Autocorrelation of Scattered Field

1 Autocorrelation of Scattered Field We assume that the scattering volume contains p identical small particles and consider the autocorrelation function of Es(f) for the scattering by the volume. Examples include a suspension of colloidal particles. The autocorrelation of the scattering by a polymer solution will be discussed in Section 3.2.6. 

Another photon detected at r and t + t is scattered by the particles at r ( = 1, 2. p) at to + T. Motion of the particles makes and r in general different. The reference point has moved to rj as weU, and the scattering occurs at to + t. The incident light has changed its phase, since it hit particle 1 at rj and to. We take into account the phase shift due to the change in the scattering by the reference. We find 

The last transformation is allowed becanse the system is stationary. The autocorrelation function for t = 0 is 

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