The vibronic analysis of the luminescence spectra of the UO2Cl2-4 ion diluted into cubic crystals

The 85 K luminescence spectra of the UO2Cl2-4 ion in Cs2SnCl6 and Cs2ZrCl6 are analysed to yield the wavenumbers of seven of the vibrational modes of the ion. Comparison with the spectrum of pure Cs2UO2Cl4 demonstrates that the impurity ion has C4v symmetry. At UO2Cl2-4 concentrations of greater than 0.3 mol% the spectra of both isolated impurity ions and pairs may be distinguished.