The laser-induced fluorescence study of A2Σ−-X2Πi band system of CuS

The laser-induced fluorescence excitation spectra of jet-cooled CuS molecules have been recorded in the energy range of 17 200-19 500 cm−1. Fourteen observed vibronic bands have been assigned as three transition progressions: A2Σ− (v′ = 0-4)-X2Π3/2 (v″ = 0), A2Σ− (v′ = 0-4)-X2Π3/2 (v″ = 1), and A2Σ− (v′ = 0-3)-X2Π1/2 (v″ = 0). Spectroscopic constants of both the X2Π ground state and the A2Σ− excited state of 63CuS and 65CuS were determined by analyzing their rotationally resolved spectra. Furthermore, the lifetimes of most observed bands were measured for the first time.