Nanocrystal and crystal structure determination by novel x-ray methods

晶体结构的测定传统上是通过单晶和多晶X射线衍射技术来完成的。这两个项目都得到了广泛的发展，并在多年来取得了巨大的成功。纳米科学提出了几个根本问题，这些问题不能用任何形式的现有技术来解决，因此阻碍了对基本问题的理解。例如，纳米晶体的原子排列和组成是什么？为了回答这些问题，必须开发新的“非传统”X射线散射方法。我的团队打算解决金、银以及二元合金的自由纳米粒子原子结构的细节问题。这些研究将用高能X射线衍射法(高分辨率径向分布法)和反常X射线衍射法进行。这些都是我们多年来一直在开发的方法，以实现纳米颗粒的原子分辨率。我们将继续用掠入射X射线衍射法研究自组装岛和其他外延系统的化学成分、应变和弹性能。该小组还将开发粉末衍射和多光束衍射，用于从头算确定从准晶到蛋白质晶体的各种体系的结构。

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.