Lattice dynamics of stishovite from powder inelastic X-ray scattering

Abstract

We have retrieved the full lattice dynamics of stishovite, SiO2, by a combination of powder inelastic x-ray scattering (IXS) and ab initio calculations. The extracted dispersion curves are confirmed by experiments on a single crystal. Thereby we have shown that IXS powder measurements over a large range of momentum transfers allow an unambiguous validation of lattice dynamics models, which then in turn can be used to derive elastic and thermodynamic properties. The proposed method can be extended to high pressure measurements on in situ synthesized samples and promises to be a valuable tool in studies of materials for which no single crystals can be obtained. Copyright 2009 by the American Geophysical Union.