Vibrational damping of molecules adsorbed on surfaces
(still) a challenge for theoretical modelling
Energy conversion at interfaces is at the centre of the rapidly growing field of basic energy science. At the macroscopic scale, engineers routinely employ continuum theories including empirically determined parameters – with (at best) limited atomistic understanding. At the atomic scale, the vibrational lifetime of small adsorbates can provide detailed information about the energy exchange with the surface. One energy dissipation channel that has received a lot of attention in the context of adsorbate dynamics on metal surfaces is given by the (electronically non-adiabatic) excitation of electron-hole pairs. High-level non-adiabatic calculations beyond the ubiquitous Born-Oppenheimer approximation are, unfortunately, either conceptually challenging or computationally intractable for extended metal surfaces. Therefore, numerically appealing electronic friction schemes have attracted significant interest. I will compare different ways to calculate the electronic friction coefficients and concomitant approximations, with a particular focus on the vibrational damping of CO adsorbed on Cu(100) and on Pt(111) surfaces. A perturbative approach rooted in time-dependent density functional theory allows us to go beyond the Markov approximation inherent to all current electronic friction theories and thus to scrutinize the influence of the coherence of the eh-pair excitations in the surface.
Jörg studied physics in Hannover (Germany) and graduated with distinction in 2006. His final research project with Prof. H. Pfnür was about theoretical modeling of functionalised organic molecules on metal surfaces. Tempted by working literally “at the interface between physics and chemistry”, Jörg moved on to the Fritz-Haber-Institute (Max-Planck-Gesellschaft) for his PhD with Prof. K. Reuter. There he dived deeper into application and development of first-principles based theory. Changing fields to gas-surface dynamics he graduated summa cum laude at FU Berlin. In 2010 Jörg relocated to TU München, where he continued some of his PhD work together with Prof. K. Reuter and students as a PostDoc. This earned him a best poster prize at the Gordon Research conferences on “Dynamics at Surfaces” both in 2011 and 2013. Jörg’s time in the Netherlands started in 2014 when he moved to Leiden to work with Prof. G.-J. Kroes on modeling electron-hole pair excitations. He successfully applied for a tenure track position in the theoretical chemistry group and has been appointed as assistant professor in Leiden since 2015. In the same year he was also awarded a NWO-VIDI grant, supporting his research on modeling of energy exchange phenomena at interfaces.
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