Direct correlation function of square well fluid with wide well: First order mean spherical approximation

An analytical expression for square-well fluid direct correlation function (DCF) obtained recently by Tang (Y.Tang, J. Chem. Phys. 127, 164504 (2007)) in the first-order mean spherical approximation is extended for wider well widths (2<lambda<3). Theoretically obtained direct correlation functions and radial distribution functions for square-well fluid with lambda=2.1 and lambda=2.5 are compared with corresponding results of Monte-Carlo simulation.