Consistently averaged hydrodynamic interaction for Rouse dumbbells: Translational diffusivity

The recently developed Hookean dumbbell model with consistently averaged hydrodynamic interaction is used to discuss the translational diffusivity of polymers in dilute solutions undergoing homogeneous flows. An anisotropic diffusivity, different diffusion tensors for different definitions of translational diffusivity, and important effects caused by the distribution of the mass of a single polymer molecule in space are found. The results of this paper imply that the well-known Nernst–Einstein equation can not be generalized to the diffusion of polymers in flowing solutions.