Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 2: Ion Scattering I
A 2.7: Vortrag
Montag, 2. April 2001, 17:15–17:30, H1028
Light from higly charged ion-atom collisions: a fingerprint for astrophysical processes — •Z. Juhász, G. Lubinski Lubinski, R. Hoekstra, and R. Morgenstern — KVI, Rijksuniversiteit Groningen, Zernikelaan 25, NL-9747 AA Groningen, The Netherlands
We have studied the emission of soft X rays, following electron capture during collisions of highly charged ions on helium atoms and hydrogen molecules, especially at collision energies as low as a few eV/amu. Such processes are relevant for diagnostics and modeling of hot (fusion-) plasmas and for the interpretation of light from astrophysical processes as e.g. the soft X ray emission recently observed from comets passing the earth. We have determined absolute partial cross sections for capture into specific projectile states, which can be used to benchmark recent theoretical predictions. In several cases we find huge discrepancies between experimental and theoretical results: for single electron capture from hydrogen molecules into the 3s orbital of N5+ at a collison energy of a few eV/amu e.g. the experimentally determined cross sections are at least 3 orders of magnitude larger than predicted.