Theoretical Calculations on Rare Earth Elements in Barium Fluoride Crystal

In the present work we used Hartree-Fock-Slater local-density discrete variational method to calculate the energy level of some rare earth doped BaF₂ crystals and proposed that the Eu, Dy and Yb elements will change their valence from +3 to +2 under irradiation and thus change the optical properties of the crystals. The results show that this radiation effect model is in good agreement with experiments.