Calculation of the energy of the 5d barycenter of La3F3[Si3O9]:Ce3+

A model that predicts the energy of the barycenter of the 5d configuration of Ce3+ in oxides and fluorides is applied to La3F3[Si3O9]:Ce3+. Because the lattice relaxation around Ce3+ is rather insignificant, this is an ideal compound to verify if the model also holds when Ce3+ is coordinated by two different types of anions. A very good agreement with the experimental value of 1.00 eV is obtained. The model predicts that the three coordinating fluorine ions contribute 0.14 eV and the eight oxygen ions 0.90 eV to the total centroid shift.