Absorption and luminescence spectra of [(C2H5)3NH]2UO2Cl4

Abstract

The 20 K electronic absorption spectra, 10 K luminescence spectra and room temperature infrared and Raman spectra of single crystals of the title compound are reported. The luminescence spectrum is analysed into (a) an electronic origin, E_g→A_1g(D_4h); (b) vibronic origins involving internal UO₂Cl^2–₄ modes; (c) vibronic origins involving internal cation modes; (d) lattice vibrations; (e) bands originating in ¹⁸O substituted anions; (f) progressions in the O—U—O and U—Cl symmetric stretching modes and the O—U—O rocking mode based on the above features. The absorption spectrum between 465 and 500 nm shows four electronic origins with associated vibronic structure. The luminescence of a high temperature modification of the compound is also discussed.