Hannover 2010 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 23: Poster II

A 23.5: Poster

Donnerstag, 11. März 2010, 16:30–19:00, Lichthof

Unexpected low-energy structure of photoelectron spectra in mid-infrared strong laser fields: classical description — •Chengpu Liu and Karen Z. Hatsagortsyan — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany

The recent experiment by Blaga et al. [Nature Phys. 5, 335-330 (2009)] on the photoionization of atoms and molecules in strong long wavelength laser fields observes previously unknown low-energy structure (LES) in the energy distribution of electrons emitting along the laser polarization direction. This work is devoted to clarification of the mechanism for the appearance of this LES. We use semiclassical Monte-Carlo simulations and successfully reproduce the experimental results. It is confirmed that the origin of LES involves the influence of the long range Coulomb potential and the forward-scattering of the tunneled electrons which unlike the back-scattering contributes to the low-energy domain. Furthermore, we investigate the scaling of the LES with the Keldysh parameter and its dependence on the atomic binding potential. As the essence of LES is the quasistatic laser assisted scattering of low energy electrons from the atomic core, it is not surprising for LES to be general and present in all atomic and molecular systems.