Post-collision interaction effects of threshold photoelectrons in Kr -shell photoionization

Abstract

A threshold photoelectron spectrum and its component spectra of Auger cascades following Kr -shell photoionization have been measured by a threshold photoelectron-ion coincidence technique. These spectra exhibit characteristic profiles of post-collision interaction effects induced by the Auger cascades. Peak shifts of the profiles increase gradually according to the times of the interactions, but peak widths of the profiles are almost independent of the times of interactions. These characteristics are analysed in terms of a simple model based on the assumption that double-Auger (Auger shake-off) decays reduce the effective number of steps of the Auger cascades.

Influence of double Auger decay on low-energy 3dphotoelectrons of krypton

“…In the case of inner-shell photoionization followed by DA decay, PCI implies the interaction of the emitted photoelectron with the two subsequent Auger electrons and with the field of the ion, which varies during the Auger decay. Previously, PCI effects in DA processes have been investigated experimentally by means of threshold photoelectron yields measured in the vicinity of inner-shell vacancies: Kr 1s −1 , Kr 2p −1 , Kr 3p −1 , Ar 1s −1 , Ar 2p −1 , Xe 4p −1 , and Xe 4d −1 [9][10][11][12][13][14][15][16][17][18]. Also an investigation of PCI-distorted photoelectron lines associated with DA decay and measured in coincidence with the two ejected Auger electrons has been carried out more recently for the case of Ar 2p photoionization [19].…”

Time dependent aspects in the ionizations following atomic photoexcitations

“…When we have post-collision effects in the cases of cascading Auger transitions after the deep inner-shell photoionization of atoms, we may observe the multiple-electron correlation effects in the energy spectra of photoelectrons or photoions [11]. Koike [9] has extended his wavepacket formalism [7] to the cases of multi-step Auger cascade.…”

“…The post-collision interaction effect is a time stamp placed on the energy spectra of emitted or scattered electrons [6][7][8]. We can, furthermore, observe the enhancement of the post-collision effects in the multiple-electron escape from the Auger cascade of the deep inner-shell photoionized atomic ions [9][10][11].…”

“…In Section 2.2, we consider the time correlations between multiple electrons which start to leave atoms at different instances. Due to the correlations among the escaping electrons, we sometimes observe the effects that are so called post-collision interaction effects [7,10,11]. An electron that is emitted from an atom at an instance will propagate forming a wavepacket.…”

Formation of multi-charged Kr ions through photoionization of 2p electrons studied with a coincidence technique

“…Recently deep core orbitals like Kr 2p, Kr 1s and Ar 1s were photoionized and generated particles were measured using some techniques (Levin et al, 1990;Armen et al, 2004;Hayaishi et al, 1999). The coincidence study using K a fluorescence in the energy region of the Kr 1s transition provided charge state distributions of Kr ions from the 2p À1 nl state and the 2p À1 state.…”