# FS-FLASH-O

 2019-07-1210:44 [PUBDB-2019-02698] Journal Article et al Evidence of Extreme Ultraviolet Superfluorescence in Xenon Physical review letters 123(2), 023201 (2019) [10.1103/PhysRevLett.123.023201]   We present a comprehensive experimental and theoretical study on superfluorescence in the extreme ultraviolet wavelength regime. Focusing a free-electron laser pulse in a cell filled with Xe gas, the medium is quasi-instantaneously population inverted by 4d-shell ionization on the giant resonance followed by Auger decay [...] OpenAccess: PDF PDF (PDFA); 2019-07-0916:47 [PUBDB-2019-02678] Journal Article et al Wavefront-propagation simulations supporting the design of a time-delay compensating monochromator beamline at FLASH2 Journal of synchrotron radiation 26(3), 899 - 905 (2019) [10.1107/S160057751900345X]   Wavefront-propagation simulations have been performed to complete the design of a monochromator beamline for FLASH2, the variable-gap undulator line at the soft X-ray free-electron laser in Hamburg (FLASH). Prior to propagation through the beamline optical elements, the parameters of the photon source were generated using the GENESIS code which includes the free-electron laser experimental data. [...] OpenAccess: PDF PDF (PDFA); Restricted: PDF PDF (PDFA); 2019-06-2110:30 [PUBDB-2019-02527] Journal Article et al Two-color XUV+NIR femtosecond photoionization of neon in the near-threshold region New journal of physics 21(6), 063034 (2019) [10.1088/1367-2630/ab2a98]   Results of angle-resolved electron spectroscopy of near-threshold photoionization of Ne atoms bycombined femtosecond extreme ultraviolet and near infraredfields are presented. The dressed-electron spectra show an energetic distribution into so-called sidebands, being separated by thephoton energy of the dressing laser [...] OpenAccess: PDF PDF (PDFA); 2019-05-2911:54 [PUBDB-2019-02388] Journal Article et al An X-ray gas monitor for free-electron lasers Journal of synchrotron radiation 26(4), 1092 - 1100 (2019) [10.1107/S1600577519005174]   A novel X-ray gas monitor (XGM) has been developed which allows the measurement of absolute photon pulse energy and photon beam position at all existing and upcoming free-electron lasers (FELs) over a broad spectral range covering vacuum ultraviolet (VUV), extreme ultraviolet (EUV) and soft and hard X-rays. The XGM covers a wide dynamic range from spontaneous undulator radiation to FEL radiation and provides a temporal resolution of better than 200 ns [...] OpenAccess: PDF PDF (PDFA); 2019-04-1816:42 [PUBDB-2019-02030] Journal Article et al Reaction microscope endstation at FLASH2 Journal of synchrotron radiation 26(3), 854 - 867 (2019) [10.1107/S1600577519002236]   A reaction microscope dedicated to multi-particle coincidence spectroscopy on gas-phase samples is installed at beamline FL26 of the free-electron laser FLASH2 in Hamburg. The main goals of the instrument are to follow the dynamics of atoms, molecules and small clusters on their natural time-scale and to study non-linear light–matter interaction with such systems. [...] Restricted: PDF PDF (PDFA); 2019-02-2017:27 [PUBDB-2019-01185] Journal Article et al Terahertz-Field-Induced Time Shifts in Atomic Photoemission Physical review letters 122(7), 073001 (2019) [10.1103/PhysRevLett.122.073001]   Time delays for atomic photoemission obtained in streaking or reconstruction of attosecond bursts by interference of two-photon transitions experiments originate from a combination of the quantum mechanical Wigner time and the Coulomb-laser coupling. While the former was investigated intensively theoretically as well as experimentally, the latter attracted less interest in experiments and has mostly been subject to calculations [...] OpenAccess: PDF PDF (PDFA); 2019-01-2909:28 [PUBDB-2019-00839] Journal Article et al Author Correction: Generation and characterization of ultrathin free-flowing liquid sheets ist Nature Communications 9(1), 2860 (2018) [10.1038/s41467-018-05365-4]   The physics and chemistry of liquid solutions play a central role in science, and our understanding of life on Earth. Unfortunately, key tools for interrogating aqueous systems, such as infrared and soft X-ray spectroscopy, cannot readily be applied because of strong absorption in water. [...] OpenAccess: PDF PDF (PDFA); 2019-01-2811:43 [PUBDB-2019-00765] Journal Article et al Hindered nematic alignment of hematite spindles in poly( N-isopropylacrylamide) hydrogels: a small-angle X-ray scattering and rheology study Journal of applied crystallography 51(1), 87 - 96 (2018) [10.1107/S1600576717017411]   Field-induced changes to the mesostructure of ferrogels consisting of spindle-shaped hematite particles and poly(N-isopropylacrylamide) are investigated by means of small-angle X-ray scattering (SAXS). Related field-induced changes to the macroscopic viscoelastic properties of these composites are probed by means of oscillatory shear experiments in an external magnetic field. [...] Restricted: PDF PDF (PDFA); 2019-01-0810:16 [PUBDB-2019-00093] Journal Article et al Symmetry breakdown of electron emission in extreme ultraviolet photoionization of argon Nature Communications 9(1), 4659 (2018) [10.1038/s41467-018-07152-7]   Short wavelength free-electron lasers (FELs), providing pulses of ultrahigh photon intensity, have revolutionized spectroscopy on ionic targets. Their exceptional photon flux enables multiple photon absorptions within a single femtosecond pulse, which in turn allows for deep insights into the photoionization process itself as well as into evolving ionic states of a target [...] OpenAccess: PDF PDF (PDFA); 2019-01-0809:36 [PUBDB-2019-00089] Journal Article et al Auger electron angular distributions following excitation or ionization of the I 3d level in methyl iodide The journal of chemical physics 149(9), 094304 (2018) [10.1063/1.5045640]   Auger electron spectra following excitation or ionization of the I 3d level in CH$_3$I have been recorded with horizontally or vertically plane polarized synchrotron radiation. These spectra have enabled the Auger electron angular distributions, as characterized by the β parameter, to be determined. [...] Published on 2018-09-06. Available in OpenAccess from 2019-09-06.: PDF PDF (PDFA);