Berlin 2014 – scientific programme

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A: Fachverband Atomphysik

A 19: Photoionization

A 19.4: Talk

Tuesday, March 18, 2014, 15:00–15:15, BEBEL E42

Non-monotonic behavior of the ionization probability of model negative ions by high-frequency laser pulses — •Koudai Toyota, Ulf Saalmann, and Jan Michael Rost — Max-Planck-Institute for the Physics of Complex Systems, Noethnitzer Str. 38, 01187, Dresden, Germany

We report on the non-monotonic behavior of the ionization probability of a model negative ion in strong high-frequency laser pulses as a function of pulse durations. Three distinct ionization processes contribute to the behavior and show characteristic features in the photo-electron spectrum. The first mechanism is single-photon absorption which dominates the ionization dynamics for long pulse durations. The second one is non-adiabatic transitions in the adiabatic picture induced by the slow deformation of the electron's effective potential as a function of time. The third mechanism is also a non-adiabatic process, similarly to the shake-off ionization, and can be understood in a sudden picture. This process strongly depends on the carrier-envelope phase of the pulse. The latter two dominate the ionization dynamics for short pulse durations.