Infrared Absorption from L·S Splittings inCo2+Salts

Abstract

A line absorption spectrum has been observed at about 0.15 ev in CoO, Co${\mathrm{Br}}_2$, Co${\mathrm{Cl}}_2$, and Co${\mathrm{F}}_2$ crystals. For the halides, the line has a complex structure. No absorption is observed in ${\mathrm{Cs}}_3$Co${\mathrm{Cl}}_5$ crystals. The absorption arises from transitions between various energy levels of the L·S fine structure multiplet. In Co${\mathrm{F}}_2$ some of the lines show changes in intensity on passing through the Néel temperature. Optical polarization effects are also observed in the Co${\mathrm{F}}_2$ spectrum.