Hannover 2013 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 38: Poster: Atomic clusters (with MO)

A 38.8: Poster

Donnerstag, 21. März 2013, 16:00–18:30, Empore Lichthof

Core-level photoemission from free SiO₂ and Fe₃O₄ nanoparticles (3-10 nm) — •Burkhard Langer¹, Markus Eritt², Denis Duft², Thomas Leisner^2,3, and Eckart Rühl¹ — ¹Physikalische Chemie, Freie Universität Berlin — ²Institut für Umweltphysik, Universität Heidelberg — ³IMK, Karlsruher Institut für Technologie - KIT

We studied inner-shell photoelectron and near-edge spectra of 5-10 nm nanoparticles which are created in a microwave discharge source from gaseous precursors using a magnetic bottle electron spectrometer. Ferrocene vapor from heated powder as well as silane diluted in helium as a carrier gas (>99%) were being mixed under controlled conditions. Nanoparticles are formed in a microwave excited plasma. The nanoparticles were transferred into the interaction region, where they were excited by the synchrotron radiation from BESSY II, using a newly optimized transfer system containing an aerodynamic lens combined with a quadrupole guide / storage trap. The experiments were carried out in the energy regimes of the 2p absorption edges of Si (100-125 eV) and Fe (700-730 eV), respectively. In addition to SiO₂ nanoparticles, which have been studied before, we verified the presence of iron and iron oxide in free 5-10 nm particles formed from ferrocene and silane precursors using near-edge spectra. The analysis in the Fe 2p regime reveals that magnetite structures (Fe₃O₄) are present. Further, SiO₄ moieties are identified, but there is no evidence for fayalite (Fe₂SiO₄).