학술논문
Atom-Specific Probing of Electron Dynamics in an Atomic Adsorbate by Time-Resolved X-ray Spectroscopy
Document Type
Working Paper
Author
Schreck, Simon; Diesen, Elias; Dell'Angela, Martina; Liu, Chang; Weston, Matthew; Capotondi, Flavio; Ogasawara, Hirohito; LaRue, Jerry; Costantini, Roberto; Beye, Martin; Miedema, Piter S.; Stenlid, Joakim Halldin; Gladh, Jörgen; Liu, Boyang; Wang, Hsin-Yi; Perakis, Fivos; Cavalca, Filippo; Koroidov, Sergey; Amann, Peter; Pedersoli, Emanuele; Naumenko, Denys; Nikolov, Ivaylo; Raimondi, Lorenzo; Abild-Pedersen, Frank; Heinz, Tony F.; Voss, Johannes; Luntz, Alan C.; Nilsson, Anders
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Subject
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Abstract
The electronic excitation occurring on adsorbates at ultrafast time scales from optical lasers that initiate surface chemical reactions is still an open question. Here, we report the ultrafast temporal evolution of X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) of a simple well known adsorbate prototype system, namely carbon (C) atoms adsorbed on a nickel (Ni(100)) surface, following intense laser optical pumping at 400 nm. We observe ultrafast (~100 fs) changes in both XAS and XES showing clear signatures of the formation of a hot electron-hole pair distribution on the adsorbate. This is followed by slower changes on a few ps time scale, shown to be consistent with thermalization of the complete C/Ni system. Density functional theory spectrum simulations support this interpretation.
Comment: 33 pages, 12 figures. Submitted to Physical Review Letters
Comment: 33 pages, 12 figures. Submitted to Physical Review Letters