Dresden 2026 – scientific programme

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O: Fachverband Oberflächenphysik

O 13: Solid-liquid interfaces: Reactions and electrochemistry I

O 13.2: Talk

Monday, March 9, 2026, 15:15–15:30, TRE/PHYS

Electrochemical Free Energy Barriers at Constant Potential — •Elias Diesen, Karsten Reuter, and Vanessa J. Bukas — Fritz-Haber-Institut der MPG, Berlin

Simulating barriers for electrocatalytic reactions is methodologically very challenging due to the intricate dynamics at the electrified solid/liquid interface. In addition, standard atomistic simulations based on periodic density-functional theory (DFT) keep the charge of the simulation cell constant instead of allowing it to fluctuate during the reaction in order to maintain a (fixed) electrode potential. Here, we introduce a method to compute electrochemical free energy barriers under well-defined potential conditions. Our approach relies on umbrella sampling on top of DFT-based molecular dynamics to access the free energy of activation, including both enthalpic and entropic contributions [1]. By carefully sampling the work function along the reaction coordinate, a Legendre transformation of the resulting canonical (constant-charge) energetics is then used to obtain grand canonical (constant-potential) results [2]. The method is demonstrated for proton deposition over Au(111). We extract potential-dependent barriers and examine kinetic scaling relations as well as use our results to benchmark common approximations in the recent literature. This work paves the way for systematic studies under realistic electrochemical conditions at e.g. varying temperatures or considering different proton-donating species.

[1] E. Diesen et al., ACS Catal. 15, 5403 (2025).
[2] S.D. Beinlich et al., J. Chem. Theory Comput. 19, 8323 (2023).

Keywords: Theoretical electrochemistry; Ab initio molecular dynamics; Free energy sampling; Kinetic barriers