Monte Carlo simulation for the hard-core two-Yukawa fluids and test of the two-Yukawa equation of state

A recently proposed analytical equation of state (EOS) for the hard-core two-Yukawa fluids is tested against the results of Monte Carlo (MC) simulation in six cases. One range parameter in the two-Yukawa potential is taken as 1.8 or 2.8647, and another is taken as 2.0, 4.0, 8.0, or 13.5485. Attractive and repulsive dominant cases of the potential outside the core are all considered. The simulation conditions selected ensure that, the interaction between two particles is attractive at enough long distance. Some of the cases can give the similar potential as that between charged colloid particles. The hard-core two-Yukawa fluid with parameters, which are obtained from fitting the Lennard-Jones potential, is also studied. The two-Yukawa EOS results fit very well with that of the MC simulation except for some points at high density (as rho*=0.9), which is found to be crystal state. It is found that the two-Yukawa EOS can be used to study the fluid-fluid equilibrium of hard-core two-Yukawa fluid. (C) 2002 American Institute of Physics.