Use of the Attractive Hard-Core Yukawa Interaction for Predicting of the Small-kBehavior of the Structure Factor for Simple Fluids

Abstract

A definition of the direct correlation function (DCF) is applied to monatomic fluids modeled by spherical particles with a pair potential given by a hard-core repulsion and a Yukawa attractive tail. This potential allows one to take advantage of the known analytical properties of the solution to the Ornstein–Zernike (OZ) equation for the case in which the DCF outside the repulsive core is improved by a linear combination of two Yukawa tails. Predictions for the structure factor, \(S(k)\), at low-wave factor are studied and compared with other liquid-state theories and experimental data available in the literature. It was found that the closure considered here provided very well the OZ behavior of \(S(k)\) at low-\(k\) for the near critical point and coexistence curve regions. For the interaction range considered here, one can realize the remarkably accurate divergence of \(S(0)\) at the near critical point, which is related to the fluctuation phenomena.