Papers by Author: Li Li Li

Abstract: 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.

Abstract: The spin Hamiltonian parameters (anisotropic g-factors and the hyperfine structure constants) and defect structure for Pt3+ in MgO are theoretically investigated by using the perturbation formulas of these parameters for a 5d7 ion in a tetragonally elongated octahedron. This impurity center is attributed to substitutional Pt3+ on host Mg2+ sites, and the [PtO6]9 cluster suffers a relative elongation of 0.08Å along the C4 axis due to the Jahn-Teller effect. In the calculations, the contributions arising from the ligand orbital and spin-orbit coupling interactions and the Jahn-Teller elongation are taken into account using the cluster approach. The calculated spin Hamiltonian parameters based upon the above defect structure show good agreement with the observed values.