Slow Non-Critical Molecular Reorientation in the Isotropic Phases of Nematogens
We present measurements of the Optical Kerr Effect in the isotropic phase of the nematogen NEMATEL 105 (p-methoxy-benzoate-p′-n-pentyl benzene). In the vicinity of the nematic-isotropic transition temperature, as is well known, the response of the medium is essentially due to the fluctuations of the macroscopic order parameter, in agreement with the Landau-De Gennes theory. However, at high temperatures, the Kerr constant decreases more slowly than predicted by the theory. An explanation for this discrepancy is proposed for the first time involving the very short range cybotactic correlations of liquid crystal molecules in the isotropic phases.
KeywordsIsotropic Phase Liquid Crystal Molecule Optical Kerr Effect Kerr Constant Molecular Reorientation
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