Heidelberg 2015 – wissenschaftliches Programm
A 29.6: Vortrag
Donnerstag, 26. März 2015, 12:30–12:45, C/HSW
Testing calculated potential energy curves of molecular oxygen by measuring vibrational wave-packets with an XUV–IR experiment — •Philipp Cörlin, Andreas Fischer, Michael Schönwald, Tomoya Mizuno, Thomas Pfeifer, and Robert Moshammer — Max-Planck-Institut für Kernphysik, Heidelberg
In our experiment XUV photons (18 eV to 40 eV) created from 10 fs IR laser pulses by high-harmonic generation are used to ionize molecular oxygen. The ionic state is probed by a delayed IR pulse with an effective intensity of 3e12 W/cm2. Charged fragments are detected with a reaction microscope and a pronounced oscillation in the count rate of very low energetic O+ ions is measured. The low KER and the oscillation period of 40.0 fs point towards a wave-packet oscillation within the binding ionic a4Πu potential which is probed via the weakly repulsive f4Πg state by resonant absorption of an IR photon [1, 2]. By comparison of experimental spectra with the results of a coupled channel simulation, we are able to test different sets of calculated potential curves. While the agreement between experiment and theory is on a level not observed for O2+ wave-packets before, some properties of the experimental spectra cannot be reproduced in a satisfying manner by our simulation, if calculated binding potentials are used. In order to demonstrate the sensitivity on the shape of the binding potential curve, we perform a simulation with a Morse potential fitted to the experimental data which reproduces the experimental spectra very well.
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