  First-order perturbation theory and many-body Green function analysis are
used to quantify the influence of size, surface reconstruction and surface
treatment on exciton transport between small silicon quantum dots. Competing
radiative processes are also considered in order to determine how exciton
transport efficiency is influenced. The analysis shows that quantum confinement
causes small (~1 nm) Si quantum dots to exhibit exciton transport efficiencies
far exceeding that of their larger counterparts. We also find that surface
reconstruction significantly influences the absorption cross section and leads
to a large reduction in both transport rate and efficiency. Exciton transport
efficiency is higher for hydrogen passivated dots as compared with those
terminated with more electronegative ligands. This is because such ligands
delocalize electron wave functions towards the surface and result in a lower
dipole moment. Such behavior is not predicted by F\"orster theory, built on a
dipole-dipole approximation, because higher order multi-poles play a
significant role in the exciton dynamics.
