Studies on the ESR Spectra of the VO²⁺ Ion Complexes in the High-Silica Zeolites

In this paper, anisotropic ESR spectra with hfs of VO²⁺ ions, which exist in HZSM-5 and H-Mordenite high-silica zeolites, have been reported. Two kinds of possible structures of VO²⁺ ion complexs with the formation of VO（H₂O）₄²⁺ have been suggested. The molecular orbits of VO（H₂O）₄²⁺ complexs have been set up by means of coordination field theory. The perturbational theory of coordination field has been applied to approximatedly calculate the d-d transition energies of VO（H₂O）₄²⁺ complexs by means of the values of g tensor and A tensor obtained from the computer simulating. According to the relative magnitude of d-d transition energies of VO（H₂O）₄²⁺ complexs of each sample, a set of g tensor and A tensor of each sample can bc related to the reciprocial structure of VO（H₂O）₄²⁺ complex.