Far-Infrared Spectra and Zeeman Effect of Rare-Earth Double Nitrates

Abstract

The far-infrared spectra of several rare-earth double nitrates have been observed over the range 30–170 cm−1. The frequencies of the low lying phonon modes have been determined by comparison of the spectra of the diamagnetic and paramagnetic salts. The absorptions due to the crystal field split ground states of the rare-earth ions have been positively identified by observations of the Zeeman effect. The experimental energies and g values have been compared with the predictions of earlier crystal field calculations based on approximate symmetries. Some of these are in reasonable agreement with the experimental results, but none of them provides a consistent description of the ground state levels for all the ions studied.