Dresden 2003 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 6: Postersitzung I (Amorphe- u. Tunnelsysteme, Niedrigdimensionale Systeme, Supraleitung: Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter)
TT 6.7: Poster
Montag, 24. März 2003, 14:30–19:00, P2c, P2d
Dependence of the thickness of an equilibrium Helium film from the non-retarded to the retarded regime — •Valentin Iov1, Armin Fubel1, Martin Zech1, J*rgen Klier1, Paul Leiderer1, and Valeri Shikin2 — 1Department of Physics, University of Konstanz, D-78457, Konstanz, Germany — 2ISSP, 142432 Chernogolovka, Moscow District, Russia
The thickness of a physisorbed liquid film on a wetted substrate can be described by van-der-Waals law. When the distance of the bulk reservoir to the substrate surface, h, is changed, then the growth of the adsorbed film thickness, d, follows different behaviors, depending on its thickness. For thin films, d ∝ h−1/3, known as the non-retarded growth dependence whereas for thick films, d ∝ h−1/4, known as retarded growth. However, little is known how these two growth dependencies intersect. Using the surface plasmon resonance technique we measured the thickness of a liquid 4He film adsorbed on an Ag substrate deposited onto a glass prism. The thickness is varied from a few up to several hundred monolayers by changing h over a wide range. The crossover from the non-retarded to the retarded regime is measured. The film thickness and its dependence on h is precisely determined and theoretically modelled. Further experiments for checking the influence of surface roughness and the adsorption behavior on a weak binding substrate, like Cs, are in progress.