Laser-induced Fluorescence Spectroscopy of CoS: Identification of a New Excited State Arising from the Ground State

Laser-induced fluorescence excitation spectra and dispersed fluorescence spectra of cobalt sulfide (CoS) have been recorded in the energy range of 22400-24400 cm^-1 (corresponding to 446-409 nm). A new electronic transition progression with six vibronic bands, stemming from the X⁴△_7/2 state of CoS, was identified and assigned to be 24.00⁴△_7/2-X⁴△_7/2. The new observed ⁴△ state most probably originates from the core10σ²4π³11σ²1δ³5π³ electronic configuration. Strong perturbations are found to extensively exist in the transition bands of this new state. The rotational constants and lifetimes of these bands have been determined