Hannover 2016 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 22: Interaction with VUV and X-ray light
A 22.19: Poster
Dienstag, 1. März 2016, 16:30–19:00, Empore Lichthof
Cross sections of iodine-containing molecular ions after inner-shell excitation — •Stephan Klumpp1, Kaja Schubert1, Karolin Mertens1, Alexander Guda2, Sadia Bari3, Jonas Hellhund4, Stefan Schippers4, Alfred Müller4, and Michael Martins1 — 1Department Physik, University of Hamburg — 2Southern Federal University, Rostov-on-Don, Russia — 3FS-SCS, DESY, Hamburg — 4Justus-Liebig-Universität Giessen
We have measured partial cross sections for the production of atomic fragments Iq+ (q=2..5) by photofragmentation of the parent ion IH1+ with the Photon-Ion-Spectrometer (PIPE) at P04 of PETRA III at DESY in Hamburg. The molecular ion parent has been excited with x-ray photons in the energy range of the iodine 3d excitation threshold. The cross sections show two broad prominent features similar to the cross sections of Xe. In contrast, the partial cross sections of the fragments Iq+ (q=2..5) for the atomic parent ion I1+ are much more structured.
Determining absolute absorption cross sections of atomic ions in a merged-beam set-up is a well established method. For molecular ions the kinetic energy release (KER) of each fragmentation process has to be taken into account, in addition because the charged molecular fragments are driven apart. We introduce a kinematic model regarding the KER for IH1+ calculating the ratio between the atomic In+ (n=2..5) fragments hitting the detector and the ones hitting the chamber walls. The ratio is then used to calibrate the measured spectra. The obtained values are compared to DFT calculations.