Theoretical approaches to the structural properties of the square-shoulder fluid

ABSTRACT

A comparison of simulation results with the prediction of the structural properties of square-shoulder fluids is carried out to assess the performance of three theories: Tang–Lu's first-order mean spherical approximation, the simplified exponential approximation of the latter and the rational-function approximation. These three theoretical developments share the characteristic of being analytical in Laplace space and of reducing in the proper limit to the Percus–Yevick result for the hard-sphere fluid. Overall, the best agreement with the simulation data is obtained with the simplified exponential approximation.

Keywords:

• Radial distribution function
• square-shoulder potential
• first-order mean spherical approximation
• simplified exponential approximation
• rational-function approximation

Acknowledgments

Mariano López de Haro wants to thank the hospitality of Universidad de Extremadura (Spain), where the first stages of this work were carried out. The authors are grateful to Stepan P. Hlushak for clarifying the reason for the discrepancy between our results and those of Ref. [24] for the SEXP/FMSA approximation.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

This paper is dedicated to the memory of Dr. Yiping Tang

Additional information

Funding

The research of Santos Bravo Yuste and Andrés Santos has been partially financed by the Ministerio de Economía y Competitividad (Spain) [grant number FIS2013-42840-P]; the Regional Government of Extremadura (Spain) [grant number GR15104] (partially financed by the ERDF).