SHARP-LINE LUMINESCENCE OF THE HEXABROMORHENATE (IV) ION AND THE HEXABROMOOSMATE (IV) ION IN CESIUM HEXABROMOZIRCONATE (IV) AT $20^{\circ}$ K

Author Institution: Chemistry Department, University of MaineStrong sharp-line luminescence has been observed for $Re^{+4} (5d^{3})$ and $Os^{+4} (5d^{4})$ in single cubic crystals of the host lattice $Cs_{2}ZrBr_{6}$ at $20^{\circ} K$. For $Re^{+4}$, luminescence and absorption spectra are reported within the $t^{3}_{2g}$ configuration between the ${\Gamma}_{7}(^{2}T_{2g})$ and ${\Gamma}_{8}(^{2}T_{2g})$ states and the ${\Gamma}_{8}(^{4}A_{2g})$ ground state. Calculated vibrational mode energies of the ground electronic state are found to be in good agreement with the available infrared and Raman data for the $ReBr^{-2}_{6}$ complex and to be somewhat different than the vibrational mode energies for the ${\Gamma}_{7} (^{2}T_{2g})$ and ${\Gamma}_{8}(^{2}T_{2g})$ excited electronic states. For the electronic-dipole portion of the ${\Gamma}_{8}(^{4}A_{2g}) \rightarrow {\Gamma}_{7}(^{2}T_{2g})$ transition short progressions are present not only in the $a_{1g}$ symmetric mode but also in the $e_{g}$ and $t_{2g}$ modes. Similar results have been obtained for the $OsBr^{-2}_{6}$ complex