Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 12: Posters Thursday (Ion/Atom/Molecule/Surface Scattering)
A 12.26: Poster
Donnerstag, 5. April 2001, 12:30–15:00, AT3
Model potential approach to collisions between ions and molecular targets — •Alexander Achenbach, Oliver J. Kroneisen, Hans Jürgen Lüdde, and Reiner M. Dreizler — Institut für Theoretische Physik, J.W. Goethe Universität, D-60054 Frankfurt, Germany
Modern COLTRIMS experiments with multi-hit detectors allow the investigation of ion-molecule collisions in coincidence with the orientation of the molecule in its gas phase. Experiments with H2 show that at impact energies above a few keV/amu, inelastic electronic processes are fairly independent of the molecular orientation during ion impact.
As an example, we investigate the scattering system N5+ + H2. The relevant three center correlation diagrams are calculated for different molecular orientations with respect to the axis defined by the projectile and the H2 center of mass. It turns out that the electronic energies are nearly independent of the molecular orientation except for distances smaller than the ground state binding distance.
This result is taken as the foundation of a dynamical calculation where the target potential is approximated by a spherical average of the H2 potential. This model potential approach has been shown to be adequate for other similar systems [1,2]. We present results for capture and ionization in collisions of N5+ ions with molecular hydrogen.
[1] D. Elizaga, L.F. Errea, J.D. Gorfinkiel, C. Illescas,
L. Méndez, A. Macías, A. Riera,
A. Rojas,
O.J. Kroneisen, T. Kirchner, H.J. Lüdde, A.
Henne,
and R.M. Dreizler,
J. Phys. B 32, 857 (1999).
[2] L.F. Errea, J.D. Gorfinkiel, C. Harel, H. Jouin,
A. Macías, L. Méndez, B. Pons,
and A. Riera,
J. Phys. B 33, 3107 (2000).