Parametric model for ƒ-shell configurations I The effective-operator Hamiltonian

Crosswhite, H. M.

doi:10.1364/josab.1.000246

Cited by 200 publications

(97 citation statements)

References 42 publications

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“…Since in addition to the indicated references, there has been a detailed review, 8 present treatment can be brief and involves primarily a description of the terms.…”

Section: Hamiltonian Structurementioning

confidence: 99%

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

Carnall

1992

The Journal of Chemical Physics

145

130

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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 Spectroscopic data were taken from the literature but in most cases supplemented by unpublished measurements in absorption and in fluorescence.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.

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“…Since in addition to the indicated references, there has been a detailed review, 8 present treatment can be brief and involves primarily a description of the terms.…”

Section: Hamiltonian Structurementioning

confidence: 99%

“…HCI (2) and HCI(3) represent two and three body interactions introduced to account for the effects of configuration interaction. The two-body operators are parameterized by a, , and y, while the three body parameters are T (k = 2, 3,4,6,7,8).…”

Section: H= Hf+hcfmentioning

confidence: 99%

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

Carnall

1992

The Journal of Chemical Physics

145

130

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“…The configuration interactions (α, β, γ), spin-spin and spin-other-orbit interactions (M h ), the two-body electrostatically correlated magnetic interactions (P f ), and the three-particle configuration interactions (T i ) represent higher order interactions that are essential in order to accurately reproduce the energy level structure of f-element ions. The physical meaning of these FI parameters has been described by Crosswhite and Carnall et al [173,174].…”

Section: Electronic Structures Of Lanthanide Ions In Sncsmentioning

confidence: 99%

“…The energy-level-fitting was performed using the f-shell empirical programs of Prof. Reid, which enabled a complete diagonalization without truncation of the 4f 11 wave functions [185]. In the least-square fitting of CF energy level structure, five FI parameters (E avg , F k , ζ f ) were allowed to vary freely whereas the others of M 2 , M 4 , P 4 , and P 6 were constrained by the Hartree-Fock-determined ratios M 2 /M 0 =0.56, M 4 /M 0 =0.38; P 4 /P 2 =0.75, P 6 / P 2 =0.5 [173]. The FI and CF parameters of LaF 3 :Er 3+ [174] were used as starting values.…”

Section: Er 3+mentioning

confidence: 99%

Lanthanide-doped semiconductor nanocrystals: electronic structures and optical properties

2015

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solid state lightings [11,12]. Nevertheless, due to the parity forbidden transition nature, the absorption cross-section of f-f transition is small and usually high power light sources such as laser are needed to excite the Ln 3+ ions. The ability to excite Ln 3+ ions efficiently in a broad spectral range is strongly desired for realizing their full potentials in signaling and lighting applications. To improve the excitation efficiency of Ln 3+ , sensitization is an efficient way to avoid the direct excitation of the Ln 3+ . Charge transfer, electronics transfer from ligand ground states (e.g., O 1s) to the Ln 3+ excited states, has proved to be an efficient means to achieve intense Ln 3+ emissions, due to its large band absorption cross-section. By employing this strategy, commercial phosphor Y 2 O 3 :Eu 3+ has been demonstrated to be an excellent red phosphor, which can be effectively excited at Eu-O charge transfer band at 255 nm. Another strategy for efficient sensitization of Ln 3+ is via the energy transfer (ET) from semiconductor nanocrystals (SNCs), which generally possess large absorption cross-section for Ln 3+ excited states. Moreover, it is known that the exciton Bohr radius of semiconductors is much larger than that of insulators [13], which could result in pronounced quantum confinement effect for small nanocrystals (NCs) (e.g., 2−10 nm for In 2 O 3 , ZnO and TiO 2 ). As a result, the optical properties of Ln 3+ incorporated in SNCs could be tailored via size control or bandgap engineering, which is very attractive in fabricating a nano-device for technological applications. It is anticipated that the luminescence of Ln 3+ ions can be efficiently sensitized via the energy transfer from the excited host to Ln 3+ , which thereby overcomes the inefficient direct absorptions of the parity forbidden 4f-4f transitions of Ln 3+ ions (Fig. 1). To realize the efficient energy transfer and intense Ln 3+ PL, the successful incorporation of Ln 3+ into the lattices of SNCs is of utmost importance, which still remains a great challenge via conventional wet-chemical methods especially for some widely used wide bandgap Trivalent lanthanide (Ln 3+ ) ions doped semiconductor nanomaterials have recently attracted considerable attention owing to their distinct optical properties and their important applications in diverse fields such as optoelectronic devices, flat plane displays and luminescent biolabels. This review provides a comprehensive survey of the latest advances in the synthesis, electronic structures and optical spectra of Ln 3+ ions in wide band-gap semiconductor nanocrystals (SNCs). In particular, we highlight the general wet-chemical strategies to introduce Ln 3+ ions into host lattices, the local environments as well as the sensitization mechanism of Ln 3+ in SNCs. The energy levels and crystal-field parameters of Ln 3+ in various SNCs determined from energy-level-fitting are summarized, which is of vital importance to understanding the optical properties of Ln 3+ ions in SNCs. Finally, some future pros...

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“…[4][5][6][7] In the conventional framework of CFT, an effective Hamiltonian including both free-ion interactions and ion-lattice interactions is usually parameterized by fitting the calculated energy levels to those observed in spectroscopic experiments. [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.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2009

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Orbital hybridization ͑mixing of electron configurations of opposite parities͒ is analyzed in the framework of crystal-field theory with a complete diagonalization of the crystal-field Hamiltonian, including both even and odd terms of crystal-field potential, and with all basis sets of the 5f 3 and 5f 2 6d configurations for the wave functions of open-shell electrons in the U 3+ ion. This method provides a fundamental understanding and quantitative analysis of the crystal-field induced 5f-6d mixing in U 3+ : LaCl 3 and U 3+ : CeCl 3 . The odd terms of the crystal-field interaction ͓B 3 3 ͑fd͒ and B 3 5 ͑fd͒ in C 3h site symmetry͔ selectively couple the states of the 5f 3 and 5f 2 6d configurations, inducing a shift of the energy levels and allow electric dipole transitions between the configuration-mixed states. The mixture of the 5f and 6d configurations is evaluated by introducing an index of configuration mixing. The exchange charge model ͑ECM͒ of crystal-field theory is used to calculate the crystal-field parameters of the U 3+ 5f and 6d electrons in terms of point-charge electrostatic interaction and orbital overlapping and covalent effect. The initial ECM estimations of the crystal-field parameters were optimized along with free-ion parameters of the Hamiltonian in nonlinear least-squares fitting of the calculated U 3+ energy levels to the experimental absorption spectra. The configuration-mixed eigenfunctions of the U 3+ states are directly used to calculate the electric dipole transition intensities and simulate the absorption spectra where the 5f 3 and 5f 2 6d configurations overlap and the Judd-Ofelt theory fails because of significant configuration mixing.

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Parametric model for ƒ-shell configurations I The effective-operator Hamiltonian

Cited by 200 publications

References 42 publications

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

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

Lanthanide-doped semiconductor nanocrystals: electronic structures and optical properties

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

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