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arXiv:1402.6853 · Physical Review Letters

Vortices Associated with the Wave Function of a Single Electron Emitted in Slow Ion-Atom Collisions

L. Ph. H. Schmidt, Christoph Goihl, Daniel Metz, H. Schmidt‐Böcking, R. Dörner, S. Yu. Ovchinnikov, J. H. Macek, David Schultz

Published Feb 24, 2014• 38 citations
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Abstract

We present measurements and calculations of the momentum distribution of electrons emitted during the ion-atom collision $10\text{ }\text{ }\mathrm{keV}/\mathrm{u}$ ${\mathrm{He}}^{2+}+\mathrm{He}\ensuremath{\rightarrow}{\mathrm{He}}^{+}+{\mathrm{He}}^{2+}+{e}^{\ensuremath{-}}$, which show rich structures for ion scattering angles above 2 mrad arising dominantly from two-electron states. Our calculations reveal that minima in the measured distributions are zeros in the electronic probability density resulting from vortices in the electronic current.

DOI
10.1103/physrevlett.112.083201

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Vortices in atomic wave functions are shown to have observable consequences. It is shown that time-dependent electron wave functions in coordinate space go over to electron emission amplitudes in the limit that time becomes infinite. This relation between wave functions and emission amplitudes is called the imaging theorem. According to this theorem vortices in wave functions at small times when particles interact in a complex way appear as vortices in electron momentum distributions where they produce observable features. Conversely, some observable structures may be interpreted in terms of vortices no matter how they are seen or computed. We verify that previously unexplained features in (e,2e) triply differential cross sections can be interpreted in terms of vortices.
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