Purchase of an X-ray Powder Diffractometer

在化学研究仪器和设备部门多用户仪器获取(CRIF-MU)计划的支持下，埃默里大学化学系将获得一台粉末X射线衍射仪(粉末X射线衍射仪)。该仪器将使以下领域的研究成为可能：a)金属氧化物簇合物及其组成的功能材料；b)螺旋多肽基序自组装衍生的纳米结构的合理设计；c)用于低温合成纳米晶体的单一来源前体；d)纳米粒子的分子动力学：电子转移和拯救；e)用于从水环境中选择性修复汞的聚合物材料；以及f)明确的负载型氧化物催化剂的开发。X射线衍射仪可以精确和精确地测量分子的全部三维结构，包括键的距离和角度，并提供关于分子相对于邻近分子的空间排列的准确信息。合成具有延伸结构的材料，如聚合物、无机固体或凝胶，通常会产生多晶或相不纯的粉末。粉末X射线衍射仪是表征这类产物结构的最有力的工具。粉末X-射线衍射谱可以解释存在的晶相的结构和相对丰度，它可以揭示材料薄膜相对于晶态衬底表面的择优晶向的存在，而X射线衍射线宽可以提供平均微晶直径的估计。此外，用粉末X射线衍射法可以研究材料的超薄薄膜(100 Nm)的结构，而用单晶X射线衍射法不能研究这种薄膜的结构。这些研究将在许多领域产生影响，特别是材料化学和纳米科学。

With support from the Chemistry Research Instrumentation and Facilities-Departmental Multiuser Instrument Acquisition (CRIF-MU) Program, the Department of Chemistry at Emory University will acquire a powder X-ray diffractometer (powder XRD). This instrument will enable research in the following areas: a) metal oxide clusters and functional materials comprised thereof; b) rational design of nanostructures derived from self-assembly of helical peptide motifs; c) single source precursors for low temperature synthesis of nanocrystals; d) molecular dynamics on nanoparticles: electron transfer and salvation; e) polymeric materials for selective mercury remediation from aqueous environments; and f) development of well-defined supported oxide catalysts. The X-ray diffractometer allows accurate and precise measurements of the full three dimensional structure of a molecule, including bond distances and angles, and it provides accurate information about the spatial arrangement of the molecule relative to the neighboring molecules. The synthesis of materials having an extended structure, such as polymers, inorganic solids, or gels, often yields a polycrystalline or phase-impure powder. Powder XRD is the most powerful tool available for the structural characterization of such products. Powder XRD pattern can elucidate the structure and relative abundance of the crystalline phases present, it can expose the existence of preferred crystalline orientation of a film of a material relative to a crystalline substrate surface, and the XRD linewidth can provide an estimate of the mean crystallite diameter. In addition, the structure of extremely thin films (100 nm) of materials can be investigated by powder-XRD whereas such films cannot be probed by single-crystal XRD. These studies will have an impact in a number of areas, in particular materials chemistry and the nanosciences.