Summary: 2.1. Summary of the scientific program
In our scientific program we study different actual subjects, which are among those where large efforts
(also financial) are currently made in theoretical and experimental physics. We are especially interested
in problems, which are investigated, e.g., at PSI, CERN (SPS & LHC), GSI (especially FAIR), CEBAF
(TJNAF), MSU (RIA) or at RHIC (BNL). The new experimental data obtained at these facilities ask for
new theoretical descriptions or at least for an improvement of existing methods.
In atomic physics, we study mainly the excitation and ionization of atoms in ion-atom collisions, because
the detailed knowledge of these processes is important, e.g., in plasma-, astro- or surface physics. We treat
these reactions by using the semiclassical approximation, the Born-approximation in first or in higher order
or in the Glauber approximation, but in all our calculations we use the full quantum mechanical description
of the electronic states, e.g., relativistic hydrogenic wave functions or Dirac-Fock wave functions. For the
ionization of electrons from outer shells, the intra-shell couplings become important, which are treated
by us in a perturbative way. In strong collaboration with experimental groups worldwide we test our
refined reaction model by comparing it with recent data and we make predictions and suggestions for new
experiments to study, e.g., correlation effects. An important application of our methods developed in atomic
physics is the calculation of excitation and breakup of exotic atoms and their propagation through matter.
The detailed knowledge of these processes is crucial for the interpretation of the experiment DIRAC at
CERN (and its possible continuation at J-PARC and/or GSI), which aims at measuring the lifetime of
pionium and in the future also of other atoms like kaonium, thus testing some important prediction of
quantum chromodynamics and chiral perturbation theory.