Multiphase equilibria using the Gibbs ensemble Monte Carlo method

Abstract

The Gibbs ensemble simulation method is extended to multiphase equilibria by increasing the number of boxes that can be used concurrently in the simulation. Atoms are moved within each box and pairs of boxes are selected at random for the volume and particle exchange moves. The equivalence between the Gibbs ensemble with an arbitrary number of boxes and the corresponding canonical ensemble is established. Simulations of two-component, three-phase equilibria and three-component, four-phase and three-phase equilibria are demonstrated for simple model systems, and the model phase diagrams are determined.