@article{WernetLeitnerJosefssonetal.2017,
  author    = {Wernet, Philippe and Leitner, T. and Josefsson, Ida and Mazza, T. and Miedema, P. S. and Schroder, H. and Beye, Martin and Kunnus, K. and Schreck, S. and Radcliffe, P. and Dusterer, S. and Meyer, M. and Odelius, Michael and Fohlisch, Alexander},
  title     = {Communication: Direct evidence for sequential dissociation of gas-phase Fe(CO)(5) via a singlet pathway upon excitation at 266 nm},
  series = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  volume    = {146},
  journal   = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0021-9606},
  doi       = {10.1063/1.4984774},
  pages     = {5},
  year      = {2017},
  abstract  = {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. Fe 3p core-level photoelectron spectra directly reflect the singlet spin state of the Fe center in Fe(CO)(5), Fe(CO)(4), and Fe(CO)(3) showing that the dissociation exclusively occurs along a singlet pathway without triplet-state contribution. Our results are important for assessing intra- and intermolecular relaxation processes in the photodissociation dynamics of the prototypical Fe(CO)(5) complex in the gas phase and in solution, and they establish time-resolved core-level photoelectron spectroscopy as a powerful tool for determining the multiplicity of transition metals in photochemical reactions of coordination complexes. Published by AIP Publishing.},
  language  = {en}
}
@article{KubinKernGuletal.2017,
  author    = {Kubin, Markus and Kern, Jan and Gul, Sheraz and Kroll, Thomas and Chatterjee, Ruchira and Loechel, Heike and Fuller, Franklin D. and Sierra, Raymond G. and Quevedo, Wilson and Weniger, Christian and Rehanek, Jens and Firsov, Anatoly and Laksmono, Hartawan and Weninger, Clemens and Alonso-Mori, Roberto and Nordlund, Dennis L. and Lassalle-Kaiser, Benedikt and Glownia, James M. and Krzywinski, Jacek and Moeller, Stefan and Turner, Joshua J. and Minitti, Michael P. and Dakovski, Georgi L. and Koroidov, Sergey and Kawde, Anurag and Kanady, Jacob S. and Tsui, Emily Y. and Suseno, Sandy and Han, Zhiji and Hill, Ethan and Taguchi, Taketo and Borovik, Andrew S. and Agapie, Theodor and Messinger, Johannes and Erko, Alexei and F{\"o}hlisch, Alexander and Bergmann, Uwe and Mitzner, Rolf and Yachandra, Vittal K. and Yano, Junko and Wernet, Philippe},
  title     = {Soft x-ray absorption spectroscopy of metalloproteins and high-valent metal-complexes at room temperature using free-electron lasers},
  series = {Structural dynamics},
  volume    = {4},
  journal   = {Structural dynamics},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {2329-7778},
  doi       = {10.1063/1.4986627},
  pages     = {16},
  year      = {2017},
  abstract  = {X-ray absorption spectroscopy at the L-edge of 3d transition metals provides unique information on the local metal charge and spin states by directly probing 3d-derived molecular orbitals through 2p-3d transitions. However, this soft x-ray technique has been rarely used at synchrotron facilities for mechanistic studies of metalloenzymes due to the difficulties of x-ray-induced sample damage and strong background signals from light elements that can dominate the low metal signal. Here, we combine femtosecond soft x-ray pulses from a free-electron laser with a novel x-ray fluorescence-yield spectrometer to overcome these difficulties. We present L-edge absorption spectra of inorganic high-valent Mn complexes (Mn similar to 6-15 mmol/l) with no visible effects of radiation damage. We also present the first L-edge absorption spectra of the oxygen evolving complex (Mn4CaO5) in Photosystem II (Mn < 1 mmol/l) at room temperature, measured under similar conditions. Our approach opens new ways to study metalloenzymes under functional conditions. (C) 2017 Author(s).},
  language  = {en}
}
@article{YinInhesterVeeduetal.2017,
  author    = {Yin, Zhong and Inhester, Ludger and Veedu, Sreevidya Thekku and Quevedo, Wilson and Pietzsch, Annette and Wernet, Philippe and Groenhof, Gerrit and F{\"o}hlisch, Alexander and Grubmueller, Helmut and Techert, Simone},
  title     = {Cationic and Anionic Impact on the Electronic Structure of Liquid Water},
  series = {The journal of physical chemistry letters},
  volume    = {8},
  journal   = {The journal of physical chemistry letters},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1948-7185},
  doi       = {10.1021/acs.jpclett.7b01392},
  pages     = {3759 -- 3764},
  year      = {2017},
  abstract  = {Hydration shells around ions are crucial for many fundamental biological and chemical processes. Their local physicochemical properties are quite different from those of bulk water and hard to probe experimentally. We address this problem by combining soft X-ray spectroscopy using a liquid jet and molecular dynamics (MD) simulations together with ab initio electronic structure calculations to elucidate the water ion interaction in a MgCl2 solution at the molecular level. Our results reveal that salt ions mainly affect the electronic properties of water molecules in close vicinity and that the oxygen K-edge X-ray emission spectrum of water molecules in the first solvation shell differs significantly from that of bulk water. Ion-specific effects are identified by fingerprint features in the water X-ray emission spectra. While Mg2+ ions cause a bathochromic shift of the water lone pair orbital, the 3p orbital of the Cl- ions causes an additional peak in the water emission spectrum at around 528 eV.},
  language  = {en}
}
@article{FondellEckertJayetal.2017,
  author    = {Fondell, Mattis and Eckert, Sebastian and Jay, Raphael Martin and Weniger, Christian and Quevedo, Wilson and Niskanen, Johannes and Kennedy, Brian and Sorgenfrei, Nomi and Schick, Daniel and Giangrisostomi, Erika and Ovsyannikov, Ruslan and Adamczyk, Katrin and Huse, Nils and Wernet, Philippe and Mitzner, Rolf and F{\"o}hlisch, Alexander},
  title     = {Time-resolved soft X-ray absorption spectroscopy in transmission mode on liquids at MHz repetition rates},
  series = {Structural dynamics},
  volume    = {4},
  journal   = {Structural dynamics},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {2329-7778},
  doi       = {10.1063/1.4993755},
  pages     = {11},
  year      = {2017},
  abstract  = {We present a setup combining a liquid flatjet sample delivery and a MHz laser system for time-resolved soft X-ray absorption measurements of liquid samples at the high brilliance undulator beamline UE52-SGM at Bessy II yielding unprecedented statistics in this spectral range. We demonstrate that the efficient detection of transient absorption changes in transmission mode enables the identification of photoexcited species in dilute samples. With iron(II)-trisbipyridine in aqueous solution as a benchmark system, we present absorption measurements at various edges in the soft X-ray regime. In combination with the wavelength tunability of the laser system, the set-up opens up opportunities to study the photochemistry of many systems at low concentrations, relevant to materials sciences, chemistry, and biology. (C) 2017 Author(s).},
  language  = {en}
}