High-Resolution X-ray Study of the Smectic A-Smectic B Phase Transition and the Smectic B Phase in Butyloxybenzylidene Octylaniline |
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Authors: | P S Pershan G Aeppli J D Luster R J Birgeneau |
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Institution: | Center for Materials Science and Engineering , Massachusetts Institute of Technology , Cambridge, MA, U.S.A. |
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Abstract: | We have carried out a high resolution X-ray study of the smectic phases of Butyloxybenzylidene Octylaniline. We find that the phase previously identified as Smectic-B in this material is crystalline with in-plane order extending over at least 1.4 μm. The in-plane Bragg peaks are accompanied by anomalously strong diffuse scattering that can be described by a form 1/(q 2⊥ + γ2 q 2 z). Unless the elastic constant C44 is more than an order of magnitude smaller than previously reported values of ~ 108 ergs/cm3 the diffuse scattering can not be due to acoustic phonons. The crystalline-B to Smectic-A melting transition is strongly first order with no observable pre-transition effects on either side of the transition. |
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Keywords: | lateral cyano-substitution 1 1: 4′ 1′-terphenyls palladium-catalysed cross-coupling |
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