Formation of complex defects involving molecular oxygen by electron-hole reactions in x-irradiated KClO4 and KBrO4, studied by ESR and IR spectroscopy

Complex defects of composition [XO−2, O2], X=Cl, Br, produced by UV or x-irradiation of solid KClO4 and KBrO4 at 26 K are characterized by ESR and IR spectroscopy. [XO−2, O2] is shown to arise during x-irradiation in a reaction between self-trapped electrons in the form of XO2−4 defects, and self-trapped holes in the form of (XO4)−2 defects. The previously described hole defect [XO2, O2] is shown to arise from oxidation of [XO−2, O2] by reaction with (XO4)−2. Thus all the abundant defects observed in x-irradiated KClO4 and KBrO4 stem from self-trapping of electrons and holes and from simple reactions of the self-trapped electrons and holes. The observed equivalence of optical excitation of the anions with electron-hole recombination may be a general property of polyatomic solids.