Accession Number : AD0808696

Title :   QUANTITATIVE DIMENSIONAL CHARACTERIZATION OF NONSPHERICAL OBJECTS FROM THEIR LIGHT SCATTERING IN STREAMING SYSTEMS.

Descriptive Note : Technical rept.,

Corporate Author : WAYNE STATE UNIV DETROIT MI DEPT OF CHEMISTRY

Personal Author(s) : Doppke, Herbert J. ; Heller, Wilfried

Report Date : 01 MAR 1967

Pagination or Media Count : 11

Abstract : The dimensions of nonspherical particles and of macromolecules which are not freely flexible coils, may be determined from light scattering by means of Zimm Plots, if the Rayleigh-Gans approximations apply. An alternate optical method is given by measurements of streaming birefringence. The present paper describes a new method which is based upon an old principle pointed out first by Freundlich and Diesselhorst (1916). The liquid containing the crystals or macromolecules is placed into a concentric cylinder apparatus, the outer cylinder being at rest and the inner being rotatable. The light scattered from the system is observed at angles of observation that can be varied between 75 and 105 degrees with respect to the streamlines, maintaining an angle of observation of 90 degrees with respect to the primary beam and to the axis of the rotating cylinder. From the angular variation of light scattering within the limits given, one can calculate the dimensions of the scattering object. On approximating them as prolate or oblate spheroids, one can use the theory of Peterlin and Stuart (1939) pertinent to streaming birefringence. Results obtained with various suspensions of colloidal crystals and with tobacco mosaic virus solutions are given. They agree very well with data obtained by electron microscopy. The effect with colloidal crystals is very large, the increase in scattered intensity being easily 40% or more in excess of the scattering observed at rest. Application of the method to a determination of the dimensions of macromolecules is underway. (Author)

Descriptors :   (*OPTICAL IMAGES, SCATTERING), (*BIREFRINGENCE, MOLECULES), (*LIGHT TRANSMISSION, OPTICAL IMAGES), OPTICS, COLLOIDS, VIRUSES, ELECTRON MICROSCOPY, CRYSTAL STRUCTURE, SPHERES, PARTICLE SIZE, REFRACTIVE INDEX, ANISOTROPY.

Subject Categories : Optics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE