Emission Spectra of Nitrogen in the Vacuum Ultraviolet

The emission spectra of nitrogen have been photographed in the vacuum ultraviolet under high resolution. Selected bands of the b′1Σu+—X1Σg+ and the a1Πg—X1Σg+ systems have been analyzed and new rotational and vibrational constants obtained. The observed Λ-type doubling of the a1Πg state was used to determine that the Fc′ doublet component lies above the Fd′ component. Rotational perturbations were found in the v=0 level of the a1Πg state, and in the v=0 and 1 levels of the b′1Σu+ state. Vibrational perturbations were found in the v=4, 5, and 6 levels of the b′1Σu+ state and a new predissociation at v=4, J=9 was observed. The new predissociation limit lies at 13.233 ev and is equally compatible with either the 9.756 ev or the 7.373 ev ground-state dissociation energy.