Document Type

Article

Publication Date

12-29-2022

Abstract

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.

Comments

This article was originally published in Physical Review Letters, volume 129, in 2022. https://doi.org/10.1103/PhysRevLett.129.276001

SM.pdf (2467 kB)
Supplemental material: Details on optical absorption in C/Ni; the two-temperature model; experimental methods; computational methods; XAS from different adsorbate geometries; and discussion of selective vibrational excitation

Copyright

American Physical Society

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