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Studies on induced smectic phases (III). Fourier transform infrared and laser‐raman spectral differences between isotropic and induced smectic phase of binary mixtures of nematogens with contrasting dielectric anisotropies
Author(s) -
Szabon J.,
Pilz W.,
Koswig H. D.
Publication year - 1983
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170180413
Subject(s) - raman spectroscopy , anisotropy , infrared , phase (matter) , analytical chemistry (journal) , materials science , isotropy , fourier transform , fourier transform infrared spectroscopy , laser , spectral line , conformational isomerism , infrared spectroscopy , chemistry , optics , molecule , organic chemistry , physics , mathematical analysis , mathematics , astronomy
The S E , S B , S A induced phase sequence was detected in binary mixtures of two nematogens, 4,4′‐di‐n‐heptyl azobenzene (7AB) with 4‐n‐pentyl‐4′‐cyano biphenyl (5CB). The mixtures as well as the single components were studied by Fourier transform IR and laser‐Raman spectroscopy at different temperatures. Charge redistribution of 5CB is demonstrated by the spectral differences found by the ratio‐recorded IR spectra and also by integrating the intensities of some Raman lines. The spectra of the different phases of the 7AB—5CB mixture, built up from components of different length, indicate a population increase of the gauche conformers of 7AB in the smectic A phase.