Frankfurt 2006 – wissenschaftliches Programm
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A: Atomphysik
A 18: Wechselwirkung mit starken Laserpulsen II: Ionisation
A 18.1: Hauptvortrag
Donnerstag, 16. März 2006, 14:00–14:30, H6
S-Matrix theory of laser-induced nonsequential double ionization — •Carla Figueira de Morisson Faria — Centre for Mathematical Science, City University, Northampton Square, London EC1V OHB, United Kingdom
We investigate laser-induced nonsequential double ionization (NSDI), considering a phsyical mechanism in which the first electron dislodges the second by electron-impact ionization, within an S-Matrix framework. We investigate the influence of the type of interaction by which the second electron is dislodged, of final-state electron-electron repulsion, of the initial electronic bound states and of the external laser field on the electron momentum distributions.
Furthermore, we have obtained a very good agreement between the S-Matrix computation and a simple classical model. The latter model has been extended to more than two electrons, and has led to an estimate, from existing experimental data, of electron thermalization times in the attosecond (10−18 s) regime.
Finally, we have shown that NSDI by few-cycle driving pulses can be used for absolute-phase measurements. In this case, the electron momentum distributions are either concentrated in the region of positive or negative parallel electron momentum. Around a critical value of the absolute phase, the distributions shift from one region to the other. Such a behavior can be traced back to a change in the dominant set of trajectories of an electron rescattering with its parent ion.
For a review c.f. C. Figueira de Morisson Faria, X. Liu and W. Becker, Progress in Ultrafast Intense Laser Science, Springer, 2005 (in press).