Theoretical Studies of the g Factors for Co2+ in MgO and CaO Crystals

2001 ◽  
Vol 56 (3-4) ◽  
pp. 249-252 ◽  
Author(s):  
Shao-Yi Wu ◽  
Wen-Chen Zheng
Keyword(s):  
Configuration Interaction ◽  
Optical Spectra ◽  
Theoretical Studies ◽  
Cluster Approach ◽  
Experimental Values ◽  
Good Agreement ◽  
G Factors

Abstract This paper presents a cluster approach to the calculation of the g factors for 3d7 ions in cubic oc­ tahedral crystals, in which the parameters related to the configuration interaction and the covalency reduction effects are obtained from optical spectra of the studied crystals, and so no adjustable parameters are applied. From the approach, the g factors for MgO:Co2+ and CaO:Co2+ are cal­culated. The calculated results show good agreement with the observed values. The experimental values of g 4.333 for CaO:Co2+ are also explained.

Theoretical studies of the anisotropic g factors for deoxygenated Y123

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542017
Author(s):  
L. J. Zhang ◽  
S. Y. Wu ◽  
C. C. Ding ◽  
Y. K. Cheng
Keyword(s):  
Experimental Data ◽  
Orbit Coupling ◽  
Theoretical Studies ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Cluster Approach ◽  
Ligand Orbital ◽  
Y123 System ◽  
Good Agreement ◽  
G Factors

The anisotropic [Formula: see text] factors of the deoxygenated YBaCuO (Y123) are theoretically studied using the perturbation formulas of the [Formula: see text] factors for a tetragonally elongated octahedral [Formula: see text] cluster. The ligand orbital and spin-orbit coupling contributions are included from the cluster approach in view of covalency. The calculated [Formula: see text] factors show good agreement with the experimental data. The anisotropy of the [Formula: see text] factors is analyzed by considering the local tetragonal elongation distortion around this five-fold coordinated [Formula: see text] site in the deoxygenated Y123 system.

Explanation of the g-factors and Hyperfine Structure Constants of Co2+ in Tetragonal K2ZnF4

2000 ◽  
Vol 55 (5) ◽  
pp. 539-544 ◽  
Author(s):  
Wen-Chen Zheng ◽  
Shao-Yi Wu
Keyword(s):  
Hyperfine Structure ◽  
Configuration Interaction ◽  
Structural Parameters ◽  
Cluster Approach ◽  
Epr Parameters ◽  
Structure Constants ◽  
The Relationship ◽  
Good Agreement ◽  
G Factors

Abstract The formulas of the g-factors gII , g┴ and the hyperfine structure constants AII.A┴ for 3d7 ions in tetragonal octahedral crystals are established from a cluster approach. Differing from previous formulas, in these formulas the role of configuration interaction (CI)-and covalency (CO)-effects is considered, and the parameters related to both effects are obtained from the optical spectra and the structural parameters of the studied crystal. From these formulas, the EPR parameters gi and Ai for K2 ZnF4 :Co2+ are calculated. The results show good agreement with the observed values. The contributions to the EPR parameters gi and Ai, from the CI and CO effects, and the relationship between the sign of Δg(=g┴ - gII) and the tetragonal distortion (elongated or compressed) of the ligand octahedron are discussed

Theoretical Studies of the EPR Parameters for Rh+ in NaCl

2010 ◽  
Vol 303-304 ◽  
pp. 125-129
Author(s):  
Zhi Hong Zhang ◽  
Shao Yi Wu ◽  
Pei Xu ◽  
Li Li Li
Keyword(s):  
Structure Constant ◽  
Theoretical Studies ◽  
Spin Orbit Coupling ◽  
Cluster Approach ◽  
Paramagnetic Resonance ◽  
Hyperfine Structure Constant ◽  
Ligand Orbital ◽  
Epr Parameters ◽  
Electron Paramagnetic ◽  
Good Agreement

The electron paramagnetic resonance (EPR) parameters g factor and the hyperfine structure constant A factor for the substitutional Rh+ in NaCl are theoretically studied from the perturbation formulas of these parameters for a 4d8 ion in cubic octahedra. In these formulas, the ligand orbital and spin-orbit coupling contributions which were normally omitted in the previous studies are taken into account using the cluster approach. The calculated g and A factors are in good agreement with the experimental data. The ligand contributions to the EPR parameters are somewhat important and should be considered in the analysis of the EPR spectra for a 4d8 ion in chlorides. The local structure of this center is also discussed.

