Structural properties of fluids interacting via piece-wise constant potentials with a hard core

Abstract

The structural properties of fluids whose molecules interact via potentials with a hard core plus two piece-wise constant sections of different widths and heights are presented. These follow from the more general development previously introduced for potentials with a hard core plus $n$ piece-wise constant sections [Condens. Matter Phys. {\bf 15}, 23602 (2012)] in which use was made of a semi-analytic rational-function approximation method. The results of illustrative cases comprising eight different combinations of wells and shoulders are compared both with simulation data and with those that follow from the numerical solution of the Percus-Yevick and hypernetted-chain integral equations. It is found that the rational-function approximation generally predicts a more accurate radial distribution function than the Percus-Yevick theory and is comparable or even superior to the hypernetted-chain theory. This superiority over both integral equation theories is lost, however, at high densities, especially as the widths of the wells and/or the barriers increase.

10 pages, 11 figures; v2: Old Fig. 1 removed, new text on the correlation length, 7 new references added, plus other minor changes

References in corpus (6)

• Water-like hierarchy of anomalies in a continuous spherical shouldered potential
• Isotropic soft-core potentials with two characteristic length scales and anomalous behaviour
• Softness dependence of the Anomalies for the Continuous Shouldered Well potential
• Complex Phase Behavior of The System of Particles with Smooth Potential with Repulsive Shoulder and Attractive Well
• Rational-function approximation for fluids interacting via piece-wise constant potentials
• Assisted crystal growing by tempering metastable vapor-liquid fluids

Cited by in corpus (7)

• Structural and Thermodynamic Properties of Hard-Sphere Fluids
• Structural properties of the Jagla fluid
• One-dimensional fluids with second nearest-neighbor interactions
• On a conjecture concerning the Fisher--Widom line and the line of vanishing excess isothermal compressibility in simple fluids
• Structural and thermodynamic properties of fluids whose molecules interact via one-, two-, and three-step potentials
• Predicting the structure of fluids with piecewise constant interactions: Comparing the accuracy of five efficient integral equation theories
• Discontinuous Structural Transitions in Fluids with Competing Interactions