Slow Electrons are "killing" Ozone - Outstanding new discoveries in ion physics

Innsbruck/Vienna (Austrian Science Fund) - Tilmann Märk from the Institute of Ion Physics at the University of Innsbruck and his team have, with the support of the Austrian Science Fund, developed unique methods and equipment to examine the interaction of electrons with atoms, molecules and clusters. And their research has been successful - they have made a number of discoveries, including a new ozone destruction process, and they have clearly established the binding energy of the "buckyball", C60 , which has long since been the subject of international research.

The destruction of the ozone in the earth's atmosphere has many different causes, many of which are unknown. Tilmann Märk and his team, in cooperation with University College London, have identified a phenomenon which was hitherto considered impossible, but which basically constitutes another ozone destruction process.
"We have proved what was previously considered impossible: slow, thermal electrons are taken up by the ozone. This happens with great frequency and has a detrimental effect on the atmosphere, since this destroys the ozone," explains Märk.
Since there are a great number of these slow electrons in the ionosphere, it is clear that the many ozone models must be recalculated in light of these results and the simulations must be re-worked.

The binding energy of the "buckyball"
A further highlight amongst Märk's results relates to the well-known football-shaped "buckyball" C60, which is characterised by its particular stability. In cooperation with the University of Jerusalem, Märk has revealed the secret of this binding energy. "Unusually for a "football", we bombarded the C60 molecule with electrons, thereby attempting to break a C2 molecule away from the ionised molecule cluster. We wanted to know the energy required for this fragmentation process, since, conversely, this also tells us the energy with which this part is bound to the rest of the molecule," explains Märk. Märk and his team succeeded in breaking a C2 carbon molecule away from the C60 ion and therefore established the measure of stability, i.e. the precise binding energy. The astonishing result: the binding energy required to break away a C2 molecule, at 10 electron volts, is considerably higher than the ionisation energy of approximately 7.6 eV - this makes C60 very different from other molecules.

Prof. Dr. Tilmann Märk
University of Innsbruck, Institute of Ion Physics
T +43 512 507-6240

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October 15th, 2001