LF-DFT Calculated and Experimental Studies of Eu³⁺ 4f energy levels in LaAlO₃

A combination of experimental optical studies and density functional theory calculations is used to explore the energy levels of Eu³⁺ doped into a LaAlO₃ perovskite host material. Combustion-synthesized samples are investigated through optical spectroscopy to measure the transitions between 4f electronic energy levels. Lanthanide impurities in LaAlO₃ occupy the lanthanum cation site with small distortions due to the difference in the ionic radii. Density functional theory calculations have been conducted to optimize the geometry of the distorted impurity sites. Using the optimized site geometry, we calculate energy levels of Eu³⁺ in LaAlO₃ using Ligand Field-DFT in the Amsterdam Modeling Suite and the Average Over Configuration (AOC) approach to deal with the partially filled 4f shell. The computed energies agree with the experimental emission spectra, to within a few hundred wavenumbers. This study is the first application of LF-DFT to impurity ion energy levels in an oxide host.