Electronically Excited S₂(x¹Δ_g) in the Disproportionation and Abstraction Reactions of Sulfur Radicals

Abstract

A transient spectrum of S2 which has been observed before only in emission and assigned to the b1Δu → x1Δg transition has been detected in flashed H2S2, H2S, COS, CS2, and SPF3 indicating the presence of S2(x1Δg) molecules in these systems. By detailed kinetic studies S2(x1Δg) has been shown to arise from the self and cross disproportionation reactions of the SH and S2H radicals and from the abstractive attack of S(1D) atoms on COS and SPF3. The recombination reaction of S(3P) atoms in the presence of CO2 also produces S2(x1Δg).