ESR of F Center in HgI2·2HgS Darkened with Sunlight

Abstract

Abstract When yellow powders of HgI2·2HgS turn black in sunlight in a few seconds, the black powders show an ESR signal, whose intensity increases with the time of irradiation; its g-value is 2.0046±0.00028. The result of analysis shows that this signal is due to F centers, consisting of electrons captured by positive holes prepared at sites of S2− ions in the crystal.