V-Centers in Alkali Halides

Abstract

V‐centers are defined as stabilized positive holes. The peak wave‐lengths of three V‐bands of KCl, KBr, and NaCl are listed. Most of the paper deals with KCl, but the results are typical for KBr and NaCl as well. Experimental data are given concerning the conditions under which the various V‐bands are obtained and their unequal stability with regard to bleaching by light and temperature. Crystals irradiated at various temperatures and observed at room temperature show superpositions of the V₂‐ and V₃‐bands with relative intensities depending greatly on the temperature at which the crystals were irradiated and on the nature of the primary radiation. The V₁‐band can be observed only at temperatures below −100°C. These data are compared with those published by other investigators, and some remarks are made concerning the possible mechanisms which are responsible for the various phenomena.