Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 31: Organische Dünnschichten III
O 31.6: Vortrag
Montag, 7. März 2005, 12:00–12:15, TU EB420
LEED-IV for the structural investigation of the NTCDA monolayer on Ag(111) — •Christian Kumpf1, Michael Scheuermann1, Christoph Stadler1, Eberhard Umbach1, and Wolfgang Moritz2 — 1Experimentelle Physik II, Physikalisches Institut, Univ. Würzburg — 2Sektion Kristallographie, Fakultät für Geowissenschaften, LMU München
The Low Energy Electron Diffraction-IV (LEED-IV) technique is a powerful tool for obtaining structural information of surfaces and is often used for the investigation of adsorbate systems or surface reconstructions on an atomic level. In the past this technique was frequently applied to inorganic systems. For organic adsorbates there is a severe demand for detailed structural information, like exact atomic coordinates, which would enable, e.g., detailed quantum chemical calculations. Even though the unit cells of organic adsorbates are often very large and beam damage effects may play an essential role, in some favorable cases LEED-IV can be used to investigate organic adsorbate systems.
We report on a LEED-IV study of a well ordered, coherent monolayer of NTCDA on Ag(111) (the so called relaxed monolayer structure). Important geometric parameters like the position of the molecules (height above the surface), their orientation within the unit cell as well as possible bending and deformation of the molecules were investigated. The effect of radiation damage is also addressed. The data are compared with results from other experimental methods (like, e.g., STM, XSW, NEXAFS and XPS).