Journal ArticleDOI
Molecular theory of the smectic E , H , and VI phases
TLDR
In this paper, the authors extended the molecular theory of the smectic $B$ and $H$ phases by including the phenyl-phenyl interaction in addition to the dipole-dipole potential used previously.Abstract:
The molecular theory of the smectic $B$ and $H$ phases is extended to the smectic $E$ and VI phases by including the phenyl-phenyl interaction in addition to the dipole-dipole potential used previously. This phenyl-phenyl interaction contains quadrupole-quradrupole, dispersive, and exchange terms. The possibility of both dipolar and "herringbone" order is considered in the self-consistent-field approximation. Four phases are found, all with a two-dimensional hexagonal lattice assumed: (1) a disordered phase (smectic $B$); (2) an oriented phase in which dipoles align (smectic $H$); (3) a herringbone phase with phenyl groups ordered (smectic $E$); (4) and a herringbone phase with both phenyl groups and dipoles ordered (smectic VI). In the phases with dipolar order the director is tilted with respect to the normal to the plane. The transitions vary in order. The temperature dependence of the order parameters, entropy, and specific heat are computed.read more
Citations
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Random motion of a uniaxial rotator in an N-fold cosine potential: Correlation functions and neutron incoherent scattering law
A.J. Dianoux,F. Volino +1 more
TL;DR: In this paper, the properties of a particle undergoing circular rotational motion in an N-fold cosine potential are investigated in detail and the rate equation for the probability function is given and order parameters are defined.
Book ChapterDOI
Polymorphism in Thermotropic Liquid Crystals
TL;DR: In this paper, a synthese sur les phases smectiques de substances avec des molecules type bâtonnet en structure en couche is presented, i.e.
Journal ArticleDOI
X-Ray Diffraction by Liquid Crystals
TL;DR: In this paper, x-ray diffraction by nematic and smectic liquid crystals is critically examined in terms of the data available and the structural models and molecular theories that have been proposed to explain it.
Journal ArticleDOI
X-ray diffraction of the smectic phases of N-(p-n-heptyloxybenzylidene)-p′-n-pentylaniline
W. H. De Jeu,J.A. De Poorter +1 more
TL;DR: Using X-ray diffraction the various smectic phases of N-(p -n -heptyloxybenzylidene)- p ′-n -pentylaniline can be classified (with increasing temperature) as S H, S B, S C and S A, respectively as discussed by the authors.
References
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Journal ArticleDOI
Eine einfache molekular-statistische Theorie der nematischen kristallinflüssigen Phase. Teil II
Wilhelm Maier,Alfred Saupe +1 more
TL;DR: In this paper, the authors describe a mittlere Innere Feld einer nematischen Molekülanordnung abgeleitet, and gezeigt, daß this Innere Field in einem gewissen Temperaturbereich einen nematicalhen Ordnungszustand bewirken muß and daß dieser ordnung sustand was with einer bestimmten Temperatur diskontinuierlich und unter Energieaufnahme in die isot
Journal ArticleDOI
Eine einfache molekulare Theorie des nematischen kristallinflüssigen Zustandes
W. Maier,Alfred Saupe +1 more
Journal ArticleDOI
Simple Molecular Model for the Smectic A Phase of Liquid Crystals
TL;DR: In this article, the Maier-Saupe model with an orientational order parameter is extended to the smectic $A$ phase by introducing a new order parameter, the amplitude of a density wave in the direction of the nematic preferred axis.
Journal ArticleDOI
An analogy between superconductors and smectics A
TL;DR: The role of the phase in the second order smectic A↔ nematic transition is similar to the role of phase functions in superconductors as mentioned in this paper, where twist and bend distortions correspond to magnetic fields.