  We show that nuclear motion of Rydberg atoms can be induced by resonant
dipole-dipole interactions that trigger the energy transfer between two
energetically close Rydberg states. How and if the atoms move depends on their
initial arrangement as well as on the initial electronic excitation. Using a
mixed quantum/classical propagation scheme we obtain the trajectories and
kinetic energies of atoms, initially arranged in a regular chain and prepared
in excitonic eigenstates. The influence of off-diagonal disorder on the motion
of the atoms is examined and it is shown that irregularity in the arrangement
of the atoms can lead to an acceleration of the nuclear dynamics.
