Electronic Structure of (nd)¹ Ions in Rutile-Type Crystals

Abstract

Electron spin resonance spectra of the (nd)¹ ions in the rutile-type crystals are explained in terms of the crystalline field theory. It is shown that the mixing of the d(z²) orbital into the d(x²−y²) orbital by the rhombic component of the crystal field with D_2h symmetry plays an essential role. The amount of this mixing together with values of ⟨1⁄r³⟩ and of the core polarization parameter χ are determined by analysing the ESR spectra. The energy levels of the excited d-orbitals are also estimated. Finally, the NMR shift of V⁵¹ in VO₂ observed by Umeda et al. is shown to be explained well by using the electronic structure of the V⁴⁺ ion in VO₂ determined from the analysis of the ESR spectra.