Hamburg 2009 – scientific programme

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A: Fachverband Atomphysik

A 34: Poster II

A 34.10: Poster

Thursday, March 5, 2009, 16:30–19:00, VMP 9 Poster

Nano-plasma formation in clusters exposed to XFEL pulses: consequences for intra-atomic processes — •Christian Gnodtke, Ulf Saalmann, and Jan-Michael Rost — Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden

We investigate the nano-plasma formation in neon clusters induced by intense femtosecond X-ray free electron (XFEL) pulses with a photon energy of 1keV, sufficient for K-shell photo-ionization of neon. Due to the low photon energy the trapping of photo-electrons becomes possible in larger clusters and a nano-plasma is formed. Electrons, which are emitted when a K-shell hole is filled in an Auger-process, may still escape leading to a delay in the build up of charge in the cluster, given by the typical Auger-decay time of about 2.5fs. The strong internal fields of the charged cluster lead to a delocalization or even ionization of the valence electrons, which has been predicted to lead to a reduction of Auger-decay rates [1]. We investigate how this reduction may become visible in the ionic charge states in a pump-probe scenario with two XFEL pulses by means of a molecular dynamics simulation combined with quantum-mechanical transition rates for photo-ionization and Auger-decay [2].

[1] U. Saalmann and J.-M. Rost, PRL 89, 143401 (2002)

[2] Ch. Gnodtke, U. Saalmann and J.-M. Rost, submitted (2009)