ESR Study of <100> Centers in γ-Irradiated CsF Crystal

The hole centers produced in CsF crystal irradiated with γ-rays at liguid nitrogen temperature have been studied by electron spin resonance. Three kinds of centers with symmetrical <100> axes were observed and designated as H 1 , H 2 and H 3 , respectively. The H 1 center has been already assigned to be a self-traped hole. It is found that the H 2 center is composed of two Cs and two F ions and is essentially a F 2 - molecular ion on the site of an anion vacancy. When this center is bleached thermally at 150 K, the H 3 center is produced. The analysis of the ESR spectrum of the H 3 center indicates that the center is composed of a Cs ion and an F ion, and that an unpaired electron spends most of the time on an F nucleus and a little on a Cs nucleus.