Frankfurt 2006 – wissenschaftliches Programm

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A: Atomphysik

A 17: Hauptvortr
äge: Cluster in starken Laserfeldern

A 17.4: Hauptvortrag

Donnerstag, 16. März 2006, 12:10–12:40, H7

Metal clusters in intense laser fields: semiclassical modelling of the ion and electron emission — •Thomas Fennel, Jörg Köhn, Tilo Döppner, Josef Tiggesbäumker, and Karl-Heinz Meiwes-Broer — Institut für Physik, Universität Rostock

The response of small metal clusters subject to strong laser excitation is investigated using a microscopic simulation including electron-electron collisions. The theoretical model is based on semiclassical time-dependent density-functional theory. The self-consistent electron dynamics are described on the level of the semiclassical Vlasov approach including exchange and correlations in LDA [1] linked to a velocity dependent Vlasov-Ühling-Uhlenbeck collision term to mimic dynamical correlations. In particular we focus on the ion and electron emission following the excitation of Na_N clusters with dual pulses. In accordance with the experimental results [2] a dramatic increase both in the atomic charge state of the ions and the maximum electron kinetic energy is observed for a certain delay of the pulses. Results of the calculations are discussed which indicate that enhanced cluster ionization as well as the generation of fast electrons coincide with resonant plasmon excitation.

[1] T. Fennel, G.F. Bertsch, and K.-H. Meiwes-Broer, Eur. Phys. J. D 29, 367 (2004)

[2] T. Döppner Th. Fennel, P. Radcliffe, J. Tiggesbäumker and K.H. Meiwes-Broer (submitted to Phys. Rev. A)