Electron Attachment and Solvation in Gamma Irradiated Organic Glasses at - 196°

Abstract

Gamma irradiation at --198 deg of organic glasses containing small amounts of solutes whose anion absorption spectra were known resulted in the formation of optically identifiable anions by electron attachmert. Using a tetrahydro-2-methylfuran glass the limiting value for G(anions) was 2.6 for naphthalene and 3.2 for biphenyl. With a hydrocarbon glass, the limiting yields were 1.1 and 1.7, respectively. For biphenyl in ethanol, G(anion) = 2.94. In all media, G(anion) = 1 for about 0.05 mole% additive. Arions of nitrobenzene, benzophenone, and tetracyanoethylene were also prepared by both methods and identified while spectra of styrene and carbon tetrachloride molecular anions, which cannot be prepared chemically, appeared to form in gamma irradiated glasses. Irradiation of glassed tetrahydro-2-methylfuran alone produced a structureless absorption band in the visible and near infrared. With less than 0.5 mole% of naphthalene, the solute anion and solvent spectra both appeared. The solvent spectrum can be selectively bleached, with a concomitant increase in the solute anion absorption bands. The facts indicate that the solvent absorption is due to solvated electrons. Similarly solvated electrons are observed in gamma irradiated ethanol but not in glassed alkanes or alkenes.