H Atom Yields in the Pulse Radiolysis of H2: Reactions with O2, ClNO, and HI

Article abstract of DOI:10.1021/j100212a025

The hydrogen atom yield in the pulse radiolysis of H2 at high dose rates was measured by four independent calibration techniques, using reactions of H with O2, ClNO, and HI.Spectrophotometrical detection of HO2 in the reaction H + O2 + H2 <*> HO2 + H2 (1), of ClNO in H + ClNO <*> HCl + NO (2), of HI in H + HI <*> H2 + I (3), and of I2 in (3) followed by I + I + NO + H2 <*> I2 + NO + H2 allowed determination of the hydrogen yield in 1 bar of H2.The H atom yield was compared with the O3 yields in pure O2 and in O2/SF6 mixtures under identical irradiation conditions, which lead to relative G(H) values: G(H)_H2 = 1.38G(O3)_O2 and G(h)_H2 = 2.07G(O3)_O2/SF6.On the basis of G(O3)_O2 = 12.8 a value G(H) = 17.6 is obtained.The rate constants of reactions 1, 2, and I + NO + H2 <*> INO + H2 (4) were measured as k₁ = 2.17E16 cm⁶ mol^-2 s^-1, k₂ = 9.24E12 cm³ mol^-1 s^-1, and k₄ = 2.7E15 cm⁶ mol^-2 s^-1.