Scattering in the Isotropic Phase of Liquid Crystals

LIGHT SCATTERING IN THE ISOTROPIC PHASE OF LIQUID CRYSTALS 

In the isotropic phase director axis orientations are random. The optical dielectric constant, a thermal average, is therefore a scalar parameter. The fluctuations in this case are due mainly to fluctuations in the density of the liquid caused by temperature fluctuations. 

Denoting the average dielectric constant in the isotropic phase by s and denoting the local change in the volume by u(r), the dielectric constant may be expressed as 

The compressional energy associated with the volume ehange is 

This finally gives the differential cross section 

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