Studies on the EPR Parameters for the Rhombic Co2+ Center in Magnesium Acetate

2005 ◽  
Vol 60 (7) ◽  
pp. 545-548 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Impurity Center ◽  
Interaction Constant ◽  
Nuclear Quadrupole Interaction ◽  
Magnesium Acetate ◽  
Paramagnetic Resonance ◽  
Crystal Fields ◽  
Rhombic Symmetry ◽  
Epr Parameters ◽  
Crystal Field Parameters ◽  
Relationship Of

The electron paramagnetic resonance (EPR) g factors gi (i = x,y, z) and the hyperfine structure constants Ai for the rhombic Co2+ center in magnesium acetate are theoretically studied from the perturbation formulas of these parameters for a 3d7 ion under rhombic symmetry. In these formulas, the contributions from the admixture among different states, covalency effect and rhombic crystal-fields are taken into account. The related crystal-field parameters are determined from the superposition model and the local geometrical relationship of the impurity center. The calculated results show reasonable agreement with the observed values. In addition, the nuclear quadrupole interaction constant Q is analyzed, and its negative sign is verified theoretically.

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.

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 Investigations on the local structure and the EPR parameters for the tetragonal Cu2+center in ZnSeF6·6H2O crystal

2016 ◽  
Vol 94 (5) ◽  
pp. 507-510 ◽  
Author(s):  
Chao-Ying Li
Keyword(s):  
Crystal Field ◽  
Local Structure ◽  
Relative Elongation ◽  
Paramagnetic Resonance ◽  
Ligand Orbital ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Epr Parameters ◽  
Structure Constants ◽  
Crystal Field Parameters

The electron paramagnetic resonance (EPR) parameters (g factors g∥, g⊥and hyperfine structure constants A∥, A⊥) and the local structure of the tetragonal Cu2+center in trigonal ZnSeF6·6H2O crystal are theoretically investigated from the perturbation formulas of these parameters for a 3d9ion in tetragonally elongated octahedra. In the calculated formulas, the contributions to the EPR parameters from ligand orbital and spin–orbit coupling are included on the basis of the cluster approach in view of moderate covalency of the studied systems, the required crystal-field parameters are estimated from the superposition model, which enables correlation of the crystal-field parameters and hence the EPR parameters with the tetragonal distortion of the studied [Cu(H2O)6]2+cluster. According to the calculations, the ligand octahedra around Cu2+are suggested to suffer relative elongation τ (≈ 0.085 Å) along the [001] (or C4) axis for the tetragonal Cu2+centers in ZnSeF6·6H2O crystal, due to the Jahn–Teller effect. The results are 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.

scholarly journals Theoretical studies of the EPR parameters and local structure for the trigonal Yb3+ center in YAl3(BO3)4 crystal

2018 ◽  
Vol 65 (1) ◽  
pp. 1
Author(s):  
Hui-Ning Dong ◽  
Rong Zhang
Keyword(s):  
Chemical Properties ◽  
Defect Structures ◽  
Paramagnetic Resonance ◽  
Yttrium Aluminium ◽  
Epr Parameters ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Physical And Chemical ◽  
Electron Paramagnetic ◽  
And Chemical Properties

Yttrium aluminium borate crystals have excellent physical and chemical properties. In this paper, the electron paramagnetic resonance (EPR) g factors g//, g^ of Yb3+ and hyperfine structure constants A//, A^ of 171Yb3+ and 173Yb3+ isotopes in YAl3(BO3)4 crystal are calculated from the perturbation formulas. The crystal field parameters are obtained from the superposition model and the crystal structure data. The EPR parameters for trigonal Yb3+ centers in YAl3(BO3)4 are reasonably explained by considering the defect structures of doped Yb3+ centers. In the calculation, we also find that Yb3+ ion does not exactly reside in Y3+ site, but suffers an angle distortion  Dq (≈ 3.98 Å) with C3 axis. 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.

THEORETICAL INVESTIGATIONS OF THE EPR PARAMETERS OF CUBICYb3+CENTER INPbS,PbSeANDPbTeSEMICONDUCTORS

2013 ◽  
Vol 27 (15) ◽  
pp. 1362032
Author(s):  
GUO-YA XIE ◽  
XIAN-RONG LIU
Keyword(s):  
Crystal Field ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Crystal Field Theory ◽  
Paramagnetic Resonance ◽  
Theoretical Investigations ◽  
Epr Parameters ◽  
Structure Constants ◽  
Diluted Magnetic ◽  
Crystal Field Parameters

The important diluted magnetic semiconductors PbS , PbSe and PbTe have been studied by the electron paramagnetic resonance (EPR) technique. But there are not reasonable explanation reported. In this work, based on the crystal-field theory, the EPR parameters g factors of Yb3+and hyperfine structure constants of171Yb3+and173Yb3+isotopes in PbS , PbSe and PbTe crystals are calculated by the aid of diagonalizing the full energy matrix. In the calculations, the contributions of various admixtures and interactions such as the J-mixing and the covalence are considered. The crystal field parameters used in the calculations are obtained from the superposition model. The calculated results are in reasonable agreement with the observed values. The results 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 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.

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