Polydispersity effects in the small-angle scattering of concentrated solutions of colloidal spheres

Calculations are presented of the intensity of radiation scattered by a polydisperse system of spherical particles at finite concentrations where interparticle interference of the scattered waves becomes important. The results apply to small-angle (x-ray and neutron) scattering and to light scattering of a solution of particles in the colloidal size range. Use is made of a closed expression for the scattering of a multicomponent mixture of hard spheres recently derived by one of us. The derivation is based on Baxter’s solution of the Percus–Yevick approximation for hard sphere fluids.