Studies on the EPR parameters and local angular distortion for the tetragonal Cu2+ center in CaWO4 crystal
© 2022 John Wiley & Sons Ltd.
| Veröffentlicht in: | Magnetic resonance in chemistry : MRC. - 1985. - 61(2023), 1 vom: 13. Jan., Seite 8-15 |
|---|---|
| 1. Verfasser: | |
| Weitere Verfasser: | , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2023
|
| Zugriff auf das übergeordnete Werk: | Magnetic resonance in chemistry : MRC |
| Schlagworte: | Journal Article CaWO4 Cu2+ defect structures electron paramagnetic resonance (EPR) |
| Zusammenfassung: | © 2022 John Wiley & Sons Ltd. The electron paramagnetic resonance (EPR) parameters-g factors gi (i = || and ⊥) and hyperfine structure constants Ai (M) and Ai (N), with M and N belonging to isotopes 63 Cu2+ and 65 Cu2+ -and local structure of Cu2+ ion occupying W6+ site in CaWO4 crystal are theoretically studied based on the perturbation formulas of these parameters for a 3d9 ion under tetragonally elongated tetrahedra. In these formulas, the ligand orbital (LO) and spin-orbit coupling (SOC) contributions are included due to the shorter impurity-ligand distance R (≈1.83 Å) and hence the strong covalency of the studied [CuO4 ]6- cluster, and the related molecular orbital coefficients are quantitatively determined from the cluster approach in a uniform way; meanwhile, the required crystal field (CF) parameters for the tetragonally distorted tetrahedron (TDT) are estimated from the superposition model and the local structure of the impurity Cu2+ center. According to the calculation, the bond angle θ between the four equivalent Cu2+ -O2- bonds and the C4 axis in the CaWO4 :Cu2+ is found to be about 2.1° smaller than that (θ0 ≈ 54.74°) for an ideal tetrahedron due to the Jahn-Teller (JT) effect and the size mismatch. The fitted results agree well with the observed values, and the validity of the present assignment for the local structure of the Cu2+ center is also discussed |
|---|---|
| Beschreibung: | Date Revised 06.12.2022 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1097-458X |
| DOI: | 10.1002/mrc.5311 |