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O: Fachverband Oberflächenphysik

O 4: Solid-Liquid Interfaces: Structure

O 4.3: Vortrag

Montag, 17. März 2025, 11:00–11:15, H4

Adatom Dynamics at Water/Pt(111) Interface from Ab Initio Free Energy Analysis — •Sung Sakong¹, Jonas Lindner², Ulrich Ross³, Michael Seibt³, Christian Jooss², and Axel Gross¹ — ¹Institute of Theoretical Chemistry, Ulm University, 89081 Ulm, Germany — ²Institute of Materials Physics, University of Göttingen, 37077 Göttingen, Germany — ³4th Institute of Physics Solids and Nanostructures, University of Göttingen, 37077, Göttingen, Germany

Recent electron diffraction experiments investigated the local structures of the water/Pt(111) interface, a selected model system for investigating the structural properties of the electric double layer (EDL). The reconstructed phase signals of the diffraction data yield the time average of the interface structures with Angstrom resolution and observe the static Pt lattice and dynamic particles above the lattice. Since the time-averaged signals from experiments are often challenging to relate to the corresponding atomic structures of dynamic particles, we probe the interface structure by including Pt adatoms using the ab initio molecular dynamics (AIMD) method. The free energy of Pt adatoms is analyzed by including the vibrational entropy calculated from the AIMD trajectories using the two-phase thermodynamics method. While the dynamics of water molecules are captured within the AIMD trajectories, the relatively slow Pt adatom dynamics are estimated by a free energy analysis, Blue Moon ensemble sampling. By comparing the Water/Pt(111) and Vacuum/Pt(111) models, we will discuss the role of surrounding water molecules and try to relate the model EDL configurations to the experimental findings.