Application of LIR in prediction of surface tension and its temperature coefficient of liquid alkali metals

An expression has been derived for radial distribution function (RDF) at contact, g(σ), for a real fluid by the use of linear isotherm regularity (LIR). This expression, which is related to intermolecular interaction, can be used to describe the temperature–density dependency of RDF at contact, g(σ,ρ,T). The expression is used for prediction of surface tension of liquid alkali metals in Evan's expression using Lang–Kohn surface energy and in molecular dynamic results for surface tension. Application of some approximation to Evan's expression shows that a correct selection of surface energy in the resultant expression for surface tension yields values that are in good agreement with the experiment. The surface tension of liquid alkali metals has been obtained from the molecular dynamic studies using g(σ,ρ,T) and SE/NkB ≈ S2/NkB, where S2 is related to two particle correlations. The calculated surface tension of liquid alkali metals is in good agreement with the experimental values. The calculated values of surface tension using g(σ,ρ,T) are in better agreement with the experiment than those of the hard sphere model.