Theoretical investigations of the spin Hamiltonian parameters and local structures for the tetragonal V3+ and Ti2+ centers in MgO and CaO

Abstract

Abstract The spin Hamiltonian parameters (zero-field splitting D , g factor and hyperfine structure constant) and the local structures for MgO:V 3+ , CaO:V 3+ and CaO:Ti 2+ are theoretically investigated from the perturbation formulas of these parameters for 3d 2 ions under tetragonally distorted octahedra. The contributions from the dynamical Jahn–Teller effect, the configuration interactions and the ligand orbital and spin–orbit coupling interactions are quantitatively taken into account based on the cluster approach in a uniform way. The ligand octahedra are found to suffer the relative elongations of about 1.5%, 4.4% and 4.6% for MgO:V 3+ , CaO:V 3+ and CaO:Ti 2+ , respectively, along the C 4 axis due to the dynamical Jahn–Teller effect. The calculated spin Hamiltonian parameters based on the above local tetragonal elongations show reasonable agreement with the experimental data for all the systems. The results are discussed.