MOLECULAR SIMULATION OF INTERMOLECULAR ATTRACTION AND REPULSION IN COEXISTING LIQUID AND VAPOR-PHASES

The contributions of intermolecular attraction and intermolecular repu lsion to the properties of coexisting liquid and vapour phases for a L ennard-Jones fluid are determined from Gibbs ensemble simulations. Int ermolecular attraction and excess intermolecular repulsion contribute almost equally to the compressibility factor. The contribution of inte rmolecular attraction to the configurational energy reported here is t ypically more than twice the contribution from excess repulsion. The s imulation data are compared with calculations for the Lennard-Jones eq uations proposed by Hansen, Ree and Nicolas et al. The equations of Ha nsen and Ree incorrectly estimate the contribution of attractive and r epulsive intermolecular interactions to the properties of both the liq uid and vapour phases. (C) 1997 Published by Elsevier Science B.V.