scholarly journals Studies Of The Epr G Factors And Hyperfine Structure Constants For Yb3+ Ions In Single Crystals Of Zircon-Structure Orthophosphates

2003 ◽  
Vol 58 (7-8) ◽  
pp. 434-438 ◽  
Author(s):  
Hui-Ning Dong ◽  
Wen-Chen Zheng ◽  
Shao-Yi Wu ◽  
Sheng Tang
Keyword(s):  
Hyperfine Structure ◽  
Crystal Field ◽  
Lattice Relaxation ◽  
Superposition Model ◽  
Zircon Structure ◽  
Local Lattice ◽  
Epr Parameters ◽  
Structure Constants ◽  
Zircon Type ◽  
G Factors

The EPR g factors g|| and g⊥ of Yb3+ and the hyperfine structure constants A|| and A⊥ of 171Yb3+ and 173Yb3+ in crystals of the zircon-structure orthophosphates YPO4, LuPO4, and ScPO4 are calculated from the calculation formulas of the EPR parameters for a 4f13 ion in tetragonal symmetry. In these formulas, the contributions to the EPR parameters from the J-mixing between the ground 2F7/2 and excited 2F5/2 states, the admixtures between the lowest Kramers doublet Γγ and the other 6 Kramers doublets (or irreducible representations) via the crystal-field and orbital angular momentum (or hyperfine structure) interactions and the covalency reduction effect are included. The calculated values agree with the observed ones. In the calculations, the superposition model is used to estimate the crystal-field parameters. It is found intrinsic parameters Ā(R0) that the superposition model with the same R0 for Yb3+ in various zircon-type compounds obtained by considering local lattice relaxation are not scattered as those obtained by using the structural data of pure zircon-type compounds. It appears that, in order to obtain suitable superposition model parameters, the local lattice relaxation should be taken in to account.

Theoretical Interpretation of the EPR Parameters for Dy3+ Ion in LuPO4 Crystal

2004 ◽  
Vol 59 (11) ◽  
pp. 765-768 ◽  
Author(s):  
Hui-Ning Dong ◽  
Hui-Ping Du ◽  
Shao-Yi Wu ◽  
Peng Li
Keyword(s):  
Field Theory ◽  
Hyperfine Structure ◽  
Crystal Field ◽  
Lattice Relaxation ◽  
Theoretical Interpretation ◽  
Superposition Model ◽  
Crystal Field Theory ◽  
Local Lattice ◽  
Epr Parameters ◽  
Structure Constants

Based on the superposition model, in this paper the EPR parameters gII and g⊥ of Dy3+, and the hyperfine structure constants AII and A⊥ of 161Dy3+ and 163Dy3+ in LuPO4 crystal are calculated by perturbation formulas from the crystal-field theory. In the calculations, the contributions of various admixtures and interactions such as J-mixing, mixtures among states with the same J-value, twoorder perturbation, covalency as well as local lattice relaxation are considered. The calculated results agree reasonably with the observed values

Theoretical Investigations of the EPR Parameters of Ti3+ in Beryl Crystal

2006 ◽  
Vol 61 (5-6) ◽  
pp. 286-288 ◽  
Author(s):  
Wen-Chen Zheng ◽  
Qing Zhou ◽  
Xiao-Xuan Wu ◽  
Yang Mei
Keyword(s):  
Hyperfine Structure ◽  
Reasonable Agreement ◽  
Lattice Relaxation ◽  
Superposition Model ◽  
Theoretical Investigations ◽  
Local Lattice ◽  
Epr Parameters ◽  
Structure Constants ◽  
Experimental Values ◽  
Crystal Field Parameters

The EPR parameters (g factors gII, g⊥ and hyperfine structure constants AII, A⊥) of Ti3+ ion at the sixfold coordinated Al3+ site with trigonal symmetry in beryl crystal are calculated by the thirdorder perturbation formulas of 3d1 ions in a trigonal octahedron. In the calculations, the crystal-field parameters are obtained by the superposition model, and the impurity-induced local lattice relaxation (which is similar to that found for Fe3+ in beryl) is considered. The calculated EPR parameters (and also the optical spectra) are in reasonable agreement with the experimental values

scholarly journals Defect Model of a Tetragonal Sm3+ Center Found from EPR Measurements in CaF2 and SrF2 Crystals

2003 ◽  
Vol 58 (5-6) ◽  
pp. 373-375
Author(s):  
Wen-Chen Zheng ◽  
Hui-Ning Dong ◽  
Shao-Yi Wu ◽  
Sheng Tang
Keyword(s):  
Hyperfine Structure ◽  
Crystal Field ◽  
Selective Excitation ◽  
Defect Model ◽  
Free Ion ◽  
Epr Parameters ◽  
Structure Constants ◽  
Epr Measurements ◽  
Crystal Field Parameters ◽  
G Factors

