Dresden 2006 – wissenschaftliches Programm

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SYET: Dynamics of electron transfer processes at surfaces

SYET 1: Dynamics of electron transfer processes at surfaces

SYET 1.3: Hauptvortrag

Donnerstag, 30. März 2006, 11:00–11:30, HSZ 04

Electronic structure and coupled electron/atom dynamics of alkali atoms on noble metals — •Hrvoje Petek — Department of Physics and Astronomy

We have investigated the unoccupied electronic structure of alkali atoms (Li-Cs) on noble metal surfaces (Cu(111) and Ag(111)). Contrary to all theoretical predictions, the unoccupied alkali atom resonance at 2.8 - 3.0 eV exhibits universal behavior with the resonance energy being independent of the principle quantum number of the alkali atom or the chemisorption distance. The excited state appears to correlate with the energy of localizing an electron on the alkali atom. We have also investigated the electronic relaxation rates of alkali atoms through the reverse charge transfer into the conduction band of the substrate. The charge transfer is hindered by the presence of the projected band gap at the alkali atom resonance, for a large range of parallel momenta. The effective relaxation rates appear to be slower than predicted by theories that treat accurately the anisotropy of the band structure of noble metals.