TY - JOUR A1 - Kunnus, Kristjan A1 - Schreck, Simon A1 - Föhlisch, Alexander T1 - Free-electron laser based resonant inelastic X-ray scattering on molecules and liquids JF - Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy N2 - The unprecedented beam properties of free-electron laser based X-ray sources enable novel resonant inelastic X-ray scattering (RIXS) experiments. Femtosecond time-resolved RIXS can be used to follow charge, spin and structural dynamics of dilute solute molecules in solution. Ultrashort X-ray pulses allow probing of highly radiation sensitive states of matter such as the metastable phase of supercooled liquid water. Nonlinear X-ray probes like amplified spontaneous emission and stimulated resonant X-ray scattering provide an enhanced selectivity and sensitivity as well as a path to control radiation damage and increase the photon yields in RIXS experiments. (C) 2015 Elsevier B.V. All rights reserved. KW - Free-electron laser KW - RIXS KW - Pump-probe KW - Nonlinear X-ray spectroscopy KW - Molecules KW - Liquids Y1 - 2015 U6 - https://doi.org/10.1016/j.elspec.2015.08.012 SN - 0368-2048 SN - 1873-2526 VL - 204 SP - 345 EP - 355 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Premont-Schwarz, Mirabelle A1 - Schreck, Simon A1 - Iannuzzi, Marcella A1 - Nibbering, Erik T. J. A1 - Odelius, Michael A1 - Wernet, Philippe T1 - Correlating Infrared and X-ray Absorption Energies for Molecular-Level Insight into Hydrogen Bond Making and Breaking in Solution JF - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry N2 - While ubiquitous, the making and breaking of hydrogen bonds in solution is notoriously difficult to study due to the associated complex changes of nuclear and electronic structures. With the aim to reduce the according uncertainty in correlating experimental observables and hydrogen-bond configurations, we combine the information from proximate methods to study the N-H center dot center dot center dot O hydrogen bond in solution. We investigate hydrogen-bonding of the N-H group of N-methylaniline with oxygen from liquid DMSO and acetone with infrared spectra in the N-H stretching region and X-ray absorption spectra at the N K-edge. We experimentally observe blue shifts of the infrared stretching band and an X-ray absorption pre-edge peak when going from DMSO to acetone. With ab initio molecular dynamics simulations and calculated spectra, we qualitatively reproduce the experimental observables but we do not reach quantitative agreement with experiment. The infrared spectra support the notion of weakening the N-H center dot center dot center dot O hydrogen bond from DMSO to acetone. However, we fail to theoretically reproduce the measured shift of the X-ray absorption pre-edge peak. We discuss possible shortcomings of the simulation models and spectrum calculations. Common features and distinct differences with the O-H center dot center dot center dot O hydrogen bond are highlighted, and the implications for monitoring hydrogen-bond breaking in solution are discussed. Y1 - 2015 U6 - https://doi.org/10.1021/acs.jpcb.5b02954 SN - 1520-6106 VL - 119 IS - 25 SP - 8115 EP - 8124 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Sellberg, Jonas A. A1 - McQueen, Trevor A. A1 - Laksmono, Hartawan A1 - Schreck, Simon A1 - Beye, Martin A1 - DePonte, Daniel P. A1 - Kennedy, Brian A1 - Nordlund, Dennis A1 - Sierra, Raymond G. A1 - Schlesinger, Daniel A1 - Tokushima, Takashi A1 - Zhovtobriukh, Iurii A1 - Eckert, Sebastian A1 - Segtnan, Vegard H. A1 - Ogasawara, Hirohito A1 - Kubicek, Katharina A1 - Techert, Simone A1 - Bergmann, Uwe A1 - Dakovski, Georgi L. A1 - Schlotter, William F. A1 - Harada, Yoshihisa A1 - Bogan, Michael J. A1 - Wernet, Philippe A1 - Föhlisch, Alexander A1 - Pettersson, Lars G. M. A1 - Nilsson, Anders T1 - X-ray emission spectroscopy of bulk liquid water in "no-man's land" JF - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr N2 - The structure of bulk liquid water was recently probed by x-ray scattering below the temperature limit of homogeneous nucleation (T-H) of similar to 232 K [J. A. Sellberg et al., Nature 510, 381-384 (2014)]. Here, we utilize a similar approach to study the structure of bulk liquid water below T-H using oxygen K-edge x-ray emission spectroscopy (XES). Based on previous XES experiments [T. Tokushima et al., Chem. Phys. Lett. 460, 387-400 (2008)] at higher temperatures, we expected the ratio of the 1b(1)' and 1b(1)" peaks associated with the lone-pair orbital in water to change strongly upon deep supercooling as the coordination of the hydrogen (H-) bonds becomes tetrahedral. In