Magneto-Optic Effects in Recombination Luminescence from Self Trapped Excitons
Intrinsic recombination luminescence which originates in triplet states of the self trapped exciton in alkali halide crystals has been investigated experimentally and theoretically with regard to effects of applied magnetic fields. Lifetimes and circular polarizations are observed to vary anisotropically with field, and a level crossing resonance is identified in CsI and, tentatively, in CsBr. This provides evaluation of the zero-field splitting for the triplet state. Splittings and lifetimes for CsI and KI are compared with a theory based on a Vk-like hole and nonequilibrium level populations, and reasonable agreement is obtained. Electronic exchange energies which occur as parameters in the theory are in rough agreement with independent estimates.
KeywordsTriplet State Circular Polarization Crystal Field Parameter Self Trap Exciton Lower Triplet State
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