FS-FLASH

 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; 2016-11-1014:14 [PUBDB-2016-04896] Journal Article et al Orbital-specific mapping of the ligand exchange dynamics of $Fe(CO)_{5}$ in solution Nature / Physical science 520(7545), 78 - 81 (2015) [10.1038/nature14296]   Transition-metal complexes have long attracted interest for fundamental chemical reactivity studies and possible use in solar energy conversion1, 2. Electronic excitation, ligand loss from the metal centre, or a combination of both, creates changes in charge and spin density at the metal site3, 4, 5, 6, 7, 8, 9, 10, 11 that need to be controlled to optimize complexes for photocatalytic hydrogen production8 and selective carbon–hydrogen bond activation9, 10, 11. [...] Published on 2015-04-01. Available in OpenAccess from 2015-10-01.: PDF; Restricted: PDF PDF (PDFA); 2016-11-1012:12 [PUBDB-2016-04869] Journal Article et al Identification of the dominant photochemical pathways and mechanistic insights to the ultrafast ligand exchange of Fe(CO)$_{5}$ to Fe(CO)$_{4}$EtOH Structural dynamics 3(4), 043204 (2016) [10.1063/1.4941602]   We utilized femtosecond time-resolved resonant inelastic X-ray scattering and ab initio theory to study the transient electronic structure and the photoinduced molecular dynamics of a model metal carbonyl photocatalyst Fe(CO)$_5$ in ethanol solution. We propose mechanistic explanation for the parallel ultrafast intra-molecular spin crossover and ligation of the Fe(CO)$_4$ which are observed following a charge transfer photoexcitation of Fe(CO)$_5$ as reported in our previous study [Wernet et al., Nature 520, 78 (2015)]. [...] OpenAccess: PDF PDF (PDFA); 2016-11-1010:20 [PUBDB-2016-04837] Journal Article et al Role of heat accumulation in the multi-shot damage of silicon irradiated with femtosecond XUV pulses at a 1 MHz repetition rate Optics express 24(14), 15468 - 15477 (2016) [10.1364/OE.24.015468]   The role played by heat accumulation in multi-shot damage of silicon was studied. Bulk silicon samples were exposed to intense XUV monochromatic radiation of a 13.5 nm wavelength in a series of 400 femtosecond pulses, repeated with a 1 MHz rate (pulse trains) at the FLASH facility in Hamburg. [...] OpenAccess: PDF PDF (PDFA); 2016-05-0911:16 [PUBDB-2016-01890] Journal Article et al New experimental perspectives for soft x-ray absorption spectroscopies at ultra-low temperatures below 50 mK and in high magnetic fields up to 7 T Review of scientific instruments 87(4), 045116 (2016) [10.1063/1.4947516]   A new ultra-low temperature experiment including a superconducting vector magnet has been developed for soft x-ray absorption spectroscopy experiments at third generation synchrotron light sources. The sample is cooled below 50 mK by a cryogen free 3He-4He dilution refrigerator. [...] Published on 2016-04-29. Available in OpenAccess from 2017-04-29.: PDF PDF (PDFA); 2016-01-1411:34 [PUBDB-2016-00292] Journal Article et al Correction of the deterministic part of space–charge interaction in momentum microscopy of charged particles Ultramicroscopy 159, 488 - 496 (2015) [10.1016/j.ultramic.2015.05.015]   Ultrahigh spectral brightness femtosecond XUV and X-ray sources like free electron lasers (FEL) and table-top high harmonics sources (HHG) offer fascinating experimental possibilities for analysis of transient states and ultrafast electron dynamics. For electron spectroscopy experiments using illumination from such sources, the ultrashort high-charge electron bunches experience strong space–charge interactions. [...] Restricted: PDF PDF (PDFA) PDF PDF (PDFA); 2016-01-1411:29 [PUBDB-2016-00290] Journal Article et al Optical laser-induced CO desorption from Ru(0001) monitored with a free-electron X-ray laser: DFT prediction and X-ray confirmation of a precursor state Surface science 640, 80 - 88 (2015) [10.1016/j.susc.2015.03.011]   We present density functional theory modeling of time-resolved optical pump/X-ray spectroscopic probe data of CO desorption from Ru(0001). The BEEF van der Waals functional predicts a weakly bound state as a precursor to desorption. [...] OpenAccess: PDF PDF (PDFA); Restricted: PDF PDF (PDFA); 2016-01-1411:25 [PUBDB-2016-00286] Journal Article et al Strong Influence of Coadsorbate Interaction on CO Desorption Dynamics on Ru(0001) Probed by Ultrafast X-Ray Spectroscopy and Ab Initio Simulations Physical review letters 114(15), 156101 (2015) [10.1103/PhysRevLett.114.156101]   We show that coadsorbed oxygen atoms have a dramatic influence on the CO desorption dynamics from Ru(0001). In contrast to the precursor-mediated desorption mechanism on Ru(0001), the presence of surface oxygen modifies the electronic structure of Ru atoms such that CO desorption occurs predominantly via the direct pathway. [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext