Anisotropy of the local field of the light wave in cholesteric liquid crystals |
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Authors: | E M Aver’yanov |
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Institution: | (1) Russian Academy of Sciences Inst. Crystallography, Leninskii prospect 69, 119333 Moscow, Russia; |
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Abstract: | The experimental values of the L
j
components of the Lorentz tensor have been obtained for the first time for the quasinematic layer of the cholesteric phase
and in the smectic phase A for homologs of cholesteric fatty ethers using the dispersion dependences of the refraction indices for the planar texture
of cholesteric liquid crystals (CLCs). The dependence of the L
j
components on the homolog number, mesophase temperature, the magnitude of birefringence, and the change in the orientational
ordering of molecules in the cholesteric phase and at the cholesteric-smectic A phase transition was determined. Isotropization
of the Lorentz tensor L and the local field tensor f was found for CLCs when the birefringence of LCs and the anisotropy of molecular polarizability decreased simultaneously.
The anisotropy Δf was found to be negative for the quasinematic layer of CLCs and the smectic phase in the visible range of the spectrum. The
values of L
j
, obtained with known local field models for CLCs and smectics A, gave positive Δf irrespective of the chemical structure of molecules, optical anisotropy of LCs, and the spectral region, which contradicts
to the experiment. |
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Keywords: | |
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