# FS-FLASH

 2017-09-1316:13 [PUBDB-2017-10736] Contribution to a conference proceedings/Contribution to a book et al Concept for a Seeded FEL at FLASH2 8th Intl. Particle Accelerator Conference, IPAC2017, Meeting locationCopenhagen, Denmark, 14 May 2017 - 19 May 2017 Geneva : JACoW, 2607-2610 (2017) [10.18429/JACoW-IPAC2017-WEPAB019]   The free-electron laser (FEL) FLASH is a user facility delivering photon pulses down to 4 nm wavelength. Recently, the second FEL undulator beamline FLASH2 was added to the facility. [...] OpenAccess: PDF PDF (PDFA); 2017-09-1214:07 [PUBDB-2017-10683] Journal Article et al Real-Time Elucidation of Catalytic Pathways in CO Hydrogenation on Ru The journal of physical chemistry letters 8(16), 3820 - 3825 (2017) [10.1021/acs.jpclett.7b01549]   The direct elucidation of the reaction pathways in heterogeneous catalysis has been challenging due to the short-lived nature of reaction intermediates. Here, we directly measured on ultrafast time scales the initial hydrogenation steps of adsorbed CO on a Ru catalyst surface, which is known as the bottleneck reaction in syngas and CO$_2$ reforming processes. [...] Published on 2017-07-31. Available in OpenAccess from 2018-07-31.: CO Hydrogenation Supplemental 2017.07.28 - Resubmitted JPCL - PDF PDF (PDFA); CO Hydrogenation 2017.07.30 - Resubmitted JPCL - PDF PDF (PDFA); Restricted: PDF PDF (PDFA); 2017-09-0423:48 [PUBDB-2017-10311] Journal Article et al Direct 3D mapping of the Fermi surface and Fermi velocity Nature materials 16(6), 615 - 621 (2017) [10.1038/nmat4875]   We performed a full mapping of the bulk electronic structure including the Fermi surface and Fermi-velocity distribution v$_F$(k$_F$) of tungsten. The 4D spectral function ρ(E$_B$; k) in the entire bulk Brillouin zone and 6 eV binding-energy (E$_B$) interval was acquired in ~3 h thanks to a new multidimensional photoemission data-recording technique (combining full-field k-microscopy with time-of-flight parallel energy recording) and the high brilliance of the soft X-rays used [...] Restricted: PDF PDF (PDFA); 2017-08-3013:56 [PUBDB-2017-10147] Contribution to a conference proceedings/Contribution to a book et al First Operation of a Harmonic Lasing Self-Seeded FEL 8th International Particle Accelerator Conference, IPAC17, Meeting locationCopenhagen, Denmark, 15 May 2017 - 19 May 2017 Geneva : JACoW, 2621-2624 (2017) [10.18429/JACoW-IPAC2017-WEPAB023]   Harmonic lasing is a perspective mode of operation of X-ray FEL user facilities that allows to provide brilliant beams of higher energy photons for user experiments. Another useful application of harmonic lasing is so called Harmonic Lasing Self-Seeded Free Electron Laser (HLSS FEL) that allows to improve spectral brightness of these facilities. [...] OpenAccess: PDF PDF (PDFA); Restricted: PDF PDF (PDFA); External link: Fulltext 2017-06-2310:06 [PUBDB-2017-05924] Journal Article et al Statistical properties of a free-electron laser revealed by Hanbury Brown?Twiss interferometry Physical review / A 95(2), 023843 (2017) [10.1103/PhysRevA.95.023843]   We present a comprehensive experimental analysis of statistical properties of the self-amplified spontaneous emission free-electron laser (FEL) FLASH by means of Hanbury Brown and Twiss interferometry. The experiments were performed at FEL wavelengths of 5.5, 13.4, and 20.8 nm [...] OpenAccess: PDF PDF (PDFA); 2017-06-0817:06 [PUBDB-2017-04558] Journal Article et al Communication: Direct evidence for sequential dissociation of gas-phase Fe(CO)$_5$ via a singlet pathway upon excitation at 266 nm The journal of chemical physics 146(21), 211103 (2017) [10.1063/1.4984774]   We prove the hitherto hypothesized sequential dissociation of Fe(CO)$_5$ in the gas phase upon photoexcitation at 266 nm via a singlet pathway with time-resolved valence and core-level photoelectron spectroscopy with an x-ray free-electron laser. Valence photoelectron spectra are used to identify free CO molecules and to determine the time constants of stepwise dissociation to Fe(CO)$_4$ within the temporal resolution of the experiment and further to Fe(CO)$_3$ within 3 ps [...] OpenAccess: PDF PDF (PDFA); 2017-05-0415:03 [PUBDB-2017-02270] Journal Article et al Catalysis in real time using X-ray lasers Chemical physics letters 675, 145 - 173 (2017) [10.1016/j.cplett.2017.02.018]   We describe how the unique temporal and spectral characteristics of X-ray free-electron lasers (XFEL) can be utilized to follow chemical transformations in heterogeneous catalysis in real time. We highlight the systematic study of CO oxidation on Ru(0 0 0 1), which we initiate either using a femtosecond pulse from an optical laser or by activating only the oxygen atoms using a THz pulse [...] OpenAccess: PDF; 2017-02-2210:40 [PUBDB-2017-01078] Journal Article et al First Operation of a Harmonic Lasing Self-Seeded Free Electron Laser   Harmonic lasing is a possible mode of operation of X-ray FEL user facilities that allows us to provide brilliant beams of higher energy photons for user experiments. Another useful application of harmonic lasing is the so-called harmonic lasing self-seeded free electron laser (HLSS FEL) that allows the improvement of spectral brightness of these facilities. [...] OpenAccess: PDF; Restricted: PDF; External link: Fulltext 2016-12-1209:36 [PUBDB-2016-06076] Journal Article et al Anti-Stokes resonant x-ray Raman scattering for atom specific and excited state selective dynamics New journal of physics 18(10), 103011 (2016) [10.1088/1367-2630/18/10/103011]   Ultrafast electronic and structural dynamics of matter govern rate and selectivity of chemical reactions, as well as phase transitions and efficient switching in functional materials. Since x-rays determine electronic and structural properties with elemental, chemical, orbital and magnetic selectivity, short pulse x-ray sources have become central enablers of ultrafast science. [...] OpenAccess: PDF PDF (PDFA); 2016-12-0514:21 [PUBDB-2016-05879] Journal Article et al Chemical Bond Activation Observed with an X-ray Laser The journal of physical chemistry letters 7(18), 3647 - 3651 (2016) [10.1021/acs.jpclett.6b01543]   The concept of bonding and antibonding orbitals is fundamental in chemistry. The population of those orbitals and the energetic difference between the two reflect the strength of the bonding interaction. [...] Published on 2016-09-01. Available in OpenAccess from 2017-09-01.: PDF;