Vibronic model of absorption spectra in CdSe-Cr(II)

In this article we report the evaluation of the vibronic Jahn-Teller (JT) coupling parameters and the vibronic optical absorption bands related to the 5T2 → 5 E transition in CdSe crystal doped with Cr2+ ion. The vibronic parameters are estimated with the aid of the exchange charge model of the crystal field accounting for the exchange and covalence effects. Coupling of the 5 E term and excited 5T2 term to tetragonal and trigonal vibrations, respectively, is shown to give rise to the optical absorption band in the infrared range. The profile of this band calculated on the basis of the numerical solution of the dynamical JT problem proves to be in quite a good agreement with the experimental data. (authors)