The two-step triple photoionization (TPI) process is investigated in the framework of many-body perturbation theory for the first time. Results on TPI partial cross sections from the Kr ground state to the fluorescing states of the Kr IV 4s-14p-2 configuration are obtained by numerical calculations in the energy range of Kr I 3d-1np resonances. Several mechanisms of two-step TPI are discussed, of which the low-energy double-Auger transitions 3d-1 → 4s-1 4p-2 + 2e are investigated in detail. The energy distribution functions of the Auger electrons for the different orbital momenta of the ejected two Auger electrons as well as the total transition probability are presented. Comparison of the calculated TPI cross section with experimental data obtained by photon-induced fluorescence spectroscopy demonstrates quite clearly the shortcomings of the two-step approximation for a quantitative description of the process, at least in the energy region under consideration. Nevertheless qualitative agreement has been achieved which explains in principle the new fluorescence transitions in Kr IV observed after excitation of the atom by photons of an energy from 90 to 100 eV.
|Number of pages||13|
|Journal||Journal of Physics B: Atomic, Molecular and Optical Physics|
|Publication status||Published - 28 Dec 1997|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physics and Astronomy(all)