Theoretical investigations of the electron paramagnetic resonance parameters for rutile TiO2:Cu2+ at low temperature

Abstract

ABSTRACT On the basis of the improved ligand field theory, the electron paramagnetic resonance (EPR) parameters for Cu2+ in rutile TiO2 at low temperature are theoretically investigated by using the improved perturbation formulas of the above EPR parameters for a 3d9 ion in rhombically (D2h) distorted octahedra. In the calculation formulas, the crystal field parameters are determined from the superposition model, and the contributions from the spin–orbit coupling of the ligands and the admixture of d-orbitals in the ground state wave function are also taken into account. Due to the Jahn–Teller effect, the Cu–O bond lengths of the parallel and perpendicular to the C2-axis are, respectively, \u2009≈\u20092.081 Å and \u2009≈\u20091.898 Å, with the planar bond angle θ’\u2009≈\u200982.52°. The calculated results are in agreement with the experimental data, and the reasonableness of these results is discussed.