A diagrammatic representation of data on scattering from large particles, corresponding to the equation: and used for the simultaneous evaluation of the mass average molar mass, , the second virial coefficient of the chemical potential, , and (usually) the z-average radius of gyration, ; is the mass concentration of the solute, the excess Rayleigh ratio, and the particle scattering function that comprises (usually) the z-average radius of gyration. depends on the solute, the temperature and the type of radiation employed. Several modifications of the Zimm plot are in frequent use; the most common one uses the excess scattering instead of the excess Rayleigh ratio.