Optical and Thermal Bistability of Two <i>F</i> _H (OH ^- ) Center Configurations in KBr and KI

Abstract

F center/OH- defect pairs ("FH(OH-) centers") in KBr and KI exhibit a novel and unpredicted twofold optical absorption behavior, which at low temperatures can be optically converted and reconverted in a stable and reversible way. Obviously this effect is caused by the bistability of two different orientational configurations of the OH- impurity ion relative to the F center. The temperature dependence of the two absorption bands and their magnetic circular dichroism have been determined.