Generalized Langevin equation for non-spherical colloidal particles

A general theory is presented to describe the effects of the direct interactions between a labelled non-spherical colloidal particle with other (spherical or non-spherical) particles diffusing around it, on the translational and rotational tracer-diffusion properties of the former. Approximate, but general, expressions are derived for these dynamic properties of terms of static structural properties of the system, in the generic case in which the particles with which the non-spherical tracer interacts are spherical. The specific use of these results is illustrated with the calculation of the rotational diffusion coefficient of a Brownian dipole that interacts with a Brownian one-component plasma, and of an ellipsoidal polyion interacting with its own electrical double layer (electrolyte friction on tobacco mosaic virus).