Structure of Nanocrystals by X-ray Diffraction

Valeri Petkov

Department of Physics

Central Michigan University

Knowledge of the atomic-scale structure is an important prerequisite to understand and predict the properties of materials. In the case of crystals it is obtained from the positions and the intensities of the Bragg peaks in the diffraction data. However, many materials of technological importance, in particular nanophase materials, are not perfect crystals. The diffraction patterns of such materials show only a few Bragg peaks and a pronounced diffuse component. This poses a real challenge to the usual techniques for structure determination. The challenge can be met by employing the so-called atomic pair distribution function (PDF) technique and high energy x-ray diffraction. The basic features of the PDF technique and high-energy x-ray diffraction will be introduced and their potential demonstrated with results from recent experiments on V2O5.nH2O xerogel, V2O5 nanotubes, polymeric macromolecules, gold nanoparticles, organic/inorganic nanocomposites, nanophase carbons, ZrO2 nanoceramics and GdAl2 nanomagnets.