Polarized crystal spectra of CrF2 from 6000 to 38 OOO cm−1

Polarized absorption spectra of single crystal CrF2 from 6000 to 38 000 cm−1, at temperatures of 293, 80, 21 and 5.5 °K, are reported. In the (010) plane the principal axes of refractive index are near the [100] and (001) crystallographic directions. Spectra are presented with light propagated along [100], [010], (001), [101], and (101), each with two polarizations. Four narrow lines, of full width at half-height 4 cm−1 and identified from their polarization properties as magnetic dipole transitions, were found at 10 394, 16 986, 18 122, and 20 270 cm−1. Oscillator strengths of the lines and bands are calculated. The observed spectra are interpreted as electronic transitions of a Cr2+ ion in approximate D4h symmetry from a ground 5B1g level to excited quintette and triplet levels. Ligand field parameters are B=895 cm−1, C=3152 cm−1, Dq=1039.4 cm−1, Ds=−371 cm−1, and Dt=320 cm−1. CrF2 was found to be transparent between 1323 and 5000 cm−1.