Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 9: Adsorption an Oberfl
ächen I

O 9.7: Vortrag

Montag, 24. März 2003, 16:30–16:45, FOE/ANOR

Adsorption of Krypton and Xenon on Au(110)-(1x2) — •Klaus J. Schmidt, J. Michael Gottfried, and Klaus Christmann — Institut für Chemie der Freien Universität Berlin, D-14195 Berlin, Takustr. 3

We have investigated the adsorption of krypton and xenon on the (1x2)-reconstructed surface of Au(110) between 28 and 300 K by means of TPD, work function measurements, LEED and UPS (He I). For Xe/Au(110), TPD reveals two desorption states at 103 and 92 K in the submonolayer range. For coverages beyond 1 ML, Xe desorbs via zero-order kinetics. The work function decreases during xenon adsorption to -0.63 eV at monolayer coverage. For small Xe-coverages a striped LEED pattern is observed, which changes with increasing coverage to defined spots indicating an uniaxial commensurate (UC) phase. In the UP-Spectra two species of Xe-atoms in the submonolayer range can be distinguished because of the different binding energys of their spin-orbit-splitted 5p1/2 and 5p3/2-states. TPD-Spectra of Kr/Au(110) show in the submonolayer range three desorption peaks with maxima at 70, 63 and 56 K. The desorption from the 2nd and 3rd layers is clearly resolved in the TPD-spectra. The work function decreases with Kr-coverage and reaches -0.36 eV at monolayer coverage. As in the case of Xe adsorption, LEED reveals a striped phase at small and an UC phase at higher coverages. The UP-spectra indicate two krypton species with different 4p1/2 and 4p3/2 binding energy in the submonolayer range.