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  - Xin, Hong
A1  - LaRue, Jerry
A1  - Oberg, Henrik
A1  - Beye, Martin
A1  - Turner, J. J.
A1  - Gladh, Jörgen
A1  - Ng, May L.
A1  - Sellberg, Jonas A.
A1  - Kaya, Sarp
A1  - Mercurio, G.
A1  - Hieke, F.
A1  - Nordlund, Dennis
A1  - Schlotter, William F.
A1  - Dakovski, Georgi L.
A1  - Minitti, Michael P.
A1  - Föhlisch, Alexander
A1  - Wolf, Martin
A1  - Wurth, Wilfried
A1  - Ogasawara, Hirohito
A1  - Norskov, Jens K.
A1  - Ostrom, Henrik
A1  - Pettersson, Lars G. M.
A1  - Nilsson, Anders
A1  - Abild-Pedersen, Frank
T1  - Strong Influence of Coadsorbate Interaction on CO Desorption Dynamics on Ru(0001) Probed by Ultrafast X-Ray Spectroscopy and Ab Initio Simulations
JF  - Physical review letters
N2  - 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. This phenomenon is directly observed in an ultrafast pump-probe experiment using a soft x-ray free-electron laser to monitor the dynamic evolution of the valence electronic structure of the surface species. This is supported with the potential of mean force along the CO desorption path obtained from density-functional theory calculations. Charge density distribution and frozen-orbital analysis suggest that the oxygen-induced reduction of the Pauli repulsion, and consequent increase of the dative interaction between the CO 5 sigma and the charged Ru atom, is the electronic origin of the distinct desorption dynamics. Ab initio molecular dynamics simulations of CO desorption from Ru(0001) and oxygen-coadsorbed Ru(0001) provide further insights into the surface bond-breaking process.
Y1  - 2015
U6  - https://doi.org/10.1103/PhysRevLett.114.156101
SN  - 0031-9007
SN  - 1079-7114
VL  - 114
IS  - 15
PB  - American Physical Society
CY  - College Park
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  -