Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 12: Posters Thursday (Ion/Atom/Molecule/Surface Scattering)

A 12.23: Poster

Donnerstag, 5. April 2001, 12:30–15:00, AT3

Polarization of N₂-molecules in very slow collisions with Kr⁸⁺-ions: Theory — •Ulf Saalmann — Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany

By means of a self–consistent description of electronic transitions and nuclear motion (Non–adiabatic quantum molecular dynamics, na-qmd) we have investigated the dissociation dynamics of nitrogen molecules induced by slow collisions with Kr⁸⁺ ions. These collisions have been studied recently by coincidence measurements of the fragment ions and the final projectile charge state in the energy range from 19 to 171 eV/u [see contribution by Ehrich et al. in this volume].

The calculated final fragment charges as function of impact parameter and impact energy are compared to the measured data which show a strong dependence on the scattering angle. The experimentally observed anisotropy of the fragmentation at low collision energies (<50 eV/u) can be understood by our microscopic na-qmd investigations which allow a detailed study of the time evolution of the collision process. It turned out that at these impact energies the strong field of the Kr ion does not only polarize the fragmenting molecule but also crucially affects the dissociation dynamics.