Absolute free energies and equilibrium ensembles of dense fluids computed from a nondynamic growth method

Abstract

We demonstrate a nondynamical Monte Carlo method to compute free energies and generate equilibrium ensembles of dense fluids. In this method, based on step-by-step polymer growth algorithms, an ensemble of n+1 particles is obtained from an ensemble of n particles by generating configurations of the n+1st particle. A statistically rigorous resampling scheme is utilized to remove configurations with low weights and to avoid a combinatorial explosion; the free energy is obtained from the sum of the weights. In addition to the free energy, the method generates an equilibrium ensemble of the full system. We consider two different system sizes for a Lennard-Jones fluid and compare the results with conventional Monte Carlo methods.