Berlin 2001 – wissenschaftliches Programm

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MO: Molekülphysik

MO 1: Posters Monday: Clusters, Fullerenes and Nanotubes

MO 1.25: Poster

Montag, 2. April 2001, 12:30–15:00, AT3

Alkali endohedral fullerenes — •Andreas Lassesson, Andrej Glotov, and Eleanor E. B. Campbell — Dept. of Experimental Physics, Göteborg University/Chalmers University of Technology, SE-412 96 Göteborg, Sweden

The endohedral fullerene Li@C₆₀ was produced using low-energy bombardment of thin films of C₆₀. A new ion source was tested which could provide µA of alkali ion current used for the production. Quantities of mg of Li@C₆₀ could be produced and purified using High Performance Liquid Chromatography (HPLC). The production and characterisation of other alkali endohedral fullerenes such as Na@C₆₀ is currently under investigation. The HPLC of Na@C₆₀ material seems to contain similar components as for Li@C₆₀, but in smaller amounts. These are to be investigated with Laser Desorption Time-of-Flight Mass Spectrometry (LD-TOF) and optical spectroscopy. The stability of Li@C₆₀ were investigated using LD-TOF. The high temperature in the experiment combined with the relatively long life time of Li@C₆₀ is evidence of the endohedral nature of the molecules. From the time scale of the Li@C₆₀⁺ →Li⁺ + C₆₀ fragmentation the dissociation energy was found to be 5.4 eV. This is consistent with gas phase experiments and theory. New STM studies of individual endohedral fullerenes are in progress and preliminary results will be reported.