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Spectroscopic study of monosubstituted amides. VII— low frequency Raman spectra of crystallized N‐methylacetamide
Author(s) -
Fillaux F.,
Baron M. H.,
De Loze C.,
Sagon G.
Publication year - 1978
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.1250070504
Subject(s) - raman spectroscopy , chemistry , spectral line , crystallite , isotopic shift , resonance (particle physics) , crystallography , nuclear magnetic resonance , computational chemistry , analytical chemistry (journal) , atomic physics , organic chemistry , physics , optics , astronomy
The Raman spectra of 10 isotopic species of polycrystalline NMA were recorded at 35 K between 6 and 200 cm −1 . Below 110 cm −1 at least 8 transitions are observed which are mainly due to external modes. Bands located between 110 and 170 cm −1 show unexpected isotopic effects and are interpreted taking into account IR and NIS spectra. A new internal torsional mode around the bond is proposed. The corresponding potential function involves two minima (Δω = ± 10°) separated by a weak barrier (∼600 cal/mole) indicating a nonplanar molecular skeleton.