Calculation of the surface tension and the surface energy of Lennard–Jones fluids from the radial distribution function in the interface zone

Abstract

A detailed study is presented of the calculation of the surface tension and the surface energy of Lennard–Jones fluids from the radial distribution function and the density profile. To do so, a modification is made to Lekner and Henderson's statistical mechanics approach by introducing two simple analytical expressions for the radial distribution function of the interface zone. In these expressions the radial distribution functions of the liquid and vapour phases are weighted via step or exponential variations. The well- known exponential model for the density profile in the interface zone is considered. Finally, results are compared with values from experiment, from computer simulation and from relevant theoretical developments. It is shown that the use of the proposed radial distribution function in the interface zone represents a significant improvement in applying Lekner and Henderson's approach.

Acknowledgements

This research was supported by the ‘Dirección General de Investigación’ of the Spanish ‘Ministerio de Educación y Ciencia’ and the ‘Fondo Europeo de Desarrollo Regional’ (FEDER) of the European Union, through the project BFM2002-00643.