Heidelberg 2015 – scientific programme
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A: Fachverband Atomphysik
A 2: Atomic clusters (with MO)
A 2.6: Talk
Monday, March 23, 2015, 13:00–13:15, M/HS1
Wide angle X-ray scattering of silica nanoparticles — •Burkhard Langer1, Christian Goroncy1, Christopher Raschpichler1, Felix Gerke1, Toralf Lischke2, Bernhard Wassermann1, Christina Graf1, and Eckart Rühl1 — 1Physikalische Chemie, Freie Universität Berlin — 2Max-Planck-Institut für Mikrostrukturphysik, Halle
Amorphous silica nanoparticles are widely used as model systems in materials and life sciences as well as in industrial and pharmaceutical applications. The structure of these particles consists of an amorphous network of SiO2 containing pores in the nanometer range (1-10 nm). Chemically synthesized silica nanoparticles with a diameter between 150 and 350 nm which are prepared with porous layers are focused with an aerodynamical lens into the interaction region with synchrotron radiation from BESSY II. The experiments were performed in the energy range of the Si 2p regime (E≈100 eV), where the photon wavelength is comparable to the pore sizes. Deviations in the angle dependent scattering intensity compared to calculations obtained by pure Mie theory for spherical particles are attributed to Rayleigh scattering at the pores of the nanoparticles. Calculations using Discrete Dipole Approximation Scattering Theory (DDSCAT) and a modified Mie algorithm, both using realistic pore sizes and size distributions, are successfully applied to describe the wide angle X-ray scattering intensities.