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.

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 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.

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 Theoretical studies on the electron paramagnetic resonance parameters for the tetragonal VO2+ center in CaO-Al2O3-SiO2 system

2018 ◽  
Vol 64 (1) ◽  
pp. 13 ◽  
Author(s):  
J.Z. Lin ◽  
B.F. Zhang
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Tetragonal Symmetry ◽  
Theoretical Studies ◽  
Paramagnetic Resonance ◽  
Resonance Parameters ◽  
Sio2 System ◽  
Epr Parameters ◽  
Experimental Values ◽  
Electron Paramagnetic

In this work, thehighorderperturbationformulaeoftheelectronparamagneticresonance (EPR) parameters, g \& A for a VO$^{2+}$3d$^1$ ion in tetragonal symmetry (compressedoctahedron) are adopted to theoreticallystudytheseparametersofthe tetragonal VO$^{2+}$ center in CaO-Al$_2$O$_3$-SiO$_2$ system. Becausethespin-orbit (SO) couplingparameter$\zeta_p$ ($\approx$151 cm$^{-1}$) ofligand O$^{2-}$ is close to that ($\approx$248 cm$^{-1}$) ofthe central V$^{4+}$ ion in thecluster [VO$_6$]$^{8-}$withstrongcovalence, theeffectofthe SO couplingparameter$\zeta_p$onEPRparameters are consideredonthebasisofclusterapproach. TheobtainedEPRparameters show goodagreementwiththe experimental values and needfeweradjustableparametersthanpreviousstudies. Andthe local structureofthe tetragonal VO$^{2+}$ center in CaO-Al$_2$O$_3$-SiO$_2$ system due to Jahn-Tellereffect is obtained from theanalysisoftheEPRparameters. Theresults 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.

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.

Studies of local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) crystals

2021 ◽  
Vol 76 (4) ◽  
pp. 299-304
Author(s):  
Fu Chen ◽  
Jian-Rong Yang ◽  
Zi-Fa Zhou
Keyword(s):  
Crystal Field ◽  
Elongation Ratio ◽  
Paramagnetic Resonance ◽  
Local Structures ◽  
Epr Parameters ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
Theoretical Results ◽  
Good Agreement

Abstract The electron paramagnetic resonance (EPR) parameters (g factor g i , and hyperfine structure constants A i , with i = x, y, z) and local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) are theoretically investigated using the high order perturbation formulas of these EPR parameters for a 3d 9 ion under orthorhombically elongated octahedra. In the calculations, contribution to these EPR parameters due to the admixture of d-orbitals in the ground state wave function of the Cu2+ ion are taken into account based on the cluster approach, and the required crystal-field parameters are estimated from the superposition model which enables correlation of the crystal-field parameters and hence the studied EPR parameters with the local structures of the Cu2+ centers. Based on the calculations, the Cu–H2O bonds are found to suffer the axial elongation ratio δ of about 3 and 2.9% along the z-axis, meanwhile, the planar bond lengths may experience variation ratio τ (≈3.8 and 1%) along x- and y-axis for Cu2+ center in (NH4)2Zn(SO4)2·6H2O and Rb2Zn(SO4)2·6H2O, respectively. The theoretical results show good agreement with the observed values.

INVESTIGATIONS OF ELECTRON-PARAMAGNETIC-RESONANCE PARAMETERS OF OCTAHEDRAL (CrO6)9- and (MnO6)8- CLUSTER IN MgTiO3:Cr3+, SrTiO3:Cr3+ AND SrTiO3:Mn4+ CRYSTALS

2011 ◽  
Vol 25 (21) ◽  
pp. 1779-1785
Author(s):  
MINJIE WANG ◽  
LIANXUAN ZHU ◽  
JIANLIANG DANG
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Crystal Field ◽  
Valence State ◽  
Spin Orbit ◽  
Contribution Rate ◽  
Paramagnetic Resonance ◽  
Epr Parameters ◽  
Experimental Values ◽  
Electron Paramagnetic ◽  
G Factors

The complete high-order perturbation formulas are established by both crystal-field (CF) and charge-transfer (CT) mechanisms. The EPR g factors of MgTiO 3: Cr 3+, SrTiO 3: Cr 3+ and SrTiO 3: Mn 4+ crystals are calculated from the formulas. The calculations of the EPR g factors are in agreement with the experimental values. The contribution rate of the CT mechanism (|ΔgT/ΔgF|) to EPR parameters, increases with the growth of the valence state for the 3dn ions in the crystals. For the higher valence state 3d3 ion Mn 4+ in crystals, the explanation of the EPR parameters reasonably involves both CF and CT mechanisms. The g values are also given from one-spin-orbit-parameter model and crystal-field (CF) mechanism for comparison.

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.

scholarly journals Defect Structures for Fe3+, Mn2+, and Ni3+ Impurities in Wuritzite GaN Crystals

2001 ◽  
Vol 56 (6-7) ◽  
pp. 473-477 ◽  
Author(s):  
Wen-Chen Zheng ◽  
Shao-Yi Wu ◽  
Jian Zi
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Strong Field ◽  
Zero Field ◽  
Spin Orbit ◽  
Defect Structures ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Impurity Ions ◽  
Epr Parameters ◽  
Electron Paramagnetic

Abstract Electron paramagnetic resonance (EPR) zero-field splittings D for Mn2+ and Fe3+ in wurtzite GaN crystals are studied from high-order perturbation formulas based on the spin-orbit mechanism in both weak- and strong-field schemes. From these studies it can be seen that the Mn2+ or Fe3+ impurity does not occupy the exact Ga3+ position, but is displaced by ΔR on the C3 axis. The displacements are confirmed from a study of the superposition model, based on which a normal value of b̅2 (Ro) ( ≈ -0 .34 (15) cm-1 ) for the Fe3+-N3- combination is suggested. The EPR parameters D, g|| and g ⟂ for Ni3+ in GaN crystals are also studied. It is found that Ni3+ is almost not displaced. The impurity displacements in GaN are discussed by considering the valences and radii of these impurity ions and the replaced Ga3+ ion. - Pacs: 61.16Hn; 76.30Fc; 71.70Ch

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