Dynamics of electron emission in double photoionization processes near the krypton 3d threshold

Abstract

Abstract.Two electron emission following photoabsorption near the Kr 3d threshold is investigated both experimentally and theoretically. On the experimental side, electron / electron coincidences using a magnetic bottle time of flight spectrometer allow us to observe the complete Double Photo Ionisation (DPI) continua of selected Kr 2+ final states, and to see how these continua are affected by resonant processes in the vicinity of the Kr 3d threshold. The analysis is based on a quantum mechanical approach that takes into account the contribution of three different processes: A) Auger decay of the inner 3d vacancy with the associated post collision interaction (PCI) effects, B) capture of slow photoelectrons into discrete states followed by valence multiplet decay (VMD) of the excited ionic states and C) valence shell DPI. The dominant process for each Kr 2+ (4p −2 ) final state is the photoionization of the inner shell followed by Auger decay of the 3d vacancies. Moreover, for the 4p −2 ( 3 P ) and 4p −2 ( 1 D) final ionic states an important contribution comes from the processes of slow photoelectron capture followed by VMD as well as from double ionization of the outer shell involving also VMD.Confidential: not for distribution.

Angular Correlation between Photoelectrons and Auger Electrons fromK-Shell Ionization of Neon

“…PCI effects in photoionization have been studied extensively, both theoretically and experimentally, by numerous groups [4][5][6][7][8][9] (and references therein). In the specific case of neon, the work by Ueda and collaborators [6][7][8] demonstrated that the escape probability and energy shifts in the electron spectra are fully consistent with the two-step, sudden-approximation model.…”

“…In the specific case of neon, the work by Ueda and collaborators [6][7][8] demonstrated that the escape probability and energy shifts in the electron spectra are fully consistent with the two-step, sudden-approximation model. More recently, Penent et al [9] used a magnetic bottle time-of-flight technique developed by Eland et al [10] to measure the energies of the two emitted electrons in coincidence, showing the correlation between the two electrons in energy space. The angular correlation, however, between the Auger and photoelectron has only been studied theoretically for the case of equal or nearly equal continuum energies [11,12].…”

Low-energy photoelectron dynamics in Kr3d5/2photoionization followed by Auger decay

“…The physical process of photoabsorption followed by sequential double ionization has been studied extensively in the past decades [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The first electron emitted from the nucleus is called the photoelectron because its ionization is due to photoabsorption.…”

“…During the past decades, this problem has been investigated within different atomic systems, namely, 4d 3/2,5/2 photoionization following N -OO Auger decay in Xe [1][2][3][4][5][6][7], Ar 3d photoionization followed by Auger decay [12,13], 1s or 2s photoionization with subsequent Auger decay in Ne [8][9][10][11]17], and 3d 5/2,3/2 photoionization followed by Auger decay in Kr [15,16]. These papers covered a wide energy range.…”

“…Different cases with low initial photoelectron energy have been investigated in Refs. [8,12,13,15,16]. Because the e-e interaction was not fully considered, only the energy distribution was calculated, and the angular distribution was rarely involved.…”