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O: Oberflächenphysik

O 15: Postersitzung (Adsorption an Oberfl
ächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Rastersondentechniken, Zeitaufgelöste Spektroskopie, Methoden)

O 15.76: Poster

Freitag, 4. März 2005, 17:00–20:00, Poster TU D

New measurements on the Casimir-van der Waals potential — •Lodewijk Arntzen — Physikalisches Institut, Heidelberg University, 69120 Heidelberg

We recently measured quantum reflection of cold helium atoms from a purely attractive potential. The interaction could be identified as originating from the Casimir force between a single atom and semi-conducting surface. We are now specifically investigating the temperature behavior of the Casimir-van der Waals potential. Within the incident energy range between µeV and neV, the surface temperature is varied from 300 K to 1200 K. These new measurements show that the quantum reflected intensities decrease sharply and reproducibly with increasing temperature. We will present different mechanisms that may account for this observation. In addition the Debye-Waller effect, the temperature dependence of the electric permittivity and magnetic effects will be adressed.