Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 78: Surface Dynamics I

O 78.5: Vortrag

Donnerstag, 14. März 2013, 17:00–17:15, H42

The effect of vibrational amplitude on electronic energy dissipation via electron-hole pair-vibrational coupling — •Michael Grotemeyer and Eckhard Pehlke — Institut für Theoretische Physik und Astrophysik, Universität Kiel, Germany

Time-dependent density functional calculations for vibrational highly excited HCl molecules in front of an Al(111)-surface have revealed a large non adiabatic energy dissipation. At the first glance this may appear to be in contrast to observations from scattering experiments for HCl/Au(111), which yield only a small energy dissipation into electron-hole pairs in case of low initial vibrational excitation of incoming molecule [1]. To explain this, we have studied the non adiabatic energy transfer by ab initio molecular dynamics simulations as a function of initial vibrational excitation energy, thereby filling the gap between experiment and previous calculations. We find a strong increase of dissipation with vibrational energy, which increases faster than linear and clearly deviates from the prediction by the linear friction ansatz. Results are further elucidated by means of a 1D tight binding model.

[1] I. Rahinov et al., J. Chem. Phys. 129. 214708 (2008).