  Laser control of ultrafast double proton transfer is investigated for a
two-dimensional model system describing stepwise and concerted transfer
pathways. The pulse design has been done by employing optimal control theory in
combination with the multiconfiguration time-dependent Hartree wave packet
propagation. The obtained laser fields correspond to multiple pump-dump pulse
sequences. Special emphasis is paid to the relative importance of stepwise and
concerted transfer pathways for the driven wave packet and its dependence on
the parameters of the model Hamiltonian as well as on the propagation time.
While stepwise transfer is dominating in all cases considered, for high barrier
systems concerted transfer proceeding via tunneling can make a contribution.
