Zhang, Z orcid.org/0000-0003-2282-3406 and Gleeson, HF orcid.org/0000-0002-7494-2100 (2019) Understanding liquid crystal order parameters deduced from different vibrations in polarised Raman spectroscopy. Liquid Crystals, 46 (2). pp. 219-233. ISSN 0267-8292
Abstract
Polarised Raman Spectroscopy (PRS) has been used to measure order parameters in liquid crystalline materials for decades. However, it is well known that different values of the order parameters are deduced for the same material when different vibrational modes are used in the analysis. This is an undesirable discrepancy that has somewhat hindered the use of the technique. Here we use two Raman active bands namely the phenyl (1606 cm−1) and cyano (2220 cm−1) stretching modes in the nematic phase of 5CB (4-cyano-4ʹ-pentylbiphenyl) as the example to explore the origin of such discrepancy. Two approaches are proposed in the data a nalysis taking either non-axial or non-cylindrical symmetric vibration into consideration. Together with a systematic discussion based on experimental data, we can conclude that whether or not the vibration satisfies the conditions associated with cylindrical symmetry is the correct physical explanation for the discrepancy in the order parameters.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2018, Informa UK Limited, trading as Taylor & Francis Group. This is an author produced version of a paper published in Liquid Crystals. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Nematic, polarised Raman spectroscopy, order parameter, molecular biaxiality |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Soft Matter Physics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 09 Jul 2018 14:47 |
Last Modified: | 21 Jun 2019 00:39 |
Status: | Published |
Publisher: | Taylor & Francis |
Identification Number: | 10.1080/02678292.2018.1485980 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:133033 |