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

The dynamic light scattering from an assembly of axially symmetric model particles is studied with the purpose of showing the effects that occur when the scatterers are strongly anisotropic or their size is large. The particles that we deal with are built as linear chains of spherical scatterers, because we are able to calculate with no approximation the field scattered by these compound objects and to perform analytically the orientational averages that are necessary for calculating the scattered intensity. The latter turns out to be a linear combination of terms that are classified by the same quantum number L that labels the rotational states of the scatterers. Unlike the case in which the scattering is described in the Rayleigh approximation, our terms have an intrinsic dependence on the angle of scattering that is superposed upon the angular dependence that is due to the dynamic structure factor. In cross polarization our treatment yields nonnegligible terms with L = 4 that cannot appear in the Rayleigh scattering approximation.