Hamburg 2009 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 34: Poster II
A 34.8: Poster
Donnerstag, 5. März 2009, 16:30–19:00, VMP 9 Poster
Size dependence of L2,3 branching ratio and 2p core hole screening in X-ray absorption of transition metal clusters — •Konstantin Hirsch1, Jochen Rittmann1, Marlene Vogel1, Vicente Zamudio-Bayer1, Andreas Langenberg1, Philipp Klar1, Jürgen Probst1, Robert Richter1, Fabian Lofink1, Thomas Möller1, Bernd von Issendorff2, and Tobias Lau1 — 1Technische Universität Berlin, Institut für Optik und Atomare Physik, EW 3-1, Hardenbergstraße 36, D-10623 Berlin — 2Universität Freiburg, Fakultät für Physik, Stefan-Meier-Straße 21, D-79104 Freiburg
Only very recently the first X-ray absorption spectra of size-selected free clusters could be recorded [1], marking an important breakthrough on the way to a detailed study of the local electronic structure of isolated nanoparticles. To achieve this aim, size-selected metal cluster cations were accumulated and studied in a linear ion trap. For the 3d transition metals Ti, V, Cr, Mn, Fe, and Co an atomic multiplet structure is only present up to the trimer, while tetra- and pentamers already show bulk-like line shapes. The L2,3 branching ratio and the L3 X-ray absorption onset, however, evolve over a much larger size range. Our analysis shows that the evolution of the L2,3 branching ratio in 3d transition metals is independent of their effective 2p spin-orbit splitting and can rather be attributed to size-dependent electron delocalization and core hole screening effects. Furthermore, we show how spectral features in L2,3 X-ray absorption of bulk transition metals can now be traced back to their atomic origin.
J.T. Lau et al., Phys. Rev. Lett. 101 153401 (2008).