Hamburg 2009 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 18: Photoionization I

A 18.4: Vortrag

Mittwoch, 4. März 2009, 15:30–15:45, VMP 8 R208

Angular resolved photoemission from Xenon and C60 — •Slawomir Skruszewicz, Nguyen Xuan Truong, Johannes Passig, Andreas Przystawik, Thomas Fennel, Josef Tiggesbäumker, and Karl-Heinz Meiwes-Broer — Universität Rostock, Universitätsplatz 3 18051 Rostock, Deutschland

Angular resolved photoelectron spectroscopy is a key method to gain deeper insight into the strong-field photoionization of complex systems, such as multi-electron atoms, molecules, and clusters. A powerful and direct technique for the simultaneous measurement of the energy and angular distribution of the photoelectrons is offered by Velocity Map Imaging spectroscopy [1]. In order to resolve electrons with up to 1 keV kinetic energy we have developed a modified five-electrode setup. As a system benchmark we have analyzed the emission spectra from Xe atoms for fs laser excitation and find clear signatures from intermediate resonant states involved in the ionization process [2,3]. A detailed analysis of photoelectron spectra enables us to estimate lifetimes of the resonances which are of the order of a few femtoseconds. By systematic investigation of the angular resolved photoemission from C60 as a function of the laser intensity we are able to identify signatures for above-threshold ionization in agreement with earlier study [4].

[1] H. Helm et al., Phys. Rev. Lett. 70, 3221 (1993).

[2] R.R. Freeman et al., Phys. Rev. Lett. 59, 1092 (1987).

[3] V. Schyja et al., Phys. Rev. A 57, 3692 (1998).

[4] E.E.B. Cambpell et al., Phys. Rev. Lett. 84, 2128 (2000).