The High Dose Rate Radiolysis of H₂S: Sulfur as an Electron Scavenger

Abstract

The radiolysis of gaseous hydrogen sulfide has been studied in the presence of added sulfur at 200–250 °C. At 2 × 1027 eV g−1 s−1 sulfur reduces the hydrogen yield from G(H2) = 12.0 ± 0.3 to G(H2) = 7.3 ± 0.3. This reduction in yield appears to be due to electron attachment by the sulfur thereby suppressing formation of hydrogen from dissociative neutralization. Assuming the sulfur is S8 we estimate the attachment rate of electrons to sulfur to be about 1 × 1014 M−1 s−1.At 25 °C the reduction in the H2 yield at 2 × 1027 eV g−1 s−1 with increasing dose appears to be due to polysulfanes rather than radiolytic sulfur.Over the range of 1026 – 1028 eV g−1 s−1 the H2 yield increases from G(H2) = 11 to G(H2) = 13. Mechanisms to account for this increase are discussed.

Ozone yields from the Febetron radiolysis of oxygen – rare gas mixtures

“…We used the short intense pulses available from Febetrons because as we have shown, these result in a suppression of charge transfer to products or impurities (7). Previous measurements of these mixtures have been made using 60Co y-rays (8) but at the dose rates from these sources there is no contribution of ion neutralization to the ozone yield.…”

Isotope effects in the gas phase radiolysis of H2S and D2S

“…However, with short high intensity electron pulses these products do not reach sufficient concentration during the pulse to compete effectively with dissociative neutralization. Using these pulses, in excess of 30% of the hydrogen produced results from dissociative neutralization (5,6). It has been suggested (5) that the variation of G(H2) at high dose rates may be explained in terms of competition between the dissociative neutralizations of various clustered ions such as H3S+(H2S) and H3S+(H2S)n where n > 1.…”

“…Boyd, Willis, and Miller (5) suggest that H3Sf(H2S) may give two H atoms per neutralization, while the more highly clustered ions (n > 1) give less than two. Dissociative neutralization and clustering are parallel reactions with the rate constants for dissociative neutralization being --lo3 times those for clustering (5). Increasing the dose rate (and hence the concentration of the electrons) will favour dissociative neutralization over clustering.…”