Heidelberg 2015 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 38: Interaction with VUV and X-ray light II
A 38.6: Vortrag
Freitag, 27. März 2015, 12:30–12:45, C/HSW
Electron dynamics in He nanodroplets resonantly induced by intense XUV pulses — •Y. Ovcharenko1, A. LaForge2, M. Mudrich2, P. O'Keeffe3, A. Ciavardini3, O. Plekan4, P. Finetti4, M. Devetta5, P. Piseri5, A. Mika6, R. Richter4, K.C. Prince4,7, M. Drabbels6, C. Callegari4, F. Stienkemeier2, and T. Möller1 — 1TU Berlin, Germany — 2Universität Freiburg, Germany — 3CNR Istituto di Metodologie Inorganiche e dei Plasmi, Monterotondo Scalo, Italy — 4Elettra-Sincrotrone Trieste, Trieste, Italy — 5Universita di Milano, Milano, Italy — 6EPFL, Lausanne, Switzerland — 77IOM-CNR TASC Laboratory, Trieste, Italy
Since the first seeded Free Electron Laser FERMI became available for users, it offers unique possibility to perform detailed investigations in complex atomic and molecular systems due to the narrow bandwidth, fine energy tunability and high intensity in XUV energy range. By using this new source the ionization dynamics in He nanodroplets has been explored with electron spectroscopy in a wide energy range above first ionization potential (IP) as well as below it, going through the surface as well as bulk excitations. In addition to the conventional sequential multi-step ionization (MSI) with a photon energy well above IP a novel collective ionization process [1] following resonant bulk excitation is observed. It is due to autoionization of two or more electronically excited cluster atoms as predicted recently. The process is very efficient and can exceed the rate of direct photoionization above IP.
[1] Y. Ovcharenko et al., Phys. Rev. Lett. 112, 073401 (2014)