No abstract

No abstract

The Kr 4s-electron photoionization cross section as a function of the excitingphoton energy in the range between 30 eV and 90 eV was calculated using the configuration interaction (CI) technique in intermediate coupling. In the calculations the 4p spin-orbital interaction and corrections due to higher orders of perturbation theory (the so-called Coulomb interaction correlational decrease) were considered. Energies of Kr n states were calculated and agree with spectroscopic data within less than 10 meV. For some of the Kr 11 states new assignments were suggested on the basis of the largest component among the calculated CI wavefunctions.

Absolute cross sections for the transitions of the Kr atom into the 4s land 4p4nl states of the Kr + ion were measured in the 4s-electron threshold region by photon-induced fluorescence spectroscopy (PIFS). The cross sections for the transitions of the Kr atom into the 4sland 4p4nl states were also calculated, as weIl as the 4p4nln'I' doubly excited states, in the frame of LS-coupling many-body technique. The cross sections of the doubly-excited atomic states were used to illustrate the pronounced contributions of the latter to the photoionization process, evident from the measurements. The comparison of theory and experiment led to conclusions about the origin of the main features observed in the experiment.

No abstract