title: Two-Color Pump-Probe Experiments on Small Quantum Systems at the Free-Electron Laser in Hamburg
creator: Schmid, Georg
subject: ddc-530
subject: 530 Physics
description: Within this thesis, the dynamical response of small quantum systems after the absorption of multiple extreme-ultraviolet (XUV) photons is studied via two-color pump-probe experiments at the free-electron laser (FEL) in Hamburg  (FLASH) by employing many-particle recoil-ion momentum spectroscopy.  The multi-photon ionization of argon atoms is investigated at a photon energy of 27 eV and FEL intensities of 10^13 - 10^14 W/cm^2. The sequential ionization channel is found to dominate and intermediate resonances are revealed by a delayed infrared (IR) laser pulse.  Molecular hydrogen (H2) is studied at a photon energy of 28.2 eV. Dissociation via excited states and fragmentation by sequential two-photon ionization are observed. In addition, it is shown how the ground-state dissociation of H2+ can be used as a tool to determine the temporal overlap between an XUV and IR laser pulse.  In the argon dimer, multiple interatomic relaxation processes are triggered by the absorption of several 27-eV-photons. Besides interatomic Coulombic decay (ICD), frustrated triple ionization and charge transfer at crossings of potential energy curves are observed. The lifetime of charge transfer is determined to be (531 +- 136) fs using an XUV-IR pump-probe scheme.  The employed reaction microscope is upgraded by an in-line XUV split-delay and focussing optics, which was designed and commissioned as part of this thesis.
date: 2018
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/24786/1/PhD_Georg_Schmid.pdf
identifier: DOI:10.11588/heidok.00024786
identifier: urn:nbn:de:bsz:16-heidok-247867
identifier:   Schmid, Georg  (2018) Two-Color Pump-Probe Experiments on Small Quantum Systems at the Free-Electron Laser in Hamburg.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/24786/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng