SPIN-FORBIDDEN TRANSITIONS IN NIAR+

Quartet-doublet optical transitions in the isolated NiAr+ ion have bee n observed by photodissociation excitation spectroscopy. Three low-lyi ng quartet states correlating to two different spin-orbit components o f the Ni+ d(8)s (F-4(J))+Ar(S-1) dissociation limit have been characte rized and the vibrational frequency, anharmonicity, and diabatic bindi ng energy of these states has been measured. The adiabatic binding ene rgy of the ground state of the ion is accurately determined from the t wo excited limits as 4572+/-5 cm(-1), more than twice the diabatic bin ding of the excited quartet states. The mechanism for the photodissoci ation of the excited states is found to involve coupling between adjac ent spin-orbit components of the quartet asymptote.