B-X and C-X Band Systems of CuCl Revisited: Laser-induced Fluorescence Study in 465–490 nm

Abstract

We have reinvestigated the X B − and X C − band systems of CuCl by recording the laser-induced fluorescence excitation spectra in 20400-21800 cm -1 . The rotational analyses in Hund's case (a) revealed unambiguously a singlet-to-singlet transition nature. The measured lifetimes of a few microseconds seem too long for singlets and too short for triplets, which we think is actually in favor of a picture of singlet ( Π 1 and + Σ 1 )-triplet ( 2 , 1 , 0 3 Π ) mixed states in the B and C band systems of CuCl. The two excited states we observed in our spectra may be the singlets that have been strongly "contaminated" by their triplet neighbors.