Photon correlation spectroscopy of particle distributions

A least‐squares method for correlation function profile analysis using a histogram approximation is described. The method is completely general, especially for bimodal distributions, and compares favorably with the method of cumulants. The measured photoelectron time‐correlation function yields a histogram of the linewidth distribution which can be related uniquely to the particle size. The analysis is tested using simulated data with unimodal and bimodal size distributions. In our verification of the method using aqueous suspensions of Dow latex spheres, we have shown that our method is not only consistent with the results from electron microscopy, but that it is more precise and truly measures the hydrodynamic size of particles suspended in fluids.