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O: Fachverband Oberflächenphysik

O 17: Solid-Liquid Interfaces I: Reactions and Electrochemistry

O 17.4: Hauptvortrag

Montag, 16. März 2020, 15:45–16:15, TRE Phy

Tales of 1000 and 1.2 electrons: Grand Canonical Simulations of Electrified Interfaces using Implicit Solvation Models — •Nicolas G. Hörmann — Chair of Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Germany

In this talk I will present an overview over recent developments in simulation strategies of electrochemical interfaces using hybrid QM/continuum models. In these approaches, grand canonical (GC) interface energies are derived by varying the total number of electrons in the system [1] and by self-consistently including the energy contributions from solvent and electrolyte through an appropriate mean-field (implicit solvation) description. GC calculations allow to determine a wide range of electrochemical observables that are inaccessible by traditional calculations at zero-net-charge – typically referred to as the Computational Hydrogen Electrode (CHE) approach. Examples discussed in the talk are non-trivial shifts of electrosorption peaks with pH, non-integer electrosorption valencies or potential-induced surface reconstructions of metallic electrodes. In this context, I will also elaborate on the general limitations of the prevalent CHE method and show how it originates from a low-order Taylor expansion of the GC energetics. Likewise, inherent accuracy limitations of the GC method and of implicit solvation models in general will also be assessed, and possible improvements presented, e.g. using hybrid models with explicitly treated interfacial water [2].

[1] N.G. Hörmann, et al., J. Chem. Phys. 150, 041730 (2019). [2] N.G. Hörmann et al., npj Computational Materials 5, 100 (2019).