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Proceedings Paper

Controlled modification of surface state lifetimes by physisorbed adsorbates
Author(s): A. Hotzel; E. Knoesel; Martin Wolf; G. Ertl
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Paper Abstract

Femtosecond time-resolved two-photon photoemission is used to study the influence of physisorbed xenon and oxygen adlayers on the lifetime of image potential states and interfacial quantum well states on Cu(111). Adsorption of 0 to 3 layers of Xe leads to a pronounced increase of the n equals 1 image state lifetime from 22 fs to 300 fs, respectively. However, for adsorbate heterostructures consisting of one monolayer (ML) O2 on top of Xe spacer layers with variable thickness it is found that the lifetime of an oxygen induced quantum well state (0.35 eV below Evac) decreases from 650 fs to 90 fs when the number of spacer layers is raised from 1 ML to 5 ML. The results can be semiquantitatively reproduced by a model calculation which accounts for the modified image potential due to the Xe and O2 adlayers. The changes of the lifetimes are explained by the differences in the penetration of the excited state wave function into the Cu substrate.

Paper Details

Date Published: 30 April 1998
PDF: 10 pages
Proc. SPIE 3272, Laser Techniques for Surface Science III, (30 April 1998); doi: 10.1117/12.307125
Show Author Affiliations
A. Hotzel, Fritz-Haber Institut der Max-Planck-Gesellschaft (Germany)
E. Knoesel, Fritz-Haber Institut der Max-Planck-Gesellschaft (Germany)
Martin Wolf, Fritz-Haber Institut der Max-Planck-Gesellschaft (Germany)
G. Ertl, Fritz-Haber Institut der Max-Planck-Gesellschaft (Germany)


Published in SPIE Proceedings Vol. 3272:
Laser Techniques for Surface Science III
Hai-Lung Dai; Hans-Joachim Freund, Editor(s)

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