FAR-IR SPECTROSCOPIC INVESTIGATIONS OF NEMATIC LIQUID-CRYSTALS WITH HYDROGEN-BONDED MOLECULES

Citation
K. Antonova et al., FAR-IR SPECTROSCOPIC INVESTIGATIONS OF NEMATIC LIQUID-CRYSTALS WITH HYDROGEN-BONDED MOLECULES, Journal of molecular structure, 325, 1994, pp. 189-201
Citations number
29
Categorie Soggetti
Chemistry Physical
ISSN journal
00222860
Volume
325
Year of publication
1994
Pages
189 - 201
Database
ISI
SICI code
0022-2860(1994)325:<189:FSIONL>2.0.ZU;2-9
Abstract
Far-IR spectroscopy (200-30 cm-1) was used to study the temperature ev olution of the hydrogen bonds in the nematic liquid crystal phase of 4 , n-heptyl-, octyl- and nonyl-oxybenzoic acids (HOBA, OOBA and NOBA). The observed absorption bands (v(OH) = 82, 68, 63 and 42 cm-1) are ass igned to the four predominant vibrations respectively - stretching, be nding (out of and in the dimer ring plane) and twisting. From a spectr al band half-width temperature analysis hydrogen-bond evolution in the isotropic and nematic phases is investigated. A cyclic reversible ope n dimer transformation at different vibrational frequencies and polari zations is indicated.