Observation of participator Auger decay following valence photoionization with excitation

‘‘Complete’’ valence photoelectron spectra of neon and argon have been measured at several photon energies between 50 and 150 eV. Besides a symmetric shake-off energy spectrum as anticipated theoretically many unexpected electron lines with fixed kinetic energy were observed, particularly in the low-energy part of the spectra. These lines are identified as due to participator Auger transitions from inner-valence satellite states. The consequence of the measured strengths of the valence Auger transitions regarding the common interpretation of valence double-ionization rates in terns of shake-off processes is discussed.