München 2004 – wissenschaftliches Programm
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A: Atomphysik
A 15: Poster 2
A 15.18: Poster
Donnerstag, 25. März 2004, 14:00–16:00, Schellingstr. 3
Double ionization in high-intensity ultrashort laser pulses: influence of the molecular structure — •Ekaterina Eremina1, H. Rottke1, X. Liu1, W. Sandner1, M.G. Schätzel2, A. Dreischuh2, G.G. Paulus2, H. Walther2, R. Moshammer3, and J. Ullrich3 — 1Max-Born-Institut, Max-Born-Str. 2A, 12489 Berlin — 2Max-Plank-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching — 3Max-Plank-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg
We investigated double ionization of the homonuclear diatomic molecules N2 and O2 in high-intensity laser pulses by using coincident electron-ion momentum spectroscopy. We employed 35 fs laser pulses with central wavelength at 800 nm in the regime of light intensities where non-sequential double ionization (NSDI) is expected. We observed a pronounced difference in the momentum correlation of the photoelectrons emitted after double ionization: O2 shows a maximum at zero momentum, whereas N2 exhibits structures characteristic of rescattering - the main atomic NSDI mechanism. To understand this difference we performed a simplified qualitative model calculation based on a classical analog of the S-matrix for double ionization by rescattering. It incorporates classical rescattering and the quantum mechanical transition matrix elements. The result indicates that the symmetry of the initial state wave function, which is symmetric for N2 and asymmetric for O2, plays a decisive role for the final electron momentum distribution, leading to the present experimental results