Electronic Structures of Fe2+ and Fe3+ Impurities in BaTiO3 and LiNbO3 Ferroelectric Hosts

The spin-unrestricted Xα method is used to obtain the energy level diagrams of Fe2+ and Fe3+ impurities trapped in ferroelectric BaTiO3 and LiNbO3 hosts at room temperature. The mechanisms of ligand-metal, intervalence and crystalfield transitions are analysed and compared to experimental optical data.