CHARACTERIZATION OF TRIPLET-STATES IN DOUBLY CHARGED POSITIVE-IONS - ASSIGNMENT OF THE 3-PI-G-3-SIGMA-U+ ELECTRONIC-TRANSITION IN N22+

The first direct spectroscopic evidence and characterization of triplet states in a molecular dication is reported. The 3-PI-g <-- 3-SIGMA-u+ electronic absorption between excited states of N2(2+) is recorded by ion-laser coaxial beam photofragmentation spectroscopy. Over 300 rotational lines are resolved, and 13 parameters characterizing the upper and lower electronic states are determined. The results are compared with calculated potential energy curves. Dissociation lifetimes of the upper rotational levels are measured, and possible mechanisms of dissociation are discussed.