Effect of a finite collection aperture on autocorrelation light-scattering spectroscopy*

We have discussed the effect of using a finite aperture in the collection optics of autocorrelation light-scattering experiments. Finite-aperture broadening has no substantial effect on the central Rayleigh component in the absence of external fields. However, such effects are very important for Brillouin and electrophoretic light-scattering experiments. Finite-aperture effects cannot explain the discrepancy between the measurements by Berge et al. and Jamieson and Walton of the mutual diffusion coefficient of the carbon disulfide-acetone system.