Self-consistent Ornstein-Zernike approximation for the Sogami-Ise fluid.

We generalize the self-consistent Ornstein-Zernike approximation (SCOZA) to a fluid of particles with a pair potential consisting of a hard-core repulsion and a linear combination of Sogami-Ise tails, w(r)=-epsilonsigma summation operator (nu)(K(nu)/r+L(nu)z(nu))e(-z(nu)(r-sigma)). The formulation and implementation of the SCOZA takes advantage of the availability of semianalytic results for such systems within the mean-spherical approximation. The predictions for the thermodynamics, the phase behavior and the critical point are compared with optimized random phase approximation results; further, the effect of thermodynamic consistency is investigated.