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Feng W.-L.,Chongqing University of Technology | Feng W.-L.,CAS International Center for Materials Physics | Feng W.-L.,Chongqing Key Laboratory of Time Grating Sensing and Advanced Testing Technology | Wang K.,Chongqing University of Technology | And 3 more authors.
Journal of Physics and Chemistry of Solids | Year: 2014

The spin-Hamiltonian (or EPR) parameters of tetragonal Cu2+ octahedral centers in ZnCdO nanopowders are calculated from the high-order perturbation formulas based on the cluster approach. In these formulas, the contributions to spin-Hamiltonian parameters due to the admixture between the d orbitals of dn ion and the p orbitals of ligand ions via covalence effect are considered. The crystal field parameters are calculated from the superposition model and so the optical absorption bands (related to the crystal field energy levels) and local structure of Cu2+ octahedral centers in ZnCdO nanopowder are also studied. The calculated spin-Hamiltonian parameters and optical absorption bands are in reasonable agreement with the experimental values. The tetragonal elongation ΔR (=R//-R ⊥) of Cu2+ octahedron in ZnCdO nanopowder due to Jahn-Teller effect is acquired from the calculations. The results are discussed. © 2014 Elsevier Ltd. Source


Feng W.-L.,Chongqing University of Technology | Feng W.-L.,CAS International Center for Materials Physics | Feng W.-L.,Chongqing Key Laboratory of Time Grating Sensing and Advanced Testing Technology | Xue J.-Y.,Chongqing University of Technology
Physica B: Condensed Matter | Year: 2012

In this work, the complete matrix of optical spectral levels in trigonal symmetry of 3d 2 (3d 8) ions are established on basis of strong field coupling mechanism by using two spin-orbit coupling parameters model. The contribution of the spin-orbit coupling of ligand to the optical spectra has been included in these formulas. As an application, the optical spectra of Cr 4 in Y 2Ti 2O 7 and Y 2Sn 2O 7 have been studied by the complete diagonalization (energy matrix) method. The covalent effect has been studied and the difficulty about Dq parameter in explanation of optical spectra of Cr-doped Y 2Ti 2O 7 and Y 2Sn 2O 7 is removed. The theoretical results are in good agreement with observed data. © 2012 Elsevier B.V. All rights reserved. Source


Feng W.-L.,Chongqing University of Technology | Feng W.-L.,CAS International Center for Materials Physics | Feng W.-L.,Chongqing Key Laboratory of Time Grating Sensing and Advanced Testing Technology
Physica B: Condensed Matter | Year: 2012

The optical absorption spectra and electronic spin resonance parameters (ESR g factors g||, g⊥ and hyperfine structure constants A||, A⊥) for Cu2+ in shattuckite crystal are calculated from the two spin-orbital coupling parameters model, high-order perturbation formulas and complete diagonalization (of energy matrix) method (CDM) of 3d9 ion in tetragonal symmetry. The calculated results are in good agreement with the observed values. Since the ESR parameters are sensitive to the local structure of a paramagnetic impurity center, the defect structure of Cu2+ center in shattuckite crystal is estimated. The results are discussed. © 2012 Elsevier B.V. All rights reserved. Source


Feng W.-L.,Chongqing University of Technology | Feng W.-L.,Chongqing Key Laboratory of Time Grating Sensing and Advanced Testing Technology | Feng W.-L.,CAS International Center for Materials Physics
Journal of Magnetism and Magnetic Materials | Year: 2012

The electron paramagnetic resonance (EPR) spectral data (the g factors and hyperfine structure constants) and d-d transition spectra for the tetragonal Mo 5 centre in [Mo 6O 19][N(C 4H 9) 4] 3 salt are theoretically investigated from the complete diagonalization method (CDM) for a 4d 1 ion in tetragonally compressed octahedron. The theoretical results are in good agreement with the experimental data. The dependency of the g factors of the ground state on the R ∥(MoO bond length) has been studied. It is shown that the g factors varied with the R ∥ approximately in a linear way. © 2012 Elsevier B.V. All rights reserved. Source


Feng W.-L.,Chongqing University of Technology | Feng W.-L.,Chongqing Key Laboratory of Time Grating Sensing and Advanced Testing Technology | Feng W.-L.,CAS International Center for Materials Physics
Philosophical Magazine Letters | Year: 2012

The Raman spectra and electronic spin resonance (ESR) parameters (spin-Hamiltonian parameter g factors, zero-field splitting parameter D, and hyperfine structure constant A) for the trigonal V 3+ centers in salt guanidinium vanadium sulfate hexahydrate (GVSH) are calculated from the complete diagonalization (of energy matrix) method. The theoretical results are in agreement with the experimental findings and the trigonal crystal-field parameters are determined. The difficulty in explaining ESR parameters of V 3+ in GVSH is removed. © 2012 Taylor & Francis. Source

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