The ESR Study of Growth and Decay Processes of Self-Trapped Holes in AgCl Crystals Doped with Cu

Abstract

The effects of irradiation on AgCl crystals doped with Cu 2+ ion are studied by the electron spin resonance. A hole released from the Cu 2+ site by irradiation with blue light is self-trapped at an Ag + ion site forming an Ag 2+ center. The Ag 2+ center decays by irradiation with infrared light and the Cu 2+ center is reformed. Reorientation of the symmetry axis of the Ag 2+ center by irradiation with polarized IR light is remarkably observed. The result of the analysis shows that the IR absorption band of the Ag 2+ center is composed of two components and the oscillator strength of the predominant component is about 4 times larger than that of the other, where the former and the latter correspond to the absorption of light polarized perpendicular and parallel to the axis of the Jahn-Teller distortion, respectively. The optical transition process is discussed using a model of the tetragonally distorted (AgCl 6 ) -4 molecule.