Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.21/3586
Título: Biaxial Nematic Order in the Hard-boomerang Fluid
Autor: Teixeira, Paulo Ivo Cortez
Palavras-chave: Biaxial nematic phase
Molecular theory
Onsager approximation
Data: 1998
Editora: Gordon Breach Publishing
Citação: TEIXEIRA, P. I. C.; MASTERS, A. J.; MULDER, B.M. - Biaxial Nematic Order in the Hard-boomerang Fluid. Molecular Crystals and Liquid Crystals Science and Techonology Section A-Molecular Crystals and Liquid Crystals. ISSN: 1058-725X. Vol. 323 (1998), p. 167-189.
Resumo: We consider a fluid of hard boomerangs, each composed of two hard spherocylinders joined at their ends at an angle Psi. The resulting particle is nonconvex and biaxial. The occurence of nematic order in such a system has been investigated using Straley's theory, which is a simplificaton of Onsager's second-virial treatment of long hard rods, and by bifurcation analysis. The excluded volume of two hard boomerangs has been approximated by the sum of excluded volumes of pairs of constituent spherocylinders, and the angle-dependent second-virial coefficient has been replaced by a low-order interpolating function. At the so-called Landau point, Psi(Landau)approximate to 107.4 degrees, the fluid undergoes a continuous transition from the isotropic to a biaxial nematic (B) phase. For Psi not equal Psi(Landau) ordering is via a first-order transition into a rod-like uniaxial nematic phase (N(+)) if Psi > Psi(Landau), or a plate-like uniaxial nematic (N(-)) phase if Psi < Psi(Landau). The B phase is separated from the N(+) and N(-) phases by two lines of continuous transitions meeting at the Landau point. This topology of the phase diagram is in agreement with previous studies of spheroplatelets and biaxial ellipsoids. We have checked the accuracy of our theory by performing numerical calculations of the angle-dependent second virial coefficient, which yields Psi(Landau)approximate to 110 degrees for very long rods, and Psi(Landau)approximate to 90 degrees for short rods. In the latter case, the I-N transitions occur at unphysically high packing fractions, reflecting the inappropriateness of the second-virial approximation in this limit.
Peer review: yes
URI: http://hdl.handle.net/10400.21/3586
ISSN: 1058-725X
Versão do Editor: http://www.tandfonline.com/doi/abs/10.1080/.U4dIPYZJ6vw
Aparece nas colecções:ISEL - Física - Artigos

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