https://doi.org/10.1351/goldbook.09354
Multi-electron process in which an atom is left in an excited state following a photoionization or Auger electron process, so that the outgoing electron has a characteristic kinetic energy slightly less than that of the parent photoelectron.
Note: Shakeup peaks are usually observed within \(\pu{10 eV}\) of the parent peak. However, for gases where the background is low, shakeup peaks have been identified at kinetic energies up to \(\pu{100 eV}\) less than that of the parent peak.
See also: shakeoff