| Issue |
J. Phys. II France
Volume 7, Number 12, December 1997
|
|
|---|---|---|
| Page(s) | 1817 - 1828 | |
| DOI | https://doi.org/10.1051/jp2:1997216 | |
J. Phys. II France 7 (1997) 1817-1828
Optical Properties and Phenomenological Theory of Ferri-Ferri Phase Transitions in Antiferroelectric Liquid Crystals
P. Gisse1, M. Sidir1, V.L. Lorman1, R. Farhi1, J. Pavel1 and H.T. Nguyen21 Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules-Verne, 33 rue Saint-Leu, 80039 Amiens Cedex, France
2 Centre de Recherche Paul Pascal, avenue A. Schweitzer, 33600 Pessac, France
(Received 20 January 1997, revised 16 July 1997, accepted 2 September 1997)
Abstract
Optical rotatory power and Raman scattering experiments on chiral liquid crystals belonging to a series which exhibits one
or two ferrielectric phases have been performed. The results of these non-perturbative techniques show that, depending upon
the aliphatic chain length, a first order transition with a jump in sign and value of the helical pitch, or a divergence and
sign reversal of the pitch with no transition can occur in these systems. These observations are in agreement with a generalized
Landau-de Gennes phenomenological model predicting that the ferrielectric phases, when both exist, should be isostructural.
© Les Editions de Physique 1997