Simulating Phase Equilibria using Wang-Landau-Transition Matrix Monte Carlo

Abstract

We will examine the strengths and weaknesses of the Wang-Landau and transition matrix Monte Carlo methods for simulating phase equilibria of continuous molecular systems alone and as a combined Wang-Landautransition matrix Monte Carlo algorithm. Although a combined Wang-Landau transition matrix Monte Carlo algorithm has been previously reported in the literature, the details of the method and a discussion of its performance for phase equilibria simulations has not been presented. The hybrid method combines the rapid initial estimate of the density of states from the Wang-Landau algorithm with the continual improvement in convergence of transition matrix Monte Carlo. The hybrid Wang-Landau-transition matrix (WL-TM) algorithm is found to be more efficient and has much better convergence properties than the Wang-Landau algorithm and is more robust than the transition matrix algorithm, enabling the simulations to reach relatively low reduced temperatures with ease.