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

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 ( z 2 ) orbital into the d ( x 2 - y 2 ) orbital by the rhombic component of the crystal field with D 2 h symmetry plays an essential role. The amount of this mixing together with values of <1/ r 3 > 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 V 51 in VO 2 observed by Umeda et al. is shown to be explained well by using the electronic structure of the V 4+ ion in VO 2 determined from the analysis of the ESR spectra.