Hannover 2016 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 4: Collisions, scattering and correlation phenomena I
A 4.1: Vortrag
Montag, 29. Februar 2016, 11:00–11:15, f107
Electron-impact ionization of beryllium-like carbon ions — •Benjamin Ebinger1,2, Alexander Borovik Jr.1,2, Stefan Schippers1,2, and Alfred Müller2 — 1I. Physikalisches Institut, Justus-Liebig-Universität Gießen — 2Institut für Atom- und Molekülphysik, Justus-Liebig-Universität Gießen
Reliable atomic input data are of crucial importance for the modelling of ionized-matter environments. Cross sections for electron-impact ionization of atoms and ions are particularly important. Besides the fairly well understood direct-ionization process, indirect ionization mechanisms such as excitation-autoionization (EA) and resonant-excitation double autoionization (REDA) may significantly contribute to net single-ionization [1]. Benchmark experiments uncovering fine structures that arise from indirect ionization in few-electron systems provide guidance for theoretical efforts to adequately describe total single ionization by electron collisions. Here, we present measurements of electron-impact single-ionization cross sections of the C2+ ion, i. e., of a fairly simple four-electron system. Complications arise, however, from the presence of both 1s2 2s2 1S0 ground-level and 1s2 2s 2p 3P0,1,2 metastable-level ions in the experiment. Employing the well-established fine-step energy-scan technique [2], contributions of indirect-ionization processes invoked by excitation of the K-shell were uncovered with a statistical uncertainty of less than 0.03% thus helping to disentangle the various cross-section contributions.
[1] Liu et al., Phys. Rev. A 92 (2015) 012701
[2] A. Müller et al., Phys. Rev. Lett. 61 (1988) 70