Theoretical Studies Of The Optical And Magnetic Properties Of Cu²⁺ Ions In D_4h Symmetry

The ligand field theory which is developed from the crystal theory combined with LCAO-MO method, together with the electron paramagnetic resonance (EPR) theory, functions as the important tools to study the microstructure, optical and magnetic properties of transition metal and rare earth ions in crystals. For the present, there are two theoretical methods to calculate the optical spectra and EPR parameters of transition metal and rare earth ions in crystals: perturbation method and complete diagonalization procedure (CDP). Perturbation method is an approximate one which can only gives approximation, while complete diagonalization procedure (CDP), on the basis of a set of ground function in point-group symmetry, can gain all Hamiltonian matrix elements first and then diagonalize them. The latter not only works out accurate parameters of optical spectra and EPR, but also produces all the eigenvector corresponding to eigenvalue.Most researchers pay more attention to perturbation method rather than to complete diagonalization procedure (CDP). Accordingly, this paper, guided by ligand field theory found by former researchers, gained the crystal field matrix and S ? O coupling matrix in which the crystal parameters were confirmed by local structure of point-charge model such as bond-length, bond-angle and symmetry properties. The paper also gave the g-factors'expressions of Cu 2+ (3d9) in D 4h symmetry by complete diagonalization procedure (CDP) and the A-factors'expressions. This paper worked out the optical and magnetic properties of crystals of NH 4 Cl:Cu2+, Cu 6 Si6O18? 6H2O and CdCl 2 :Cu2+, and the theoretical calculations are in good agreement with experiment. The calculated results, compared with the former researchers', explained some experiments.