Monteswitch: A package for evaluating solid-solid free energy differences via lattice-switch Monte Carlo

TL;DR

Monteswitch is a versatile software package that implements lattice-switch Monte Carlo to efficiently evaluate free energy differences between solid phases, including complex and multicomponent systems, with support for various interatomic potentials.

Contribution

The paper introduces monteswitch, a flexible and efficient package for lattice-switch Monte Carlo simulations of solid-solid free energy differences across diverse potentials.

Findings

Supports multiple interatomic potentials including Lennard-Jones and embedded atom models

Enables evaluation of free energy differences in multicomponent and defected systems

Offers high efficiency compared to existing methods

Abstract

Lattice-switch Monte Carlo (LSMC) is a method for evaluating the free energy between two given solid phases. LSMC is a general method, being applicable to a wide range of problems and interatomic potentials. Furthermore it is extremely efficient, ostensibly more efficient than other existing general methods. Here we introduce a package, monteswitch, which can be used to perform LSMC simulations. The package can be used to evaluate the free energy differences between pairs of solid phases, including multicomponent phases, via LSMC for atomic (i.e., non-molecular) systems in the NVT and NPT ensembles. It could also be used to evaluate the free energy cost associated with interfaces and defects. Regarding interatomic potentials, monteswitch currently supports various commonly-used pair potentials, including the hard-sphere, Lennard-Jones, and Morse potentials, as well as the embedded atom model. However the main strength of the package is its versatility: it is designed so that users can easily implement their own potentials.