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Title: Analysis of the crystal-field spectra of the actinide tetrafluorides. II. AmF[sub 4], CmF[sub 4], Cm[sup 4+]:CeF[sub 4], and Bk[sup 4+]:CeF[sub 4]

Journal Article · · Journal of Chemical Physics; (United States)
DOI:https://doi.org/10.1063/1.468093· OSTI ID:6841563
; ; ;  [1]
  1. Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

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. [bold 95], 7194 (1991)] provided interpretation of the absorption spectra of UF[sub 4], NpF[sub 4], and PuF[sub 4]. To extend our analysis to heavier elements of the series, low-temperature absorption spectra of AmF[sub 4] and CmF[sub 4], and site selective laser-induced emission and excitation spectra of Cm[sup 4+]:CeF[sub 4] and Bk[sup 4+]:CeF[sub 4] 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 [ital J] mixing in the excited states, but ground state wave functions are still relatively pure in [ital J] character for the tetravalent actinide ions Am[sup 4+], Cm[sup 4+], and Bk[sup 4+]. 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 [ital S]-state ion Bk[sup 4+] in CeF[sub 4] and color center formation in AmF[sub 4] are also discussed.

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
6841563
Journal Information:
Journal of Chemical Physics; (United States), Vol. 101:10; ISSN 0021-9606
Country of Publication:
United States
Language:
English