Prediction of surface tension for pure non-polar fluids based on density functional theory

A method for the prediction of surface tension of non-polar fluids has been developed based on the density functional theory. The Barker-Henderson perturbation theory and statistical associating fluid theory are used to establish an equation of state (EOS). The parameters m, sigma and epsilon /k of the EOS are correlated by simultaneously fitting the saturated vapor pressure and the liquid density data. The surface region of a pure liquid is divided into many extreme thin layers. The chemical potentials of different layers in the surface region are equal and lead to a constant by optimizing the surface thickness. The density profile is obtained from the optimized surface thickness and a hyperbolic tangent function. By use of the regressed parameters in the EOS, the surface tensions for 18 pure non-polar fluids are predicted and the results are satisfactory. (C) 2001 Elsevier Science Ltd. All rights reserved.