/en/research/projects/2.3/topics/Attosecond spectroscopy/index.html
2.3 Time-resolved XUV-science
Project coordinator(s): A. Rouzée, S. Patchkovskii
Topic: Attosecond electronic and nuclear dynamics and control using IR/XUV pump-probe spectroscopy

Topic Goals

Investigating real-time electronic and nuclear dynamics in atoms and molecules is the central aim of project 2.3. This topic contributes to this general goal by employing IR/XUV pump-probe spectroscopy, which allows to follow light induced dynamics with attosecond time resolution. Correlated electron dynamics and electron localization and the subsequent nuclear dynamics are of particular interest. Different approaches are presently pursued in the laboratories to achieve this goal.

Present key activities

Tracking of Fano wavepackets in atoms
H. Geiseler, N. Zhavoronkov, H. Rottke

We are interested here in electron dynamics in the ionization continuum of atoms and eventually molecules where the ionization cross section shows structures due to excited discrete electron configurations embedded in the continuum. The origin of these structures can be multiple-electron excited configurations or single inner shell or inner valence shell excitations. They give rise to Fano resonance structures. The typical multi-electron dynamics can be tracked in real time by probing either the part of the wavepacket that leaves the atom by formation of photoelectron sidebands by a delayed probe pulse. Or, as we did it in a first experimental investigation, by "photoionizing" that part of the wavepacket that stays close to the ion core.

Attosecond control of the photoionization and fragmentation reaction of simple and complex molecular systems
Jesse Klei, Niels Ligterink, Christian Neidel, Chung-Hsin Yang, Nick Zhavarankov

Attosecond spectroscopy is an ideal tool to study light induced electron dynamics in molecular systems. In combination with carrier envelope phase (CEP) stable IR pulses it enables experiments not only to interrogate but also to steer the electronic wave function. This has recently been demonstrated in XUV/IR pump-probe experiments on H2, where the electron localization in dissociative ionization has been observed. Present activities this laboratory are centered on the application of this method to other diatomic and larger molecules with the aim to observe e.g. ionization induced core hole dynamics as predicted by theoretical studies.

Attosecond electron dynamics and nuclear motion in molecules probed by coincident electron-ion momentum spectroscopy
Sascha Birkner, Federico Furch, Claus Peter Schulz

Coincident electron-ion momentum spectroscopy permits a direct measurement of the full momentum distribution of all charged particles in a light induced process. We are combining this technique with XUV/IR pump-probe methods to study molecular electron dynamics and the subsequent nuclear motion in great detail. We will start this study with small diatomic molecules like H2, N2, and O2, where already data from other laboratories of this project are available. Prerequisite for efficient coincidence experiments is the availability of a high repetition rate laser system, which is presently being developed in our laboratory (see project 4.1).