Theoretical study of divalent samarium defects in lanthanum fluoride crystals

The results from a theoretical study of the electron structure of an impurity rare-earth Sm2+ defect in a LaF3 crystal are presented. The electron energy levels of the rare-earth impurity defect and the transitions between them are studied using the multiconfigurational CASSCF/CASPT2 method. The absorption spectrum obtained during the calculations is consistent with the experimental data. Based on our model, we can state definitively that a vacancy on an anion sublattice serves as a charge compensator for a divalent ion.