scholarly journals Theoretical Studies On The Gyromagnetic Factors For Nd3+ In Scheelites-Type ABO4 Compounds

2004 ◽  
Vol 59 (12) ◽  
pp. 947-951 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Crystal Field ◽  
Energy Levels ◽  
Tetragonal Symmetry ◽  
Theoretical Studies ◽  
Superposition Model ◽  
Crystal Field Parameters ◽  
Relationship Of ◽  
Geometrical Relationship ◽  
Theory And Experiment ◽  
G Factors

The gyromagnetic factors for Nd3+ in scheelite-type ABO4 compounds (A = Cd, Ca, Pb, Ba;B = Mo, W) are theoretically studied by the perturbation formulas of the anisotropic g factors g∥ and g⊥ for a 4f3 ion in tetragonal symmetry. In these formulas, the contributions to the g factorsdue to the second-order perturbation terms and the admixtures of various energy levels are takeninto account. The relevant crystal-field parameters are determined by the superposition model andthe local geometrical relationship of the A2+ sites occupied by the impurity Nd3+. The obtained gfactors agree reasonably with the observed values. The discrepancies between theory and experimentare discussed.

Investigations of the EPR g Factors for Er3+ in CaMoO4

2004 ◽  
Vol 59 (6) ◽  
pp. 341-345 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Crystal Field ◽  
Structural Data ◽  
Order Perturbation ◽  
Tetragonal Symmetry ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
G Factors

The electron paramagnetic resonance (EPR) g factors g‖ and g⊥ for Er3+ in CaMoO4 are theoretically investigated by using the perturbation formulas of the g factors for a 4f11 ion in tetragonal symmetry. In these formulas, the contributions to the g factors arising from the second-order perturbation terms and the admixture of various states are considered. The crystal-field parameters for the tetragonally distorted tetrahedra are determined by using the superposition model and the structural data of the impurity Er3+ on the host Ca2+ site in CaMoO4. The calculated g factors agree with the observed values. The validity of the results is discussed.

Theoretical Studies of the EPR Parameters of Nd3+ in LiYF4

2004 ◽  
Vol 59 (4-5) ◽  
pp. 235-238 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Crystal Field ◽  
Structural Parameters ◽  
Tetragonal Symmetry ◽  
Theoretical Studies ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Epr Parameters ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic

The perturbation formulas of the electron paramagnetic resonance (EPR) parameters g∥, g⊥, A∥ and A⊥ for a 4f3(Nd3+) ion in tetragonal symmetry are established in this work. In these formulas, the contributions to the EPR parameters arising from the second-order perturbation terms and the admixtures of different states are included. Then the above formulas are applied to a tetragonal Nd3+ center in LiYF4, where the related crystal-field parameters are calculated from the superposition model and the local structural parameters of the Y3+ site occupied by the impurity Nd3+. The EPR parameters and the optical spectra within the 4I9/2 and 4I11/2 states obtained in this work agree reasonably with the observed values.

Theoretical Investigations of the Electron Paramagnetic Resonance g Factors for the Trivalent Cerium Ion in LiYF4 Crystal

2003 ◽  
Vol 58 (9-10) ◽  
pp. 507-510
Author(s):  
Hui-Ning Dong ◽  
Shao-Yi Wu
Keyword(s):  
Tetragonal Symmetry ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Cerium Ion ◽  
Theoretical Investigations ◽  
Epr Parameters ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
Perturbation Equations ◽  
G Factors

The perturbation equations of the EPR parameters g‖ and g⊥ for the lowest Kramers doublet of a 4f1 ion in tetragonal symmetry are established. In these equations, the contributions of the covalency effects, the admixture between J = 7/2 and J = 5/2 states and the second-order perturbation (which is not considered previously) are included. The crystal field parameters for the studied Ce3+ center are calculated from the superposition model. Based on the above perturbation equations and related parameters, the EPR g factors for the Ce3+ center in LiYF4 crystals are reasonably explained. The results are discussed.

scholarly journals Calculation Of The Crystal Field Parameters For Eu3+ Doped In SrAl2O4 And SrIn2O4 Spinels

