Bonn 2025 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 16: Collisions, Scattering and Correlation Phenomena I

A 16.2: Vortrag

Mittwoch, 12. März 2025, 15:00–15:15, HS PC

Recoil-Ion and Electron Momentum Spectroscopy of Anion Neutral Interactions at a Cryogenic Ion Storage Ring — •Michael Schulz, Felix Herrmann, Weiyu Zhang, David Chicharro, Alexander Dorn, Manfred Grieser, Florian Grussie, Holger Kreckel, Oldrich Novotny, Florian Trost, Andreas Wolf, Thomas Pfeifer, Claus Dieter Schröter, and Robert Moshammer — Max-Planck-Institut für Kernphysik Heidelberg

We have measured momentum analyzed recoil ions and ejected electrons in triple coincidence with projectiles neutralized in collisions of slow anions with atoms. The experiment was performed at the Heidelberg cryogenic storage ring. From the data we extracted multiple differential cross sections for electron loss from the projectile (detachment) and for detachment accompanied by single and double target ionization (DI and DDI). Surprisingly large DI (and DDI) to detachment cross section ratios were found. Furthermore, in the differential momentum distributions of electrons ejected in DI we only observe signatures of a correlated mechanism while uncorrelated channels appear to be insignificant. This is also surprising because the projectile energy is well below the threshold for the correlated mechanism and DI is kinematically possible only because of the initial momentum distribution of the electrons in their initial bound states.

Keywords: Detachment; Ionization; Ion storage ring; Momentum imaging