Cage effect in the viscoelasticity of a suspension of hard spheres withouthydrodynamic interaction

The linear viscoelastic response of a suspension of Brownian hard spheres w ithout hydrodynamic interaction is studied in an approximation in which the influence of neighboring particles on the dynamics of a selected pair is t aken into account via the potential of mean force. It is shown that the cag e effect due to the barrier imposed by neighbors has a profound influence o n the frequency-dependence of the viscoelastic response. Analytic calculati ons are performed for a square well-barrier model of the potential of mean force. (C) 2001 American Institute of Physics.