Parts | Days | Selection | Search | Updates | Downloads | Help

A: Fachverband Atomphysik

A 22: Interaction with VUV and X-ray light

A 22.19: Poster

Tuesday, March 1, 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 I^q+ (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 I^q+ (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.