Berlin 2001 – scientific programme
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MO: Molekülphysik
MO 12: Posters Friday: Spectroscopy
MO 12.33: Poster
Friday, April 6, 2001, 12:30–15:00, AT3
The orientation of oxonine-molecules in the nano channels of zeolite L — •Christina Debus1, Andreas Drechsler1, M. Andreas Lieb1, Alfred J. Meixner1, Silke Megelski2, Marc Pauchard2, Stephan Glaus2 und Gion Calzaferri2 — 1Physikalische Chemie, Universität Siegen, 57068 Siegen — 2Departement für Chemie und Biochemie, Universität Bern, CH-3012 Bern
The orientation of the S1 ← S0 π , π ⋆ transition dipole moment of oxonine in the channels of zeolite L crystals was investigated by means of fluorescence microscopy and single-crystal imaging. We found, that the transition moments, which are oriented parallel to the molecules’ long axis are not aligned along the zeolite’s channel axis as expected but show a cone-shaped distribution with a half cone angle of 72 ∘. However, geometrical space-filling arguments based on the zeolite L structure give room for only two possible arrangements of the molecules’ long axis: a half cone angle of up to 40 ∘ or an angle of about 90 ∘ with respect to the c-axis of zeolite L. The surprising discrepancy between geometrical considerations and the results of the fluorescence measurements can be explained by assuming that oxonine is exposed to a considerable anisotropic electrical field in the zeolite channels.