Analysis of the crystal-field spectra of the actinide tetrafluorides. II. AmF4, CmF4, Cm4+:CeF4, and Bk4+:CeF4.

Autor: Liu, G. K., Carnall, W. T., Jursich, G., Williams, C. W.
Předmět:
Zdroj: Journal of Chemical Physics; 11/15/1994, Vol. 101 Issue 10, p8277, 13p
Abstrakt: We report a systematic analysis of the crystal-field spectra of four fluoride compounds containing tetravalent actinide ions. The first part of this work [J. Chem. Phys. 95, 7194 (1991)] provided interpretation of the absorption spectra of UF4, NpF4, and PuF4. To extend our analysis to heavier elements of the series, low-temperature absorption spectra of AmF4 and CmF4, and site selective laser-induced emission and excitation spectra of Cm4+:CeF4 and Bk4+:CeF4 were obtained. A model energy level calculation was found to be in good agreement with the experimental results. It is shown that the crystal-field interaction in combination with spin–orbital coupling results in significant J mixing in the excited states, but ground state wave functions are still relatively pure in J character for the tetravalent actinide ions Am4+, Cm4+, and Bk4+. Trends in the parameters of the effective operator Hamiltonian are compared with those of a Hartree–Fock free-ion model. Interpretation of the ground-state splitting of the nominal S-state ion Bk4+ in CeF4 and color center formation in AmF4 are also discussed. [ABSTRACT FROM AUTHOR]
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