Simple model potential and model wave functions for (H-alkali)(+) and (alkali-alkali)(+) ions

A simple model potential is proposed to describe the interaction of a valen ce electron with the alkali core, which incorporates the correct asymptotic behavior in terms of dipolar polarizabilities, and the short-range exchang e effects in terms of a hard core adjusted to give the correct energy for t he valence electron. Based on this potential, simple wave functions are dev eloped to describe the (H-alkali)(+) and (alkali-alkali)(+) ions. These wav e functions exhibit some important structures of the ions, and provide a un iversal description of the properties of all (H-alkali)(+) and (alkali-alka li)(+) ions, in particular, the equilibrium separations of the nuclei and t he corresponding dissociation energies. They also allow us to calculate the dipolar polarizabilities of Li-2(+), Na-2(+), K-2(+), Rb-2(+), and Cs-2(+) . (C) 2000 American Institute of Physics. [S0021-9606(00)01325-8].