Heat capacity of square-well fluids of variable width

Abstract

We have obtained by Monte Carlo NVT simulations the constant-volume excess heat capacity of square-well fluids for several temperatures, densities and potential widths. Heat capacity is a thermodynamic property much more sensitive to the accuracy of a theory than other thermodynamic quantities, such as the compressibility factor. This is illustrated by comparing the reported simulation data for the heat capacity with the theoretical predictions given by the Barker-Henderson perturbation theory as well as with those given by a non-perturbative theoretical model based on Baxter's solution of the Percus-Yevick integral equation for sticky hard spheres. Both theories give accurate predictions for the equation of state. By contrast, it is found that the Barker-Henderson theory strongly underestimates the excess heat capacity for low to moderate temperatures, whereas a much better agreement between theory and simulation is achieved with the non-perturbative theoretical model, particularly for small well widths, although the accuracy of the latter worsens for high densities and low temperatures, as the well width increases.

11 pages, 4 figures; figures now include additional perturbation data; to be published in Mol. Phys

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Cited by in corpus (7)

• Pair correlation function of short-ranged square-well fluids
• Microcanonical-ensemble computer simulation of the high-temperature expansion coefficients of the Helmholtz free-energy of a Square-well fluid
• Alternative Approaches to the Equilibrium Properties of Hard-Sphere Liquids
• How `sticky' are short-range square-well fluids?
• Structure of the square-shoulder fluid
• On the radial distribution function of a hard-sphere fluid
• Microcanonical ensemble simulation method applied to discrete potential fluids