TY  - JOUR
A1  - Kunnus, Kristjan
A1  - Rajkovic, Ivan
A1  - Schreck, Simon
A1  - Quevedo, Wilson
A1  - Eckert, Sebastian
A1  - Beye, Martin
A1  - Suljoti, Edlira
A1  - Weniger, Christian
A1  - Kalus, Christian
A1  - Gruebel, Sebastian
A1  - Scholz, Mirko
A1  - Nordlund, Dennis
A1  - Zhang, Wenkai
A1  - Hartsock, Robert W.
A1  - Gaffney, Kelly J.
A1  - Schlotter, William F.
A1  - Turner, Joshua J.
A1  - Kennedy, Brian
A1  - Hennies, Franz
A1  - Techert, Simone
A1  - Wernet, Philippe
A1  - Föhlisch, Alexander
T1  - A setup for resonant inelastic soft x-ray scattering on liquids at free electron laser light sources
JF  - Review of scientific instruments : a monthly journal devoted to scientific instruments, apparatus, and techniques
N2  - We present a flexible and compact experimental setup that combines an in vacuum liquid jet with an x-ray emission spectrometer to enable static and femtosecond time-resolved resonant inelastic soft x-ray scattering (RIXS) measurements from liquids at free electron laser (FEL) light sources. We demonstrate the feasibility of this type of experiments with the measurements performed at the Linac Coherent Light Source FEL facility. At the FEL we observed changes in the RIXS spectra at high peak fluences which currently sets a limit to maximum attainable count rate at FELs. The setup presented here opens up new possibilities to study the structure and dynamics in liquids.
Y1  - 2012
U6  - https://doi.org/10.1063/1.4772685
SN  - 0034-6748
VL  - 83
IS  - 12
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Schreck, Simon
A1  - Beye, Martin
A1  - Sellberg, Jonas A.
A1  - McQueen, Trevor
A1  - Laksmono, Hartawan
A1  - Kennedy, Brian
A1  - Eckert, Sebastian
A1  - Schlesinger, Daniel
A1  - Nordlund, Dennis
A1  - Ogasawara, Hirohito
A1  - Sierra, Raymond G.
A1  - Segtnan, Vegard H.
A1  - Kubicek, Katharina
A1  - Schlotter, William F.
A1  - Dakovski, Georgi L.
A1  - Moeller, Stefan P.
A1  - Bergmann, Uwe
A1  - Techert, Simone
A1  - Pettersson, Lars G. M.
A1  - Wernet, Philippe
A1  - Bogan, Michael J.
A1  - Harada, Yoshihisa
A1  - Nilsson, Anders
A1  - Föhlisch, Alexander
T1  - Reabsorption of soft x-ray emission at high x-ray free-electron laserfluences
JF  - Physical review letters
N2  - We report on oxygen K-edge soft x-ray emission spectroscopy from a liquid water jet at the Linac Coherent Light Source. We observe significant changes in the spectral content when tuning over a wide range of incident x-ray fluences. In addition the total emission yield decreases at high fluences. These modifications result from reabsorption of x-ray emission by valence-excited molecules generated by the Auger cascade. Our observations have major implications for future x-ray emission studies at intense x-ray sources. We highlight the importance of the x-ray pulse length with respect to the core-hole lifetime.
Y1  - 2014
U6  - https://doi.org/10.1103/PhysRevLett.113.153002
SN  - 0031-9007
SN  - 1079-7114
VL  - 113
IS  - 15
PB  - American Physical Society
CY  - College Park
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  - Eckert, Sebastian
A1  - Beye, Martin
A1  - Pietzsch, Annette
A1  - Quevedo, Wilson
A1  - Hantschmann, Markus
A1  - Ochmann, Miguel
A1  - Ross, Matthew
A1  - Minitti, Michael P.
A1  - Turner, Joshua J.
A1  - Moeller, Stefan P.
A1  - Schlotter, William F.
A1  - Dakovski, Georgi L.
A1  - Khalil, Munira
A1  - Huse, Nils
A1  - Föhlisch, Alexander
T1  - Principles of femtosecond X-ray/optical cross-correlation with X-ray induced transient optical reflectivity in solids
JF  - Applied physics letters
N2  - The discovery of ultrafast X-ray induced optical reflectivity changes enabled the development of X-ray/optical cross correlation techniques at X-ray free electron lasers worldwide. We have now linked through experiment and theory the fundamental excitation and relaxation steps with the transient optical properties in finite solid samples. Therefore, we gain a thorough interpretation and an optimized detection scheme of X-ray induced changes to the refractive index and the X-ray/optical cross correlation response. (C) 2015 AIP Publishing LLC.
