Trapping of Electrons in Low-Temperature Glasses. A Pulse Radiolysis Study

Abstract

The pulse radiolysis of 3-methylpentane, 3-methylhexane, 2-methyltetrahydrofuran, cumene, ethanol, and alkaline ice glasses have been studied at 77°K using 12-nsec pulses of 3-MeV electrons. Trapped electrons in varying yields were observed in all cases and in some instances short-lived species were observed. These short-lived transients have been correlated with different trap depths in the various media, and the trapping process and types of sites have been discussed. The effect of carbon tetrachloride and biphenyl on the transients observed in 3-methylhexane has been studied and the results interpreted in terms of electron capture by these solutes in accord with previous 60Co γ-radiolysis data. Addition of positive hole scavengers to the later system has also been investigated. Pulse radiolysis of 10−2-M naphthalene in 3-methylhexane glasses at 77°K produced small yields of solute ions, which recombined on warming to about 123°K giving the naphthalene triplet (G = 0.95) and naphthalene singlet.