Dresden 2011 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 31: Postersitzung II

MM 31.21: Poster

Mittwoch, 16. März 2011, 17:15–18:45, P5

X-ray Raman Scattering Studies of Si-based Compounds Under Extreme Conditions — •Christoph Sahle¹, Christian Sternemann¹, John Tse², Max Wilke³, Christian Schmidt³, Alexander Nyrow¹, Julien Dubrail³, Valentina Giordano⁴, Laura Simonelli⁴, Serge Desgreniers⁵, and Metin Tolan¹ — ¹Fakultät Physik/DELTA Technische Universität Dortmund, Otto-Hahn-Str. 4, 44227 Dortmund, Germany. — ²Department of Physics, University of Saskatchewan, Saskatoon S7N0W0, Canada. — ³Geoforschungszentrum Potsdam, Telegraphenberg, 14773 Potsdam, Germany. — ⁴ESRF, Rue Jules Horowitz, 38043 Grenoble Cedex, France. — ⁵Laboratoire de physique des solides denses, University of Ottawa, Ottawa K1N6N5, Canada.

The in situ study of low Z elements’ absorption edges under extreme conditions is only feasible using hard x-rays. Here, non-resonant x-ray Raman scattering as an energy loss technique enables one to choose the energy of the primary x-ray beam freely and thus gives access to shallow absorption edges of samples in highly absorbing sample environments, e.g. diamond anvil cells, which do not permit electrons and soft x-rays as probe. Here, we present two studies of Si-based compounds under extreme conditions: a high pressure study of the peculiar phase transitions in silicon clathrate Ba₈Si₄₆ via measurements of the Ba N₄₅ and Si L₂₃ edges. In addition, we present the first in situ high pressure – high temperature study at the Si L₂₃ and Na L₂₃ edge on hydrous Na₂Si₃O₇ melt, which may serve as a model for geologically relevant hydrous silicate melts in the deep earth.