Y1  - 2015
U6  - https://doi.org/10.1063/1.4907949
SN  - 0003-6951
SN  - 1077-3118
VL  - 106
IS  - 6
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Schick, Daniel
A1  - Eckert, Sebastian
A1  - Pontius, Niko
A1  - Mitzner, Rolf
A1  - Föhlisch, Alexander
A1  - Holldack, Karsten
A1  - Sorgenfrei, Florian
T1  - Versatile soft X-ray-optical cross-correlator for ultrafast applications
JF  - Structural dynamics
N2  - We present an X-ray-optical cross-correlator for the soft (> 150 eV) up to the hard X-ray regime based on a molybdenum-silicon superlattice. The cross-correlation is done by probing intensity and position changes of superlattice Bragg peaks caused by photoexcitation of coherent phonons. This approach is applicable for a wide range of X-ray photon energies as well as for a broad range of excitation wavelengths and requires no external fields or changes of temperature. Moreover, the cross-correlator can be employed on a 10 ps or 100 fs time scale featuring up to 50% total X-ray reflectivity and transient signal changes of more than 20%. (C) 2016 Author(s).
Y1  - 2016
U6  - https://doi.org/10.1063/1.4964296
SN  - 2329-7778
VL  - 3
SP  - 054304-1
EP  - 054304-8
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Eckert, Sebastian
A1  - Miedema, P. S.
A1  - Quevedo, W.
A1  - Fondell, Mattis
A1  - Beye, Martin
A1  - Pietzsch, Annette
A1  - Ross, M.
A1  - Khalil, M.
A1  - Föhlisch, Alexander
T1  - Molecular structures and protonation state of 2-Mercaptopyridine in aqueous solution
JF  - Chemical physics letters
N2  - The speciation of 2-Mercaptopyridine in aqueous solution has been investigated with nitrogen 1s Near Edge X-ray Absorption Fine Structure spectroscopy and time dependent Density Functional Theory. The prevalence of distinct species as a function of the solvent basicity is established. No indications of dimerization towards high concentrations are found. The determination of different molecular structures of 2-Mercaptopyridine in aqueous solution is put into the context of proton-transfer in keto-enol and thione-thiol tautomerisms. (C) 2016 The Authors. Published by Elsevier B.V.
Y1  - 2016
U6  - https://doi.org/10.1016/j.cplett.2016.01.050
SN  - 0009-2614
SN  - 1873-4448
VL  - 647
SP  - 103
EP  - 106
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Eckert, Sebastian
A1  - Norell, Jesper
A1  - Miedema, Piter S.
A1  - Beye, Martin
A1  - Fondell, Mattis
A1  - Quevedo, Wilson
A1  - Kennedy, Brian
A1  - Hantschmann, Markus
A1  - Pietzsch, Annette
A1  - van Kuiken, Benjamin
A1  - Ross, Matthew
A1  - Minitti, Michael P.
A1  - Moeller, Stefan P.
A1  - Schlotter, William F.
A1  - Khalil, Munira
A1  - Odelius, Michael
A1  - Föhlisch, Alexander
T1  - Untersuchung unabhängiger N‐H‐ und N‐C‐Bindungsverformungen auf ultrakurzen Zeitskalen mit resonanter inelastischer Röntgenstreuung
JF  - Angewandte Chemie
N2  - Die Femtosekundendynamik nach resonanten Photoanregungen mit optischen und Röntgenpulsen ermöglicht eine selektive Verformung von chemischen N‐H‐ und N‐C‐Bindungen in 2‐Thiopyridon in wässriger Lösung. Die Untersuchung der orbitalspezifischen elektronischen Struktur und ihrer Dynamik auf ultrakurzen Zeitskalen mit resonanter inelastischer Röntgenstreuung an der N1s‐Resonanz am Synchrotron und dem Freie‐Elektronen‐Laser LCLS in Kombination mit quantenchemischen Multikonfigurationsberechnungen erbringen den direkten Nachweis dieser kontrollierten photoinduzierten Molekülverformungen und ihrer ultrakurzen Zeitskala.
KW  - Photochemie
KW  - Protonierung
KW  - RIXS (resonante inelastische Röntgenstreuung)
KW  - Selektiver Bindungsbruch
KW  - Stickstoff
Y1  - 2017
U6  - https://doi.org/10.1002/ange.201700239
SN  - 1521-3757
SN  - 1521-3773
VL  - 129
IS  - 22
SP  - 6184
EP  - 6188
ER  - 
TY  - JOUR
A1  - Eckert, Sebastian
A1  - Norell, Jesper
A1  - Miedema, Piter S.
