Ab initio calculations for SrF₂ with F- and M-centers

In an ab initio study of vacancies in the alkaline earth fluoride SrF₂ we calculated the electronic bulk properties of perfect SrF₂ crystals and with F- and M-centers. By means of the hybrid B3PW method, in which Hartree-Fock exchange is mixed with density functional theory exchange functionals, using Becke's three-parameter method, combined with the non-local correlation functionals by Perdew and Wang, our result for the band gap of SrF₂(11.31 eV) agrees with experimental data (11.25 eV) very well. Different kinds of vacancy basis sets for the F- and M-center in SrF₂ are tested to find the best description for simulating structural and electronic properties of such defects in SrF₂. The resulting set is found to work also best for vacancies in CaF₂ and BaF₂.