Simple analysis of intermolecular potentials - the mBq pair potential for collisions and energy transfer

We have investigated and compared four different theoretical and empirical procedures for the generation of simple but reliable pairwise atom-atom pot entials to be used as components in the construction of intermolecular pote ntials. A method is proposed wherein the parameters of a modified Buckingha m potential with atomic monopoles (mBq potential) is obtained by fitting to MP2 energies for interacting molecules confined to approach in selected sy mmetry directions. The results for 31 atomic pairs are compared with earlie r results obtained by electron gas density functional theory, best availabl e quantum chemical calculation or spectroscopic fit. The evidence is that t he mBq potentials can be of significant practical value in a wide range of applications.