ESR of trapped centers in γ irradiated silver chlorates single crystals

Abstract

The paramagnetic centers O⁻₃, ClO₂, and (ClO₂–Cl)⁻ have been identified in irradiated AgClO₃ single crystals by X and Q band ESR experiments at room temperatures and by the optical absorption bands at 480 and 360 nm, characteristic of the first two centers, respectively. The ESR spectrum and its angular dependence show that the first two centers have two magnetically inequivalent sites per unit cell. The third center was clearly observed only at certain orientations. The data for ClO₂ show that the principal directions of the g and A tensors do not coincide; the two magnetically inequivalent sites have similar principal values of the g and A tensors related by a 90° rotation about the tetragonal crystal axis of symmetry, and can therefore be assumed to be chemically equivalent. It is found that the ClO₂ center is formed substitutionally in the ClO⁻₃ ion position, but that the ozonide O⁻₃ is not. The thermal annealing of the γ irradiated AgClO₃ has revealed an increase in the concentration of the O⁻₃ radical that seems to be connected with the simultaneous destruction of the ClO₂ center. 149