DPG Phi
Verhandlungen
Verhandlungen
DPG

Dresden 2006 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

O: Oberflächenphysik

O 14: Poster session I (Adsorption, Epitaxy and growth, Phase transitions, Surface reactions, Organic films, Electronic structure, Methods) (sponsored by Omicron Nanotechnology GmbH)

O 14.24: Poster

Monday, March 27, 2006, 18:00–21:00, P2

PIRS and LEED study of quasi-orthorhombic acetylene thin films on KCl(100) — •Jochen Vogt and Helmut Weiss — Chemisches Institut der Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany

The epitaxial growth of acetylene thin films on KCl(100) single crystal surfaces has been studied by means of low-energy electron diffraction (LEED) and polarization infrared spectroscopy (PIRS) in transmission geometry at 40 K. IR spectra in the regions of the infrared active fundamentals ν3 and ν5 were recorded at increasing coverages up to 20 layers. In both cases a triplet structure of the spectra was observed. LEED experiments without extensive adsorbate charging effects were possible up to coverages of 4 layers and indicated a (√2×√2)R45 symmetry, consistent with the results of helium atom diffraction experiments [1]. All experiments support a parallel orientation of the molecules in the layers, as expected for the low-temperature orthorhombic phase of C2H2. Based on the structure model of this phase the PIRS film spectra were analyzed using a dynamic dipole-dipole coupling model. Good agreement between simulated and experimental spectra is obtained for both fundamental modes if the possibility of azimuthal misorientations of adjacent layers by 90 is taken into account.

[1] J. P. Toennies et al., Phys. Rev. B 65, 165427 (2002)

100% | Mobile Layout | Deutsche Version | Contact/Imprint/Privacy
DPG-Physik > DPG-Verhandlungen > 2006 > Dresden