Absorption Spectrum and Magnetic Properties of Ytterbium Chloride*

Abstract

The absorption spectrum of YbCl3·6H2O has two sharp lines near 9700 A which are interpreted as the transitions from the M=5/2 Stark component of the 2F7/2 level of the Yb+++ ion to the M=3/2 and 5/2 levels of the other doublet component 2F5/2. The Zeeman splittings of the two lines were investigated at 4°K as a function of the orientation of the crystal. They can be interpreted by assuming that the crystal field has a pronounced magnetic symmetry axis (probably sixfold) perpendicular to the twofold symmetry axis of the crystal. The magnetic ellipsoid is degenerate into a pair of planes perpendicular to this axis. The direction of the magnetic axis is slightly different for the three observed states and bears no relation to the optic axes of the crystal.