Theory of dynamic light scattering from polydisperse systems

Abstract

Analytical expressions for the light scattering autocorrelation function of Schulz distributed Rayleigh–Debye particles are presented. The theory is shown to be valid for spheres, thin rods, disks, and Gaussian coils executing translational diffusion. The polydisperse form factors for these shapes are also given. Analysis of polydisperse data with the expressions given yields the diffusion coefficient of the number average species and the Schulz polydispersity parameter. The effects of polydispersity on the angular dependence of the decay time and the conditions under which the form factor can be neglected are discussed.