THEORETICAL DESCRIPTION OF DYNAMIC LIGHT-SCATTERING FROM AN ASSEMBLY OF LARGE AXIALLY-SYMMETRICAL PARTICLES

The dynamic light scattering from an assembly of axially symmetric mod el particles is studied with the purpose of showing the effects that o ccur when the scatterers are strongly anisotropic or their size is lar ge. The particles that we deal with are built as linear chains of sphe rical scatterers, because we are able to calculate with no approximati on the field scattered by these compound objects and to perform analyt ically the orientational averages that are necessary for calculating t he scattered intensity. The latter turns out to be a linear combinatio n of terms that are classified by the same quantum number L that label s the rotational states of the scatterers. Unlike the case in which th e scattering is described in the Rayleigh approximation, our terms hav e an intrinsic dependence on the angle of scattering that is superpose d upon the angular dependence that is due to the dynamic structure fac tor. In cross polarization our treatment yields nonnegligible terms wi th L = 4 that cannot appear in the Rayleigh scattering approximation.