2012 ◽  
Vol 56 (1) ◽  
pp. 132-138
Author(s):  
M. L. Stanciu
Keyword(s):  
Experimental Data ◽  
Rare Earth ◽  
Crystal Field ◽  
Energy Levels ◽  
Superposition Model ◽  
Strontium Aluminate ◽  
Intrinsic Parameters ◽  
Broadband Emission ◽  
Host Materials ◽  
Crystal Field Parameters

AbstractStrontium aluminate (SrAl2O4) and the indium aluminate (SrIn2O4) spinels have been proven to be efficient host materials, which offer the possibility of generating broadband emission after doping with rare earth trivalent ions. The present work is devoted to the calculation of the crystal field parameters and the energy levels of the trivalent europium doped in SrAl2O4 and SrIn2O4 spinels, using the superposition model of the crystal field. Using the intrinsic parameters for Eu3+-O2− bonds, and the geometry structure of the each crystal, we modeled the CFPs and simulated the low-lying energy levels schemes. The obtained results are compared with the experimental data and discussed.

STUDIES ON THE EPR g FACTORS FOR THE ORTHORHOMBIC NdBa2Cu3O7

2007 ◽  
Vol 21 (24) ◽  
pp. 1627-1633
Author(s):  
SHAO-YI WU ◽  
HUA-MING ZHANG ◽  
ZHI-HONG ZHANG ◽  
LI-HUA WEI
Keyword(s):  
Crystal Field ◽  
Reasonable Agreement ◽  
Structural Data ◽  
Orthorhombic Symmetry ◽  
Superposition Model ◽  
Crystal Field Parameters ◽  
Theoretical Results ◽  
G Factors

The perturbation formulas of the EPR g factors for a 4f3 ion in orthorhombic symmetry are established, by considering the contributions from the admixtures of various states. The formulas are applied to the studies of the g factors for the orthorhombic NdBa 2 Cu 3 O 7. The related crystal-field parameters in the calculations are obtained from the superposition model and the local structural data of the orthorhombic Nd 3+ site in NdBa 2 Cu 3 O 7. The calculated g factors are in reasonable agreement with the observed values. The theoretical results are discussed.

scholarly journals Theoretical Investigation of the EPR g-factors for Yb3+ in YBa2Cu3O7-δ

2004 ◽  
Vol 59 (6) ◽  
pp. 346-348 ◽  
Author(s):  
Hui-Ning Dong ◽  
Shao-Yi Wu ◽  
Xiao-Bing Luo
Keyword(s):  
Structural Data ◽  
Tetragonal Symmetry ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Cluster Approach ◽  
Epr Parameters ◽  
Experimental Values ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters ◽  
G Factors

The EPR g factors g‖, g⊥ for Yb3+ in YBa2Cu3O7−δ are studied with perturbation formulas based on the cluster approach of the spin-Hamiltonian parameters for a 4f13 ion in tetragonal symmetry. In these formulas, the contributions to the EPR parameters of the covalency effects, the admixture between the J = 7/2 and J = 5/2 states and the second-order perturbation terms are all included. The used crystal-field parameters are calculated with the superposition model and the local structural data of Yb3+ in YBa2Cu3O7−δ . The resulting EPR g factors for Yb3+ ions in the superconductor YBa2Cu3O7−δ agree reasonably with the experimental values. The results are discussed.

Theoretical Investigations Of The Epr G Factors For Er3+ In Pr2cuo4 Superconductor

2003 ◽  
Vol 58 (7-8) ◽  
pp. 439-442
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong ◽  
Peng Li
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Structural Parameters ◽  
Tetragonal Symmetry ◽  
Model Parameters ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Theoretical Investigations ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
G Factors

The electron paramagnetic resonance g factors g|| and g⊥ for Er3+ in the superconductor Pr2CuO4 are investigated by using the perturbation formulas of g factors for a 4f11 ion in tetragonal symmetry. In these formulas, the contributions to the g factors due to the second-order perturbation terms and the admixture of different states are considered. The crystal field parameters used in the calculations are obtained from the superposition model and the local structural parameters of the impurity Er3+ located on the host Pr3+ site. The superposition model parameters adopted in this paper are comparable with those for similar tetragonal Er3+ centers in some zircon compounds in previous work. The above investigations may be helpful to understand the electronic and magnetic properties and hence the superconductivity of the Er3+ doped Pr2CuO4.

