  Intense light with frequencies above typical atomic or molecular ionization
potentials as provided by free-electron lasers couples many photons into
extended targets such as clusters and biomolecules. This implies, in contrast
to traditional multi-photon ionization, multiple single-photon absorption.
Thereby, many electrons are removed from their bound states and either released
or trapped if the target charge has become sufficiently large. We develop a
simple model for this photo activation to study electron migration and
interaction. It satisfies scaling relations which help to relate quite
different scenarios. To understand this type of multi-electron dynamics on very
short time scales is vital for assessing the radiation damage inflicted by that
type of radiation and to pave the way for coherent diffraction imaging of
single molecules.
