Postcollision interaction in sequential x-ray radiative and Auger decays after atomic inner-shell photoionization

A quantum many-body approach to treat the postcollision interaction (PCI) effect in the process of innershell atomic photoionization followed by sequential x-ray radiative and electron Auger decays of inner-shell vacancies has been developed. The energy spectra of both the emitted photoelectrons and Auger electrons have been calculated, compared with experimental measurements, and its PCI distortion has been analyzed. The energy sharing between three emitted particles, photoelectron, Auger electron, and photon, drastically changes the energy distribution of electron emission compared to the case of single Auger decay of inner vacancy. Experimentally, the photoelectron energy distribution has been measured in argon 1s ionization in coincidences with L-2,L-3 - M2,3M2,3 Auger electrons and doubly charged ions. Comparison of calculated and experimental spectra confirms the validity of the developed theory. Calculated line shapes of the Auger electrons also fairly reproduce the measured earlier LMM Auger lines in Ar atom.