Scattering pattern of a quasitransparent core-shell particle

Abstract
Nonisotropic scattering patterns showing a minimum for small and almost transparent core-shell particles are discussed. It is shown that the Rayleigh-Gans theory will not predict accurately the scattering by such particles. A law of corresponding patterns is established for small core-shell particles with an effective index of refraction as close as possible to that of the medium. Based on this nonisotropic scattering phenomenon, a method for determining the thickness itself and its distribution of very thin coatings on small colloidal particles is proposed.