Elastic Scattering of Light From Particles

Elastic scattering is divided into two types: Rayleigh, or small-particle scattering, and large-particle scattering. Rayleigh scattering occurs when the scattering particle’s largest dimension is less than 5% of the radiation’s wavelength. The intensity of the scattered radiation is proportional to its frequency to the fourth power, ν⁴—accounting for the greater scattering of blue light than red light—and is symmetrically distributed, as shown in (a) below. For larger particles, scattering increases in the forward direction and decreases in the backwards direction as the result of constructive and destructive interferences, as shown in (b).