Berlin 2014 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 16: Atomic clusters (with A)

MO 16.3: Vortrag

Donnerstag, 20. März 2014, 11:15–11:30, BEBEL E44/46

Electron re-localization dynamics in Xenon clusters under intense XUV pump-probe excitation — •M. Arbeiter, Ch. Peltz, and Th. Fennel — Institute of Physics, University of Rostock

Intense and temporally structured light fields from free-electron lasers enable the time-resolved investigation of ionization dynamics in finite systems at shortwavelength, as demonstrated in a recent femtosecond XUV pump-probe experiment on Xenon clusters [1] at FLASH. Sub-picosecond relaxation dynamics in the XUV driven cluster nanoplasma are revealed via the delay dependent charge states of emitted atomic ions. Our semiclassical molecular dynamics study reveals that the process of electron re-localization in the ionized cluster is key to understand the delay-dependent ion charge states [2]. We show that nanoplasma expansion cooling rapidly diminishes three-body-recombinations within a few picoseconds leading to a bimodal electron energy distribution of strongly bound electrons (re-localized) and weakly bound (quasifree, Rydberg-like). A suitable criterion to account for electron re-localization is found by microscopic analysis of the local quasi continuum between neighboring atoms, leading to an appropriate definition of effective ion charge states. A systematic pump-probe analysis reveals that electron re-localization provides a fingerprint of electron cooling and nanoplasma rarefaction through cluster expansion and yield a good qualitative agreement with the observed experimental findings [1].

[1] M. Krikunova et al. J. Phys. B 45, 105101 (2012)

[2] M. Arbeiter, Ch. Peltz, Th. Fennel, to be submitted