An integral equation theory for the Widom-Rowlinson mixture

摘要

The Widom Rowlinson mixture is a two-component fluid in which like species do, not interact and unlike species interact via a hard-core repulsion. As the density is increased, this fluid phase separates. Standard integral equation approaches. such as the Percus-Yevick or hypernetted chain, or thermodynamically self-consistent hybrids of these two, make very inaccurate predictions for the location of this critical point in the three-dimensional model. In this article we suggest a family of new approximations for this model that rely on incorporating ic rms in the density expansion of the direct correlation function into the closure approximation. We show that the simplest uf these closures is significantly more accurate than previous theories for the structure and thermodynamics of the fluid. [References: 21]