Calculation and prediction the charge transfer energy of O ^2--Zr⁴⁺ in inorganic crystals

This paper presents a new computational model to study the high-energy charge transfer (CT) energy of O^2--Zr⁴⁺ in inorganic crystals by using the dielectric theory of chemical bond for complex crystals. It is found that covalency, bond volume polarization, and presented charge of the ligand in the chemical bond are three determinative parameters for the CT energy. An empirical formula between these three parameters and the experimental CT energy is obtained. This model can serve as a prediction tool, which allows one, for the first time, to assign and reassign the charge-transfer position of O^2--Zr⁴⁺. The model predicts CT band positions of CaZrSi₂O₇ and PbWO⁴:Zr⁴⁺ at 6.814 and 6.887 eV, respectively. We reassign the CT band of La₂Zr ₂O₇ at 177 nm, not 190 nm.