Excluded-volume effect on quasi-elastic light scattering by flexible macromolecules.

First-order perturbation expressions are developed for the first cumulant (initial time derivative) of the dynamic structure factor observable by photon-correlation measurements of the light scattered by flexible chain molecules in solution. A dimensionless coefficient C, which measures the initial departure of the first cumulant from proportionality to the square of the scattering vector, is found to be only slightly altered by excluded-volume effects.