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A: Fachverband Atomphysik
A 16: Atomic Clusters II
A 16.6: Vortrag
Mittwoch, 4. März 2009, 15:45–16:00, VMP 6 HS-B
X-rays reveal high symmetry and electronic shells in transition metal doped silicon clusters — •Jochen Rittmann1, Konstantin Hirsch1, Philipp Klar1, Andreas Langenberg1, Fabian Lofink1, Jürgen Probst1, Robert Richter1, Marlene Vogel1, Vicente Zamudio-Bayer1, Thomas Möller1, Bernd von Issendorff2, and Tobias Lau1 — 1Technische Universität Berlin, Institut für Optik und Atomare Physik, Hardenbergstraße 36, 10623 Berlin — 2Universität Freiburg, Fakultät für Physik/FMF, Stefan-Meier-Str. 21, 79104 Freiburg
Incorporation of a transition metal atom leads to a complete geometric rearrangement of silicon clusters. X-ray absorption spectroscopy at the dopant atom 2p edge unravels a high symmetry of TiSi16+, VSi16+, and CrSi16+ cages. We show that Ti, V, and Cr adopt the same local electronic structure when embedded into Si16. Our data can be explained within the spherical potential model, where the electronic shell structure of the cage interacts with the dopant atom orbitals of the same character. Charge transfer to the silicon cage leads to a local d0 configuration of the transition metal dopant, quenching the magnetic moment. Because of its closed electronic shells, VSi16+ can be described as a spherically aromatic system according to the 2(N+1)2 rule. Our findings are further corroborated by the fact that the local electronic structure of the dopant is unchanged when replacing the Si16 cage by Ge16.