An Electron spin resonance study of γ- irradiated sodium bromate single crystals

Abstract

The object of this work is to determine the nature of paramagnetic species produced when single crystals of sodium meta-periodate and sodium bromate are exposed to high energy radiation. It is now well known that paramagnetic species or fragments can be trapped in a crystal matrix. These trapped species can be introduced by doping processes or by radiation damage to the host crystal, and it is fortunate that the trapped species are almost always orientated; that is, they lie in a limited number of precisely aligned orientations or sites which are related to the crystal symmetry. The paramagnetic species produced by the high energy irradiation of inorganic crystals are generally simple and symmetric. For example, the radical NO3 has been characterised in γ-irradiated lead nitrate crystals [1.1]. The literature contains a considerable amount of data on the nature of paramagnetic species produced in irradiated oxy-salts, but there are no reports of the detection of paramagnetic species in sodium meta-periodate by electron spin resonance spectroscopy, and one negative report for sodium bromate, [1.2]. The project is undertaken in an attempt to extend the knowledge of paramagnetic species produced by γ-radiation in oxy-halogen salts.