This self-contained text introduces readers tothe field of high-energy atomic physics - a new
regime of photon-atominteractions in which the photon energies significantly exceed the atomic
ormolecular binding energies and which opened up with the recent advent of newsynchrotron
sources.From a theoretical point of view a small-parametercharacteristic of the bound system
emerged making it possible to performanalytic perturbative calculations that can in turn serve
as benchmarks formore powerful numerical computations. The first part of the book introduces
readersto the foundations of this new regime and its theoretical treatment. Inparticular the
validity of the small-parameter perturbation expansion and ofthe lowest-order approximation is
critically reviewed. The following chaptersthen apply these insights to various atomic
processes such as photoionizationas a many-body problem dominant mechanisms for the
production of ions athigher energies Compton scattering and ionization accompanied by creation
ofe-e+ pairs and the photoionization of endohedral atoms (e.g. fullerene). Lastbut not least
the computationally challenging transitions in the electronshell during certain types of
nuclear decays are investigated in detail.
