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Study of a high‐temperature Raman‐sensitive mode of TBDA at the solid–smectic G transition
Author(s) -
Singh Ranjan K.,
Singh S. C.,
Dash S. K.,
Asthana B. P.,
Verma A. L.
Publication year - 2000
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 - 10.1002/1097-4555(200007)31:7<543::aid-jrs481>3.0.co;2-q
Subject(s) - raman spectroscopy , phase transition , wavenumber , chemistry , alkyl , amplitude , benzene , phase (matter) , planar , analytical chemistry (journal) , materials science , condensed matter physics , optics , physics , organic chemistry , computer graphics (images) , computer science
Raman spectra of terephthal‐bis‐ p ‐ n ‐decylaniline (TBDA) were recorded in the wavenumber region 900– 1050 cm −1 at room temperature and higher temperatures up to 473 K. The Raman‐sensitive mode at ca 975 cm −1 splits into two bands, the new band appearing at ca 968 cm −1 . The variation of the deconvoluted linewidths of these two bands with temperature exhibits clearly a phase transition at 346 K. The dynamics of the phase transition are discussed in terms of large‐amplitude vibration of the alkyl tail causing a strain on the core consisting of three staggered benzene rings and hence reduces the inter‐planar spacing. The study reveals that the selection of a suitable Raman mode to characterize and study a phase transition is crucial. Copyright © 2000 John Wiley & Sons, Ltd.