Semi-empirical and ab initio DFT modeling of the spin-Hamiltonian parameters for Fe⁶⁺: K₂MO₄(M=S, Cr, Se)

In this paper we calculated the spin-Hamiltonian parameters (g factors g∥, g⊥ and zero field splitting parameter D) for Fe⁶⁺ions doped in K₂MO₄(M = S, Cr, Se) crystals, taking into account the actual site symmetry of the Fe⁶⁺impurity ion. The suggested method is based on the successful application of two different approaches: the crystal field theory (CFT) and density functional based (DFT). Within the CFT model we used the cluster approach and the perturbation theory method, based on the crystal field parameters, which were calculated in the superposition model.Within the DFT approach the calculations were done at the self-consistent field (SCF) by solving the coupled perturbed SCF equations. Comparison with experimental data shows that the obtained results are quite satisfactory, which proves applicability of the suggested calculating technique.