Theoretical Investigations of the Spin Hamiltonian Parameters and Defect Structure for Pt3+ in MgO

2009 ◽  
Vol 293 ◽  
pp. 71-76
Author(s):  
Yue Xia Hu ◽  
Shao Yi Wu ◽  
Xue Feng Wang ◽  
Li Li Li
Keyword(s):  
Defect Structure ◽  
Relative Elongation ◽  
Impurity Center ◽  
Spin Hamiltonian ◽  
Theoretical Investigations ◽  
Ligand Orbital ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Structure Constants ◽  
Hamiltonian Parameters

The spin Hamiltonian parameters (anisotropic g-factors and the hyperfine structure constants) and defect structure for Pt3+ in MgO are theoretically investigated by using the perturbation formulas of these parameters for a 5d7 ion in a tetragonally elongated octahedron. This impurity center is attributed to substitutional Pt3+ on host Mg2+ sites, and the [PtO6]9 cluster suffers a relative elongation of 0.08Å along the C4 axis due to the Jahn-Teller effect. In the calculations, the contributions arising from the ligand orbital and spin-orbit coupling interactions and the Jahn-Teller elongation are taken into account using the cluster approach. The calculated spin Hamiltonian parameters based upon the above defect structure show good agreement with the observed values.

Theoretical investigations on the spin Hamiltonian parameters and the local structure for Rh2+ in rutile

2010 ◽  
Vol 88 (1) ◽  
pp. 49-53 ◽  
Author(s):  
S. X. Zhang ◽  
S. Y. Wu ◽  
P. Xu ◽  
L. L. Li
Keyword(s):  
Local Structure ◽  
Impurity Center ◽  
Angular Distortion ◽  
Spin Hamiltonian ◽  
Theoretical Investigations ◽  
Rhombic Distortion ◽  
Ligand Orbital ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Hamiltonian Parameters

The spin Hamiltonian parameters, the g factors gi (i = x, y, z) and the hyperfine structure constants Ai, and the local structure for Rh2+ in rutile (TiO2) are theoretically investigated from the perturbation formulas of these parameters for a 4d7 ion under rhombically elongated octahedra. In view of the covalency, the ligand orbital and spin-orbit coupling contributions are taken into account from the cluster approach. The planar bond angle in the impurity center is found to be 7.5° larger than that of the host Ti4+ site because of the Jahn–Teller effect via bending of the planar Rh2+-O2– bonds, leading to much smaller rhombic distortion. The theoretical spin Hamiltonian parameters based on the above Jahn–Teller angular distortion show reasonable agreement with the experimental data.

Investigations on the Spin Hamiltonian Parameters and the Local Structures for Various Rh2+ Centers in NaCl

2010 ◽  
Vol 65 (6-7) ◽  
pp. 591-598 ◽  
Author(s):  
Hua-Ming Zhang ◽  
Shao-Yi Wu ◽  
Pei Xu ◽  
Li-Li Li
Keyword(s):  
Relative Elongation ◽  
Spin Hamiltonian ◽  
Local Structures ◽  
Tetragonal Center ◽  
Unpaired Spin ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
Spin Densities

The spin Hamiltonian parameters (the g factors, the hyperfine structure constants, and the superhyperfine parameters) and the local structures for various Rh2+ centers OI, OII, and RTAX in NaCl are theoretically investigated from the perturbation formulas of these parameters for a 4d7 ion in tetragonally and orthorhombically elongated octahedra. The related molecular orbital coefficients and the ligand unpaired spin densities are determined quantitatively from the cluster approach in a uniform way. The centers OI, OII (orthorhombic) or RTAX (tetragonal) are attributed to the substitutional Rh2+ on Na+ site, associated with two, one or none next nearest neighbour cation vacancies VNa along [100] (or [010]) axis, respectively. The ligand octahedra in the orthorhombic centers OI and OII are found to suffer the relative elongations ΔZ ≈0.071 and 0.068 °A along the [001] axis due to the Jahn-Teller effect, and the intervening ligand(s) in the VNa and the Rh2+ may undergo the inward displacements ΔX ≈ 0.001 and 0.011 A° towards Rh2+, respectively. As for the tetragonal center RTAX, the uncompensated [RhCl6]4− cluster is found to experience the relative elongation ΔZ ≈ 0.067 °A along the [001] axis of the Jahn-Teller nature. The calculated spin Hamiltonian parameters based on the above local structures show good agreement with the observed values for all the centers.

