科研之友
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摘要
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 Delta f 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 Delta f irrespective of the chemical structure of molecules, optical anisotropy of LCs, and the spectral region, which contradicts to the experiment.
- 出版日期2010-5
