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

Abstract

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 the vapor/liquid coexistence line for different ranges of attractive interaction have been evaluated and found to agree well with the Gibbs ensemble Monte Carlo data reported in the literature. To obtain surface tension, the normal and tangential components of the pressure tensor have been calculated during simulations by using a hybrid molecular dynamics algorithm (which combines the hard-core and continuous forces) and by using an original numerical algorithm for the hard-core contribution to the virial in Monte Carlo simulations. We found that surface tension is strongly dependent on the range of attractive interaction, i.e., it drops when the attraction becomes short-ranged. The relation of the attractive hard-core Yukawa potential to the spherically-truncated Lennard-Jones potential in terms of the interfacial properties is discussed.