Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 12: Posters Thursday (Ion/Atom/Molecule/Surface Scattering)
A 12.3: Poster
Donnerstag, 5. April 2001, 12:30–15:00, AT3
Current Density Analysis in Ion-Atom Collisions — •Matthias Keim, Alexander Achenbach, Hans Jürgen Lüdde, and Reiner M. Dreizler — Institut für Theoretische Physik, J.W. Goethe Universität, D-60054 Frankfurt, Germany
The Basis Generator Method (BGM) [1,2] has successfully been used to calculate total cross sections for electron excitation, transfer, and ionization in ion-atom [3], ion-ion [4], and ion-molecule [5] collisions. As a next step, we want to extend this picture to include differential ionization cross sections. Based on Time Dependent Density Functional Theory (TDDFT) [6], the knowledge of the single particle current density allows the calculation of various n-fold differential electron loss cross sections for arbitrary collision systems. As it is not easy to implement this in an exact fashion, which would require integration of the radial component of the current density (jr) over all times, we use a different approach that allows us to start from jr(r,tf) at a single finite time tf only. Assuming a classical relation between e− distance from the target center and its time of flight, our goal is to approximate the time integral in terms of a spatial (i.e. radial) integral with respect to the target center. The validity of this model – although exact for tf → ∞ – has to be investigated regarding the regions of almost classical behaviour of the emitted electrons at finite tf. As an immediate consequence of the classical picture, one has to exclude the vicinity of the target and the projectile, leaving only a sub-set of ionization channels that can be described. We present results for p and p colliding with atomic targets.
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