A1  - Beye, Martin
A1  - Fondell, Mattis
A1  - Quevedo, Wilson
A1  - Kennedy, Brian
A1  - Hantschmann, Markus
A1  - Pietzsch, Annette
A1  - Van Kuiken, Benjamin E.
A1  - Ross, Matthew
A1  - Minitti, Michael P.
A1  - Moeller, Stefan P.
A1  - Schlotter, William F.
A1  - Khalil, Munira
A1  - Odelius, Michael
A1  - Föhlisch, Alexander
T1  - Ultrafast Independent N-H and N-C Bond Deformation Investigated with Resonant Inelastic X-Ray Scattering
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - The femtosecond excited-state dynamics following resonant photoexcitation enable the selective deformation of N-H and N-C chemical bonds in 2-thiopyridone in aqueous solution with optical or X-ray pulses. In combination with multiconfigurational quantum-chemical calculations, the orbital-specific electronic structure and its ultrafast dynamics accessed with resonant inelastic X-ray scattering at the N 1s level using synchrotron radiation and the soft X-ray free-electron laser LCLS provide direct evidence for this controlled photoinduced molecular deformation and its ultrashort time-scale.
KW  - nitrogen
KW  - photochemistry
KW  - protonation
KW  - RIXS (resonant inelastic X-ray scattering)
KW  - selective bond cleavage
Y1  - 2017
U6  - https://doi.org/10.1002/anie.201700239
SN  - 1433-7851
SN  - 1521-3773
VL  - 56
SP  - 6088
EP  - 6092
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Vaz da Cruz, Vinicius
A1  - Ertan, Emelie
A1  - Couto, Rafael C.
A1  - Eckert, Sebastian
A1  - Fondell, Mattis
A1  - Dantz, Marcus
A1  - Kennedy, Brian
A1  - Schmitt, Thorsten
A1  - Pietzsch, Annette
A1  - Guimaraes, Freddy F.
A1  - Ågren, Hans
A1  - Odelius, Michael
A1  - Föhlisch, Alexander
A1  - Kimberg, Victor
T1  - A study of the water molecule using frequency control over nuclear dynamics in resonant X-ray scattering
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - In this combined theoretical and experimental study we report a full analysis of the resonant inelastic X-ray scattering (RIXS) spectra of H2O, D2O and HDO. We demonstrate that electronically-elastic RIXS has an inherent capability to map the potential energy surface and to perform vibrational analysis of the electronic ground state in multimode systems. We show that the control and selection of vibrational excitation can be performed by tuning the X-ray frequency across core-excited molecular bands and that this is clearly reflected in the RIXS spectra. Using high level ab initio electronic structure and quantum nuclear wave packet calculations together with high resolution RIXS measurements, we discuss in detail the mode coupling, mode localization and anharmonicity in the studied systems.
Y1  - 2017
U6  - https://doi.org/10.1039/c7cp01215b
SN  - 1463-9076
SN  - 1463-9084
VL  - 19
SP  - 19573
EP  - 19589
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Eckert, Sebastian
A1  - Niskanen, Johannes
A1  - Jay, Raphael Martin
A1  - Miedema, Piter S.
A1  - Fondell, Mattis
A1  - Kennedy, Brian
A1  - Quevedo, Wilson
A1  - Iannuzzi, Marcella
A1  - Föhlisch, Alexander
T1  - Valence orbitals and local bond dynamics around N atoms of histidine under X-ray irradiation
JF  - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2  - The valence orbitals of aqueous histidine under basic, neutral and acidic conditions and their X-ray induced transformations have been monitored through N 1s resonant inelastic X-ray scattering. Using density functional ab initio molecular dynamics simulations in the core-hole state within the Z + 1 approximation, core-excitation-induced molecular transformations are quantified. Spectroscopic evidence for a highly directional X-ray-induced local N-H dissociation within the scattering duration is presented for acidic histidine. Our report demonstrates a protonation-state and chemical-environment dependent propensity for a molecular dissociation, which is induced by the absorption of high energy photons. This case study indicates that structural deformations in biomolecules under exposure to ionizing radiation, yielding possible alteration or loss of function, is highly dependent on the physiological state of the molecule upon irradiation.
Y1  - 2017
U6  - https://doi.org/10.1039/c7cp05713j
SN  - 1463-9076
SN  - 1463-9084
VL  - 19
SP  - 32091
EP  - 32098
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -