Bonding in ground-state and excited-state A+•Rg van der Waals ions (A = atom, Rg = rare-gas atom):: A model-potential analysis

A review is given of the extensive experimental and theoretical information now available for A+·Rg diatomic ion interactions. Data for several A+·Rg ground and excited states are interpreted using a model potential consisting of calculated attractive terms with dependence on A+/Rg distances ranging from 1/R4 to 1/R8 and an AebR repulsive term derived empirically from experimental or ab initio data on bond energies De, bond distances Re, and fundamental vibrational frequencies we. It is shown that in most cases, such a "physical" model of bonding in A+·Rg diatomic molecules is adequate, qualitatively reasonable, and quite useful in comparing the A+/Rg interactions for a wide variety of such complexes.