Analysis of the absorption and emission spectra of U4+ in -ThBr 4


2014 The low temperature form 03B1-ThBr4 has a scheelite structure I41/a in which the tetravalent uranium occupies the thorium site which is S4. Assuming that the ground state remains 03934 as in the 03B2-ThBr4 form, the polarized absorption spectrum at 4.2 K shows that D2d is a good approximation. A peculiarity of this host is the exaltation of very numerous fluorescences of U4+ which permit to assign four Stark levels of the ground state 3H4 : 03935 at 110 cm-1, 03931 at 473 cm-1, 03931 at 623 cm-1 and 03935 at 830 cm-1. 30 levels have been assigned and the crystal field parameters of U4+ (5f2) have been calculated in the D2d approximation : B20 = 382, B40 = 3 262, B44 = 1734, B60 = 851 and B64 = 1828 cm-1. It is interesting to note that a small distortion in the scheelite structure of the 03B1-ThBr4 compared with the zircon structure 03B2-ThBr4 induces important changes in the crystal field parameters. J. Phys. France 49 (1988) 1425-1434 AOÚT 1988,

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@inproceedings{Simoni2016AnalysisOT, title={Analysis of the absorption and emission spectra of U4+ in -ThBr 4}, author={{\'E}ric Simoni and S{\'e}bastien Hubert and Marie Genet}, year={2016} }