The EPR parameters (g factors g∥, g⊥ and hyperfine structure constants A∥, A⊥) of a tetragonal(C4v) Sm3+ center in CaF2 and SrF2 crystals are calculated by considering the crystal-field Jmixingamong the ground 6H5/2, the first excited 6H7/2 and second excited 6H9/2 state multiplets.In the calculations the free-ion and crystal-field parameters of the tetragonal Sm3+-F− centerobtained from polarized laser-selective excitation spectroscopy are used. The calculated resultssuggest that the tetragonal Sm3+-F− center is the Sm3+ center found by later EPR measurements.The g factors g∥, g⊥ and hyperfine structure constants A∥, A⊥ of this EPR center are satisfactorilyexplained.

Investigation of the Spin Hamiltonian Parameters of Yb3+ in CaWO4 Crystal

2004 ◽  
Vol 59 (12) ◽  
pp. 943-946 ◽  
Author(s):  
Hui-Ning Dong ◽  
Shao-Yi Wu
Keyword(s):  
Hyperfine Structure ◽  
Local Structure ◽  
Reasonable Agreement ◽  
Second Order ◽  
Order Perturbation ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

In this paper, the spin Hamiltonian parameters g factors g∥ and g⊥ of Yb3+ and hyperfine structure constants A∥ and A⊥ of 171Yb3+ and 173Yb3+ in CaWO4 crystal are calculated from the two-order perturbation formulae. In these formulae, the contributions of the covalence effects, the admixture between J =7/2 and J =5/2 states as well as the second-order perturbation are included. The needed crystal parameters are obtained from the superposition model and the local structure of the studied system. The calculated results are in reasonable agreement with the observed values. The results are discussed.

CALCULATION OF EPR PARAMETERSgFACTORS FORCe3+ION INYBa2Cu3O6+xSUPERCONDUCTOR

2005 ◽  
Vol 19 (01n03) ◽  
pp. 143-146 ◽  
Author(s):  
HUI-NING DONG ◽  
HUI-PING DU ◽  
CHANG-KUI DUAN ◽  
XIAO-BING LUO
Keyword(s):  
Angular Momentum ◽  
Crystal Field ◽  
Orbital Angular Momentum ◽  
Second Order ◽  
Order Perturbation ◽  
Orthorhombic Symmetry ◽  
Superposition Model ◽  
Epr Parameters ◽  
Kramers Doublet ◽  
G Factors

The perturbation formulae of EPR parameters g factors gx, gyand gzfor the lowest Kramers doublet of 4f1ion in orthorhombic symmetry are established. In these formulae, the contributions of the covalency effects, the admixture between J=7/2 and J=5/2 states as well as the second-order perturbation (which is not considered in the previous works) via crystal-field and orbital angular momentum interactions are all included. According to these formulae, and by using the superposition model, the g-factors gx, gyand gzfor Ce3+center in YBa2Cu3O6+ xsuperconductor are calculated. The results are discussed.

INVESTIGATIONS OF THE EPR PARAMETERS FORDy3+CENTER INZrSiO4CRYSTAL

2010 ◽  
Vol 24 (03) ◽  
pp. 289-296 ◽  
Author(s):  
HUI-NING DONG ◽  
DENG-FENG LI ◽  
JUN LIU ◽  
DAVID J. KEEBLE
Keyword(s):  
Crystal Field ◽  
Tetragonal Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Hamiltonian ◽  
Field Interaction ◽  
Paramagnetic Resonance ◽  
Epr Parameters ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

The electronic paramagnetic resonance g factors g‖, g⊥of Dy3+centers and the hyperfine structure constants A‖and A⊥of161Dy3+and163Dy3+isotopes in ZrSiO4crystal are theoretically studied from the perturbation formulas of the spin Hamiltonian parameters for a 4f9ion in tetragonal symmetry. In these formulas, the contributions to g factors due to the J-mixing among the ground6H15/2, the first excited6H13/2and second excited6H11/2states via crystal-field interaction, the admixtures among the states with the same J value via spin-orbit coupling interaction and the interactions between the lowest Kramers doublet Γγ and other 20 Kramers doublets ΓXwithin the states6HJ(J=15/2, 13/2 and 11/2) via crystal-field and orbital angular momentum interactions are considered. The calculated EPR parameters show reasonable agreement with the observed values. The results are discussed.

scholarly journals Investigation Of The Epr Parameters Of An Orthorhombic Cu2+ Center In Cs2zncl4 Crystal

2005 ◽  
Vol 60 (5) ◽  
pp. 373-375 ◽  
Author(s):  
Hui-Ning Dong ◽  
Shao-Yi Wu ◽  
Xian-Rong Liu ◽  
Wei-Dong Chen
Keyword(s):  
Crystal Structure ◽  
Electron Paramagnetic Resonance ◽  
Hyperfine Structure ◽  
Hamiltonian Matrix ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Epr Parameters ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic

The electron paramagnetic resonance (EPR) anisotropic g-factors gx, gy and gz and hyperfine structure constants Ax, Ay and Az of Cu2+ in Cs2ZnCl4 crystal are theoretically investigated by the method of diagonalizing the full Hamiltonian matrix. The crystal-field parameters are obtained from the crystal structure by the superposition model. The results, agreeing reasonably with the observed values, are discussed.

