PHOTOFRAGMENT SPECTROSCOPY OF RESONANCES IN THE A1-PI-U STATE OF N-2(2+)

A photopredissociation spectrum of the A (1)PI(mu)-X (1)SIGMA(g)+ (8,2) transition in N2(2+) is reported. The spectrum was recorded by detecting the photofragment signal as a function of excitation wavelength in a merged laser-ion beam apparatus. Line positions for the (8,2) band were measured and reduced to molecular constants. The natural linewidths, and hence predissociation rates, of all observed upsilon' = 8 levels were measured. The predissociation rates were found to be e/f symmetry dependent and, in particular, for the f levels, also J dependent. Somewhat surprisingly it appears as if tunneling does not contribute to the observed predissociation; rather, the upsilon' = 8 level of the A (1)PI(u) state is depleted by coupling to the continua of the (1)SIGMA(u)-, (3)SIGMA(u)+, and (3)DELTA(u) states.