Third-order contributions to the 7 F 0 5 D 2 two-photon transition of Eu 3 in a cubic lattice (original) (raw)
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Third-order contributions to the 8 S 7/2 6 P 7/2 , 6 P 5/2 two-photon transitions of Eu 2+ in KMgF 3
Journal of Physics: Condensed Matter, 2004
The direct calculation of transition line strengths and relative intensities is presented for two intraconfigurational two-photon absorption (TPA) transitions of Eu 3+ in the cubic Cs 2 NaYF 6 host. Crystal field wavefunctions were utilized for the initial and final f N -electron states and various approaches were used in constructing all the 4f N −1 5d 1 intermediate-state wavefunctions. The calculated relative intensities of the ( 7 F 0 ) 1g → ( 5 D 2 ) 5g , 3g TPA transitions are in reasonable agreement with experiment. The neglect of J -mixing in the initial state has only a small effect upon the calculation, whereas the neglect of spinorbit couplings within the initial and terminal states drastically reduces the calculated transition linestrengths, but does not markedly change the intensity ratios. In the case of the ( 7 F 0 ) 1g → ( 5 L 6 ) 1g , a 5g transitions, serious discrepancies between experiment and theory are found if the intermediate states are constructed from a 4f 5 core comprising free ion states and the 5d 1 crystal field states. Satisfactory agreement is, however, found when the 4f 5 crystal field states are utilized in constructing the intermediate states.
The direct calculation of transition line strengths and relative intensities is presented for two intraconfigurational two-photon absorption (TPA) transitions of Eu3+ in the cubic Cs2NaYF6 host. Crystal field wavefunctions were utilized for the initial and final fN-electron states and various approaches were used in constructing all the 4fN-1 5d1 intermediate-state wavefunctions. The calculated relative intensities of the (7F0) Gamma1g-->(5D2)Gamma5g, Gamma3g TPA transitions are in reasonable agreement with experiment. The neglect of J-mixing in the initial state has only a small effect upon the calculation, whereas the neglect of spin-orbit couplings within the initial and terminal states drastically reduces the calculated transition linestrengths, but does not markedly change the intensity ratios. In the case of the (7F0)Gamma1g-->(5L6)Gamma1g, aGamma5g transitions, serious discrepancies between experiment and theory are found if the intermediate states are constructed from ...
Inorganic Chemistry, 1996
Polarized optical absorption and emission measurements are used to locate and assign 52 crystal-field energy levels split out of the 4f 6 electronic configuration of Eu 3+ in single crystals of Na 3 [Yb 0.95 Eu 0.05 (dpa) 3 ]‚NaClO 4 ‚ 10H 2 O (where dpa ≡ dipicolinate dianion ≡ 2,6-pyridinedicarboxylate). In these crystals, each Eu 3+ is coordinated to three dipicolinate (dpa) ligands, and the tris-terdentate Eu(dpa) 3 3chelate structures have trigonal-dihedral (D 3) symmetry. The combined optical absorption and emission measurements provide access to the energy-level structures of 27 different 4f 6 [SL]J multiplet manifolds of Eu 3+ , and 21 of these multiplet manifolds are represented among the 52 crystal-field levels that are characterized with respect to both location (energy) and symmetry properties. The energy-level data obtained from experiment are analyzed in terms of a model Hamiltonian that includes consideration of both isotropic and nonisotropic 4f-electron/crystal-field interactions. A parametrized form of this Hamiltonian is used to perform parametric fits of calculated-to-experimental energy-level data, and the results obtained from these data fits show a root mean square (rms) deviation of 9.8 cm-1 between calculated and observed energies. The Hamiltonian parameters evaluated from the energy-level analyses provide information about both the anisotropies and the overall strength of the 4f-electron/crystal-field interactions that contribute to the energy-level structure of Eu(dpa) 3 3complexes. In addition to energy-level data, the absorption measurements performed in this study permit the quantitative determination of relative optical line strengths for 22 different Stark-level-to-Stark-level transitions observed in the low-temperature axial absorption spectra of Eu(dpa) 3 3in Na 3 [Yb 0.95 Eu 0.05 (dpa) 3 ]‚NaClO 4 ‚10H 2 O.
Interpretation of the 4f-5d Excitation Spectra of Eu3+ and Tb3+ Doped in Crystals
Journal of Rare Earths, 2006
The structure of the low-temperature 4 f N 4 4 f N -' 5 d excitation spectra of Eu3+ and Tb3' doped in crystals LiYF4, YP04 and CaF2 measured by van Pieterson et al. in 2002 was analyzed and assigned based on the simple model proposed by Duan and co-worken in the last few years. Some complemental discussion on effects of J-mixing on the f-d transition intensities for Eu3' due to the f-electron crystal-field interaction H&),
2002
Predictions of the two-photon transition intensities for Eu 2ϩ in CaF 2 generally give poor agreement with experiment because the low-lying excited states make a straightforward application of perturbation theory unreliable. In this work we explicitly include the effective Coulomb interaction and the crystal-field interaction for the excited configuration in the zeroth-order Hamiltonian, and treat the spin-orbit interaction as a perturbation. We obtain a good agreement with measured multiplet to multiplet two-photon absorption intensities. The linewidths of the two-photon absorption peaks, which vary dramatically, are explained by selection rules for nonradiative relaxation.
Theoretical analysis of optical spectra of Ce3+ in multi-sites host compounds
Journal of Luminescence, 2014
Ce 3 þ 5d-4f emission Crystal field splitting Electron-vibrational coupling a b s t r a c t Theoretical analysis of optical properties of two recently synthesized phosphors with the Ce 3 þ ions (Na 3 LuSi 2 O 7 and NaSr 4 (BO 3 ) 3 ) was performed. The exchange charge model of crystal field was used to calculate the crystal field parameters and cerium 5d states splittings for each site in Na 3 LuSi 2 O 7 . Analysis of vibronic coupling of Ce 3 þ in NaSr 4 (BO 3 ) 3 resulted in a quantitative modeling and theoretical simulation of the experimental spectra. Electronic energy levels, vibrational frequencies and ion-lattice vibronic coupling strength are determined specifically for Ce 3 þ at different sites. The performed analysis allows for getting detailed description of the optical properties of trivalent cerium in the considered crystals and provides a general guide to understanding and characterizing other Ce 3 þ activated phosphors.
Simultaneous excitation of Ce 3+ and Eu 3+ ions in Tb 3Al 5O 12
Radiation Measurements, 2004
Y3Al5O12:Ce 3+ (YAG:Ce) and Tb3Al5O12:Ce 3+ (TAG:Ce) both show the typical Ce 3+ ion luminescence of the allowed Ce 3+ d-f transition. Eu 3+ codoping, however, reveals di erent results for both matrices: in YAG:Ce,Eu, only the luminescence of the Ce 3+ ion occurs by excitation within the Ce 3+ absorption bands. Here, the Eu 3+ luminescence cannot be sensitized by the Ce 3+ ion. But in TAG:Ce,Eu, both Ce 3+ and Eu 3+ luminescence are measured at several excitation wavelengths: an excitation within the Tb-sublattice results in both Ce 3+ and Eu 3+ luminescence, which is not surprising as an energy transfer from Tb 3+ to Ce 3+ and Eu 3+ is well known in literature. In addition, an excitation in the lowest 5d level of Ce 3+ delivers Eu 3+ luminescence at room temperature. This means that the Ce 3+ ion can be used as a sensitizer in the TAG lattice that transfers its energy via the Tb sublattice to the activator Eu 3+ .