Accession Number : AD0621938

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

Corporate Author : HOLMAN (JOHN F) CO INC WASHINGTON D C

Personal Author(s) : Chatelain,Pierre

Report Date : OCT 1965

Pagination or Media Count : 16

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)

Descriptors :   (*CRYSTALS, LIQUIDS), (*LIGHT, SCATTERING), (*LIQUIDS, CRYSTALS), CRYSTAL STRUCTURE, ISOTROPISM, DIFFUSION, OPTICAL PROPERTIES, POLARIZATION, ORGANIC NITROGEN COMPOUNDS, ETHERS, FRANCE

Distribution Statement : APPROVED FOR PUBLIC RELEASE