Nanocrystal and crystal structure determination by novel x-ray methods

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The determination of crystalline structure has traditionally been accomplished by means of single crystal and polycrystalline x-ray diffraction techniques. Both have been developed extensively and have had great success over the years. Nanoscience has presented several fundamental problems that cannot be solved by current techniques of any kind, therefore hindering the progress in the understanding of basic issues. For instance, what is the atomic arrangement and composition of a nanocrystal? New, 'non-traditional' x-ray scattering methods must be developed in order to answer these questions. My group intends to resolve fine details of the atomic structure of free nanoparticles of gold and silver as well as binary alloys. These studies will be performed by high energy x-ray diffraction, (high resolution radial distribution method) and by anomalous x-ray diffraction method. These are methods that we have been developing over the years to allow the atomic resolution of nanoparticles. We will continue to study the chemical composition, strain and elastic energy of self-assembled islands and other epitaxial systems by means of grazing incidence x-ray diffraction. The group will also develop powder diffraction and multiple beam diffraction for ab-initio structure determination of systems ranging from quasicrystals to protein crystals.