On the structure and physical origin of van der Waals interaction in zinc, cadmium and mercury dimers

The supermolecular CCSD(T) ab initio calculations of potential energy curves for the electronic ground states of van der Waals complexes formed from the atoms of IIB group are presented. The physical origin of the stability of studied structures was analyzed by the symmetry adapted perturbation theory. The mutual comparison of interaction energy contributions reveals the close similarity between the Cd and Hg clusters. The theoretical temperature dependences of low-density dynamic viscosity show the greater disagreement with experimental data for zinc atoms in comparison with cadmium and mercury atoms.