Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 9: Poster 1

HL 9.84: Poster

Montag, 23. März 2009, 14:30–17:00, P2

Deposition of PTCDA on an Ultra Thin Optical Fibre from a Helium Nanodroplet Beam — •Tobias Knoblauch, Matthieu Dvorak, Oliver Bünermann, and Frank Stienkemeier — Physikalisches Institut, Universität Freiburg, 79104 Freiburg

Helium nanodroplet isolation (HENDI) spectroscopy is a powerful technique to analyse the electronic structure of molecules. Because of the very low temperature of the droplets (0.4 K) and their superfluid property, helium nanodroplets provide a cold and weakly interacting matrix. Furthermore, it can be used to form peculiar complexes of molecules inside the droplets. The high spectral resolution of this technique allows disentangling the contributions of different complex sizes.

Vibronic spectra of PTCDA isolated in helium droplets have been extensively studied in our group [1]. To link our results with film spectroscopy we extended our molecular beam apparatus in order to deposit molecules and complexes formed in the droplets on an ultra thin optical fibre. Light passing through the optical fibre exhibits a pronounced evanescent field that interferes with the deposited material on its surface and allows high sensitive transient absorption spectroscopy [2]. We will present the status and first results of this setup.

[1] M. Wewer and F. Stienkemeier, J. Chem. Phys. 120, 1239 (2004)

[2] F. Warken, E. Vetsch, D. Meschede, M. Sokolowski and A. Rauschenbeutel, Optics Express 15, 11952 (2007)