Berlin 2014 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 18: Interaction with strong or short laser pulses II

A 18.6: Vortrag

Dienstag, 18. März 2014, 15:30–15:45, BEBEL E34

Quantum trajectory analysis of clusters and molecules in strong laser fields — •Thomas Keil and Dieter Bauer — Universität Rostock, Institut für Physik

The strong field approximation (SFA) is the underlying theory describing the interaction of intense laser light with atoms or molecules. However, it has been noted that several spectral features are not reproduced by the plain SFA because the Coulomb force on the outgoing photoelectron is neglected. It is well-known that photoelectrons generated by strong-field ionization of atoms have a cut-off energy of 2U_p if they move directly to the detector (or 10U_p if they rescatter once from their parent ion). Electrons emitted from laser-irradiated clusters may have much higher kinetic energies, especially at resonance [1,2]. We apply the methodology developed for the Coulomb-corrected SFA (CCSFA) based on quantum trajectories [3] to a SFA that is corrected for the collective electric field in the cluster. We show that it is this collective field, which arises because of the coherent oscillation of the electron cloud with respect to the ionic background, that generates multi-U_p electrons. This finding comfirms the “surface-plasmon-assisted rescattering in clusters” revealed earlier via classical molecular dynamics simulations [1]. Results from the CCSFA for molecules will be also presented.

[1] Th. Fennel et al., Phys. Rev. Lett. 98, 143401 (2007).
[2] Th. Keil, D. Bauer, J. Phys. B (submitted).
[3] T.-M. Yan et al., Phys. Rev. Lett. 105, 253002 (2010); T.-M. Yan et al., Springer Series in Chemical Physics vol. 104 (2013).