contrast, we observed only minor changes in the lone-pair spectral region, challenging an interpretation in terms of two interconverting species. A number of alternative hypotheses to explain the results are put forward and discussed. Although the spectra can be explained by various contributions from these hypotheses, we here emphasize the interpretation that the line shape of each component changes dramatically when approaching lower temperatures, where, in particular, the peak assigned to the proposed disordered component would become more symmetrical as vibrational interference becomes more important. (C) 2015 AIP Publishing LLC. Y1 - 2015 U6 - https://doi.org/10.1063/1.4905603 SN - 0021-9606 SN - 1089-7690 VL - 142 IS - 4 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Wernet, Philippe A1 - Kunnus, Kristjan A1 - Josefsson, Ida A1 - Rajkovic, Ivan A1 - Quevedo, Wilson A1 - Beye, Martin A1 - Schreck, Simon A1 - Gruebel, S. A1 - Scholz, Mirko A1 - Nordlund, Dennis A1 - Zhang, Wenkai A1 - Hartsock, Robert W. A1 - Schlotter, William F. A1 - Turner, Joshua J. A1 - Kennedy, Brian A1 - Hennies, Franz A1 - de Groot, Frank M. F. A1 - Gaffney, Kelly J. A1 - Techert, Simone A1 - Odelius, Michael A1 - Föhlisch, Alexander T1 - Orbital-specific mapping of the ligand exchange dynamics of Fe(CO)(5) in solution JF - Nature : the international weekly journal of science N2 - Transition-metal complexes have long attracted interest for fundamental chemical reactivity studies and possible use in solar energy conversion(1,2). Electronic excitation, ligand loss from the metal centre, or a combination of both, creates changes in charge and spin density at the metal site(3-11) that need to be controlled to optimize complexes for photocatalytic hydrogen production(8) and selective carbon-hydrogen bond activation(9-11). An understanding at the molecular level of how transition-metal complexes catalyse reactions, and in particular of the role of the short-lived and reactive intermediate states involved, will be critical for such optimization. However, suitable methods for detailed characterization of electronic excited states have been lacking. Here we show, with the use of X-ray laser-based femtosecond-resolution spectroscopy and advanced quantum chemical theory to probe the reaction dynamics of the benchmark transition-metal complex Fe(CO)(5) in solution, that the photo-induced removal of CO generates the 16-electron Fe(CO)(4) species, a homogeneous catalyst(12,13) with an electron deficiency at the Fe centre(14,15), in a hitherto unreported excited singlet state that either converts to the triplet ground state or combines with a CO or solvent molecule to regenerate a penta-coordinated Fe species on a sub-picosecond timescale. This finding, which resolves the debate about the relative importance of different spin channels in the photochemistry of Fe(CO)(5) (refs 4, 16-20), was made possible by the ability of femtosecond X-ray spectroscopy to probe frontier-orbital interactions with atom specificity. We expect the method to be broadly applicable in the chemical sciences, and to complement approaches that probe structural dynamics in ultrafast processes. Y1 - 2015 U6 - https://doi.org/10.1038/nature14296 SN - 0028-0836 SN - 1476-4687 VL - 520 IS - 7545 SP - 78 EP - 81 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Yin, Zhong A1 - Rajkovic, Ivan A1 - Veedu, Sreevidya Thekku A1 - Deinert, Sascha A1 - Raiser, Dirk A1 - Jain, Rohit A1 - Fukuzawa, Hironobu A1 - Wada, Shin-ichi A1 - Quevedo, Wilson A1 - Kennedy, Brian A1 - Schreck, Simon A1 - Pietzsch, Annette A1 - Wernet, Philippe A1 - Ueda, Kyoshi A1 - Föhlisch, Alexander A1 - Techert, Simone T1 - Ionic solutions probed by resonant inelastic X-ray scattering JF - Zeitschrift für physikalische Chemie : international journal of research in physical chemistry and chemical physics N2 - X-ray spectroscopy is a powerful tool to study the local charge distribution of chemical systems. Together with the liquid jet it becomes possible to probe chemical systems in their natural environment, the liquid phase. In this work, we present X-ray absorption (XA), X-ray emission (XE) and resonant inelastic X-ray scattering (RIXS) data of pure water and various salt solutions and show the possibilities these methods offer to elucidate the nature of ion-water interaction. KW - X-ray Spectroscopy KW - XAS KW - XES KW - RIXS KW - Anions KW - Cations KW - Liquid Jet KW - Synchrotron Radiation Y1 - 2015 U6 - https://doi.org/10.1515/zpch-2015-0610 SN - 0942-9352 VL - 229 IS - 10-12 SP - 1855 EP - 1867 PB - De Gruyter CY - Berlin ER -