Chemically Modified Surface Clusters: Formation and Properties

化学改性表面簇：形成和性质

• 批准号: 9980222
• 负责人: Gert Ehrlich
• 金额: $ 30万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9980222&HistoricalAwards=false
• 关键词: Chemically; Modified; Surface; Clusters; Formation

9980222EhrlichThe aim of this project is to study the role of chemical composition and its influence on the physical and chemical properties of clusters. The extent to which doping with foreign atoms can be used to affect cluster behavior will been explored. The formation of chemically modified surface clusters will be examined on the atomic level, in order to devise methods for introducing chemically different atoms into well-defined locations in a cluster of known structure. Through the use of the field ion microscope, which can reveal the location and behavior of individual atoms, metal clusters will be assembled on iridium (111), a model surface for which considerable background information is already available. Clusters will be constructed with well characterized defects in them. There after, foreign atoms, such as rhenium or tungsten, will be deposited on the surface and their incorporation into the cluster will be followed in atomic detail. Attempts will also be made to grow doped clusters by first depositing chemically different atoms and then allowing them to assemble into a cluster. Once reasonable techniques for chemical modification have evolved, the effect of chemical doping on cluster behavior will be explored, with the initial emphasis on how the presence of a foreign atom affects the diffusion characteristics of clusters.Metal clusters formed on solids play an important role in chemical technology as catalysts for chemical reactions. More recently, their importance in affecting the growth of crystals and films has also been recognized, and as a result of studies on the atomic level, it is now clear that these clusters constitute interesting chemical entities whose properties are strongly affected by the overall atomic arrangement. This area is of high importance to industry. There are good job opportunities for students trained in this integrated area of education and research.

9980222Ehrlich该项目的目的是研究化学成分的作用及其对团簇物理和化学性质的影响。 将探讨外来原子掺杂在多大程度上可以影响团簇行为。 将在原子水平上检查化学改性表面簇的形成，以便设计将化学上不同的原子引入已知结构簇中明确定义的位置的方法。 通过使用场离子显微镜，可以揭示单个原子的位置和行为，金属簇将在铱（111）上组装，铱（111）是一个模型表面，已经有大量的背景信息可用。 将构建具有明确特征的缺陷的簇。 此后，外来原子（例如铼或钨）将沉积在表面上，并且将详细跟踪它们并入簇中的情况。 还将尝试通过首先沉积化学上不同的原子然后让它们组装成簇来生长掺杂簇。 一旦合理的化学改性技术得到发展，化学掺杂对团簇行为的影响将被探索，最初的重点是外来原子的存在如何影响团簇的扩散特性。在固体上形成的金属团簇作为化学反应的催化剂在化学技术中发挥着重要作用。 最近，它们在影响晶体和薄膜生长方面的重要性也得到了认识，并且作为原子水平研究的结果，现在很明显，这些簇构成了有趣的化学实体，其性质受到整体原子排列的强烈影响。 该领域对工业非常重要。 在这个教育和研究综合领域接受培训的学生有很好的就业机会。