Electron Spin Resonance Study of the Reaction of Hydrogen Atoms with Hydrogen Sulphide

Abstract

The reaction between H atoms and hydrogen sulphide, with and without added nitric oxide, has been studied by following the H atom, S atom and SH radical concentrations with time using electron spin resonance detection. The results are fully explained by the mechanism (1)–(4) H + H2S→H2+ SH, k1= 5.0 × 108 l. mol–1 s–1(1), H + SH → H2+ S, k2= 2.5 × 1010 l. mol–1 s–1(2), SH + NO → stable species, k3= 6.3 × 108 l. mol–1 s–1(3), SH + SH → H2S + S, k4= 7.8 × 109 l. mol–1 s–1. (4) with no evidence for significant surface effects (the walls were coated with boric acid). The results demonstrate conclusively that reaction (2) is very important in this system and that previous measurements of k1 which neglect this reaction may require correction.