@article{ObergGladhAnniyevetal.2015,
  author    = {Oberg, H. and Gladh, J{\"o}rgen and Anniyev, Toyli and Beye, Martin and Coffee, Ryan and F{\"o}hlisch, Alexander and Katayama, T. and Kaya, Sarp and LaRue, Jerry and Mogelhoj, Andreas and Nordlund, Dennis and Ogasawara, Hirohito and Schlotter, William F. and Sellberg, Jonas A. and Sorgenfrei, Florian and Turner, Joshua J. and Wolf, Martin and Wurth, W. and Ostrom, Henrik and Nilsson, Anders and Norskov, Jens K. and Pettersson, Lars G. M.},
  title     = {Optical laser-induced CO desorption from Ru(0001) monitored with a free-electron X-ray laser: DFT prediction and X-ray confirmation of a precursor state},
  series = {Surface science},
  volume    = {640},
  journal   = {Surface science},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0039-6028},
  doi       = {10.1016/j.susc.2015.03.011},
  pages     = {80 -- 88},
  year      = {2015},
  abstract  = {We present density functional theory modeling of time-resolved optical pump/X-ray spectroscopic probe data of CO desorption from Ru(0001). The BEEF van der Waals functional predicts a weakly bound state as a precursor to desorption. The optical pump leads to a near-instantaneous (<100 fs) increase of the electronic temperature to nearly 7000 K. The temperature evolution and energy transfer between electrons, substrate phonons and adsorbate is described by the two-temperature model and found to equilibrate on a timescale of a few picoseconds to an elevated local temperature of similar to 2000K. Estimating the free energy based on the computed potential of mean force along the desorption path, we find an entropic barrier to desorption (and by time-reversal also to adsorption). This entropic barrier separates the chemisorbed and precursor states, and becomes significant at the elevated temperature of the experiment (similar to 1.4 eV at 2000 K). Experimental pump-probe X-ray absorption/X-ray emission spectroscopy indicates population of a precursor state to desorption upon laser-excitation of the system (Dell'Angela et al., 2013). Computing spectra along the desorption path confirms the picture of a weakly bound transient state arising from ultrafast heating of the metal substrate. (C) 2015 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{KunnusSchreckFoehlisch2015,
  author    = {Kunnus, Kristjan and Schreck, Simon and F{\"o}hlisch, Alexander},
  title     = {Free-electron laser based resonant inelastic X-ray scattering on molecules and liquids},
  series = {Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy},
  volume    = {204},
  journal   = {Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0368-2048},
  doi       = {10.1016/j.elspec.2015.08.012},
  pages     = {345 -- 355},
  year      = {2015},
  abstract  = {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.},
  language  = {en}
}