SURFACE-TENSION AND PHASE COEXISTENCE PROPERTIES OF THE LATTICE FLUIDFROM A VIRTUAL SITE REMOVAL MONTE-CARLO STRATEGY

A thin liquid film of lattice fluid in equilibrium with its vapor is s tudied in 2 and 3 dimensions with canonical Monte Carlo simulation (MC ) and Self-Consistent Field Theory (SCF) in the temperature range 0.45 T(c) to T-c, where T-c the liquid-gas critical temperature. Extending the approach of Gates et al. [Philos. Mag. B 61, 337 (1990)] to anisot ropic systems, we develop a method for the MC computation of the trans verse and normal pressure profiles, hence of the surface tension, base d on virtual removals of individual sites or blocks of sites from the system. Results from implementation of this new method, obtained at ve ry modest computational cost, are in reasonable agreement with exact v alues and other MC estimates of the surface tension of the 2-d and 3-d model systems, respectively. SCF estimates of the interfacial density profiles, the surface tension, the vapor pressure curve and the binod al curve compare well with MC results away from T-c, but show the expe cted deviations at high temperatures. (C) 1997 American Institute of P hysics.