Atom—atom potential parameters for van der Waals complexes of aromatics and rare-gas atoms

Abstract The structure of the dispersion terms in the interaction for van der Waals complexes of aromatics and rare-gas atoms is examined and found to contain important three-body terms. Using calculations for benzene with a sequence of rare gases, the errors in approximating the three-body π-electron dispersion energy by atom—atom terms are found to be generally significant, but small for certain symmetrical positions (including the equilibrium position). For these positions, the total interaction coefficients are compared with empirically determined values using a Lennard-Jones model. Agreement is good after scaling to allow for higher-order terms.