2 research outputs found
Molecular theory of elastic constants of liquid crystals. III. Application to smectic phases with tilted orientational order
Using the density functional formalism we derive expression for the
distortion free energy for systems with continuous broken symmetry and use it
to derive expression for the elastic constants of smectic phases in which
director is tilted with respect to the smectic layer normal. As in the previous
papers of the series (Phys. Rev. A {\bf 45}, 974 (1992), E {\bf 49}, 501,
(1994)) the expressions for the elastic constants are written in terms of order
and structural parameters. The structural parameters involve the generalised
spherical harmonic coefficients of the direct pair correlation function of an
effective isotropic liquid. The density of this effective isotropic liquid
depends on the nature and amount of ordering present in the system and is
evaluated self- consistently. We estimate the value of elastic constants using
reasonable guess for the order and structural- parameters.Comment: 31 pages; 1 Fig. in GIF format, To be appear in Phys. Rev.