The analysis of post-collision interactions in ejected-electron spectra

The quantal shake-down model is used to analyse structures observed in the spectra of electrons ejected from autoionizing states of helium excited by near-threshold electron impact. Relative amplitudes and phases are obtained for the excitation at an incident energy of 60.2 eV of the (2s2)1S and (2s2p)3P states. The existence of coherence between the electrons ejected from these two states is discussed.