Electron Spin Resonance of VO²⁺ in (NH₄)₂SeO₄

Abstract

The electron spin resonance of VO²⁺ in ammonium selenate has been studied in X-band and at 298 K. The ions reside in at least two chemically distinct sites. Vanadium does not appear to enter the lattice at substitutional sites. The spin-Hamiltonian parameters have been evaluated for the two sites. The principal values of g and A and the direction cosines in which the principal axes lie along the crystallographic axes are found for the predominant vanadyl complex. The ESR results in conjunction with the optical data were used to evaluate the molecular orbital coefficients.