Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 84: Poster Session - Solid-Liquid Interfaces: Reactions and Electrochemisty

O 84.13: Poster

Wednesday, March 18, 2020, 18:15–20:00, P2/EG

DFT study of the effect of Br co-adsorbates on the adsorption energy and diffusion energy barrier of S ad-atoms on Ag(100) — •Sönke Buttenschön and Eckhard Pehlke — Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany

Halides affect adsorption and diffusion of ad-atoms on coinage metal surfaces (see the work of O. Magnussen and his group, e.g. Ref. [1]). We have carried through density-functional total-energy calculations using the code PWscf and PWneb from the Quantum Espresso package [2] to quantify the effect of a single or few Br co-adsorbates on the adsorption energy and diffusion energy barrier of a sulfur ad-atom on the Ag(100) surface. We find a repulsive S–Br interaction, which amounts to a decrease of the absolute value of the sulfur adsorption energy by about 0.06 eV if S and Br occupy next-nearest neighbor positions on the p(1×1) substrate lattice. The repulsion decreases rapidly with separation. The S–Br interaction is compared with a superposition of the interaction energies of individual S–Br pairs. The energy of the transition state for sulfur surface diffusion varies less. We discuss the correlation with the adsorption energies of the respective initial and final S-adsorption configurations.

[1] B. Rahn, O. M. Magnussen, ChemElectroChem 5, 3073 (2018).

[2] P. Giannozzi et al., J. Phys. Condens. Matter 21, 395502 (2009),

ibid. 29, 465901 (2017).