Abstract

At room temperature, alkalihalides are dielectric solids, while at high temperatures, they present electrolytic conductivity. As the current flows through the crystals, a simultaneous coloring takes place. An electronic conductivity is also observed during this process. Different F-center diffusion mechanisms are observed, depending on the temperature range. In this work, KCl crystals have been electrolitically colored. When current and optical transmissions are measured at the same time, an almost simultaneous coloring is detected within the first zone of current. At temperatures under 778 K, the mobility suffers a substantial drop, in a way that resembles what is suggested for K1 crystals. This suggests the possibility of a different diffusion mechanism at low temperature. © 1999 Elsevier Science B.V. All rights reserved.