@article{XinLaRueObergetal.2015,
  author    = {Xin, Hong and LaRue, Jerry and Oberg, Henrik and Beye, Martin and Turner, J. J. and Gladh, J{\"o}rgen and Ng, May L. and Sellberg, Jonas A. and Kaya, Sarp and Mercurio, G. and Hieke, F. and Nordlund, Dennis and Schlotter, William F. and Dakovski, Georgi L. and Minitti, Michael P. and F{\"o}hlisch, Alexander and Wolf, Martin and Wurth, Wilfried and Ogasawara, Hirohito and Norskov, Jens K. and Ostrom, Henrik and Pettersson, Lars G. M. and Nilsson, Anders and Abild-Pedersen, Frank},
  title     = {Strong Influence of Coadsorbate Interaction on CO Desorption Dynamics on Ru(0001) Probed by Ultrafast X-Ray Spectroscopy and Ab Initio Simulations},
  series = {Physical review letters},
  volume    = {114},
  journal   = {Physical review letters},
  number    = {15},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.114.156101},
  pages     = {6},
  year      = {2015},
  abstract  = {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.},
  language  = {en}
}
@article{OstromObergXinetal.2015,
  author    = {Ostrom, H. and Oberg, H. and Xin, H. and Larue, J. and Beye, Martin and Gladh, J. and Ng, M. L. and Sellberg, J. A. and Kaya, S. and Mercurio, G. and Nordlund, D. and Hantschmann, Markus and Hieke, F. and Kuehn, D. and Schlotter, W. F. and Dakovski, G. L. and Turner, J. J. and Minitti, M. P. and Mitra, A. and Moeller, S. P. and F{\"o}hlisch, Alexander and Wolf, M. and Wurth, W. and Persson, Mats and Norskov, J. K. and Abild-Pedersen, Frank and Ogasawara, Hirohito and Pettersson, Lars G. M. and Nilsson, A.},
  title     = {Probing the transition state region in catalytic CO oxidation on Ru},
  series = {Science},
  volume    = {347},
  journal   = {Science},
  number    = {6225},
  publisher = {American Assoc. for the Advancement of Science},
  address   = {Washington},
  issn      = {0036-8075},
  doi       = {10.1126/science.1261747},
  pages     = {978 -- 982},
  year      = {2015},
  abstract  = {Femtosecond x-ray laser pulses are used to probe the carbon monoxide (CO) oxidation reaction on ruthenium (Ru) initiated by an optical laser pulse. On a time scale of a few hundred femtoseconds, the optical laser pulse excites motions of CO and oxygen (O) on the surface, allowing the reactants to collide, and, with a transient close to a picosecond (ps), new electronic states appear in the OK-edge x-ray absorption spectrum. Density functional theory calculations indicate that these result from changes in the adsorption site and bond formation between CO and O with a distribution of OC-O bond lengths close to the transition state (TS). After 1 ps, 10\% of the CO populate the TS region, which is consistent with predictions based on a quantum oscillator model.},
  language  = {en}
}
@article{BeyeOebergXinetal.2016,
  author    = {Beye, Martin and {\"O}berg, Henrik and Xin, Hongliang and Dakovski, Georgi L. and F{\"o}hlisch, Alexander and Gladh, Jorgen and Hantschmann, Markus and Hieke, Florian and Kaya, Sarp and K{\"u}hn, Danilo and LaRue, Jerry and Mercurio, Giuseppe and Minitti, Michael P. and Mitra, Ankush and Moeller, Stefan P. and Ng, May Ling and Nilsson, Anders and Nordlund, Dennis and Norskov, Jens and {\"O}str{\"o}m, Henrik and Ogasawara, Hirohito and Persson, Mats and Schlotter, William F. and Sellberg, Jonas A. and Wolf, Martin and Abild-Pedersen, Frank and Pettersson, Lars G. M. and Wurth, Wilfried},
  title     = {Chemical Bond Activation Observed with an X-ray Laser},
  series = {The journal of physical chemistry letters},
  volume    = {7},
  journal   = {The journal of physical chemistry letters},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1948-7185},
  doi       = {10.1021/acs.jpclett.6b01543},
  pages     = {3647 -- 3651},
  year      = {2016},
  abstract  = {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. Weakening the bond is expected to reduce this energetic splitting, but the transient character of bond-activation has so far prohibited direct experimental access. Here we apply time-resolved soft X-ray spectroscopy at a free electron laser to directly observe the decreased bonding antibonding splitting following bond-activation using an ultrashort optical laser pulse.},
  language  = {en}
}