Luminescence and absorption spectra ofM2UO2Cl4·xH2O

Abstract

Polarized luminescence and electronic absorption spectra have been recorded at temperatures down to 4 K for M 2UO2Cl4·xH2O (M=K, Rb, NH4). The most important difference between these luminescence spectra and that of Cs2UO2Cl4 arises from the contribution of vibrations of water molecules to the vibronic intensity. In the electronic absorption spectra the wavenumbers of these vibrations may be used to locate and identify electronic origins. Ten electronic origins have been identified at similar wavenumbers to those reported by Denning et al. for Cs2UO2Cl4. New ground state vibrational assignments for M 2UO2Cl4·xH2O are made from 85 K infrared and 120 K Raman data.