# FS-CFEL-3

 2019-08-0709:21 [PUBDB-2019-02925] Journal Article et al Detecting coherent core-hole wave-packet dynamics in N$_2$ by time- and angle-resolved inner-shell photoelectron spectroscopy The journal of chemical physics 151(5), 054107 (2019) [10.1063/1.5109867]   We propose an imaging technique to follow core-hole wave-packet oscillations in the nitrogen molecule. In this scheme, an attosecond x-ray pulse core-ionizes the nitrogen molecule and a subsequent attosecond x-ray pulse probes the evolution of the electron dynamics. [...] OpenAccess: PDF PDF (PDFA); 2019-08-0215:17 [PUBDB-2019-02902] Book/Report/Dissertation / PhD Thesis et al Ultrafast Nuclear Dynamics Induced by Light from the XUV to the THz Range [DESY-THESIS-2019-017] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 79 pp. (2019) [10.3204/PUBDB-2019-02902] = Dissertation, Universität Hamburg, 2019   With recent advances in the generation of ultrashort laser pulses, electron and nuclear dynamics in molecules can be investigated on their natural, atto- to femtosecond timescale. This opens up the investigation of many interesting phenomena, including primary events in chemistry and biology. [...] OpenAccess: Thesis_CArnold_Defended_Print_fixed - PDF PDF (PDFA); desy-thesis-19-017.title - PDF PDF (PDFA); 2019-07-2411:15 [PUBDB-2019-02799] Journal Article et al Hole dynamics in a photovoltaic donor-acceptor couple revealed by simulated time-resolved X-ray absorption spectroscopy Structural dynamics 6(4), 044102 (2019) [10.1063/1.5097653]   Theoretical and experimental methodologies that can characterize electronic and nuclear dynamics, and the coupling between the two, are needed to understand photoinduced charge transfer in molecular building blocks used in organic photovoltaics. Ongoing developments in ultrafast pump-probe techniques such as time-resolved X-ray absorption spectroscopy, using an X-ray free electron laser in combination with an ultraviolet femtosecond laser, present desirable probes of coupled electronic and nuclear dynamics [...] OpenAccess: PDF PDF (PDFA); 2019-07-0412:46 [PUBDB-2019-02638] Journal Article et al Theoretical evidence for the sensitivity of charge-rearrangement-enhanced x-ray ionization to molecular size Physical review / A 100(1), 013402 (2019) [10.1103/PhysRevA.100.013402]   It was recently discovered that molecular ionization at high x-ray intensity is enhanced, in comparison with that of isolated atoms, through a phenomenon called CREXIM (charge-rearrangement-enhanced x-ray ionization of molecules). X-ray absorption selectively ionizes heavy atoms within molecules, triggering electron transfer from neighboring atoms to the heavy-atom sites and enabling further ionization there [...] OpenAccess: PDF PDF (PDFA); 2019-06-1309:08 [PUBDB-2019-02472] Journal Article et al Ultrafast anisotropic disordering in graphite driven by intense hard X-ray pulses High energy density physics 32, 63 - 69 (2019) [10.1016/j.hedp.2019.05.002]   We present results from the SPring-8 Angstrom Compact free electron LAser (SACLA) X-ray free electron laser (XFEL) facility, using an X-ray pump, X-ray probe scheme to observe ultrafast changes in the structure of heated graphite. The 9.8 keV XFEL beam was focused to give an intensity on the order of  ∼ 10$^{19}$ W/cm$^2$, and the evolution of the diffraction pattern observed up to delays of 300 fs [...] OpenAccess: PDF PDF (PDFA); 2019-06-1214:56 [PUBDB-2019-02460] Journal Article et al xcalib : a focal spot calibrator for intense X-ray free-electron laser pulses based on the charge state distributions of light atoms Journal of synchrotron radiation 26(4), 1017 - 1030 (2019) [10.1107/S1600577519003564]   The xcalib toolkit has been developed to calibrate the beam profile of an X-ray free-electron laser (XFEL) at the focal spot based on the experimental charge state distributions (CSDs) of light atoms. Characterization of the fluence distribution at the focal spot is essential to perform the volume integrations of physical quantities for a quantitative comparison between theoretical and experimental results, especially for fluence-dependent quantities. [...] OpenAccess: PDF PDF (PDFA); Restricted: PDF PDF (PDFA); 2019-04-0910:50 [PUBDB-2019-01910] Preprint/Report et al Scientific Opportunities with an X-ray Free-Electron Laser Oscillator [arXiv:1903.09317]   An X-ray free-electron laser oscillator (XFELO) is a new type of hard X-ray source that would produce fully coherent pulses with meV bandwidth and stable intensity. The XFELO complements existing sources based on self-amplified spontaneous emission (SASE) from high-gain X-ray free-electron lasers (XFEL) that produce ultra-short pulses with broad-band chaotic spectra [...] OpenAccess: PDF PDF (PDFA); 2019-04-0210:40 [PUBDB-2019-01792] Journal Article Santra, R. Analytical Theory of Attosecond Transient Absorption Spectroscopy of Perturbatively Dressed Systems Applied Sciences 9(7), 1350 (2019) [10.3390/app9071350] special issue: "Attosecond Science and Technology: Principles and Applications"   A theoretical description of attosecond transient absorption spectroscopy for temporally and spatially overlapping XUV and optical pulses is developed, explaining the signals one can obtain in such an experiment. To this end, we employ a two-stage approach based on perturbation theory, which allows us to give an analytical expression for the transient absorption signal [...] OpenAccess: PDF PDF (PDFA); 2019-03-2008:43 [PUBDB-2019-01624] Journal Article Welsch, R. Probing photodissociation dynamics using ring polymer molecular dynamics The journal of chemical physics 150(11), 114105 (2019) [10.1063/1.5086218]   The performance of the ring polymer molecular dynamics (RPMD) approach to simulate typical photodissociation processes is assessed. The correct description of photodissociation requires the calculation of correlation functions or expectation values associated with non-equilibrium initial conditions, which was shown to be possible with RPMD very recently [J. [...] Published on 2019-03-18. Available in OpenAccess from 2020-03-18.: PDF PDF (PDFA); 2019-03-1910:24 [PUBDB-2019-01603] Journal Article Santra, R. Time-resolved x-ray/optical pump-probe simulations on $\mathrm{N_2}$ molecules Structural dynamics 6(2), 024101 (2019) [10.1063/1.5053995]   The dynamics of $N_2^{2+}$ dications after x-ray-induced Auger decay and their probing with a delayed infrared probe pulse are theoretically investigated based on a quantum-mechanical model including all relevant electronic states for which wave-packet calculations on ab-initio potential energy curves are performed. Our results demonstrate that the $N_2^{2+}$ yield modulated by the delay of the probe pulse contains dynamical information on the wave-packet evolution in the quasi-bound final electronic states [...] OpenAccess: PDF PDF (PDFA);