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O: Fachverband Oberflächenphysik
O 69: Poster: Solid-Liquid Interfaces
O 69.8: Poster
Wednesday, March 29, 2023, 18:00–20:00, P2/EG
Density functional calculations of diffusion paths of methyl thiolate on c(2x2)Cl- and Br-covered Cu(100) surfaces — •Falk Wendorff and Eckhard Pehlke — Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
The surface dynamics of methyl thiolate on Cu(100) surfaces has been studied with video-STM in an electrochemical environment by Yang et al. [1]. Here we present density functional calculations for the diffusion paths and diffusion energy barriers using PWscf and PWneb from the Quantum ESPRESSO package [2]. The diffusion path of CH3Sad substitutionally adsorbed on the c(2x2)Cl- or Br-Cu(100) surface without further halogen vacancies has been inspired by the ’rotation’ diffusion path of Sad on these surfaces [3]. Additional vacancies in the halogen adlayer enable further diffusion paths of CH3Sad with significantly lower energy barriers. In case of the Cl coadsorbate the barrier decreases from 1.2 eV to 0.7 eV and in case of Br from 1.6 eV to 0.8 eV. The dipole moment change between the adsorption position and the transition state is negative, which is consistent with the experimental observations by Yang et al. that a more positive sample potential leads to a higher energy barrier [1,4].
[1] Y.-C. Yang et al., Langmuir. 28, 40, 14143–14154 (2012).
[2] P. Giannozzi et al., J. Phys. Condens. Matter 21, 395502 (2009), ibid. 29, 465901 (2017).
[3] B. Rahn et al., Angew. Chem. Int. Ed. 57, 6065 (2018).
[4] M. Giesen et al., Surface Science. 595, 127–137 (2005).