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Atom-Specific Probing of Electron Dynamics in an Atomic Adsorbate by Time-Resolved X-Ray Spectroscopy

2022; American Physical Society; Volume: 129; Issue: 27 Linguagem: Inglês

10.1103/physrevlett.129.276001

1092-0145

Simon Schreck, Elias Diesen, Martina Dell’Angela, Chang Liu, Matthew Weston, Flavio Capotondi, Hirohito Ogasawara, Jerry LaRue, Roberto Costantini, Martin Beye, Piter S. Miedema, Joakim Halldin Stenlid, Jörgen Gladh, Boyang Liu, Hsin-Yi Wang, Fivos Perakis, Filippo Cavalca, Sergey Koroidov, Peter Amann, Emanuele Pedersoli, Denys Naumenko, I. Nikolov, Lorenzo Raimondi, Frank Abild‐Pedersen, Tony F. Heinz, Johannes Voss, A. C. Luntz, Anders Nilsson,

Laser-Matter Interactions and Applications

The electronic excitation occurring on adsorbates at ultrafast timescales 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 picoseconds timescale, shown to be consistent with thermalization of the complete C/Ni system. Density functional theory spectrum simulations support this interpretation.