High resolution infrared and visible luminescence spectra of OsCl62-and OsBr62-in cubic crystals

The high resolution infrared luminescence spectra of OsCl6 2- in Cs2TeCl6 and of OsBr6 2- in Cs2SnBr6 have been measured between 11 000 cm-1 and 3000 cm-1 at liquid helium temperatures. Comparison with new visible luminescence data has enabled ten luminescence transitions between six of the seven states derived from the t 2g 4 configuration to be assigned unambiguously. The assignment of two further luminescence transition involving the seventh (Γ3, 1 Eg ) state is considered. Each electronic transition shows extensive vibronic structure which can be analysed to yield the vibrational frequencies of the OsX6 2- ion in each state. The mechanisms of the various electronic and vibronic radiative and non-radiative transitions are discussed.