Effect of radical scavengers and electric fields on the γ-radiolysis of gaseous hydrogen sulphide

Abstract

In the γ-radiolysis of H₂S with added buta-1,3-diene, H atoms appear to react before they become thermalised. With added benzene, propene, and but-1-ene insufficient scavenging occurs to say with certainty whether a similar situation applies, but indications are that it may be so for propene, and but-1-ene. Investigation of the effect of but-1-ene on the sulphur yield, indicates a dose rate effect which is explained by a competition between ion-recombination and diffusion to the wall enhanced by convenction currents. Yields of G(H₂)=G(S)= 0.5 unscavengable by buta-1,3-diene are indicated, and evidence is given that excited sulphur atoms (S^*) and S⁺ ions are probable precursors of these yields. Nitric oxide appears to react with SH radicals in a chain process producing H₂O, N₂O and S. Electric fields do not affect the radiation yields until electron acceleration just before saturation occurs, causes increased decomposition. The ratio of sulphur scavengable in the presence of a field is ∼4 : 1, which is much lower than in the absence of a field (13:1). This is evidence for production of excited S atoms by field accelerated electrons.