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A: Atomphysik
A 10: Posters Wednesday (Cooling and Trapping, Electron Scattering and Recombination)
A 10.15: Poster
Wednesday, April 4, 2001, 12:30–15:00, AT3
Deep-Core Dielectronic-Capture Resonances in the Electron-Impact Ionization of Sm Ions — •F. Scheuermann1, K. Aichele1, W. Arnold1, D. Hathiramani1, A. Müller1, E. Salzborn1, D. Mitnik2, J. Colgan2, and M. S. Pindzola2 — 1Institut für Kernphysik, University of Giessen, Giessen, Germany — 2Department of Physics, Auburn University, Auburn, Alabama, USA
Experimental measurements and theoretical calculations have been carried out for the electron-impact ionization of Smq+ (q=5−12). The measurements have been performed using the dynamic crossed-beams technique from threshold up to 1 keV electron energy. The low energy region of the single ionization cross sections for Smq+ ions is found to be dominated by contributions of the indirect process of excitation-autoionization. Below 1 keV, strong resonance features are found in the measurements for single, double and triple ionization of Sm9+-Sm13+ performed in energy-scan mode at high resolution. Calculations for resonance energies and autoionization rates confirm that the observed resonances are due to dielectronic capture followed by sequential double, triple and quadruple Auger decay. Similar unusual high energy resonances are also found in ionization cross sections of Prq+ and Baq+ ions. This opens the door for future systematic studies of how heavy ions achieve final stabilization after dielectronic-capture.