No abstract available

No abstract available

[en] Two types of correlations with experimental results are reported. For even-f-electron systems, a center of gravity was computed based on the energies of the observed states, and calculated optimized sets of atomic energy level parameters. For odd-electron systems complete crystal field calculations were performed in which parameters of both the atomic and crystal-field parts of the interaction were adjusted to experimental data. The result is a set of eigenvectors for all the ionic states in each configuration. Spectroscopic results for all lanthanides doped into LaF₃ (In³⁺:LaF₃) except Pm³⁺ and Eu³⁺ are reported. 89 references, 29 tables

[en] This report provides a summary of theoretical and experimental studies of actinide spectra in condensed phases. Much of the work was accomplished at Argonne National Laboratory, but references to related investigations by others are included. Spectroscopic studies of the trivlent actinides are emphasized, as is the use of energy level parameters, evaluated from experimental data, to investigate systematic trends in electronic structure and other properties. Some reference is made to correlations with atomic spectra, as well as with spectra of the (II), (IV), and higher valence states. 207 refs., 39 figs., 38 tabs

[en] Volume A5 of the ''Uranium'' series of the Gmelin Handbook deals with the various types of absorption and emission spectra of uranium and its compounds, covering atomic, absorption, luminescence, X-ray, photoemission, infrared, NMR, ESR, and Moessbauer spectra. The several authors have given not only a critical compilation of the published material but also an up-to-date interpretation. (orig./GSCH)

[en] A feature of the actinide elements is the stability of the f orbitals against changes in the ionic environment and a consequent relative insensitivity of actinide spectra to such changes. Free-ion calculations can be used, therefore, to assist in the interpretation of the spectra arising from condensed phases. The theoretical model for free-ions as applied to f-element spectra is outlined in this review and the modifications required to take account of the crystal field in a condensed-phase medium are discussed. Analysis of the electronic structure of other valence states is also considered. This is much more tentative although the spectra of actinide compounds and solutions involving states other than the trivalent are well known. (author)

[en] Fits to spectral energy levels for Ho³⁺:LaCl₃ and Gd³⁺:LaCl₃ establish, for the first time, empirical values of the lanthanide spin-correlated crystal field parameters. The fitted rank 6 parameters are consistent with the superposition model analysis and provide the solution to a long standing problem in the fitted values of the crystal field parameters for trivalent lanthanide ions in LaCl₃

[en] The atomic spectroscopic data available for plutonium are among the rickest of any in the periodic system. They include high-resolution grating and Fourier-transform spectra as well as extensive Zeeman and isotope-shift studies. We summarize the present status of the term analysis and cite the configurations that have been identified. A least-squares adjustment of a parametric Hamiltonian for configurations of both Pu I and Pu II has shown that almost all of the expected low levels are now known. The use of a model Hamiltonian applicable to both lanthanide and actinide atomic species has been applied to the low configurations of Pu I and Pu II making use of trends predicted by ab initio calculations. This same model has been used to describe the energy levels of Pu³⁺ in LaCl₃, and an extension has permitted preliminary calculations of the spectra of other valence states

[en] A 20-parameter least-squares fit to the levels of Ho³⁺:LaCl₃ observed by Dieke and Pandey has been obtained. The results are in substantial agreement with their assignments and with the subsequent analysis of Rajnak and Krupke. A considerably more extensive atomic Hamiltonian was used, including operators for two- and three-particle electrostatic interactions, spin--orbit and spin--other-orbit magnetic interaction, two-particle pseudomagnetic configuration-mixing interactions, and single-particle crystal-field interactions. The fit of twenty parameters to 128 observed levels resulted in a mean error of 5.2 cm^-1. The results are consistent with similar recent studies of Nd³⁺ and Pm³⁺ in the LaCl₃ host

[en] We demonstrate that the Dy III line list from the laboratory study of Hussain represent pure Dy but in many stages of ionization; when known Dy I and Dy II lines are purged from this list, many of the remaining lines coincide with hitherto unidentified lines in the hotter Ap and Bp stars, notably for HR 465 at rare earth maximum. A search list of 34 relatively unblended lines of Dy III is proposed, and the Dy III spectrum is shown to be present in about 16 well-known chemically peculiar stars