On H-centers conversion into I-centers in alkali iodides

The interaction of F, H centers created by excitons in KI and RbI crystals has been studied at 12 K. In the crystals coloured by excitons the recombination lUminescence due to an optical stimulation of electron centers has been investigated. The preliminary orientation of the hole-centers indicates that the emission bands at 440 nm (2.82 eV) in KI and 490 nm (2.54 eV) in RbI are due to a luminescence center based on the H-center. A new type of luminescence center is obtained in form of H-plus- electron center. It has been shown that in the case of the thermally stable H, F centers the optical stimulation of electron centers leads to the H centers conversion into I-centers. The kinetic investigations of luminescence let us to assume that close placed F, H centers in pairs spontaneously convert into α, I-centers which annihilate reestablishing the non- defect crystal structure