RAMAN-SPECTRA AND STRUCTURAL CHARACTERISTICS OF RARE-EARTH ELEMENT DISULFIDES

The Raman and IR spectra of a new group of layer compounds LnS2 are presented. The vibrations are classified in symmetry types, and the frequencies are broken down into three groups, i.e., vibrations of the cationic sublattice (70-160 cm-1), vibrations of the sulfur ions in the Flao layer (160-350 cm-1), and vibrations of the S2 molecular groups. The changes of the spectral characteristics in the series indicate structural transformations, beginning with SmS2.