Absorption Spectra of the Ce⁺⁺⁺ Ion in Solution

Abstract

THE experiments of J. Becquerel and W. J. de Haas¹ on the paramagnetic rotation of the plane of polarisation of light in a crystal of tysonite (which is a fluoride of cerium and lanthanum) has created an interest in the absorption spectra due to the Ce⁺⁺⁺ ion. These authors, as a result of their measurements at low temperatures, and on the assumption that the dispersion produced in tysonite is due to the presence of a single absorption band, came to the conclusions that (i.) the rotation phenomena are due to the presence of the Ce⁺⁺⁺ ion, and (ii.) the position of the absorption band is somewhere in the region of 2370 A.