Determination of vapour-liquid equilibrium using cavity-biased grand canonical Monte Carlo method

Abstract

In a previous paper a new simulation method was introduced for the determination of vapour-liquid equilibrium (VLE) of pure fluids in the grand canonical ensemble (Boda, D., Liszi, J., and Szalai, I., 1996, Chem. Phys. Lett., 256, 474). Its basic idea is the extrapolation of the pressure in the directions of reciprocal temperature and configurational chemical potential via third-order Taylor series expansion: p(β, μ). The coefficients of the series can be obtained from fluctuation formulae by performing grand canonical Monte Carlo (GC MC) simulations on both vapour and liquid sides. It was found that the main shortcoming of the method originates from the inaccurate calculation of the pressure on liquid side because of the slow convergence of the original GC MC simulation used. It is now shown that the application of the cavity-biased GC MC method of Mezei on the liquid side can overcome this difficulty. The linked-cell method to fasten the cavity-searching algorithm is proposed. The results of test calculations for the Lennard-Jones system show excellent agreement with those obtained by the NpT plus test particle method. The method can be implemented for the determination of phase separation in mixtures in a straightforward manner.