Rostock 2019 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 8: XUV and X-ray Excitation and Spectroscopy

MO 8.4: Vortrag

Montag, 11. März 2019, 17:00–17:15, S HS 001 Biologie

XUV-photoion spectra from neutral gases measured with a radio frequency ion trap — •Simon Reinwardt¹, Ivan Baev¹, Karolin Mertens¹, Florian Trinter^2,3, and Michael Martins¹ — ¹Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany — ²FS-PE, DESY, Hamburg, Germany — ³Molecular Physics, Fritz-Haber-Institut, Berlin, Germany

Photoion spectra of the neutral gases CO₂ and CH₄ were measured using a radio frequency ion trap at the soft X-ray beamline P04 of the synchrotron PETRA III at DESY in Hamburg. The used ion trap is part of the stationary Photon-Ion-Spectrometer (PIPE) [1]. In this experiment the neutral gas was photo ionized with monochromatized synchrotron light and the generated photoions were trapped in the radio frequency potential of the ion trap. In this way it was possible to measure a photoion NEXAFS spectrum at the carbon K-edge (290 eV) and for CO₂ also at the oxygen K-edge (535 eV).

Besides that we could show that the trapped ionized gas molecules are able to react with neutral gas to form larger molecular ions. At CO₂ we observed a small amount of CO₃⁺ and at CH₄ we found products with up to two carbon atoms. Depending on the resonant excitation, it is possible to change the generated ion as well as the electronic state of the ion so that the subsequent reaction is influenced. In addition similar measurements could be performed on ethene. Possible channels for these photochemical reactions will be discussed.

[1] S. Schippers et al., J. Phys. B: At. Mol. Opt. Phys 47, 115602, 2014.