The observation of electronic motion remains a key target in the development of the eld of attoscience.
However, systems in which long-lived oscillatory charge migration may be observed must be selected carefully,
particularly because it has been shown that nuclear spatial delocalization leads to a loss of coherent electron
density oscillations. Here we demonstrate electron dynamics in norbornadiene and extended systems where
the hole density migrates between two identical chromophores. By studying the e ect of nuclear motion
and delocalization in these example systems, we present the physical properties that must be considered in
candidate molecules in which to observe electron dynamics. Furthermore, we also show a key contribution to
nuclear delocalization arises from motion in the branching plane of the cation. For the systems studied, the
dephasing time increases with system size while the energy gap between states, and therefore the frequency of
the density oscillation, decreases with size (obeying a simple exponential dependence on the inter-chromophore
distance). We present a system that balances these two e ects and shows several complete oscillations in the
spin density before dephasing occurs.