Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 59: Solid-liquid interfaces: Reactions and electrochemisty IV (joint session O/CPP)

CPP 59.2: Vortrag

Mittwoch, 14. März 2018, 17:00–17:15, MA 144

First-Principles Calculation of Solvent-Mediated Proton Transfer at the TiO₂(110) Surface: Kinetic Barriers and the Effect of Functionals — •Ahmad Agung, Thomas Stecher, Karsten Reuter, and Harald Oberhofer — Technische Universität München

To date, a majority of theoretical studies of (photo-)electrochemical surface reactions focuses on their thermodynamic feasibility. Only recently an ab initio molecular dyamics (AIMD) approach utilizing QM-MM embedding, explicit solvation and the HSE06 hybrid functional was applied to determine the kinetic barrier of H₂O dissociation on a rutile TiO₂(110) surface [1]. Despite advanced sampling techniques and a comparatively small QM region, the use of the hybrid functional rendered these simulations computationally extremely expensive. To this end, we assess in how much generalized-gradient approximation (GGA) functionals can be employed to reduce the computational cost. Not too surprisingly, we find the inferior GGA energetics to yield a significantly different reaction barrier, when directly evaluating GGA-based AIMD trajectories. We therefore assess in how much these GGA trajectories yield at least an appropriate sampling of phase space, thereby offering computational savings by restricting the expensive hybrid level calculations to snapshots along these trajectories.

[1] T. Stecher, K. Reuter and H. Oberhofer, Phys. Rev. Lett. 117, 276001 (2016).