A parametrisation of the direct correlation function for the square-shoulder fluid

Abstract

We introduce a parametrisation of the direct correlation function for the square-shoulder fluid and demonstrate that this parametrisation is in quantitative agreement with the numerical solution of the Ornstein–Zernike equation within the Percus–Yevick approximation. Moreover, the radial distribution function obtained from the parametrisation reproduces quantitatively Monte Carlo simulation data. Our results show that the parametrisation is accurate over a large regime of densities for different interaction ranges and potential strengths.

Keywords:

• square-shoulder fluid
• simple fluids
• direct correlation functions
• Ornstein–Zernike

Acknowledgements

This work is partially supported by Conacyt (grants 46373/A-1 and 61418/2007) and PROMEP-Mexico (PIFI 3.3 and 3.4). ESP gratefully acknowledges support by the Hochschuljubiläumsstiftung der Stadt Wien under Project Number 1757/2007 and the Elise Richter project V132-N19 of the Austrian Science Fund. RCP thanks A. Benavides for useful discussions.

Notes

Note

1. This assumption was already corroborated by using the resulting solution of Equation (15) into the numerical evaluation of the crossed terms (data not shown).