Jahn-Teller vibronic coupling in CdSe doped with Cr2+ ions

In this article we report the study of the vibronic Jahn-Teller interaction in CdSe crystals doped with Cr2+ ions. The vibronic coupling constants are evaluated in the framework of the exchange charge model of the crystal field accounting for the exchange and covalence effects. The calculations demonstrate the leading role of the trigonal vibrations for the 5T2 term although the contribution of tetragonal modes is also important; the full symmetric and tetragonal vibrations for the 5E term significantly contribute to the formation of the optical band 5E ↔ 5T2 for CdSe:Cr2+ system.