Study of a high-temperature Raman-sensitive mode of TBDA at the solid–smectic G transition
✍ Scribed by Ranjan K. Singh; S. C. Singh; S. K. Dash; B. P. Asthana; A. L. Verma
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 65 KB
- Volume
- 31
- Category
- Article
- ISSN
- 0377-0486
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✦ Synopsis
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.