Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 84: Electronic Structure of Surfaces I: Spectroscopy, Surface States
O 84.10: Vortrag
Donnerstag, 21. März 2024, 12:45–13:00, MA 144
Mode selectivity in electron mediated vibrational relaxation of adsorbed hydrogen on metal surfaces. — •Nils Hertl1, Connor L. Box1, and Reinhard J Maurer1,2 — 1Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, United Kingdom — 2Department of Physics, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, United Kingdom
Vibrational relaxation induced by electron-hole pair (ehp) excitations is a common phenomenon in gas-surface experiments on metallic surfaces. Specific adsorbate vibrational degrees of freedom can be more strongly coupled to ehps at metal surfaces than others, which opens an opportunity for mode-selective energy transfer processes that can activate chemical dynamics. In order to promote mode-selective chemical reactions at solid interfaces a detailed understanding of the coupling of the individual vibrations of adsorbates with the electrons and phonons of the metal substrate is essential. To shed light on the mechanisms involved in energy transfer processes present in gas-surface systems, we study adsorbed hydrogen on single crystalline surfaces. Herein, we calculate the lifetimes of vibrational modes of hydrogen adsorbed on the (100) and (110) surfaces of Mo and W via first-principles first-order perturbation theory based on Density Functional Theory (DFT). Our results show a strong mode dependency on the electron-driven relaxation rates of the vibrations. For the vibrations with a Fano-lineshape, our predicted lifetimes are in good agreement with experiments, indicating that the relaxation of those vibrations is dominated by ehp excitations.
Keywords: Electron-Phonon coupling; Vibrational relaxation; Fano lineshapes; Hydrogen; Density Functional Theory