Energy transfer processes in reactions of He(2 3S) and Ne( 3P 0,2) with CS 2

Abstract

A comparative spectroscopic study in the visible and ultraviolet ranges was conducted on the flowing afterglows resulting from the reactions of He(2 3S) and Ne( 3P 0,2) metastables with CS 2. Penning ionization was found to be the predominant energy transfer process. However, electron—ion recombination within the afterglows constitutes a major secondary process and gives rise to the most intense emitting system, CS(A 1 Π → X 1Σ +). Both afterglows were found to produce the CS + 2( B 2Σ + u- X 2Π g), CS + 2( A 2Π u- X 2Π g) and CS(a 3Π-X 1Σ +) emission systems as well as some atomic sulfur emission lines. Some intensity differences were observed and are interpreted in terms of energetics and the formation mechanisms of the emitting species. A moderately strong CS +(A 2Π i-X 2Σ +) emission system was also observed in the ehlium afterglow. In addition, a weak, sharp group of bands in the 390–420 nm range in the helium afterglow has been determined to be due to the presence of a small amount of He + ions. This group of bands consists of two overlapping emission systems and are identified as CS(B 1Σ + → A 1Π) and CS +(B 2Σ + → A 2Π i).