Heidelberg 2015 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 2: Atomic clusters (with MO)
A 2.4: Vortrag
Montag, 23. März 2015, 12:30–12:45, M/HS1
Tracing efficient autoionization processes in nanoplasmas — •Bernd Schütte1,2, Mathias Arbeiter3, Thomas Fennel3, Ghazal Jabbari4, Kirill Gokhberg4, Alexander I. Kuleff4, Jan Lahl5, Tim Oelze5, Maria Krikunova5, Marc J. J. Vrakking1, and Arnaud Rouzée1 — 1Max-Born-Institut, Berlin, Germany — 2Imperial College London, United Kingdom — 3Universität Rostock, Germany — 4Universität Heidelberg, Germany — 5Technische Universität Berlin, Germany
Nanoplasmas are generated during the interaction of clusters and large molecules with intense laser pulses from the NIR to the X-ray regime. It was shown that electron-ion recombination leads to a substantial excited state population in nanoplasmas. At sufficiently high laser intensities, multiply-excited atoms and ions can be formed and decay via autoionization. Here we demonstrate an efficient autoionization process in molecular oxygen and atomic clusters interacting with intense NIR pulses. In the case of oxygen clusters, superexcited atoms are formed during the cluster expansion that decay on a time scale of 1 ns. THz streaking reveals that a substantial portion of the electron emission is delayed, which is explained by autoionization processes on (sub-)ps to ns scales. Furthermore, we show that singly-excited Rydberg atoms decay by transferring the excess energy to an electron or to a second Rydberg atom in the environment that gets ionized, similar to interatomic Coulombic decay. The results demonstrate that autoionization processes are crucial for the understanding of nanoplasma dynamics and may strongly influence ion charge state distributions.