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## AP-THEORY-04 Correlated double-electron capture with emission of a single photon

### BibTeX

@MISC{_ap-theory-04correlated,

author = {},

title = {AP-THEORY-04 Correlated double-electron capture with emission of a single photon},

year = {}

}

### OpenURL

### Abstract

Double photoionization of an atom caused by the absorption of a single photon, the so-called double photoeffect, is a fundamental phenomenon, in which correlation effects play a crucial role. Since the photon interacts only with a single electron, the simultaneous ejection of two electrons is exclusively caused by the electron-electron interaction. So far experiments have been performed with helium and a few neutral atoms in the region of moderate values of the nuclear charge number Z. In contrast to neutral atoms, the study of the double photoeffect in multicharged ions is of particular interest. The photoionization processes on the simplest many-electron systems such as heliumlike ions allow for a rigorous treatment within the framework of QED perturbation theory. This problem could also serve as a testing ground for numerous theoretical approaches developed recently for the description of the complete photofragmentation of helium. An experimental study of the double photoeffect via the time-reversed process has been undertaken in fast collisions of bare ions with light target atoms [1, 2, 3]. However, several measurements, which have been performed at GSI, have provided only upper limits for the total cross sections of the process under investigation. The advantage of studying of the double photoeffect via its time-reversed version utilizing beams of multicharged ions is that it opens the possibility to investigate the process involving excited electron states. We have investigated the correlated double-electron capture into the inner shells of a bare ion with the emission of a single photon [4, 5]. The total cross section for the correlated double-electron capture into the K shell of a bare ion can be expressed as σ (2)

### Keyphrases

single photon bare ion ap-theory-04 correlated double-electron capture double photoeffect multicharged ion total cross section neutral atom correlated double-electron capture complete photofragmentation time-reversed version single electron qed perturbation theory several measurement light target atom time-reversed process inner shell crucial role double photoionization particular interest fast collision fundamental phenomenon nuclear charge number so-called double photoeffect excited electron state many-electron system electron-electron interaction numerous theoretical approach upper limit experimental study testing ground correlation effect moderate value heliumlike ion simultaneous ejection rigorous treatment