Explanation of the g-factors and Hyperfine Structure Constants of Co2+ in Tetragonal K2ZnF4

2000 ◽  
Vol 55 (5) ◽  
pp. 539-544 ◽  
Author(s):  
Wen-Chen Zheng ◽  
Shao-Yi Wu
Keyword(s):  
Hyperfine Structure ◽  
Configuration Interaction ◽  
Structural Parameters ◽  
Cluster Approach ◽  
Epr Parameters ◽  
Structure Constants ◽  
The Relationship ◽  
Good Agreement ◽  
G Factors

Abstract The formulas of the g-factors gII , g┴ and the hyperfine structure constants AII.A┴ for 3d7 ions in tetragonal octahedral crystals are established from a cluster approach. Differing from previous formulas, in these formulas the role of configuration interaction (CI)-and covalency (CO)-effects is considered, and the parameters related to both effects are obtained from the optical spectra and the structural parameters of the studied crystal. From these formulas, the EPR parameters gi and Ai for K2 ZnF4 :Co2+ are calculated. The results show good agreement with the observed values. The contributions to the EPR parameters gi and Ai, from the CI and CO effects, and the relationship between the sign of Δg(=g┴ - gII) and the tetragonal distortion (elongated or compressed) of the ligand octahedron are discussed

scholarly journals Investigation of the EPR Parameters of a Trigonal Dy3+ Center in La2Mg3(NO3)12 · 24H2O Crystal

2007 ◽  
Vol 62 (5-6) ◽  
pp. 343-346 ◽  
Author(s):  
Hui-Ning Dong ◽  
Shao-Yi Wu ◽  
David J. Keeble
Keyword(s):  
Hyperfine Structure ◽  
Crystal Field ◽  
Irreducible Representations ◽  
Spin Orbit Coupling ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Epr Parameters ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
Good Agreement

The electron paramagnetic resonance parameters g‖ and g⊥ of Dy3+, and the hyperfine structure parameters A‖ and A⊥ of 161Dy3+ and 163Dy3+ in a La2Mg3(NO3)12 · 24H2O crystal are calculated by the perturbation formulas of the EPR parameters for a 4f9 ion in trigonal symmetry. In these formulas, the J-mixing among the 6HJ (J = 15/2, 13/2 and 11/2) states via crystal-field interactions, the mixtures of the states with the same J-value via spin-orbit coupling interaction and the interactions between the lowest Kramers doublet Γγ and the same irreducible representations in the other 20 Kramers doublets ΓX via the crystal-field and orbital angular momentum (or hyperfine structure) are all considered. The crystal-field parameters for the studied Dy3+ center are obtained with the superposition model. The calculated results are in good agreement with the observed values.

Investigations of the spin Hamiltonian parameters for the cubic Mn2+ centers in ZnX (X = S, Se, Te) and CdTe

2010 ◽  
Vol 88 (5) ◽  
pp. 301-306 ◽  
Author(s):  
Xue-Feng Wang ◽  
Shao-Yi Wu ◽  
Li-Li Li ◽  
Shan-Xiang Zhang
Keyword(s):  
Charge Transfer ◽  
Hyperfine Structure ◽  
Crystal Field ◽  
Pure Spin ◽  
Spin Orbit Coupling ◽  
Spin Hamiltonian ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
Good Agreement ◽  
G Factors

The spin Hamiltonian parameters (g factors and the hyperfine structure constants) for the cubic Mn2+ centers in ZnX (X = S, Se, Te) and CdTe are investigated theoretically using the perturbation formulas of these parameters for a tetrahedral 3d5 cluster containing both the crystal-field and charge-transfer contributions. The relevant molecular orbital coefficients are uniformly determined from the cluster approach, and the calculated spin Hamiltonian parameters are in good agreement with the observed values. The g-shifts of the g factors related to the pure spin value gs (≈ 2.0023) arising from the charge transfer contributions are opposite (positive) in sign and much larger in magnitude than those from the crystal field contributions. On the other hand, the contributions from the charge-transfer mechanism to the hyperfine structure constants are the same in sign and about 20%–30% in magnitude of those from the crystal-field mechanism. The importance of the charge transfer contributions increases significantly with the increase of the covalency and the spin–orbit coupling coefficient of the ligand, i.e., S2− < Se2− < Te2−.

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