Deuterium isotope effects in the radiation chemistry of glassy and polycrystalline hydrocarbons

摘要

TheGvalue (radicals produced per 100 eV absorbed) of trapped free radicals produced by ggr; radiolysis of five polycrystalline alkanes (nhyphen;pentane,nhyphen;hexane,nhyphen;octane, cyclohexane, 3hyphen;methylheptane and methylcyclohexane) is in each case higher by a factor of 1.6plusmn;0.2 in the protiated compound than in the deuterated (gsim;98 at.percnt; D) compound. This indicates a radiolytic mechanism which favors Cndash;H over Cndash;D bond rupture with similar probability independent of molecular structure or crystallinity. In hydrocarbon glasses containing certain additives, theGvalues of trapped or scavenged electrons are higher in the deuterated than the protiated matrices. Possible mechanistic origins of these isotope effects are considered.