Zeeman and hyperfine infrared spectra of Pr3+ centers in alkaline earth fluoride crystals

Zeeman infrared studies of Pr3+ centers in alkaline earth fluorides identif y principal centers of tetragonal C-4v symmetry for CaF2 and SrF2. Crystal- field analyses for these C-4v centers yield crystal-field parameters simila r to those found for other trivalent rare-earth ions in CaF2 and SrF2. In B aF2:Pr3+, the principal center has a Pr3+ site of trigonal C-3v symmetry. H yperfine structure on sharp infrared-absorption lines of the tetragonal cen ters are interpreted with magnetic-hyperfine constants calculated for the e xcited multiplets together with parameters introduced to account for the ra ndom-strain disorder.