The Radiolysis of Water Vapor at Very High Dose Rates. II. Isotope Effects in the Hydrogen Yield from H2O–D2O Mixtures

Abstract

The isotope effect in the formation of hydrogen has been measured for H2O–D2O mixtures (10–90% H2O, 0.5–1.0 mg ml−1, 412–138 °C) with and without 1 mol% SF6 at 2 × 1027 eV g−1 s−1. The values of α ((H/D) radiolytic hydrogen/(H/D) H2O–D2O) for the reactions of hydrogen atoms are in the range 3–6 varying with H/D ratio of the substrate. Consideration of possible mechanisms for these large α values leads to the conclusions that reaction of the hydrogen atoms to form hydrogen involves the substrate and that the species H3O may be formed as an intermediate.