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A: Fachverband Atomphysik
A 34: Poster II
A 34.49: Poster
Donnerstag, 5. März 2009, 16:30–19:00, VMP 9 Poster
Multiple Ionization of N2 by VUV Free-Electron Laser Radiation — •Yuhai Jiang1, Artem Rudenko2, Moritz Kurka1, Kai-Uwe Kühnel1, Thorsten Ergler1, Lutz Foucar3, Markus Schöffler3, Sven Schössler3, Tilo Havermeier3, Mathias Smolarski3, Kyra Cole3, Reinhard Dörner3, Stefan Düsterer4, Rolf Treusch4, Michael Gensch4, Claus Dieter Schröter1, Robert Moshammer1, and Joachim Ullrich1 — 1Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany — 2Max-Planck Advanced Study Group at CFEL, 22607 Hamburg, Germany — 3Institut für Kernphysik, Universität Frankfurt, 60486 Frankfurt, Germany — 4DESY, Notkestrasse 85, 22607 Hamburg, Germany
Few-photon multiple ionization of N2 was studied differentially in a Reaction Microscope using 43.5 eV, ∼25 fs, intense (∼1013 W/cm2) photon pulses from the free-electron laser in Hamburg (FLASH). Sequential ionization is observed to dominate. For various intermediate charge states N2n+ we find a considerable excess of photons absorbed compared to the minimum number that would energetically be required. Photo ionization of aligned N2n+ ions, produced by photon absorption in sequential steps, is explored and few-photon absorption pathways are traced by inspecting kinetic energy releases and fragment-ion angular distribution. In the beam-time given just two weeks ago we were able to successfully commission the split-mirror delay stage and record first time-dependent data for dissociating N2n+ molecules at 45.5 eV.