Stuttgart 2012 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 31: Interaction with strong or short laser pulses IV

A 31.1: Hauptvortrag

Donnerstag, 15. März 2012, 10:30–11:00, V57.05

Coulomb potential effect on the tunneling electron from molecules — •Jian Wu and Reinhard Dörner — Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, D-60438 Frankfurt, Germany

What is the influence of the remaining ionic core on an electron wave emitted from an atom or molecule and on the ionization process itself? This question is general across all ionization phenomena. We study the electron recapture and Coulomb asymmetry in the strong field ionization of diatomic molecules. By measuring the kinetic energy release and angular distribution of the multiply ionized argon dimers, we can trace the recapture of up to two electrons by the highly charged compound at the end of the laser pulse. The trapping of the electron leads to population of a Rydberg orbital of the charged dimer. Subsequently the system dissociates. Upon its dissociation, the Rydberg electron prefers to localize at the atomic ion with the higher charge state. We further study the Coulomb asymmetric effect in the strong field ionization of molecules. We measure the angular distribution of an electron emitted from exploding doubly charged molecular nitrogen. The emission from the down-field core leads to a slight rotation with respect to the internuclear axis in the direction expected by the Coulomb effect of the remaining ion; while for emission from the up-field core this direction is inversed. Our semi-classical simulations suggest that this unexpected rotation is caused by an initial longitudinal momentum of the electron freed by over the barrier ionization above the inner barrier in the molecule.