High-resolution laser photofragment spectrum of N 2+2(1πu–1Σ +g)

Abstract

Laser photofragment spectra of the ¹Π_u–¹Σ⁺_g electronic transition in ¹⁴N¹⁴N²⁺ and ¹⁵N¹⁵N²⁺ have been recorded by tunable dye laser excitation of a fast ion beam and detection of N⁺ ions which arise from predissociation of the ¹Π_u state. Molecular parameters for both electronic states are reported and the vibrational level numbering in the excited state is determined by measurement of the spectral isotope shift. There is no evidence for perturbations or weakening of lines involving levels near J= 23 in the v= 1 level of the ¹Σ⁺_g state. We conclude that perturbations and breaking-off observed near J= 23 in emission spectra of the (1,1) band of the _g system occur in the excited ¹Σ⁺_u electronic state.