A systematic analysis of the spectra of trivalent actinide chlorides in D3h site symmetry

Abstract

The optical spectra of actinide ions in the compound AnCl3 and doped into single-crystal LaCl3 were interpreted in terms of transitions within 5fN configurations. Energy-level calculations were carried out using an effective-operator Hamiltonian, the parameters of which were determined by fitting experimental data. Atomic and crystal-field matrices were diagonalized simultaneously assuming an approximate D3h site symmetry. Spectroscopic data were taken from the literature but in most cases supplemented by unpublished measurements in absorption and in fluorescence. Data for each ion were analyzed independently, then the model parameters were intercompared and in many cases adjusted such that in the final fitting process the principal interactions showed uniform trends in parameter values with increasing atomic number. Consistent with analyses of the spectra of lanthanide ions in both LaCl3 and LaF3, abrupt changes in magnitude of certain crystal-field parameters were found near the center of the 5fN series. This resulted in two groups of parameter values, but with consistent trends for both halves of the series, and generally very good agreement between observed and computed energies. A new energy-level chart based on computed crystal-field level energies for each trivalent actinide ion has been prepared.

Highly Luminescent and Stable Hydroxypyridinonate Complexes: A Step Towards New Curium Decontamination Strategies

“…[15,19] Based on these results and on the relative electronic energy levels of metals from the 4f and 5f series, the 1,2-HOPO and Me-3,2-HOPO ligands have the potential to act as antenna chromophores for Cm III . [21,22] In such case, spectroscopic characterization of the corresponding complexes could not only provide information on the localization of the best accepting states for the Cm III ion and on the effects of the larger spinorbit coupling and smaller electrostatic interactions of the actinides in comparison to the lanthanides, it could also be utilized to characterize solution thermodynamics parameters for Cm III complexes with both experimental chelating agents.…”

Self-consistent density functional calculations of the crystal field levels in lanthanide and actinide dioxides

“…Since the Slater integrals F k (k = 2, 4, 6) inV ee are heavily correlated 31 , the following approximation has been adopted:…”

5f−6dorbital hybridization of trivalent uranium in crystals of hexagonal symmetry: Effects on electronic energy levels and transition intensities

“…10͒ and LaBr 3 . 27 For the energy levels below 15 000 cm −1 , the characteristics of the 5f 3 configuration are obvious, and, as demonstrated by Carnall 11 and Crosswhite et al, 10 the single-configuration approximation is effective. However, discrepancies between experiment and theory increase for higher energy states.…”

“…͑1͒. Therefore, in comparison with the parameter values determined in previous work by Crosswhite et al 10 and by Carnall 11 we expect some differences in the free ion and crystal-field parameters for the 5f 3 configuration. This means that, in parameterization, the effects of these higher order perturbations are more or less absorbed by other parameters.…”

“…[6][7][8][9] This method is also effective for isolated multiplets of the 5f n configurations of actinide ions in crystals where configuration coupling is weak. [10][11][12][13] Based on the symmetry properties of crystal field, the intraconfiguration crystal-field interactions are induced by the crystal-field operators of even ranks ͑B q k , k =2,4,6͒, whereas the odd ranks of crystal-field operators ͑k =1,3,5͒ only couple the free-ion states of two configurations with different parities. 1,14 Therefore, coupling between two configurations with different parities is expected for an optical center in crystals without inversion symmetry.…”