Ph Klar

Publications (3)9.24 Total impact

• Article: X-ray spectroscopy on size-selected clusters in an ion trap: from the molecular limit to bulk properties

  K Hirsch, J T Lau, Ph Klar, A Langenberg, J Probst, J Rittmann, M Vogel, V Zamudio-Bayer, T Möller, B von Issendorff
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  ABSTRACT: An experiment was designed to perform x-ray and VUV spectroscopy on size-selected clusters in the gas phase. Using a radio frequency ion trap and a quadrupole mass filter combined with an intense magnetron sputter source made it possible to record x-ray absorption spectra of mass-selected clusters in ion yield mode. These measurements clearly reveal the development from richly structured atomic spectra to bulk-like line shapes in transition metal clusters.
  Journal of Physics B Atomic Molecular and Optical Physics 07/2009; 42(15):154029. · 1.88 Impact Factor
• Source

  Available from: Fabian Lofink

  Article: Size dependence of L2,3 branching ratio and 2p core-hole screening in x-ray absorption of metal clusters.

  J T Lau, J Rittmann, V Zamudio-Bayer, M Vogel, K Hirsch, Ph Klar, F Lofink, T Möller, B v Issendorff
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  ABSTRACT: Resonant 2p x-ray absorption spectra of size-selected transition metal ions and clusters consisting of 1<or=n<or=200 atoms are reported. Remnants of atomic multiplet splitting in L(2,3)-edge x-ray absorption can be resolved up to the trimer, above which the overall line shape is already bulklike. A strong cluster size dependence of the L(2,3) branching ratio was found for titanium, vanadium, and cobalt clusters. While 3d electron delocalization increases with cluster size, the apparent 2p spin-orbit splitting remains constant within the error bars. The size dependence of the L(2,3) branching ratio can be attributed to cluster size specific screening of the 2p-3d Coulomb interaction by 3d/4s valence electrons.
  Physical Review Letters 10/2008; 101(15):153401. · 7.37 Impact Factor
• Article: Size Dependence of L{sub 2,3} Branching Ratio and 2p Core-Hole Screening in X-Ray Absorption of Metal Clusters

  J. T. Lau, J. Rittmann, V. Zamudio-Bayer, M. Vogel, K. Hirsch, Ph. Klar, F. Lofink, T. Moeller, B. von Issendorff
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  ABSTRACT: Resonant 2p x-ray absorption spectra of size-selected transition metal ions and clusters consisting of 1{
  Physical Review Letters - PHYS REV LETT. 01/2008; 101(15):153401-153401.