Theoretical Studies of the EPR g Factors and the Hyperfine Structure Constants of Cr3+ in MgS and SrS

2003 ◽  
Vol 58 (9-10) ◽  
pp. 503-506
Author(s):  
Shao-Yi Wu ◽  
Xiu-Ying Gao ◽  
Wei-Zi Yan
Keyword(s):  
Hyperfine Structure ◽  
Coupling Coefficient ◽  
Structure Constant ◽  
Theoretical Studies ◽  
Spin Orbit ◽  
Cluster Approach ◽  
Hyperfine Structure Constant ◽  
Structure Constants ◽  
G Factors

The EPR g factors and the hyperfine structure constant A factors for Cr3+ in MgS and SrS are theoretically studied by using the two-spin-orbit (S.O.)-coupling-coefficient formulas for a 3d3 ion in octahedra based on the cluster approach. In these formulas, both the contributions due to the S.O. coupling coefficient of the central 3d3 ion and that of ligands are taken into account. Based on these studies, the g and A factors of Cr3+ in both MgS and SrS are satisfactorily explained. The results are discussed.

STUDIES OF THE OPTICAL SPECTRA AND EPR PARAMETERS FOR Dy3+ ION IN CaMoO4 CRYSTAL

2013 ◽  
Vol 27 (29) ◽  
pp. 1350209
Author(s):  
GUO-YA XIE ◽  
XIAN-RONG LIU
Keyword(s):  
Optical Spectra ◽  
Tetragonal Symmetry ◽  
Crystal Field Theory ◽  
Paramagnetic Resonance ◽  
Epr Parameters ◽  
Structure Constants ◽  
Experimental Values ◽  
Yellow Region ◽  
Electron Paramagnetic ◽  
Good Agreement

CaMoO 4: Dy 3+ used as solid-state laser single crystal, which operate in the yellow region, have important technological applications. In this paper, based on the crystal-field theory, the optical spectra of Dy 3+ in CaMoO 4 crystal are calculated by diagonalizing the 42 × 42 energy matrix. The electron paramagnetic resonance (EPR) parameters g factors g‖ and g⊥ and hyperfine structure constants A‖ and A⊥ of 161 Dy 3+ and 163 Dy 3+ isotopes in CaMoO 4 crystal are investigated using the perturbation formulas of the 4f9 ion in tetragonal symmetry. The needed crystal parameters are determined from the superposition model and the local structure of the studied system. The calculated results are in good agreement with the experimental values.

Weak Extinction Limits of Turbulent Heterogeneous Fuel/Air Mixtures

1980 ◽  
Vol 102 (2) ◽  
pp. 416-421 ◽  
Author(s):  
D. R. Ballal ◽  
A. H. Lefebvre
Keyword(s):  
Liquid Fuel ◽  
Drop Size ◽  
Air Pressure ◽  
Theoretical Studies ◽  
Turbulence Level ◽  
Test Program ◽  
Stabilized Flames ◽  
Experimental Values ◽  
Experimental And Theoretical Studies ◽  
Good Agreement

Experimental and theoretical studies are made of the factors governing the weak extinction limits of stabilized flames supplied with flowing mixtures of liquid fuel drops and air. The test program includes wide variations in inlet air pressure, velocity and turbulence level, and also covers wide ranges of fuel volatility and mean drop size. The influence of flameholder size and blockage is also examined. An equation is derived for predicting weak extinction limits which shows good agreement with the corresponding experimental values.

scholarly journals Weak Extinction Limits of Turbulent Heterogeneous Fuel/Air Mixtures

