Theoretical and computational investigation of the Eu3+ ion local symmetry in fluorides compounds

We employed the computational modelling technique with crystal field models to indicate the local symmetry of the Eu3+ ion in AF2 (A = Ca, Sr and Ba) crystals. Using a set of Buckingham potential parameters, the lattice parameters and the unit cell volume for all these crystals were reproduced satisfactorily with good fit in comparison with experimental data. Bound extrinsic defects calculations through low solution energy revealed that the Eu3+ occupies the A2+ site compensated by cationic vacancies. The spectroscopic study using the SOM with the MENN showed that the Eu3+ occupies a distorted inversion centre being a distorted S6 symmetry. In this indication, we used a set of phenomenological charge factors that reproduced the 7F1 level splitting and the 7F1, 7F2 and 5D1 energy sublevels.