AB-INITIO ENERGIES AND TUNNELING LIFETIMES OF THE DOUBLY-CHARGED AH(2-AR) DIATOMICS() (A=MG)

Potential energy curves for the ground and low-lying excited states of the AH(2+) (A = Mg-Ar) dications have been calculated using high-leve l ab initio methods with large atomic orbital basis sets. Quasi-bound potential energy curves with local minima and deprotonation barriers h ave been found for most of the dications studied. The energies, tunnel ing lifetimes, and widths of the quasi-bound states have been calculat ed by numerical solution of the radial Schrodinger equation using the Numeov method. All these dications except ArH2+ have low-lying states which support quasi-bound vibrational states. The ArH2+ dication has a (2) Pi(i) potential energy curve with a minimum so shallow that it do es not support any quasi-bound vibrational states. Results of our calc ulations are compared with previous ab initio calculations and availab le experimental data. (C) 1995 John Wiley & Sons, Inc.