Studies of the Spin Hamiltonian Parameters for Cubic V2+, Cr3+, and Mn4+ Centers In MgO and CaO, Based on Two Mechanism Models

2004 ◽  
Vol 59 (10) ◽  
pp. 689-693 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Charge Transfer ◽  
Hyperfine Structure ◽  
Crystal Field ◽  
Structure Constant ◽  
Order Perturbation ◽  
Spin Hamiltonian ◽  
Mechanism Model ◽  
Hyperfine Structure Constant ◽  
Hamiltonian Parameters ◽  
Theoretical Results

The high-order perturbation formulas of the spin Hamiltonian (SH) parameters g-shift Δg (=g−gs) and the hyperfine structure constant A for a 3d3 ion in cubic octahedra are established, based on the two mechanism model. In this model, not only the contributions from the conventional crystal-field (CF) mechanism, but also those from the charge-transfer (CT) mechanism are taken into account. These formulas are applied to the investigation of the SH parameters of cubic V2+, Cr3+ and Mn4+ centers in MgO and CaO. Based on these studies, the sign of Δg due to the CT mechanism is opposite to that due to the CF mechanism, while the signs of the A factor due to the CF and CT mechanisms are equal. The theoretical results, including the contributions from the CF and CT mechanisms, agree better with the observed values than those containing only the conventional CF mechanism.

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−.

Studies of the g Factors and the Hyperfine Structure Constants for the Octahedral Interstitial Mn2+ and Cr+ Impurities in Silicon

2013 ◽  
Vol 68 (5) ◽  
pp. 337-342 ◽  
Author(s):  
Bo-Tao Song ◽  
Shao-Yi Wu ◽  
Zhi-Hong Zhang ◽  
Li-Li Li
Keyword(s):  
Experimental Data ◽  
Charge Transfer ◽  
Hyperfine Structure ◽  
Crystal Field ◽  
Structure Constant ◽  
Cluster Approach ◽  
Hyperfine Structure Constant ◽  
Structure Constants ◽  
Good Agreement ◽  
G Factors

The g factors and the hyperfine structure constants for the octahedral interstitial Mn2+ and Cr+ impurities in silicon are theoretically studied using the perturbation formulas of these parameters for an octahedral 3d5 cluster. In the calculations, both the crystal-field and charge transfer contributions are taken into account in a uniform way, and the related molecular orbital coefficients are quantitatively determined from the cluster approach. The theoretical g factors and the hyperfine structure constants are in good agreement with the experimental data. The charge transfer contribution to the g-shift (≈g-gs, where gs ≈ 2:0023 is the spin only value) is opposite (positive) in sign and about 51% - 116% in magnitude as compared with the crystal-field one for Mn2+ and Cr+, respectively. Nevertheless, the charge transfer contribution to the hyperfine structure constant has the same sign and about 12% - 19% that of the crystal-field one. Importance of the charge transfer contribution shows the order Cr+ < Mn2+ due to increase of the impurity valence state in the same host, especially for the g factor.

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.

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 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.

STUDIES OF THE SPIN-HAMILTONIAN PARAMETERS AND DEFECT STRUCTURES FOR Cu2+ IONS IN AgCl and NaCl CRYSTALS FROM A TWO-MECHANISM MODEL

2010 ◽  
Vol 24 (18) ◽  
pp. 3619-3625 ◽  
Author(s):  
YANG MEI ◽  
WEN-CHEN ZHENG ◽  
LV HE
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Relative Importance ◽  
Defect Structures ◽  
Spin Hamiltonian ◽  
Mechanism Model ◽  
Octahedral Clusters ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
Metal Ligand

In this paper, based on a two-mechanism model, we derive the complete high-order perturbation formulas of the spin-Hamiltonian (SH) parameters (g factors g‖, g⊥ and hyperfine structure constants A‖, A⊥) for 3d9 ions in tetragonally elongated octahedral clusters. In the model, the contributions to SH parameters due to the crystal-field (CF) mechanism related to CF excited states and the charge-transfer (CT) mechanism related to CT exacted states (the CT mechanism is neglected in CF theory, which is widely used to study the SH parameters) are taken into account. From these formulas, the SH parameters of Cu 2+ ions in AgCl and NaCl crystals are calculated. It is found that for the exact explanation of SH parameters of ( CuCl 6)4- clusters in crystals, the contribution due to CT mechanism should be considered. The relative importance of CT mechanism (characterized by Q CT /Q CF , where Q = Δgi or [Formula: see text], i = ‖ or ⊥) increases with the decreasing metal-ligand distance in ( CuCl 6)4- clusters. The causes are discussed. The signs of Ai and the defect structures of Cu 2+ centers in AgCl and NaCl crystals are suggested from the calculations.

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.

STUDIES OF THE SPIN-HAMILTONIAN PARAMETERS AND OPTICAL SPECTRUM BAND POSITIONS FOR THE Yb3+ ION IN Tm3Al5O12 CRYSTALS

2009 ◽  
Vol 23 (20n21) ◽  
pp. 2457-2462 ◽  
Author(s):  
HONG-GANG LIU ◽  
WEN-CHEN ZHENG ◽  
WEN-LIN FENG ◽  
WEI-QING YANG
Keyword(s):  
Hyperfine Interaction ◽  
Hyperfine Structure ◽  
Matrix Method ◽  
Optical Spectrum ◽  
Spin Hamiltonian ◽  
Energy Matrix ◽  
Interaction Terms ◽  
Structure Constants ◽  
Spectrum Band ◽  
Hamiltonian Parameters

The spin-Hamiltonian parameters (g factors gi and hyperfine structure constants Ai, where i = x, y, z) and optical spectrum band positions of the Yb 3+ ion in the rhombically-distorted Tm 3+ site of Tm 3 Al 5 O 12 garnet crystal are calculated by a complete diagonalization (of the energy matrix) method, in which the Zeeman and hyperfine interaction terms are also included in the conventional Hamiltonian. From the calculations, the observed spin-Hamiltonian parameters of Tm 3 Al 5 O 12: Yb 3+ are explained reasonably and the optical spectrum band positions are suggested. The rationality of these suggested optical spectrum band positions is discussed by comparing them with the observed values of Yb 3+ ions in similar aluminum garnet ( Yb 3 Al 5 O 12, Y 3 Al 5 O 12 and Lu 3 Al 5 O 12) crystals.

Pressure Shifts in the Hyperfine Structure Constant of Potassium

1960 ◽  
Vol 119 (6) ◽  
pp. 1946-1947 ◽  
Author(s):  
Arnold L. Bloom ◽  
John B. Carr
Keyword(s):  
Hyperfine Structure ◽  
Structure Constant ◽  
Hyperfine Structure Constant
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