SIMPLE ESTIMATION OF SURFACE-TENSION OF SINGLE-COMPONENT FLUIDS

A new form of the generalized van der Waals functional is introduced, the GvdW (HS-B2) functional, with the advantages of yielding a simple cubic equation of state, accurate critical parameters for simple fluids, and ease of use for the estimation of inhomogeneous properties such as surface tension. It is compared with earlier functionals of the GvdW or mean field type. The focus is on the surface tension of simple fluids which can be represented as LJ (12-6) fluids. We show that the new functional combined with an optimized Fermi function profile gives an excellent fit to experimental and simulated argon surface tension and to other small molecules equivalent to argon by the law of corresponding states. The dependence of the surface tension on the density difference between the two phases or on the reduced temperature is found to be in good agreement with the experimentally determined power laws. (C) 1994 Academic Press, Inc.