The luminescent triplet state of VO^3-₄ in YPO₄

Abstract

The Zeeman tensor g and the ⁵¹V hyperfine tensor A of the metastable spin triplet state of the VO^3- ₄ ion are determined by optically detected magnetic resonance experiments. The experimental values of the elements of these tensors are compared with theoretical predictions made with the aid of perturbation theory. The analysis confirms that there is a pronounced Jahn-Teller distortion of the system and the excited state cannot even approximately be described in terms of molecular orbitals of the tetrahedral ion. A model in which this excited state is described by an excitation of an electron from a 2p_π atomic orbital on a single oxygen to a molecular orbital that consists largely of a vanadium 3d orbital is compatible with the experimental observations.