Theoretical Investigations of the Spin Hamiltonian Parameters and the Local Structure of a Trigonal Co2+ Center in Bi4Ge3O12

2004 ◽  
Vol 59 (9) ◽  
pp. 563-567
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dongb
Keyword(s):  
Hyperfine Structure ◽  
Local Structure ◽  
Reasonable Agreement ◽  
Spin Hamiltonian ◽  
Cluster Approach ◽  
Trigonal Symmetry ◽  
Theoretical Investigations ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

The spin Hamiltonian parameters anisotropic g factors g||, g⊥ and hyperfine structure constants A||and A⊥, as well as the local structure of the trigonal Co2+ center in Bi4Ge3O12 (BGO) are theoreticallyinvestigated by the perturbation formulas of the spin Hamiltonian parameters for a 3d7 ion intrigonal symmetry, based on the cluster approach. It is found that the impurity Co2+ substituting thehost Bi3+ undergoes an off-center displacement ΔZ(≈ −0.132 Å ) away from the center of the oxygenoctahedron along the C3 axis. The spin Hamiltonian parameters based on the above displacementshow reasonable agreement with the observed values. The results are discussed.

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.

STUDIES ON THE LOCAL STRUCTURE AND THE SPIN HAMILTONIAN PARAMETERS FOR THE TRIGONAL Mn2+ CENTER IN Bi4Ge3O12

2008 ◽  
Vol 22 (14) ◽  
pp. 1381-1387 ◽  
Author(s):  
XUE-FENG WANG ◽  
SHAO-YI WU ◽  
ZHI-HONG ZHANG ◽  
LI-HUA WEI ◽  
YUE-XIA HUA
Keyword(s):  
Hyperfine Structure ◽  
Local Structure ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Trigonal Symmetry ◽  
Oxygen Octahedron ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
Good Agreement

The local structure and the spin Hamiltonian parameters (the zero-field splitting D, the g factors g//, g⊥ and the hyperfine structure constants A// and A⊥) for the trigonal Mn 2+ center in Bi 4 Ge 3 O 12 are theoretically studied from the perturbation formulas of these parameters for a 3d5 ion in trigonal symmetry. The impurity Mn 2+ replacing host Bi 3+ is not found to occupy the exact Bi 3+ site but to suffer a large off-center displacement by about 0.36 Å towards the center of the oxygen octahedron along the C3-axis due to the size and charge mismatching substitution. The calculated spin Hamiltonian parameters based on the above displacement show good agreement with the observed values. The results and the mechanism of the impurity displacement are discussed.

INVESTIGATIONS ON THE SPIN HAMILTONIAN PARAMETERS FOR Nd3+ IN ThGeO4

2007 ◽  
Vol 21 (02) ◽  
pp. 191-197
Author(s):  
SHAO-YI WU ◽  
HUI-NING DONG
Keyword(s):  
Hyperfine Structure ◽  
Second Order ◽  
Experimental Results ◽  
Order Perturbation ◽  
Tetragonal Symmetry ◽  
Theoretical Studies ◽  
Spin Hamiltonian ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

The spin Hamiltonian parameters, g factors g‖ and g⊥, for Nd 3+ in ThGeO 4 are theoretically investigated from the perturbation formulas of the g factors for a 4f3 ion in tetragonal symmetry. In these formulas, the contributions to the g factors from the second-order perturbation terms and the admixture of various states are taken into account. It is found that the calculated g factors of this work are smaller than the experimental results, but close to those in the previous theoretical studies by Gutowska et al. Moreover, the calculated hyperfine structure constants A‖ and A⊥ as well as the energies of the 4I9/2 Stark levels in this work are also consistent with those in the previous investigations. The discrepancy between theoretical and experimental g factors is discussed.

THEORETICAL INVESTIGATIONS OF THE SPIN HAMILTONIAN PARAMETERS FOR THE TETRAGONALCu2+CENTERS INNH4X(X = Cl, Br, I)

2008 ◽  
Vol 22 (07) ◽  
pp. 843-850 ◽  
Author(s):  
SHAO-YI WU ◽  
XIU-YING GAO ◽  
JI-ZI LIN ◽  
QIANG FU ◽  
HUA-MING ZHANG
Keyword(s):  
Experimental Data ◽  
Reasonable Agreement ◽  
Tetragonal Symmetry ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Energy Matrix ◽  
Theoretical Investigations ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters

The spin Hamiltonian (SH) parameters g factors g‖, g⊥and the hyperfine structure constants A‖and A⊥for the tetragonal Cu2+centers (i.e., [ CuX4( H2O )2] clusters) in NH4X ( X = Cl, Br, I ) are theoretically investigated by means of the diagonalization procedure of complete (10×10) energy matrix (DPCEM) for a 3d9ion in tetragonal symmetry. The crystal-field parameters in the energy matrix are determined from the superposition model. The calculated SH parameters are in reasonable agreement with the experimental data.

