Browsing by Author "Huyton, D. W."

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Effect of Radical Scavengers and Electric Fields on the y-Radiolysis of Gaseous Hydrogen Sulphide
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1973, 69 (2), 1973) Huyton, D. W.; Woodward, T. W.
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.
Energy Partition in the y-Radiolysis of Gaseous H2S+N2, H2S+Ar and H2S+Xe Mixtures
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (10), 1972) Ahmad, M.; Huyton, D. W.; Woodward, T. W.
Ionization measurements in H24-N2, H2S4-Ar, and H2S4-Xc mixtures arc used to determine apparent stopping power ratios for the mixtures, or “ energy partition parameters ”. The values found for H2S4- N2, H2S4-Ar, and H2S4-Xc are 0.20, 0.95, and 3.60 respectively, as compared to the calculated values of 0.82, 0.95, and 2.46. In H2S4-Ar mixtures a “Jesse effect ” is observed that increases the ion yield by 2 units, this effect being quenched out between stopping power fractions Z = 0.2-0.4. Measurement of sulphur yields in H2S4-N2 mixtures enables an energy partition parameter of 0.5 to be evaluated. The difference from the value obtained by ionization measurements being explained by a small “Jesse effect" In H2S4-Ar mixtures the sulphur yield G(S) was always >G(S) = 7.0 found in pure H2S and approached values as high as 24. The sulphur yield also increased between Z = 0.2 and 0.4 by twice the decrease in the ion yield. G(S) in H2S4-Xe mixtures never rises above 7.0, and the values can be justified by energy transfer from Xe* (G ~ 5.0) to H2S to give H2 4- S*, where S* is not a ground state S(3P) atom. No such simple mechanism will explain the results in H2S4-Ar mixtures. Butadiene was used as an SH and S(3P) scavenger, and the ratio of scavengeablc to non-scavengcablc sulphur in H2 4-Ar mixtures is similar to that in H2S i.e. ^43. In H2S4-Xc mixtures this ratio is ~3-4, and is explained by production of excited S atoms (S*), which react with H2S to give H2 and S2.
y-Radiolysis of Gaseous Hydrogen Sulphide in the presence of Hydrogen Chloride, Carbon Disulphide and Nitrous Oxide
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1973, 69 (6), 1973) Huyton, D. W.; Woodward, T. W.
Addition of HC1 to H2S increases the radiation yield of H2 G(H2) 7.0->10.0 by an electron scavenging process involving HC1 and H2S. CS2 lowers the H2 yield in pure H2S probably by reaction with hot H atoms and also scavenges the electrons in H2S + HC1 mixtures, lowering G(H2) in the process to < 7.0. Electron scavenging by addition of N2O to H2S to produce N2 is shown to be a very complex system with surface reactions probably playing a part.