Investigations of the spin-Hamiltonian parameters, optical absorption bands, and local structure for the tetragonal Cu~(2+) center in Cu~(2 +)-doped ZnCdO nanopowder

摘要

The spin-Hamiltonian (or EPR) parameters of tetragonal Cu~(2+) 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 d~n 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 Cu~(2+) 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 Cu~(2+) octahedron in ZnCdO nanopowder due to Jahn–Teller effect is acquired from the calculations. The results are discussed.