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A Raman study of the misfit layer compounds, (SnS) 1.17 NbS 2 and (PbS) 1.18 TiS 2
Author(s) -
Sourisseau C.,
Cavagnat R.,
Tirado J. L.
Publication year - 1992
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250231114
Subject(s) - raman spectroscopy , lattice (music) , wavenumber , g band , crystallography , chemistry , resonance (particle physics) , raman scattering , materials science , analytical chemistry (journal) , molecular physics , optics , physics , atomic physics , acoustics , chromatography
The Raman and resonance Raman spectra (850–20 cm −1 ) of powdered samples of the misfit layer compounds (SnS) 1.17 NbS 2 and (PbS) 1.18 TiS 2 at 300 K have been investigated. In partial agreement with structural data, vibrational assignments are proposed for most of the internal modes of the ‘MS’ and ‘TS 2 ’ sublattices and the band wavenumbers are compared to those in the 2H‐NbS 2 and IT‐TiS 2 prototypes, in order to understand the interaction in which ‘MS’ acts as the donor part of the structure. Owing to their incommensurate modulated structures along the {ξ00} direction, characteristic Raman bands at 197 cm −1 (‘SnNbS 3 ’) or 203 cm −1 (‘PbTiS 3 ’), assigned to mostly TA or LA type modes, become Raman active due to a zone folding mechanism. New information about the lattice dynamics in the ‘TS 2 ’ sublayers is thus obtained.