Surface tension at the vapor/liquid interface in an attractive hard-core Yukawa fluid

Canonical ensemble molecular dynamics and Monte Carlo simulations have been performed to study the vapor/liquid coexistence in a hard-core fluid with an attractive Yukawa interaction. Coexisting densities and pressure along t he vapor/liquid coexistence line for different ranges of attractive interac tion have been evaluated and found to agree well with the Gibbs ensemble Mo nte Carlo data reported in the literature. To obtain surface tension, the n ormal and tangential components of the pressure tensor have been calculated during simulations by using a hybrid molecular dynamics algorithm (which c ombines the hard-core and continuous forces) and by using an original numer ical algorithm for the hard-core contribution to the virial in Monte Carlo simulations. We found that surface tension is strongly dependent on the ran ge of attractive interaction, i.e., it drops when the attraction becomes sh ort-ranged. The relation of the attractive hard-core Yukawa potential to th e spherically-truncated Lennard-Jones potential in terms of the interfacial properties is discussed. (C) 2001 American Institute of Physics.