Phase coexistence in polydisperse liquid mixtures: Beyond the van der Waals approximation

The solution of the mean spherical approximation for a polydisperse fluid mixture of particles interacting via a set of (factorizable) hard-sphere Yukawa potentials allows one to represent those thermodynamic quantities that are relevant to determine phase coexistence (i.e., pressure and chemical potential) by a limited number of (generalized) moments. Being thus a member of "truncatable free energy models," the equilibrium conditions reduce to a set of coupled and highly nonlinear equations; we have solved these relations, we have determined phase diagrams for polydisperse fluid mixtures (i.e., cloud and shadow curves as well as binodals), and have extracted the daughter distribution functions of the coexisting phases. (C) 2003 American Institute of Physics.