The thermodynamics of molecules with discrete potentials

Abstract

Fluids formed by molecules interacting with discrete potentials are examined in the context of perturbation theory and the reference hypernetted chain equation (RHNC) solution to the Ornstein—zernike equation. A perturbation theory for discrete-potential fluids (DPT) is presented, which only requires one to know the properties of a square-well fluid of variable range. Several potentials are studied: square-shoulder, a combination of a square-well and square-shoulder, and a discrete representation of a continuous potential model. We have found that the DPT approach reproduces the RHNC predictions in most of the cases.