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O: Fachverband Oberflächenphysik

O 100: Metal Substrates: Adsorption and Reactivity

O 100.8: Vortrag

Freitag, 20. März 2015, 12:15–12:30, MA 043

Following “hot” adatoms wherever they go: QM/Me with multiple embedding regions — •Vanessa Jane Bukas¹, Jörg Meyer², and Karsten Reuter¹ — ¹Technische Universität München, Germany — ²Universiteit Leiden, The Netherlands

Exothermic surface chemical reactions may easily release several electron volts of energy. This challenges first-principles based dynamical simulations to account for adequate energy dissipation channels. Focusing on phononic dissipation we recently presented a novel embedding scheme for metallic substrates (QM/Me [1]), in which energy dissipation out of a quantum-mechanically described reaction zone occurs into a computationally undemanding, yet reliably described extended bath. In the application to oxygen dissociation over Pd(100) this predicted translationally “hot” dissociation fragments as a consequence of nonimmediate energy transfer to the metal surface. Here, we advance this approach to include the concurrent treatment of multiple reaction zones centered around individual fragments and dynamically following their motion. This suppresses unphysical interactions between reaction partners through periodic images, allows to use smaller suppercells, and most importantly enables the application to chemical reactions for which the lateral direction of “hot” translational motion is not clear a priori. We demonstrate this new functionality by comparing oxygen dissociation at Pd(111) to the previously studied Pd(100).

[1] J. Meyer and K. Reuter, Angew. Chem. Int. Ed., 53, 4721 (2014).