A diagrammatic representation of data on scattering from large particles, corresponding to the equation: \[\frac{K_{c}}{\Delta R (\theta)} = \frac{1}{\bar{M}_{\text{w}}\ P (\theta)}+2\ A_{2}\ c+\text{ ... }\] and used for the simultaneous evaluation of the mass average molar mass, M ̄ w, the second virial coefficient of the chemical potential, A2, and (usually) the z-average radius of gyration, s 2 z 1 2; c is the mass concentration of the solute, ΔRθ the excess Rayleigh ratio, and P θ the particle scattering function that comprises (usually) the z-average radius of gyration. K 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.