

Contribution

It presents a Hamiltonian thermodynamic integration approach to incorporate free energy data into potential fitting, compatible with existing property-based fitting methods.

Findings

Validated with Uhlenbeck-Ford model

Effective for Ni phase potentials

Applicable to high-pressure Fe-O liquids

Abstract

We develop a method to fit high-temperature Gibbs free energy data for the development of interatomic potentials for atomic systems. The approach is based on Hamiltonian thermodynamic integration, enabling the identification of suitable potential parameters such that the system's free energy matches a specified target. The method can be readily combined with conventional fitting techniques for properties such as elastic tensors and liquid pair distribution functions. We validate the effectiveness of the approach using the Uhlenbeck-Ford model and embedded-atom method potentials for pure Ni phases and binary Fe1-xOx liquids under high-pressure and high-temperature conditions. Our framework provides an efficient strategy for incorporating free energy into interatomic potential fitting.