# CFEL-UDSS

 2020-01-2314:54 [PUBDB-2020-00522] Journal Article et al Time- and momentum-resolved photoemission studies using time-of-flight momentum microscopy at a free-electron laser Review of scientific instruments 91(1), 013109 - (2020) [10.1063/1.5118777]   Time-resolved photoemission with ultrafast pump and probe pulses is an emerging technique with wide application potential. Real-time recording of nonequilibrium electronic processes, transient states in chemical reactions, or the interplay of electronic and structural dynamics offers fascinating opportunities for future research. [...] OpenAccess: PDF PDF (PDFA); 2020-01-2214:41 [PUBDB-2020-00485] Report/Journal Article et al A Coincidence Velocity Map Imaging Spectrometer for Ions and High-Energy Electrons to Study Inner-Shell Photoionization of Gas-Phase Molecules [arXiv:1904.09938] Review of scientific instruments 90(5), 055103 - (2019) [10.1063/1.5093420]   We report on the design and performance of a double-sided coincidence velocity map imaging spectrometer optimized for electron-ion and ion-ion coincidence experiments studying inner-shell photoionization of gas-phase molecules with soft X-ray synchrotron radiation. The apparatus employs two microchannel plate detectors equipped with delay-line anodes for coincident, time- and position-resolved detection of photoelectrons and Auger electrons with kinetic energies up to 300 eV on one side of the spectrometer and photoions up to 25 eV per unit charge on the opposite side. [...] Fulltext: PDF PDF (PDFA); OpenAccess: PDF PDF (PDFA); 2019-11-2211:23 [PUBDB-2019-04420] Journal Article et al A zone-plate-based two-color spectrometer for indirect X-ray absorption spectroscopy Journal of synchrotron radiation 26(4), 1266 - 1271 (2019) [10.1107/S1600577519003898]   Fulltext: PDF PDF (PDFA); 2019-11-1122:09 [PUBDB-2019-04137] Journal Article et al Absorption spectra at the iodine 3d ionisation threshold following the $CH_{x}I^{+}$ ( x = 0–3) cation sequence Physical chemistry, chemical physics 21(45), 25415-25424 (2019) [10.1039/C9CP04640B]   Yields of atomic iodine Iq+ (q Z 2) fragments resulting from photoexcitation and photoionisation of thetarget cations CHxI+ (x = 0–3) have been measured in the photon-energy range 610 eV to 670 eV,which comprises the threshold for iodine 3d ionisation. The measured ion-yield spectra show twostrong and broad resonance features due to the excitation of the 3d3/2,5/2 electrons into ef states similarto atomic iodine. [...] OpenAccess: PDF PDF (PDFA); 2019-07-0917:13 [PUBDB-2019-02681] Journal Article et al Surface structure determination by x-ray standing waves at a free-electron laser New journal of physics 21(3), 033031 (2019) [10.1088/1367-2630/aafa47]   We demonstrate the structural sensitivity and accuracy of the x-ray standing wave technique at a high repetition rate free-electron laser, FLASH at DESY in Hamburg, by measuring the photoelectron yield from the surface SiO$_2$ of Mo/Si multilayers. These experiments open up the possibility to obtain unprecedented structural information of adsorbate and surface atoms with picometer spatial and femtosecond temporal resolution [...] OpenAccess: PDF PDF (PDFA); 2019-07-0418:33 [PUBDB-2019-02655] Journal Article et al Inner-shell X-ray absorption spectra of the cationic series $\mathrm{NH_y^+ ( y = 0–3)}$ Physical chemistry, chemical physics 21(30), 16505-16514 (2019) [10.1039/C9CP02864A]   Ion yields following X-ray absorption of the cationic series $\mathrm{NH_y^+ ( y = 0–3)}$ were measured to identify the characteristic absorption resonances in the energy range of the atomic nitrogen K-edge. Significant changes in the position of the absorption resonances were observed depending on the number of hydrogen atoms bound to the central nitrogen atom. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2019-06-2111:31 [PUBDB-2019-02530] Journal Article et al Ultrafast charge redistribution in small iodine containing molecules New journal of physics 21(3), 033017 (2019) [10.1088/1367-2630/ab1056]   We present studies on intra-molecular charge redistribution in iodine containing molecules upon iodine-4d photoionization. For this, we employed an XUV-pump-XUV-probe scheme based on time-delayed femtosecond pulses delivered by the free-electron laser at DESY in Hamburg (FLASH) [...] OpenAccess: PDF PDF (PDFA); 2019-05-2607:50 [PUBDB-2019-02368] Journal Article et al The photon‐ion merged‐beams experiment PIPE at PETRA III—The first five years X-ray spectrometry XXX, 10 (2019) [10.1002/xrs.3035]   The Photon-Ion Spectrometer at PETRAIII—in short, PIPE—is a permanentlyinstalled user facility at the "Variable Polarization XUV Beamline" P04 of thesynchrotron light source PETRA III operated by DESY in Hamburg, Germany.The careful design of the PIPE ion-optics in combination with the record-highphoton flux at P04 has lead to a breakthrough in experimental studies ofphoton interactions with ionized small quantum systems. This short reviewprovides an overview over the published scientific results from photon-ionmerged-beams experiments at PIPE that were obtained since the start of P04operations in 2013. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2019-04-1013:20 [PUBDB-2019-01919] Journal Article et al Light Source Upgrades at DESY: PETRA IV and FLASH2020+ Synchrotron radiation news 32(1), 27 - 31 (2019) [10.1080/08940886.2019.1559605]   Restricted: PDF PDF (PDFA); 2019-02-2714:52 [PUBDB-2019-01266] Journal Article/Contribution to a conference proceedings et al XMCD going ultra-cold: Experiments at 100 mK and 7 T XXX International Conference on Photonic, Electronic, and Atomic Collisions, ICPEAC30, CairnsCairns, Australia, 26 Jul 2017 - 1 Aug 2017   First experiments along with the general capabilities of the TTXMCD endstation at P04, PETRA III, DESY are presented. The TTXMCD endstation allows measuring the magnetic properties of solids, thin films, molecules or atomic adsorbates at ultra-cold temperatures in an element specific way [...] OpenAccess: PDF PDF (PDFA);