  The population of rotational states in the ground-state band of neutron-rich
fragments emitted in the spontaneous fission of $^{252}$Cf is described within
a time-dependent quantum model similar to the one used for Coulomb excitation.
The initial population probability of the states included in the selected basis
is calculated according to the bending model at scission. Subsequently these
initial amplitudes are feeding the coupled dynamical equations describing the
population of rotational states in both fragments during the tunneling and
post-barrier (pure Coulomb) motion. As application we consider the high yield
Mo-Ba pair for different number of emitted neutrons.
