Overview on Intermolecular Potentials

Abstract

The various types of contributions to the interaction between two molecules and their representations are discussed. In particular the employment of spherical harmonic and atom-atom (or site-site) expansions, as well as other analytic representations, such as the generalized Lennard-Jones form, is described. A brief description of spin-dependent potentials, which arise when open-shell molecules interact, is also given. The question of additivity of intermolecular potentials is addressed, and the importance of many-body interactions, especially for liquid and solid-state properties, is considered. An overview is presented of recent ab initio calculations of interaction potentials for simple molecular systems, such as N2, 02, CO, H2,Ar-H20,and Ar-NH3. Finally, the status of intermolecular potentials is presented, and illustrated by means of their applications to the calculation of second virial coefficients, Van der Waals spectra, and the properties of molecular solids, including lattice dynamics. It is concluded that for the near future the best multi-dimensional intermolecular potentials will likely be obtained by combining the results of ab initio calculations with the fitting of a limited number of variable parameters to accurate experimental data.KeywordsVirial CoefficientMultipole MomentIntermolecular PotentialMolecular SolidSpherical ExpansionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.