Raman spectra of the rare earth disulfides

• Published in: Materials research bulletin 1992, Vol.27 (6), p.775-781
• Main Authors: Kolesov, B.A., Vasilyeva, I.G.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Infrared and raman spectra and scattering; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Physics
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/0025-5408(92)90086-F

Raman, IR and VIS-reflection spectra of a new group of layered compounds, LnS 2, have been studied. All Ag and Bg modes in the orthorhombic and monoclinic structural modification were assigned and peculiarities of spectra were interpreted as resulting from three kinds of vibrations: cation sublattice (70–160 1/cm), S 2− ions connected with Ln 3+ in one layer (160–350 1/cm) and dumb-bell pairs S 2− 2 related to the other layer of structure (380–420 1/cm). Series of the LnS 2 spectra (La = La/1bEr) as a function of the rare earth elements ionic radius are given. Every variation in spectral features, beginning with SmS 2, is attributed to the structural phase transition for the LnS 2 compounds. Raman spectroscopy is shown to be a very usefull method for the characterization of unknown structures of heavy rare earth disulfides.