Issue |
Europhys. Lett.
Volume 38, Number 2, April II 1997
|
|
---|---|---|
Page(s) | 107 - 112 | |
Section | Condensed matter: structure, thermal and mechanical properties | |
DOI | https://doi.org/10.1209/epl/i1997-00209-3 | |
Published online | 01 September 2002 |
Low-frequency dynamics of liquid crystals
1
Department of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3JZ, Scotland, United Kingdom
2
Institute of High Temperature and High Pressure Physics, Sichuan Union University - Chengdu 610065, Sichuan, P. R. China
Received:
31
October
1996
Accepted:
3
March
1997
The nature of low-frequency (0 to 200 cm-1) dynamics of liquid crystal molecules is explored using a combination of high-resolution Raman spectroscopy and first principles computer simulations implemented on a parallel computer. The frequencies and displacement patterns associated with these vibrations have been determined by diagonalisation of a dynamical matrix. Results indicate that in the prototypical nematogen 5CB, complex internal modes have frequencies comparable to those of lattice modes in the low-temperature solid polymorphs. We expect this result is not specific to 5CB and that such behaviour is common to many liquid-crystal systems. Such low-frequency modes may be related to the conformational changes which have been observed to occur near liquid crystalline phase transitions. In smectic 8CB, very low-frequency features (near 10 cm-1) in the Raman spectrum are observed and are attributed to interlayer interactions in the smectic phase.
PACS: 64.70.Md – Transitions in liquid crystals / 78.30.-j – Infrared and Raman spectra / 31.15.Ar – Ab initio calculations
© EDP Sciences, 1997
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.