Photoelectron recapture observed via second-step Auger decay

Abstract

Electron spectra of second-step Auger decay were taken in small steps in the vicinity of the Ne 1s → np resonances and in the near threshold regime. The spectra reveal that above the K-shell ionization limit energetically forbidden second-step Auger decay has still considerable intensity. We attribute this intensity to a recapture process of the primary photoelectron into unoccupied states and subsequent emission of a valence electron via second-step or cascade Auger decay. It is to our knowledge the first observation of delayed cascade Auger post collision interaction.