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O: Fachverband Oberflächenphysik

O 27: Surface Dynamics: Theory

O 27.2: Vortrag

Dienstag, 21. März 2017, 11:00–11:15, TRE Phy

Non-adiabatic vibrational damping of molecular adsorbates: Beyond electronic friction — •Simon P. Rittmeyer¹, Jörg Meyer², and Karsten Reuter¹ — ¹Technische Universität München — ²Universiteit Leiden

The availability of low-energy electron-hole (eh) pair excitations generally questions the validity of the ubiquitous Born-Oppenheimer approximation for adsorbate dynamics on metal surfaces. An in-depth scrutiny thus requires to consider the non-adiabatic coupling of nuclear motion to these eh-pair excitations. Unfortunately, an explicit calculation from first principles remains a formidable challenge. Electronic friction theory is very popular to capture the effects of the non-adiabatic energy loss on the nuclear dynamics in a computationally convenient way. This avoids explicit electron dynamics and concomitant ultrafast time scales, but for these reasons also precludes a more fundamental understanding of the underlying eh-pair excitations.

In this situation, we advance a perturbative approach rooted in time-dependent density-functional theory which allows to actually evaluate eh-pair excitation spectra [1]. Applying this to non-adiabatic vibrational damping of CO on Cu(100) and Pt(111), we find that the non-adiabatic energy loss obtained from our spectra is consistent with experimentally measured lifetimes. Moreover, we discuss intriguing deviations from the linear relationship between non-adiabatic energy loss and kinetic energy predicted by electronic friction theory that might be measurable in new experiments.
J. Meyer and K. Reuter, New. J. Phys. 13, 085010 (2011).