A link between the two-body and three-body interaction energies of fluids from molecular simulation

Molecular simulation data are reported that indicate that there is a simple empirical relationship between two-body and three-body interaction energie s. The significance of this relationship is that three-body interactions ca n be estimated accurately from two-body interactions without incurring the computational penalty of three-body calculations. The relationship is teste d by performing Gibbs ensemble simulations for the vapor-liquid equilibria of argon. The results are in good agreement with calculations that explicit ly evaluate all three-body interactions. (C) 2000 American Institute of Phy sics. [S0021-9606(00)50413-9].