Book of Abstracts Book of Abstracts - Universität Konstanz

The magnetic moments of isolated metal clusters
Gereon Niedner-Schatteburg 1 and Wilfried Wurth 2
1 Fachbereich Chemie, TU Kaiserslautern, Germany (gns@chemie.uni-kl.de)
2 Institut für Experimentalphysik, Universität Hamburg, Germany (wilfried.wurth@desy.de)
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Within the last fiveteen years X-ray Magnetic Circular Dichroism (XMCD) has made itself
useful in solid state physics and in surface science [2] since it allows for the elucidation of
magnetic properties that would be unavailable otherwise. For chemists XMCD has become a
valuable tool when investigating paramagnetic organometalic and coordination compounds [2].
In a few cases even paramagnetic metalloproteins have been studied successfully [3]. Only
recently size selected iron clusters became subject of XMCD measurements [4]. All of these
studies, however, have utilized condensed phase samples. Substrates and solvents may exert
decisive but unknown influence on the magnetic properties of deposited and desolved samples,
respectively. It is mandatory to identify suitable model systems for direct investigation and void
of such an interference.
We propose to apply XMCD to isolated gas phase metal clusters of selected sizes. This novel
experimental scheme shall allow for determination of total magnetic moments as arising
through spin and orbit contributions. Temperature tuning shall enable the recording of
magnetization curves.
This shall be enabled through application of circularly polarized x-ray synchrotron radiation
(600eV) to isolated gas phase transition metal clusters which have been size selected and stored
in an ion trap [5,6] under high vacuum.
The talk shall outline the basic features of the proposed scheme and it is going to suggest a
particular way to carry out actual experiments.
References
[1] G. Schütz et al., Phys. Rev. Lett. 58, 737 (1987); C. T. Chen, N.V. Smith, and F. Sette, Phys. Rev.
B 43, 6785 (1991); B. T. Thole et al., Phys. Rev. Lett. 68, 1943 (1992); M. Altarelli, Phys. Rev. B
47, 597 (1993); C. T. Chen et al., Phys. Rev. B 48, 642 (1993); Y. U. Idzerda et al., Surf. Science
287/288, 741 (1993)
[2] S. P. Cramer in: ACS Symposium series Vol. 858 (2003)
[3] J. Van Elp. et al., Proc. Nat. Acad. Sci. U.S.A. 90, 9664 (1993)
[4] S. T. Lau, A. Föhlisch, R. Nietubyc, M. Reif, and W. Wurth, Phys. Rev. Lett. 89, 057201 (2002)
[5] G. Niedner-Schatteburg and V. E. Bondybey, Chem. Rev. 100, 4059 (2000)
[6] A. Lagutschenkov et al., Poster, S 3 C, Brand 2005
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