Energy transfer processes between He(2 3S) and Ne( 3P 0.2) metastable atoms and CS radicals

Abstract

Energy transfer processes between He(2 3S) and Ne( 3P 0.2) metastable atoms and CS radicals have been investigated by UV-visible emission spectroscopy. Two exit channels have been identified, Penning ionization leading to CS + ions and dissociative excitation transfer leading to C and S atoms. In both reactions of He(2 3S) and Ne( 3P 0.2) with CS radicals, Penning ionization was the prominent exit channel, while dissociative excitation transfer was the minor competitive exit channel. Relative vibrational populations of the CS +(B: υ′= 0–6) state were determined from both CS +(B 2Σ +-A 2Π) and CS +(B 2Σ +-X 2Σ +) emissions. The vibrational populations have given a strong preference for the lowest vibrational level, particularly in the case of Ne( 3P 0.2), in comparison with the calculated Franck-Condon factors (FCF) for the CS(X) → CS +(B) vertical ionization. The deviation from FCF was discussed in terms of interactions occurring before and after ionization.