Energy partition in the γ-radiolysis of gaseous H₂S + N₂O mixtures

Abstract

Measurement of ion yields Gm(= lOO/W,), where W, is the average energy required to produce an ion pair in the mixture) in gaseous H2S-N20 mixtures indicates that the energy partition parameter " a " = 0.53 holds for mixtures of stopping power fraction Z = P1[P1+(S2/S1)P21 from 0.15 41.0, and perhaps over the whole range of 2. PI and P2 are the partial pressures and S1 and S2 are the stopping powers relative to air of H2S and N20 respectively. The radiation yields of H2 and N2 in the mixtures G(H,), and G(N2)m yield this value of " a " = 0.53 probably restricted to the range 2 = 0.45 +1.0. A scheme of energy transfer from an excited state of N 2 0 to H2S is suggested for the deviation below 2 = 0.45. For 2 ~0.45 an excited state of N20 is postulated that does not transfer energy to H2S. A mechanism of ionization energy transfer plus reactions of 0 and NO2 with H2S is suggested as an explanation of the high sulphur yields at low 2.Recent articles 1v have shown that N 2 0 does not appear to lower the yield of H,, G(H2), in the radiolysis of H,S. However, at a gas pressure of 106 kN m-2, N2 was produced with a G(NJ fi 1.7 for > 2 % N,O. This figure is well below the value of G (ion) Because of this lack of effect on G(H,) in H2S, and the rather peculiar value of G(N,). we decided to investigate the energy partition between the two gases. 4.0 in H,S, expected if N,O captures all the electrons. EXPERIMENTAL Details of materials used, irradiation equipment and procedure, ion current measurements and hydrogen and sulphur analyses have been given previ~usly.~ Dosimetry in Pyrex vessels was based on G(H2) = 7.0 in pure H2S.3Gaseous products not condensable at 77K, H2, N2 and 02, were collected in a gas burette and the total observed. H2 was diffused away through a palladium thimble, and the remaining N2 and O2 measured and analyzed by mass spectroscopy. N2 yields were '

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

“…Rcently several studies of the radiolysis of hydrogen sulfide have been reported (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) and we have proposed a mechanism based on our measurements at high dose rates (13). While this mechanism is in general agreement with the observed yields there are problems which need further investigation.…”