Thermotropic biaxial nematic order parameters and phase transitions deduced by Raman scattering

Southern, C. D. and Brimicombe, P. D. and Siemianowski, S. D. and Jaradat, S. and Roberts, N. and Gortz, V. and Goodby, J. W. and Gleeson, H. F. (2008) Thermotropic biaxial nematic order parameters and phase transitions deduced by Raman scattering. EPL, 82 (5). ISSN 0295-5075

Full text not available from this repository.

Abstract

Raman Scattering was used to investigate biaxiality in the nematic phase formed by the bent-core material, C5-Ph-ODBP-Ph-OC12. Linearly polarised light was normally incident on a homogeneously aligned sample, and the depolarisation ratio was measured over a 360 degrees rotation of the incident polarisation for the Raman-active phenyl stretching mode. By modeling the bent-core structure and fitting to the depolarisation data, both the uniaxial ([P(200)] and [P(400)]) and biaxial ([P(220)], [P(420)] and [P(440)]) order parameters, are deduced. We show unequivocally the presence of a uniaxial to biaxial nematic phase transition approximately 30 degrees C above the underlying smectic phase. Further, we report the temperature evolution of the biaxial and uniaxial order parameters, which increase in magnitude continuously with reducing temperature, reaching values of 0.1, -0.15 and -0.18 for [P(220)], [P(420)] and [P(440)], respectively. Copyright (c) EPLA, 2008.

Item Type:
Journal Article
Journal or Publication Title:
EPL
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/3100
Subjects:
ID Code:
65903
Deposited By:
Deposited On:
07 Aug 2013 10:30
Refereed?:
Yes
Published?:
Published
Last Modified:
25 Feb 2020 07:11