Spin transfer versus charge transfer in the excited states of 3d" tetroxo ions
The first absorption bands in the optical spectra of the 3d° tetroxo-ions, VO ≡ 4 , CrO = 4 , MnO - 4 , are commonly assumed to arise from electron transfer from t 1 ligand MO to an MO centered on the metal. First electron-spin-resonance experiments on the luminescent triplet state of VO ≡ 4 in an YPO 4 host are reviewed. These show that unpaired electron indeed resides on the metal; the other is not a t 1 -type MO but localized on single ligand