DOUBLE-SCATTERING EFFECTS IN DEPOLARIZED LIGHT-SCATTERING SPECTROMETRY

Measurements of rotational diffusion coefficients by depolarised light scattering spectrometry are often disturbed by double-scattering effects. These effects may be reduced by minimising the concentration of scatterers and by using an appropriate geometry. Such an optimum geometry is proposed. Explicit expressions for the contribution of double scattering to the field correlation function are computed for the optimum geometry. The correlation functions evaluated numerically are compared with experimental data in the case of polystyrene latex spheres. The agreement is excellent. The expressions derived can be used to correct correlation functions obtained experimentally in case double scattering cannot be avoided.