Radiation-induced Formation of the Univalent Mg⁺, Zn⁺ and Cd⁺ from the Divalent Cations in γ-Irradiated Ice

Abstract

IT is now well established that the principal primary reducing species formed in the radiolysis of water and aqueous solutions are the negative polarons¹. Their occurrence in these media has been directly demonstrated by observation of their transient optical absorption spectrum in pulsed radiolysis experiments^2,3. Although their direct observation by electron spin resonance or optical absorption spectroscopy has not been possible in the case of pure ice, trapped at defect sites, they have been characterized in alkaline ice at 77° K by both these techniques^4,5. Their reactions with Brönsted acid solutes present in ice to form hydrogen-atoms (identified through their characteristic electron spin resonance spectra) both in the presence and absence of various competing electron scavengers have been reported previously^6,7. In this communication we describe their reactions with metal cations such as Mg⁺⁺, Zn⁺⁺, and Cd⁺⁺ to form lower oxidation states which are normally unstable. Evidence for the occurrence of Zn⁺ and Cd⁺, but not Mg⁺, in aqueous solutions had been previously obtained⁸ in pulsed radiolysis investigations.