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O: Fachverband Oberflächenphysik

O 27: Surface Dynamics: Theory

O 27.1: Hauptvortrag

Dienstag, 21. März 2017, 10:30–11:00, TRE Phy

The role of nonadiabatic friction in chemical dynamics at metal surfaces — •Reinhard Maurer — Department of Chemistry, Yale University, New Haven CT 06520, USA

Despite a large mass discrepancy, hydrogen atoms show inelastic scattering from metal surfaces and, despite vibrational decoupling of intramolecular stretch motion from substrate phonons, adsorbate vibrations are damped efficiently on metals. Both of these effects can be attributed to low-lying electronic excitations or "hot electrons" in the metal substrate that interact with the adsorbate via nonadiabatic coupling. The importance of such effects in elementary processes in surface photophysics, molecular device physics, heterogeneous photocatalysis and ultrafast reaction dynamics motivates the development of efficient first-principles electronic structure methods that account for coupled electron-nuclear dynamics in materials. On examples ranging from hydrogen scattering to vibrational energy dissipation and molecular switching at metal surfaces, I will present our Density-Functional Theory-based approach to describe nonadiabatic effects in two limiting regimes, the surface hopping and the electronic friction regime. In comparison with experiment and current state-of-the-art simulation methods, we find a qualitatively correct description of nonadiabatic effects for a variety of systems. In combining our method with mixed quantum-classical molecular dynamics, I will show how nonadiabatic friction affects the reaction dynamics and contributes to adsorbate-substrate energy transfer.