University of Oulu

Jukka Jokisaari (2019) NMR of quadrupole noble gases in liquid crystals, Liquid Crystals, https://doi.org/10.1080/02678292.2019.1630489

NMR of quadrupole noble gases in liquid crystals

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Author: Jokisaari, Jukka1
Organizations: 1NMR Research Unit, University of Oulu, P.O.Box 3000, 90014 University of Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 3.5 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe202002276668
Language: English
Published: Informa, 2020
Publish Date: 2020-07-16
Description:

Abstract

NMR spectroscopy of quadrupolar noble gases, 21Ne (spin 3/2), 83Kr (9/2), 131Xe (3/2), dissolved in thermotropic liquid crystals enables the derivation of versatile information about the physical properties of the materials. The spectra display fine structures, triplets and nonets, which reveal quadrupole couplings. These, in turn, can be used in the determination of electric field gradients (EFG), orientational order parameters, and tilt angles. Comparison of 129Xe and 131Xe chemical shifts reveals second-order quadrupole shifts (SOQS) in circumstances where the ratio of quadrupole coupling and magnetic flux density is suitable. The 131Xe SOQS is shown to distinguish between uniaxial and biaxial nematic phases. Both 83Kr and 131Xe NMR spectra may display asymmetry around the central transition because of the SOQS, which can be used to identify biaxiality in nematic phases. As a curiosity, the effect of possible hexadecapole coupling on the 83Kr NMR transitions of krypton in liquid crystals is discussed.

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Series: Liquid crystals
ISSN: 0267-8292
ISSN-E: 1366-5855
ISSN-L: 0267-8292
Volume: In press
DOI: 10.1080/02678292.2019.1630489
OADOI: https://oadoi.org/10.1080/02678292.2019.1630489
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
116 Chemical sciences
Subjects:
Copyright information: © 2019 Informa UK Limited, trading as Taylor & Francis Group. This is an Accepted Manuscript of an article published by Taylor & Francis in Liquid Crystals on 16 Jul 2019, available online: https://doi.org/10.1080/02678292.2019.1630489.