%\subsection{Calculation of excitation energies and residuals \editor{Gunter}}

At the end of the cascade, we form a fragment for further treatment in
precompound and nuclear de-excitation models (\cite{deexcitation}).

These models need information about the nuclear fragment created by the cascade.
The fragment is characterized by the number of nucleons in the fragment, 
the charge of the fragment, the number
of holes, the number of all excitons, and the number of charged excitons, and the
four momentum of the fragment.

The number of holes is given by the difference of the number of nucleons in the
original nucleus and the number of non-excited nucleons left in the fragment.
An exciton is a nucleon captured in the  fragment at the end of the cascade.

The momentum of the fragment calculated by the difference between the momentum of
the primary and the outgoing secondary particles must be split in two
components. The first is the momentum acquired by coherent elastic effects, and
the second is the momentum of the excitons in the nucleus rest frame. Only the
later part is passed to the de-excitation models. Secondaries arising from
de-excitation models, including the final nucleus, are transformed back
the frame of the moving fragment.
