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@PHDTHESIS{Magunia:612496,
author = {Magunia, Alexander},
othercontributors = {Pfeifer, Thomas and Oberthaler, Markus},
title = {{T}ime-and-{E}nergy–{R}esolved {E}lectron {D}ynamics in
{A}toms and {M}olecules with {I}ntense {S}hort-{W}avelength
{L}ight},
school = {Heidelberg University},
type = {Dissertation},
publisher = {Heidelberg University Library},
reportid = {PUBDB-2024-05349},
pages = {136},
year = {2024},
note = {Dissertation, Heidelberg University, 2024},
abstract = {This thesis investigates the interaction of ultrashort,
extreme-ultraviolet (XUV) and soft x-ray laser pulses with
atoms and molecules in the gas phase. In total, the subject
is explored from four different perspectives, which are all
based on the short- lived–coherent electronic responses to
the laser pulses, and measured with transient absorption
spectroscopy. First, a theoretical study reveals how
transient energy shifts of electronic dressed states in
atoms driven by an intense XUV Free-Electron Laser (FEL)
lead to temporal dipole phase shifts and absorption-line
changes. Second, a follow-up study investigates the
electronic-population Rabi-cycles corresponding to the
absorption-line changes of the first study. A convolutional
neural network is employed to reconstruct the temporal
population dynamics from the simulated spectral absorption
modifications. The inversion from an absorption to an
emission line is described and a potential experimental
demonstration in helium is discussed. Third, dense gas
targets enable amplification of the otherwise improbable,
non-linear process of stimulated resonant inelastic x-ray
scattering (RIXS), as well as x-ray FEL propagation-based
spatial-spectral reshaping. To this end, a new experimental
setup is built and utilized in an x-ray FEL driven RIXS
experiment in dense neon gas. Fourth, a novel experiment
combining XUV pulses from high-order harmonic generation
(HHG) and XUV-FEL pulses is demonstrated by time-resolving a
photochemical reaction in molecular oxygen. An FEL pulse
initiates coupled nuclear-electronic dissociation pathways
from molecular oxygen ions, which are time-resolved on
femto- and picosecond time scales by identifying the
reaction products in the time-delayed HHG absorption
spectra. A FEL-photon-energy–resolved study of the
fragments is performed to compare findings from absorption
spectroscopy with kinetic energy release spectra recorded in
parallel with a reaction microscope.},
keywords = {530 Physics (Other)},
cin = {DOOR ; HAS-User},
cid = {I:(DE-H253)HAS-User-20120731},
pnm = {6G2 - FLASH (DESY) (POF4-6G2)},
pid = {G:(DE-HGF)POF4-6G2},
experiment = {EXP:(DE-H253)F-FL26-20150901},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:bsz:16-heidok-351662},
doi = {10.11588/HEIDOK.00035166},
url = {https://bib-pubdb1.desy.de/record/612496},
}