Further studies of the enhanced nuclear magnet HoVO 4 - I. The crystal field and the Zeeman spectrum

1988 ◽  
Vol 416 (1850) ◽  
pp. 63-73 ◽  
Keyword(s):  
Crystal Field ◽  
Energy Levels ◽  
Zeeman Effect ◽  
Tetragonal Symmetry ◽  
Novel Approach ◽  
Magnetic Resonance Frequency ◽  
Nuclear Magnetic Resonance Frequency ◽  
Crystal Field Parameters ◽  
Van Vleck ◽  
Good Agreement

A novel approach is adopted to fit the experimental results for the Van Vleck paramagnet HoVO 4 . Within the ground manifold 5 I 8 , J = 8, the five parameters for a crystal field of tetragonal symmetry are adjusted to give values in agreement with the optical spectrum for the lowest energy levels: the ground singlet, the first excited doublet at 21 cm -1 , and the (accidental) triplet at 47 cm -1 . Within experimental error (of order 1 cm -1 ), this agreement is not impaired by a small modification in which all the crystal field parameters are multiplied by a factor 1.0225. This factor is introduced to give the correct value of the enhanced nuclear magnetic resonance frequency for the stable isotope 165 Ho ( I = 7/2), known to 0.3% (Bleaney et al. Proc. R. Soc. Lond . A 362, 179 (1978)). The optical Zeeman effect, calculated therefrom, is in good agreement with that observed experimentally for the lowest levels in magnetic fields up to 15 T, directed along the [100], [110] and [001] axes (Battison et al. Phys. Lett . A 55, 173 (1975); J. Phys . C 10, 323 (1977)).

Ground configuration splitting in UCl5

1977 ◽  
Vol 55 (10) ◽  
pp. 937-942 ◽  
Author(s):  
A. F. Leung ◽  
Ying-Ming Poon
Keyword(s):  
Crystal Field ◽  
Energy Levels ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Coupling Constant ◽  
Point Charge Model ◽  
X Ray Crystallography ◽  
Charge Model ◽  
Crystal Field Parameters

The absorption spectra of UCl5 single crystal were observed in the region between 0.6 and 2.4 μm at room, 77, and 4.2 K temperatures. Five pure electronic transitions were assigned at 11 665, 9772, 8950, 6643, and 4300 cm−1. The energy levels associated with these transitions were identified as the splittings of the 5f1 ground configuration under the influence of the spin–orbit coupling and a crystal field of C2v symmetry. The number of crystal field parameters was reduced by assuming the point-charge model where the positions of the ions were determined by X-ray crystallography. Then, the crystal field parameters and the spin–orbit coupling constant were calculated to be [Formula: see text],[Formula: see text], [Formula: see text], and ξ = 1760 cm−1. The vibronic analysis showed that the 90, 200, and 320 cm−1 modes were similar to the T2u(v6), T1u(v4), and T1u(v3) of an UCl6− octahedron, respectively.

Theoretical Investigations Of The Spin Hamiltonian Parameters Of Zrsio4:Np4+

2004 ◽  
Vol 59 (7-8) ◽  
pp. 471-475
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Experimental Data ◽  
Energy Levels ◽  
Structural Data ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Theoretical Investigations ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters ◽  
Theoretical Results

In this work, the spin Hamiltonian (SH) parameters g|| and g⊥, and the hyperfine structure constants A|| and A⊥ for ZrSiO4:Np4+ are investigated on the basis of the perturbation formulas of these parameters for a 5f3 ion in tetragonal (D2d) symmetry. In these formulas, the contributions to the SH parameters from the second-order perturbation terms, the admixtures of various energy levels and the covalency effect are taken into account. The related crystal-field parameters are calculated from the superposition model and the local structural data of the Zr4+ site occupied by the impurity Np4+. The calculated SH parameters agree reasonably with the experimental data. The validity of the theoretical results is discussed.

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