Tools
Tools
Hunt, N. T. and Meech, S. R. 
ORCID: https://orcid.org/0000-0001-5561-2782
(2004)
Orientational and interaction induced dynamics in the isotropic phase of a liquid crystal: Polarization resolved ultrafast optical Kerr effect spectroscopy.
The Journal of Chemical Physics, 120 (22).
pp. 10828-10836.
ISSN 0021-9606
Abstract
The ultrafast dynamics of the isotropic phase of a liquid crystal 4(')-pentyl-4-p-biphenylcarbonitrile (5CB) have been investigated using polarization resolved optical Kerr effect spectroscopy. Measurements were made as a function of both temperature and dilution in nonpolar solvents. To separate single molecule and interaction induced components to the relaxation of the induced birefringence, measurements of both the anisotropic and isotropic response were made. The isotropic response was found to be dominated by a damped low-frequency mode of intramolecular origin. There is a minor additional component assigned to an interaction induced contribution. There is at most an extremely weak isotropic signal beyond 1 ps, showing that the picosecond time scale dynamics of 5CB are dominated by orientational relaxation. The isotropic response is independent of temperature in the range studied (0.2-50 K above the nematic to isotropic phase-transition temperature). The anisotropic response exhibits relaxation dynamics on time scales spanning subpicosecond to several hundred picoseconds and beyond. The fastest components are dominated by a librational response, but there are smaller contributions from three low-frequency intramolecular modes, and a contribution from interaction induced effects. The low-frequency spectral density extracted from these data are independent of temperature in the range studied, 0.2-30 K above the phase-transition temperature, but shift to lower frequency on dilution in alkane solvents. In neat 5CB the picosecond time scale orientational dynamics are dominated by temperature-independent reorientation within the pseudonematic domains, while in solution these are disrupted, and the orientational response becomes faster and temperature dependent. (C) 2004 American Institute of Physics.
| Item Type: | Article |
|---|---|
| Faculty \ School: | Faculty of Science > School of Chemistry (former - to 2024) |
| UEA Research Groups: | Faculty of Science > Research Groups > Physical and Analytical Chemistry (former - to 2017) Faculty of Science > Research Groups > Chemistry of Light and Energy Faculty of Science > Research Groups > Centre for Photonics and Quantum Science |
| Depositing User: | Rachel Smith |
| Date Deposited: | 26 Jul 2011 15:16 |
| Last Modified: | 24 Sep 2024 10:05 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/34179 |
| DOI: | 10.1063/1.1737293 |
Actions (login required)
 |
View Item |