Direct Monte Carlo simulations of the equilibrium properties of n-pentane liquid-vapor interface

Direct MC calculations have been carried out to study the liquid-vapor equilibrium of n-pentane. We have used the local long range correction to the configurational energy within the Metropolis scheme and an algorithm allowing us to select randomly with equal probability two different maximum displacements. The thermal equilibrium conditions are checked by calculating the profiles of the configurational temperature in the vapor and liquid phases. We also check the mechanical equilibrium by calculating the profiles of the normal and tangential pressure components. The normal pressure profile is constant through the interface and in both phases on the conditions that the two parts of the long range corrections to the normal pressure area included in the calculations. The critical densities and temperatures are well predicted and the vapor pressures agree satisfactory with the experimental values within larger statistical fluctuations. The long range corrections to the surface tension are calculated using various analytical forms and are included in the computation to give values which are in good agreement with those available in the literature. Finally, the surface tension is computed from 299 K to 425 K for two system sizes and three cutoff values. (C) 2002 American Institute of Physics.