06-01E

# 06-01E

Phase coexistence in polydisperse multi-Yukawa hard-sphere fluid. High temperature approximation

High temperature approximation (HTA) is used to describe the phase behavior of the polydisperse multi-Yukawa hard-sphere fluid mixture. It is demonstrated that in the frames of the HTA the model belongs to the class of "truncatable free energy models", i.e. the models with thermodynamical properties (Helmholtz free energy, chemical potential and pressure) defined by the finite number of generalized moments. Using this property we were able to calculate complete phase diagram (i.e., cloud and shadow curves as well as binodals) and distribution functions of the coexisting phases of several different models of polydisperse fluids. In particular, we consider polydisperse one-Yukawa hard-sphere mixture with factorizable Yukawa coefficients and polydisperse Lennard-Jones (LJ) mixture with interaction energy parameter and/or size polydispersity. To validate the accuracy of the HTA we compare theoretical results with previously published results of more advanced mean spherical approximation (MSA) for the one-Yukawa model and with Monte Carlo (MC) computer simulation results of Wilding et al. We find that overall predictions of the HTA are in reasonable agreement with predictions of the MSA and MC.