Regensburg 2002 – wissenschaftliches Programm
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O: Oberflächenphysik
O 13: Postersitzung (Adsorption an Oberfl
ächen, Elektronische Struktur, Magnetismus in reduzierten Dimensionen, Epitaxie und Wachstum, Halbleiteroberfl
ächen und -grenzfl
ächen, Organische Dünnschichten)
O 13.20: Poster
Montag, 11. März 2002, 18:00–21:00, Bereich C
The T3-Wetting Dependency of H2-D2 Thin Films on their Species Concentration — •Masoud Sohaili, Stefan Tibus, Jürgen Klier, and Paul Leiderer — Fakultät für Physik, Universität Konstanz, Postfach M676, D-78457 Konstanz
Triple-point wetting is a well known phenomenon of many simple adsorbates on solid substrates. It implies that in the liquid phase above the triple-point temperature, T3, complete wetting with the formation of arbitrarily thick films is observed, whereas below T3 only a few monolayers of the solid phase are thermodynamically stable at saturated vapour pressure. This behaviour is also observed if one preplates the substrate in order to reduce the substrate strength, a result which is inconsistent with theoretical expectation. In this work we in particular investigate the adsorption behaviour and triple-point wetting of H2-D2-mixtures depending on the concentration ration of its species. With respect to the data presented here, we will discuss new aspects in comparison with systems like H2/Ar, H2/CH4, where Ar and CH4 are used as a preplating material. The results imply tendency towards partial mixing of the H2 and D2 molecules and the existence of an effective triple-point dependence on concentrations. Considering the persisting triple-point dewetting behaviour for all systems studied so far infers that the present theoretical picture of this effect is incomplete.
This work is supported by the DFG under grant Le 315/20.