At the intermediate x ≃ 1 of Mie scattering, interference effects develop through phase variations over the surface but when the scattering particle is very small (x ≪ 1) these disappear and the whole surface re-radiates with the same phase.
At the intermediate x ≃ 1 of Mie scattering, interference effects develop through phase variations over the surface. Rayleigh scattering applies to the case when the scattering particle is very small (x ≪ 1) and the whole surface re-radiates with the same phase.