Optical spectrum and crystal-field analysis of uranium trifluoride

Autor: Janusz Drożdżyński, Mirosław Karbowiak
Rok vydání: 2007
Předmět:
Zdroj: Chemical Physics. 340:187-196
ISSN: 0301-0104
DOI: 10.1016/j.chemphys.2007.08.017
Popis: The first low temperature absorption spectrum and crystal-field analysis of uranium trifluoride are presented. The measurements have been performed on a polycrystalline sample in the 4000–30,000 cm−1 range at 4.2 K. One may notice the largest crystal-field splitting of SLJ multiplets among all so far reported data for uranium(III) as well as in polycrystalline samples and U3+ doped single crystals. In the presented analysis 94 experimental crystal-field levels, observed in 0–24,116 cm−1 energy range, have been identified and fitted to a semiempirical Hamiltonian representing the combined atomic and crystal-field interactions at the C2 site symmetry. In order to exclude a possible influence of inaccuracy in the description of the free-ion multiplets on crystal-field parameters a number of additional freely varied parameters associated with the centroids of the free-ion multiplets were introduced. In the final step of the fitting procedure eight free-ion and 14 CF parameters were freely varied giving B 0 2 = - 833 ( 45 ) , Re B 2 2 = 272 ( 36 ) , B 0 4 = 1817 ( 89 ) , Re B 2 4 = 186 ( 106 ) , Im B 2 4 = 776 ( 82 ) , Re B 4 4 = 523 ( 104 ) , Im B 4 4 = + 1460 ( 58 ) , B 0 6 = 1081 ( 105 ) , Re B 2 6 = - 841 ( 89 ) , Im B 2 6 = - 2459 ( 74 ) , Re B 4 6 = - 665 ( 88 ) , Im B 4 6 = - 1024 ( 74 ) , Re B 6 6 = 1416 ( 56 ) , Im B 6 6 = - 1682 ( 93 ) and r.m.s. = 24 cm−1. The performed calculation procedure enabled the determination of good starting values, reliable crystal-field parameters and a small r.m.s. deviation.
Databáze: OpenAIRE
Externí odkaz: