Crystal field energy levels, spin-Hamiltonian parameters and local structures for the Cr 3+ and Mn 4+ centers in La 3 Ga 5 SiO 14 crystals

2017 ◽  
Vol 64 ◽  
pp. 310-313 ◽  
Author(s):  
Yang Mei ◽  
Bo-Wei Chen ◽  
Wen-Chen Zheng ◽  
Bang-Xing Li
Keyword(s):  
Crystal Field ◽  
Energy Levels ◽  
Field Energy ◽  
Spin Hamiltonian ◽  
Local Structures ◽  
Hamiltonian Parameters

ESR STUDY OF SPIN-HAMILTONIAN PARAMETERS AND CRYSTAL FIELD ENERGY LEVELS FOR THE LOW C3 SYMMETRY Fe3+ CENTER IN GREEN SAPPHIRE CRYSTALS AND POWDER

2007 ◽  
Vol 21 (04) ◽  
pp. 225-236 ◽  
Author(s):  
P. LIMSUWAN ◽  
N. UDOMKAN ◽  
P. WINOTAI
Keyword(s):  
Rotation Angle ◽  
Energy Levels ◽  
Heat Treating ◽  
Esr Spectra ◽  
Field Energy ◽  
Hamiltonian Matrix ◽  
Magnetic Field Direction ◽  
Spin Hamiltonian ◽  
Corundum Structure ◽  
Hamiltonian Parameters

In this report, Fe 3+ impurity ions present in green sapphire ( Al 2 O 3) were studied experimentally, by heating a light green sapphire in flowing oxygen atmosphere for 12 h from 1200, 1300, 1400, 1500 and 1600°C, respectively. Electron spin resonance (ESR) spectra in X-band (~9.45 GHz ) were recorded by mounting the crystal with the c-axis perpendicular (θ = 90°) to the magnetic field direction. The spectra were recorded and simulated by a numerical diagonalization of spin Hamiltonian matrix in the range from 0 to 180 degrees for every 15 degrees of rotation angle (φ). In our case, only the last two sets of peaks strongly depend on the rotation angle (φ), and each exhibits C 3 symmetry due to two magnetically inequivalent Fe 3+ sites in the corundum structure. For polycrystalline ESR spectra, seven main Fe 3+ ESR absorption peaks occur at the resonance magnetic fields of 100.20, 310.24, 486.80, 525.00, 550.60, 761.00 and 777.00 mT respectively. Specifically, ESR signals show that the number of paramagnetic Fe 3+ ions increase roughly linearly with the heat treating temperature, having the [Formula: see text] ratio ~1.41 at 1600°C.

Theoretical Studies of the Spin Hamiltonian Parameters and Local Distortions for Cu2+ in Alkaline Earth Lead Zinc Phosphate Glasses

2016 ◽  
Vol 71 (8) ◽  
pp. 769-775 ◽  
Author(s):  
Bo-Kun Wang ◽  
Shao-Yi Wu ◽  
Zi-Yi Yuan ◽  
Zi-Xuan Liu ◽  
Shi-Xin Jiang ◽  
...  
Keyword(s):  
Field Strength ◽  
Crystal Field ◽  
Alkaline Earth ◽  
Zinc Phosphate ◽  
Phosphate Glasses ◽  
Spin Hamiltonian ◽  
Local Structures ◽  
Crystal Field Strength ◽  
Lead Zinc ◽  
Hamiltonian Parameters

AbstractThe spin Hamiltonian parameters and local structures are theoretically studied for Cu2+-doped alkaline earth lead zinc phosphate (RPPZ, R=Mg, Ca, Sr, and Ba) glasses based on the high-order perturbation calculations for a tetragonally elongated octahedral 3d9 cluster. The relative elongation ratios are found to be ρ≈3.2%, 4.4%, 4.6%, and 3.3% for R=Mg, Ca, Sr, and Ba, respectively, because of the Jahn-Teller effect. The whole decreasing crystal-field strength Dq and orbital reduction factor k from Mg to Sr are ascribed to the weakening electrostatic coulombic interactions and the increasing probability of productivity of nonbridge oxygen (and hence increasing Cu2+–O2− electron cloud admixtures) under PbO addition, respectively, with increasing alkali earth ionic radius. The anomalies (the largest Dq and the next highest k among the systems) for R=Ba are attributed to the cross linkage of this large cation in the network. The overall increasing order (Mg≤Ba<Ca<Sr) of ρ is largely due to the decreasing crystal-field strength Dq and hence the decreasing force constant of the Cu2+–O2− bonds. The present studies would be helpful to understand local structures and the influences on the optical properties of RPPZ glasses containing copper dopants.

scholarly journals Electronic Levels Of Cr2+ Ion Doped In II-VI Compounds Of ZnS – Crystal Field Treatment

2012 ◽  
Vol 56 (1) ◽  
pp. 94-99
Author(s):  
Simona Ivaşcu
Keyword(s):  
Experimental Data ◽  
Crystal Field ◽  
Energy Levels ◽  
Electronic States ◽  
Spin Hamiltonian ◽  
Host Matrix ◽  
Absorption And Emission ◽  
Radiative Transitions ◽  
Impurity Ions ◽  
Hamiltonian Parameters

AbstractThe aim of present paper is to report the results on the modeling of the crystal field and spin-Hamiltonian parameters of Cr2+ doped in II-VI host matrix ZnS and simulate the energy levels scheme of such system taken into account the fine interactions entered in the Hamiltonian of the system. All considered types of such interaction are expected to give information on the new peculiarities of the absorption and emission bands, as well as of non-radiative transitions between the electronic states of impurity ions. The obtained results were disscused, compared with similar obtained results in literature and with experimental data.

Theoretical Investigations Of The Spin Hamiltonian Parameters Of Zrsio4:Np4+

2004 ◽  
Vol 59 (7-8) ◽  
pp. 471-475
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Experimental Data ◽  
Energy Levels ◽  
Structural Data ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Theoretical Investigations ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters ◽  
Theoretical Results

In this work, the spin Hamiltonian (SH) parameters g|| and g⊥, and the hyperfine structure constants A|| and A⊥ for ZrSiO4:Np4+ are investigated on the basis of the perturbation formulas of these parameters for a 5f3 ion in tetragonal (D2d) symmetry. In these formulas, the contributions to the SH parameters from the second-order perturbation terms, the admixtures of various energy levels and the covalency effect are taken into account. The related crystal-field parameters are calculated from the superposition model and the local structural data of the Zr4+ site occupied by the impurity Np4+. The calculated SH parameters agree reasonably with the experimental data. The validity of the theoretical results is discussed.

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