Investigations of the spin-Hamiltonian parameters and defect structure due to Jahn–Teller effect for the tetragonal Nb4+ center in cubic Cs2ZrCl6 crystal

Abstract

The spin-Hamiltonian parameters (g factors g//, , and hyperfine structure constants A//, ) of the tetragonally compressed Nb4+ center in cubic Cs2ZrCl6 crystal are calculated from two theoretical methods: one is the complete diagonalization (of energy matrix) method and another is the perturbation theory method. Both methods are based on the two-spin–orbit-parameter model where the contributions to spin-Hamiltonian parameters from the spin–orbit parameter of central dn ion (in the conventional crystal field theory) and that of ligand ion via covalence effect are contained. The calculated results from the two methods are in reasonable agreement with the experimental values. The tetragonal distortion of (NbCl6)2− octahedral cluster due to the Jahn–Teller effect for Nb4+ at the cubic Zr4+ site in Cs2ZrCl6 is also acquired. The results are discussed.