THEORETICAL STUDY OF THE SCATTERING OF LIGHT BY A FLUID DISPLAYING A SINGLE AXIS OF ISOTROPY: APPLICATION TO NEMATIC-TYPE LIQUID CRYSTALS,

Abstract

A theoretical study is made of the diffusion of light by a liquid composed of anisotropic particles which show fluctuations in orientation and are so distributed that the medium possesses a unique isotropic axis. Two cases are considered: (1) discrete anisotropic molecules; (2) large groups of parallel anisotropic molecules dispersed among isolated molecules. In the two cases the theory leads to depolarization factors greatly in excess of unity. Spherical groups, of radius 0.1 microns, containing 1,000,000 molecules of azoxy-anisole arranged parallel and inclined at an angle < 36 deg to the isotropic axis and single molecules inclined at an angle > 36 deg are discussed in detail, and the results obtained agree in order to magnitude with experiment. It can, therefore, be concluded that in nematic liquid crystals diffusion is due to fluctuations in the orientation of the molecules round the isotropic axis and that the fluctuations in two molecules can be treated as independent only if their separation exceeds 0.1 microns. (Author)

Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1965
Accession Number
AD0621938

Entities

People

  • Pierre Chatelain

Tags

DTIC Thesaurus Topics

  • Crystals
  • Depolarization
  • Diffusion
  • Liquid Crystals
  • Molecules
  • Orientation (Direction)
  • Particles

Fields of Study

  • Physics

Readers

  • Materials Science and Engineering.
  • Plasma Physics / Magnetohydrodynamics
  • Spectroscopy.