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

Abstract

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. (c) 2008 Elsevier B.V. All rights reserved.