Light scattering from non-Gaussian concentration fluctuations

Quasielastic light-scattering studies from a solution of 1-μm-diam polystyrene spheres indicate that at sufficient dilution the homodyne autocorrelation function is not consistent with the common assumption that the concentration fluctuations are Gaussian stochastic processes. In this note we show that the non-Gaussian behavior at low concentrations arises because the particles in the scattering volume are Poisson distributed. © 1972 The American Physical Society.