Absorption and Fluorescence Spectra with Magnetic Properties of ErCl3

The absorption and fluorescence spectra of ErCl3 diluted by LaCl3 are given with the Zeeman effects of many of the lines. All expected electronic levels to 30 000 cm—1 above the ground state are found, and their interpretation fits into the theoretically expected scheme. Examples are also given of the absorption and fluorescence spectrum of pure ErCl3 which show that the pure salt must have a structure quite different from that of LaCl3.