Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 27: Electron-Driven Processes
O 27.1: Vortrag
Dienstag, 6. September 2022, 10:30–10:45, H6
Surprisingly fast adsorbate excitation: CO/Ru(0001) probed with X-ray absorption spectroscopy — •Elias Diesen1, Hsin-Yi Wang2, Johannes Voss1, Alan C. Luntz1, and Anders Nilsson2 — 1SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park, California, USA — 2Stockholm University, Sweden
Energy transfer between substrate excitations and adsorbate motion plays an essential role in determining chemical reactivity and selectivity on surfaces. Femtosecond pump-probe experiments, using an X-ray probe pulse from a free electron laser, give unique insights into such processes due to the short pulse duration and species-selective probing. We measure the time evolution of the C K-edge X-ray absorption spectrum from CO/Ru(0001) after excitation by a femtosecond high-intensity optical laser pulse, and use detailed spectrum simulations to distinguish excitations of different modes [1]. We find high excitation of the CO internal stretch and frustrated rotation modes within 200 fs of laser excitation - one order of magnitude faster than theoretical predictions. Consequences for our understanding of ultrafast adsorbate excitation will be discussed.
[1] Diesen et al., Phys. Rev. Lett. 127, 016802 (2021)