Paramagnetic resonance of <i>S</i> -state ions in calcium fluoride

Abstract

Abstract Paramagnetic resonance has been observed in Mn2+, Eu2+ and Gd3+ ions in single crystals of calcium fluoride grown from the melt. The Mn2+ ion has a very small cubic-field Stark splitting (a = + 0.6 ± 0.4 x 10-4 cm-1), and a fluorine hyperfine structure of overall splitting of about 60G due to some covalent bonding with the fluorine ligands. The Eu2+ spectrum has cubic symmetry with splitting parameters b4 = 57.9 + 0.2, b6 = 0.5 + 0.2 ( x 10-4 cm-1), but the Gd3+ spectrum has tetragonal symmetry with much larger Stark splittings; neither ion shows a resolved fluorine structure. The manganese and europium hyperfine structures are closely the same as in other salts with small covalent bonding.