Laser-induced Fluorescence Spectroscopy of NiS: Identification of a Low-lying Electronic State

Laser-induced fluorescence excitation spectra of jet-cooled NiS molecules were recorded in the energy range of 12200-13550 cm^-1. Four vibronic bands with rotational structure have been observed and assigned to the 12.4³∑₀^- -X³∑₀^- transition progression. The relevant rotational constants, significant isotopic shifts, and (equilibrium) molecular parameters have been determined. In addition, the lifetimes of the observed bands have also been measured.