SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 53: Poster Session IV: Poster to Mini-Symposium: Frontiers of electronic-structure theory I
O 53.4: Poster
Dienstag, 2. März 2021, 13:30–15:30, P
The effects of quantum nuclei in metal-molecular interfaces — •Karen Fidanyan1,2 and Mariana Rossi1,2 — 1Fritz Haber Institute of the Max Planck Society, Berlin, Germany — 2Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
Hydrogen-containing molecular adsorbates on platinum-group metals often give rise to situations where the bond strength to the surface and its interplay with nuclear quantum effects (NQE) can substantially change the dynamics and equilibrium of hydrogen dissociation. In this work, we assess by means of density functional theory and path integral molecular dynamics simulations, interfaces involving non-polar molecules (cyclohexane) and polar molecules (water). For the cyclohexane/Rh(111) interface, we show that the H-Rh bond weakens the C-H bond and that NQE are responsible for a geometric isotope effect that is reflected on work-function changes. We further study the importance of simulating nuclear fluctuations including anharmonic effects, concluding that although these contributions play a pronounced role on these interfaces, most of them are concentrated on “classical” degrees of freedom, resulting in minor anharmonic quantum contributions in isotope effects [1]. For water on Pd(111) we investigate hydrogen dissociation under different potential voltage biases and analyze the impact of NQE within a quasi-harmonic approximation throughout the dissociation path.
[1] K. Fidanyan, I. Hamada and M. Rossi, arXiv:2010.03970 (2020)