INVESTIGATIONS OF THE SPIN HAMILTONIAN PARAMETERS AND THE LOCAL STRUCTURE FOR THE RHOMBICCu2+CENTER IN RUTILE

2010 ◽  
Vol 24 (22) ◽  
pp. 2357-2364 ◽  
Author(s):  
HUA-MING ZHANG ◽  
SHAO-YI WU ◽  
PEI XU ◽  
LI-LI LI
Keyword(s):  
Local Structure ◽  
Impurity Center ◽  
Angular Distortion ◽  
Spin Hamiltonian ◽  
Rhombic Distortion ◽  
Calculation Results ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Structure Constants ◽  
Hamiltonian Parameters

The spin Hamiltonian parameters (the anisotropic g factors and the hyperfine structure constants) and the local structure for the rhombic Cu2+center in rutile ( TiO2) are theoretically investigated using the formulas of these parameters for a 3d9ion in rhombically elongated octahedra. From the studies, the planar impurity-ligand bond angle is found to be about 5.8° larger than that for the host Ti4+site due to the Jahn–Teller effect via bending the planar Cu2+– O2-bonds, which yields much smaller rhombic distortion in the impurity center. The theoretical spin Hamiltonian parameters based on the above local angular distortion show good agreement with the experimental data, and the improvement of the calculation results are also achieved as compared with those of the previous works.

Theoretical Investigations of the Defect Structure for Ni3+ in ZnO

2011 ◽  
Vol 318 ◽  
pp. 41-45
Author(s):  
Zhi Hong Zhang ◽  
Shao Yi Wu ◽  
Shan Xiang Zhang
Keyword(s):  
Defect Structure ◽  
Impurity Center ◽  
Spin Hamiltonian ◽  
Theoretical Investigations ◽  
Ligand Orbital ◽  
High Valence State ◽  
Zno Crystal ◽  
Hamiltonian Parameters ◽  
Good Agreement ◽  
The Ideal

The defect structure for Ni3+ in ZnO crystal is theoretically investigated using the perturbation formulas of the spin Hamiltonian parameters for a 3d7 ion in trigonally distorted tetrahedra. In view of the significant covalency of the system due to the high valence state of Ni3+, the ligand orbital and spin-orbit coupling contributions are taken into account in a uniform way based on the cluster approach. The impurity Ni3+ is found not to occupy the ideal Zn2+ site in ZnO but to undergo the small axial displacement of about 0.044 Ǻ away from the oxygen triangle along the C3 axis. The theoretical spin Hamiltonian parameters based on the above impurity displacement show good agreement with the experimental data. The defect structure of this impurity center is compared with that for the similar Fe3+ in ZnO.

Investigations of the defect structure for Cu2+ in LaSrGa0.995Cu0.005O4 Ceramics

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542015 ◽  
Author(s):  
C. C. Ding ◽  
S. Y. Wu ◽  
Y. K. Cheng ◽  
L. J. Zhang
Keyword(s):  
Hyperfine Structure ◽  
Defect Structure ◽  
Teller Effect ◽  
Spin Hamiltonian ◽  
Elongation Ratio ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
The Relationship

The defect structure and spin Hamiltonian parameters ([Formula: see text] factors [Formula: see text], [Formula: see text] and the hyperfine structure constants [Formula: see text] and [Formula: see text]) for the tetragonal [Formula: see text] in [Formula: see text] ceramics are theoretically studied from the perturbation formulas of these parameters for a [Formula: see text] ion in a tetragonally elongated octahedron. The impurity [Formula: see text] center exhibits the larger relative tetragonal elongation ratio [Formula: see text] than that [Formula: see text] of the host [Formula: see text] site due to the Jahn–Teller effect. The relationship between the [Formula: see text] anisotropy [Formula: see text] [Formula: see text] and the local tetragonal distortion is analyzed. The present studies would be helpful to the understandings of delocalization of the [Formula: see text] [Formula: see text] orbitals under tetragonal elongation distortion and its role in superconductivity of oxygen cuprates.

A Study of Spin-Hamiltonian Parameters and Defect Structure for Co2+ Ion in the Tetragonal Zn2+ Site of Ba2ZnF6 Crystal

2010 ◽  
Vol 65 (10) ◽  
pp. 877-881
Author(s):  
Bang-Xing Lia ◽  
Wen-Chen Zheng ◽  
Wei-Qing Yang
Keyword(s):  
Defect Structure ◽  
Reduction Factor ◽  
Teller Effect ◽  
Tetragonal Symmetry ◽  
Spin Hamiltonian ◽  
Effective Spin ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Experimental Values ◽  
Hamiltonian Parameters

