Hannover 2010 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 12: Photochemistry I
MO 12.6: Vortrag
Mittwoch, 10. März 2010, 12:00–12:15, F 142
Time-resolved nuclear motion of core-excited iodine molecules — •Maria Krikunova1, Theophilos Maltezopoulos1, Philipp Wessels1, Moritz Schlie1, Armin Azima1, Nikolay Kabachnik2, Marek Wieland1, and Markus Drescher1 — 1Institut für Experimentalphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany — 2Institute of Nuclear Physics, Moscow State University, 119991 Moscow, Russia
The core-ionisation in molecules followed by a complex sequence of multi-electron relaxation processes is intimately associated with the cleavage of chemical bonds. Depending on the final molecular ionic state and the core-hole lifetime the dissociation is controlled by several competing processes i.a. Coulomb repulsion, indirect pre-dissociation or fast dissociation preceding electronic relaxation. Utilizing a XUV / optical laser pump-probe technique the complex interplay between dissociative channels was studied in molecular iodine in real time. The kinetic energy release of ionic fragments was measured following excitation with XUV pulses from the Free-Electron-LASer in Hamburg (FLASH). A methodological challenge is connected with the timing jitter of the order of a few hundred fs between XUV- and laser pulses. A tagging technique was developed and applied recently for delay measurement in a simultaneously operated experiment. Applying this technique to the current study the change in the dissociation mechanism manifested by the time-dependent loss in the kinetic energy of I3+ ion fragments can be resolved.