Studies of the Axial Shift and the Spin Hamiltonian Parameters for Mn2+ in a CdS Crystal

2009 ◽  
Vol 294 ◽  
pp. 77-83
Author(s):  
Xue Feng Wang ◽  
Shao Yi Wu ◽  
Yue Xia Hu ◽  
Pei Xu
Keyword(s):  
Reasonable Agreement ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Spin Hamiltonian ◽  
Cluster Approach ◽  
Zero Field Splitting ◽  
Ligand Orbital ◽  
Axial Shift ◽  
Structure Constants ◽  
Hamiltonian Parameters

The axial shift and the spin Hamiltonian parameters (zero-field splitting D, the g factors and the hyperfine structure constants A// and A) for Mn2+ in a CdS crystal are studied theoretically in this work. The calculations are carried out by using the perturbation formulae of these parameters for a 3d5 ion under trigonally distorted tetrahedra based upon the cluster approach, where the ligand orbital and spin-orbit coupling contributions are taken into account in a uniform way. From the studies, the impurity Mn2+ is found not to occupy the host Cd2+ site exactly but to experience a small outward shift of 0.018 Å away from the ligand triangle along the C3 axis. The above impurity axial shift leads to a much smaller trigonal distortion than the host Cd2+ site in CdS. The calculated spin Hamiltonian parameters are in reasonable agreement with the experimental data.

Theoretical Studies of the Spin Hamiltonian Parameters for Fe0 and Mn– in Silicon Center

2013 ◽  
Vol 634-638 ◽  
pp. 2518-2522
Author(s):  
Min Quan Kuang ◽  
Shao Yi Wu ◽  
Bo Tao Song ◽  
Xian Fen Hu
Keyword(s):  
Experimental Data ◽  
Hyperfine Structure ◽  
Theoretical Studies ◽  
Spin Hamiltonian ◽  
Cluster Approach ◽  
Valence States ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
Theoretical Results ◽  
Good Agreement

The spin Hamiltonian parameters (g factors and the hyperfine structure constants) for the octahedral interstitial Fe0and Mn in silicon are theoretically investigated using the perturbation formulas of these parameters for a 3d8ion under octahedral environments based on the cluster approach. The theoretical results show good agreement with the experimental data, and the ligand contributions should be considered due to the strong covalency of the systems. The interstitial occupation of the above novel 3d8impurities of rare valence states in silicon is discussed.

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−.

Investigation of the Spin Hamiltonian Parameters of a Tetragonal VO2+ Center in (NH4)2SbCl5

2006 ◽  
Vol 61 (10-11) ◽  
pp. 583-587 ◽  
Author(s):  
Ji-Zi Lin ◽  
Shao-Yi Wu ◽  
Qiang Fu ◽  
Guang-Duo Lu
Keyword(s):  
Experimental Data ◽  
Hyperfine Structure ◽  
Coupling Coefficient ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Spin Hamiltonian ◽  
Cluster Approach ◽  
Crystal Fields ◽  
Structure Constants ◽  
Hamiltonian Parameters

The spin Hamiltonian parameters g‖ and g⊥ and the hyperfine structure constants A‖ and A⊥ of a tetragonal VO2+ center in (NH4)2SbCl5 are investigated, using the perturbation formulas for a 3d1 ion in tetragonally compressed octahedra. In these formulas, the contributions to the spin Hamiltonian parameters from the s- and p-orbitals as well as the spin-orbit coupling coefficient of the Cl− ligand are taken into account, based on the cluster approach. According to these studies, compression of the ligand octahedra results from the strong axial crystal-fields due to the short V4+-O2− bond in the [VOCl4]2− cluster. The obtained spin Hamiltonian parameters agree well with the experimental data and need fewer adjustable parameters than the previous studies. The covalency of the studied system is also discussed.

Investigations of the EPR Parameters and Local Structure for one Cu2+ Center in CdS

2008 ◽  
Vol 280-281 ◽  
pp. 15-20
Author(s):  
Li Hua Wei ◽  
Shao Yi Wu ◽  
Yue Xia Hu ◽  
Xue Feng Wang
Keyword(s):  
Experimental Data ◽  
Hyperfine Structure ◽  
Local Structure ◽  
Defect Structure ◽  
Reasonable Agreement ◽  
Cluster Approach ◽  
Epr Parameters ◽  
Structure Constants ◽  
Theoretical Results ◽  
The Ideal

The EPR g factors g// and g and the hyperfine structure constants for one substitutional Cu2+ center in CdS are theoretically investigated from the perturbation formulas of these parameters for a 3d9 ion under trigonally distorted tetrahedra. In view of the significant covalency of the [CuS4]6 cluster, the ligand contributions are taken into account on the basis of the cluster approach. According to the calculations, the impurity Cu2+ is found not to occupy exactly the ideal Cd2+ site but to suffer a small inward displacement 0.12 Å toward the ligand triangle along C3 axis. The theoretical results by considering the above impurity displacement show reasonable agreement with the experimental data. The defect structure of this Cu2+ center is also discussed.

Theoretical Study of the Spin Hamiltonian Parameters of Vanadium Ions V2+ in CsMgX3 (X = Cl, Br, I)

2005 ◽  
Vol 60 (3) ◽  
pp. 145-148 ◽  
Author(s):  
Xiu-Ying Gao ◽  
Shao-Yi Wu ◽  
Wang-He Wei ◽  
Wei-Zi Yan
Keyword(s):  
Hyperfine Structure ◽  
Theoretical Study ◽  
Spin Hamiltonian ◽  
Octahedral Symmetry ◽  
Cluster Approach ◽  
G Factor ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
Theoretical Results ◽  
Vanadium Ions

The spin Hamiltonian g factors and the hyperfine structure constants for V2+ in CsMgX3 (X = Cl, Br, I) are theoretically studied by using the perturbation formulas of these parameters for a 3d3 ion in octahedral symmetry, based on the cluster approach. In such formulas, the contributions from the s-orbitals of the ligands were usually neglected. Here they are taken into account. The theoretical results (particularly the g factor for CsMgI3) show a significant improvement compared with those in absence of the ligand s-orbital contributions in the previous studies.

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