COMPARISON OF THE BONDING BETWEEN METAL-NOBLE-GAS+ AND METAL-NOBLE-GAS-2+

Ab initio calculations are reported of the spectroscopic constants for the low-lying states of the molecular ions ML2+, where MLi, Na, Mg, V, Fe, Co, Ni and Cu, and where L is usually Ar. Comparison with existing analogous calculations on the ML+ ions shows how the bonding and binding energy change with the addition of a second noble gas atom. The second binding energy is predicted to be essentially the same as the first for the Li, Na, Mg, and V ions, but larger for the Fe, Co, Ni and Cu ions. The binding energies of the transition metal noble gas ions are not accurately predicted at the SCF level, because correlation is required to describe their M0Ln+ character. All trends can be explained in terms of promotion and hybridization on the metal ion. © 1990.