Mean-spherical approximation for the Lennard-Jones-like two Yukawa model: Comparison against Monte Carlo data

Abstract

Monte Cario simulation studies are performed for the Lennard-Jones-like two Yukawa (LJ2Y) potential to show how properties of this model fluid depend on the replacement of soft repulsion by hard-core repulsion. Different distances for the positioning of hard-core have been explored. We have found that for temperatures slightly lower and slightly higher than the critical point temperature for the Lennard-Jones fluid the placement of the hard-core at distances shorter than zero-potential energy is well justified by thermodynamic properties that are practically the same as in the original LJ2Y model without hard-core. However going to extreme conditions with the high temperature one should be careful since the presence of the hard-core provokes changes in the properties of the system. The later is extremely important when the mean-spherical approximation (MSA) theory is applied to the treatment of the Lennard-Jones-like fluid. © J. Krejčí, I. Nezbeda, R. Melnyk, A. Trokhymchuk, 2011.