EFFECT OF IRRADIATION TEMPERATURE FROM 77-K TO 1.6-K ON THE OPTICAL-ABSORPTION AND SCAVENGING EFFICIENCY OF LOCALIZED-ELECTRONS IN AQUEOUS 10-M LITHIUM-CHLORIDE GLASSES

Irradiation of the 10 Μ LiCI/D2O matrix at 77 Κ stabilizes the solvated electron species, evis-(λ max∼575 nm) while irradiation at 4.2 or 1.6 Κ stabilizes two localized electron species evis -(λmax∼680 nm) attributed largely to solvated electrons and elR-(λmax>2400 nm) attributed largely to presolvated electrons. Between 4.2 and 1.6 Κ the evis- spectrum is essentially unaffected but the e lR spectrum is shifted to lower energy at 1.6 Κ. The electron scavenging efficiencies of bromate, nitrate, and Chromate for e vis- at 77, 4.2, and 1.6 Κ and for elR at 4.2 and 1.6 Κ were studied. The total scavenging efficiency for all localized electrons in the glass increases as the temperature is lowered over this range. An apparent low scavenging efficiency for evis - at 4.2 Κ seems due to competitive tunneling to the scavenger by evis- and elR-. This interpretation is supported by observations of the scavenging efficiency of nitrate in 10 M NaOH aqueous glass over this same temperature range in which only one main type of localized electron species is observed. The scavenging results support the assignments of evis- to a presolvated electron with a nonequilibrium orientation of first solvation shell waters and of evis to a solvated electron with an equilibrium orientation of first solvation shell waters. © 1979 American Institute of Physics.