  Reversible diffusion limited cluster aggregation of hard spheres with rigid
bonds was simulated and the self diffusion coefficient was determined for
equilibrated systems. The effect of increasing attraction strength was
determined for systems at different volume fractions and different interaction
ranges. It was found that the slowing down of the diffusion coefficient due to
crowding is decoupled from that due to cluster formation. The diffusion
coefficient could be calculated from the cluster size distribution and became
zero only at infinite attraction strength when permanent gels are formed. It is
concluded that so-called attractive glasses are not formed at finite
interaction strength.
