Combined empirical-model ab initio potentials for complexes of rare gas atoms with diatomic molecules

A diabatic model is presented for the ground state potential energy surfaces of rare gas dihalide and dioxide molecules, based on diatomic fragment potentials and properly taking into account the anisotropy or interactions between atoms. Calculations for ArX2 (X = F, Cl, Br, I)and RgO(2) (Rg = Xe, Ne, Ar, Kr, Xe) establish the existence of a minimum in their linear geometry, unlike a saddle Feint obtained with other, mainly empirical, models. And this minimum may be even deeper than that in the T-shaped geometry for ArF2 and, at least before the spin-orbit coupling is included, for heavier RgO(2). The model predictions are favourably verified with a high-level ab initio calculations.