The spin-Hamiltonian (SH) parameters (g factors g∥ , g⊥ and hyperfine structure constants A∥, A⊥) for the Co2+ ion in the tetragonal Zn2+ site of a Ba2ZnF6 crystal are calculated from the secondorder perturbation formulas based on the cluster approach for the SH parameters of 3d7 ions in tetragonal symmetry with the effective spin S = 1/2. In the calculations, a reduction factor due to the dynamical Jahn-Teller effect is used. The calculated results are in reasonable agreement with the experimental values, suggesting that the dynamical Jahn-Teller effect should be considered here. The defect structure of the Co2+ center in Ba2ZnF6:Co2+ is also obtained from the calculations. 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 Investigations for the Defect Structure and the Spin Hamiltonian Parameters of Divalent Cobalt in LiMgPO4

2021 ◽  
Vol 1032 ◽  
pp. 108-113
Author(s):  
Xu Sheng Liu ◽  
Shao Yi Wu ◽  
Yi Mei Fan ◽  
Xing Yuan Yu
Keyword(s):  
Defect Structure ◽  
Spin Hamiltonian ◽  
Size Mismatch ◽  
Local Structures ◽  
Distorted Octahedral ◽  
Theoretical Investigations ◽  
Divalent Cobalt ◽  
Structure Constants ◽  
Relative Compression ◽  
Hamiltonian Parameters

The spin Hamiltonian parameters (SHPs, g factors and hyperfine structure constants) defect structure for LiMgPO4 doped with 0.1% Co2+ at 4.2 K are theoretically investigated from the perturbation formulas of the SHPs for a rhombically distorted octahedral 3d7 cluster. The impurity Co2+ on host Mg2+ site is found to suffer the larger axial relative compression ratio ρ (≈ 0.76%) and the planar angular variation Δφ (≈ 6.64°) related to the host oxygen octahedron due to size mismatch. The calculated SHPs based on the above defect structure show good agreement with the measured results. Present study can be helpful to the preparation and characterization for the local structures for transition-metal impurities in lithium-magnesium phosphate, which may is helpful to search for the phosphor materials with better dosimetric characteristics.

THEORETICAL STUDIES OF THE SPIN HAMILTONIAN PARAMETERS AND LOCAL STRUCTURE FOR THE TETRAGONAL Rh2+ CENTER IN RHOMBOHEDRAL BaTiO3

2009 ◽  
Vol 23 (17) ◽  
pp. 2115-2122 ◽  
Author(s):  
HUA-MING ZHANG ◽  
SHAO-YI WU ◽  
XUE-FENG WANG ◽  
YUE-XIA HU
Keyword(s):  
Local Structure ◽  
Relative Elongation ◽  
Experimental Results ◽  
Teller Effect ◽  
Theoretical Studies ◽  
Spin Hamiltonian ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Hamiltonian Parameters ◽  
Good Agreement

The spin Hamiltonian parameters and local structure for the tetragonal Rh 2+ center in rhombohedral BaTiO 3 are theoretically studied from the perturbation formulas of these parameters for a 4d 7 ion with low spin (S=1/2) in tetragonally elongated octahedra. This center is ascribed to substitutional Rh 2+ at the Ti 4+ site in BaTiO 3. The [ RhO 6]10- cluster suffers relative elongation (characterized by the elongation parameter ρ ≈ 0.9%) along the [100] axis due to the Jahn–Teller effect. The tetragonal elongation can entirely depress the slight trigonal distortion of the original Ti 4+ site in rhombohedral BaTiO 3. The calculated spin Hamiltonian parameters based on the above Jahn–Teller elongation show good agreement with the experimental results.

Theoretical studies of the local structures and spin Hamiltonian parameters for Cu2+ in alkaline earth alumino borate glasses

2018 ◽  
Vol 32 (02) ◽  
pp. 1750331
Author(s):  
Jia-Xing Guo ◽  
Shao-Yi Wu ◽  
Min-Quan Kuang ◽  
Li Peng ◽  
Li-Na Wu
Keyword(s):  
Alkaline Earth ◽  
Relative Elongation ◽  
Reduction Factor ◽  
Spin Hamiltonian ◽  
Elongation Ratio ◽  
Local Structures ◽  
Cubic Field ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Hamiltonian Parameters

The local structures and spin Hamiltonian parameters are theoretically studied for Cu[Formula: see text] in alkaline earth alumino borate (XAB, X = Mg, Ca and Sr) glasses by using the perturbation calculations for tetragonally elongated octahedral 3d9 groups. The [Formula: see text] groups are subject to the large relative tetragonal elongation ratios of 15.4%, 13.4% and 13.0% for MgAB, CaAB and SrAB glasses, respectively, arising from the Jahn–Teller effect. The decreasing cubic field parameter Dq, orbital reduction factor k and relative elongation ratio with the increase of the radius of alkaline earth ion X from Mg to Ca or Sr are analyzed for the studied systems in a uniform way.

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