Perturbation theory of one-dimensional triangle- and square-well fluids

Abstract

The Barker–Henderson perturbation theory for free energy is investigated for one-dimensional triangle- and square-well potentials. It is found that the first-order term is equal to that obtained from an expansion of the exact result and that while the macroscopic compressibility approximation for the second-order term is better than the local compressibility approximation, it still does not agree very well with the exact second-order term at higher densities.