'From ref 18. bAbsolute rate constants measured at 24 f 2" C in EtSiH: Me&OOCMe, solvent by using benzil as probe. Errors correspond to 95% confidence limits but include only random error. cRelative rate constants measured at 40" C in EtsSiH solvent. Calculated at 24" C from the Arrhenius parameters given in the supplementary material of ref 3. tions by the triethylsilyl radical., Our results led us to propose that charge transfer in the transition ...