Hannover 2010 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 33: Cluster II
MO 33.3: Vortrag
Freitag, 12. März 2010, 14:30–14:45, F 102
Elastic soft X-ray scattering from free nanoparticles — •Burkhard Langer, Egill Antonsson, René Lewinski, Christina Graf, and Eckart Rühl — Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin
For many years elastic light scattering from free micro particles has been successfully used to probe their properties such as size, shape, and index of refraction. Similar studies on nanoparticles require the wavelength of the incident light being shifted into the VUV or X-ray regime. Here, we report first experimental results on small angle X-ray scattering (SAXS) on free SiO2 nanoparticles in the size regime between 100 and 250 nm. These particles are brought into the gas phase by using a continuous particle beam [1]. This beam is crossed by synchrotron radiation from an undulator beam line at BESSY II. The elastically scattered radiation intensity near forward direction is detected by an X-ray sensitive CCD-camera permitting the simultaneous measurement of photons in a range of 1.2∘−9∘ off the direct photon beam. Comparing the scattered intensities over a wide photon energy range (100-800 eV) to simple Mie calculations allows one to determine size distributions and optical properties of the nanoparticles. The results are in good agreement with transmission electron microscope (TEM) measurements, where these nanoparticles were deposited on a grid. In addition, we will discuss the resonant scattering in the Si 2p regime (E≈ 100 eV).
H. Bresch et al. Faraday Discuss. 137, 398-402 (2008).