Investigation of the local structure and the effects of the orbit reduction factor on the EPR g-factors for octahedral (CrO_6)~(9-)cluster in TiO_2:Cr~(3+)and MgO:Cr~(3+)systems

摘要

A theoretical method for studying the inter-relation between electronic and molecular structure hasbeen proposed based on the complete energy matrices for a d3 configuration ion in a tetragonal ligand-field. By means of this method, the local structure for CO~(3+) ion doped in oxides TiO_2(anatase) and MgOhas been determined. The calculated results indicate that the local structure of the (CrO_6)~(9-)cluster inTiO_2:Cr~(3+) and MgO:3+)systems exists as a compressed distortion relative to the regular octahedron.Meanwhile, the dependence of the EPR zero-field splitting parameter D on the local structure parameterAR (ΔR = R_1-R_2)has been revealed. In addition, the relation between EPR g-factors(g_‖,g_⊥,Δg) andthe orbit reduction factor k has been discussed for the two systems, suggesting that the orbit reductionfactor k is very important to understand the EPR g-factors.