Diffusion effects in solutions of Brownian particles

Abstract

The theory of light scattering from a solution of interacting spherical macroparticles as presented by Altenberger and Deutch (see J. Chem. Phys., vol.59, p.894, 1973) is re-examined. The Oseen model for the hydrodynamical interaction between the particles, is shown to omit a lowest order concentration term to the effective diffusion coefficient. This model is corrected to lowest order in the ratio of particle diameter to interparticle separation and the effective diffusion coefficient re-calculated. It is found that D_eff=D⁰(1+3.0 phi ), where D⁰ is the infinite-dilution self-diffusion coefficient for the particles and phi is the volume fraction. This is compared with earlier theoretical and experimental results.