Hamburg 2001 – scientific programme

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O: Oberflächenphysik

O 28: Adsorption an Oberfl
ächen (III)

O 28.11: Talk

Thursday, March 29, 2001, 13:00–13:15, C

Adsorbate induced electronic relaxation at transition metal surfaces — •Gerhard Fahsold, Andreas Priebe, Jochen Solbrig, and Annemarie Pucci — Kirchhoff-Institut für Physik, Universität Heidelberg

We investigate the relaxation of electrons at transition metal surfaces by means of IR-spectroscopy. The adsorbate induced relaxation of electrons is responsible for the DC-resistivity of metal thin films, it is connected to the damping of adsorbate motion, and it contributes to enhancement effects observed in adsorbate vibrational spectroscopy[1].
We measured the contribution of adsorbates (CO, O) to the relaxation of electrons at Fe(001) by observing adsorbate induced broadband changes, firstly, in the IR-reflectivity from thick (opague) epitaxial films and, secondly, in the IR-transmission through ultrathin (≤ 5 nm) smooth epitaxial films of Fe on MgO(001) [2]. The higher (compared to IRAS measurements) sensitivity for adsorbate resistivity in IR-transmission spectroscopy is well demonstrated by our experimental results.
We understand our results on the basis of a proper description of the optical properties of bulk iron and iron ultrathin films. The talk will focus on the importance of the inclusion of non free-electron-like properties for calculating both the magnitude, the sign, and the spectral shape of adsorbate induced broadband effects.
A.Priebe, G. Fahsold, A. Pucci, Surface Science, accepted
G. Fahsold, A.Priebe, A. Pucci, Applied Physics A, accepted