1979 ◽  
Author(s):  
D. R. Ballal ◽  
A. H. Lefebvre
Keyword(s):  
Liquid Fuel ◽  
Drop Size ◽  
Air Pressure ◽  
Theoretical Studies ◽  
Turbulence Level ◽  
Test Program ◽  
Stabilized Flames ◽  
Experimental Values ◽  
Experimental And Theoretical Studies ◽  
Good Agreement

Experimental and theoretical studies are made of the factors governing the weak extinction limits of stabilized flames supplied with flowing mixtures of liquid fuel drops and air. The test program includes wide variations in inlet air pressure, velocity and turbulence level, and also covers wide ranges of fuel volatility and mean drop size. The influence of flameholder size and blockage is also examined. An equation is derived for predicting weak extinction limits which shows good agreement with the corresponding experimental values.

Studies of EPR g-factors on Rutile (TiO2) with Co2+ Ion

2002 ◽  
Vol 57 (1-2) ◽  
pp. 45-48 ◽  
Author(s):  
Shao-Yi Wu ◽  
Wen-Chen Zheng
Keyword(s):  
Crystal Field ◽  
Configuration Interaction ◽  
Cluster Approach ◽  
Rutile Tio2 ◽  
Small Discrepancy ◽  
Rutile Crystal ◽  
G Factors

The anisotropic g-factors gx, gy , and gz for Co2+ in rutile crystal are studied from the secondorder perturbation formulas based on the cluster approach. In the studies, the contributions due to covalency effects, the configuration interaction and the rhombic crystal field are taken into account. The calculated values are close to the observed ones. The small discrepancy between calculation and experiment is discussed

scholarly journals Defect Structure of Co2+ Center in α-LiIO3 Crystal

2000 ◽  
Vol 55 (9-10) ◽  
pp. 828-832 ◽  
Keyword(s):  
Electrostatic Interaction ◽  
Configuration Interaction ◽  
Defect Structure ◽  
Structural Parameters ◽  
Interaction Model ◽  
Optical Spectra ◽  
Cluster Approach ◽  
Displacement Direction

Abstract In this paper we establish the formulas of EPR g||, g⟂, for 3d7 ions in trigonal octahedral crystals from a cluster approach. In these formulas, the contributions from configuration interaction-and covalency-effects are considered. The parameters related to both effects can be determined from the optical spectra and the structural parameters of the studied crystal. With these formulas, the defect structure of a Co2+ center in α-LiIO3 crystal is studied. It is found that, to reach good fits between the calculated and observed g||, g⟂ , the O2_ ions between Co2+ and Li+ vacancy (VLi) should shift away from the VLi by about 0.49 Å. The displacement direction is consistent with those obtained for Cr3+ , Fe3+ , and Mn2+ centers in α-LiIO3 crystals as well as with the expectation based on the electrostatic interaction model.

scholarly journals A test of composite natural orbitals for benzene

1992 ◽  
Vol 70 (2) ◽  
pp. 532-536 ◽  
Author(s):  
Yuichi Yamamoto ◽  
Takeshi Noro ◽  
Kimio Ohno
Keyword(s):  
Excited State ◽  
Configuration Interaction ◽  
Benzene Molecule ◽  
Natural Orbital ◽  
Excitation Energies ◽  
Natural Orbitals ◽  
Experimental Values ◽  
Ci Calculations ◽  
Good Agreement

Approximate natural orbitals (NO's) of a larger system can be constructed from the NO's of smaller fragment systems. These orbitals, called composite NO's (CNO's) are expected to be useful in configuration interaction (CI) calculations. The effectiveness of these NO's is shown for the benzene molecule. This molecule is considered a combination of three ethylenes. The CI calculations were carried out for the S1 – S3 and T1 – T3 states. We take into account single and double excitations from σ and π electrons in the CI calculations. The calculated excitation energies are in good agreement with the experimental values Keywords: benzene, π–π* excited state, composite natural orbital, ionic and covalent, SDCI.

Sign in / Sign up

Export Citation Format

Share Document