Quantum Chemical Research on Carbon Clusters and Other Projects

激光汽化研究已经证明了一组大小在38到150个原子之间的偶数碳团簇的稳定性。有人认为，C60是这个家族中最突出的成员，它的形状和结构与足球相似。MNDO计算证实了这种结构的振动稳定性，并表明它相对于类似尺寸的石墨片和其他竞争结构具有能量稳定性。额外的MNDO计算表明了球状C40、C50和C70团簇的稳定性。这个项目包括系统地寻找剩余的偶数碳团簇的稳定球形结构。在MNDO计算之前，将进行图理论分析，以确定哪些环组合在拓扑上是可能的，并通过Huckel计算，以确定哪些可能具有闭壳电子结构。上述类型的中空碳团簇可能在烟灰的形成和星际空间中其他分子的运输中发挥作用，并可能导致新型润滑剂。我们需要对这些结构有一个基本的了解，这个项目也解决了这个问题。此外，该项目还将为有才华的本科生提供接触先进计算技术和设备的机会，从而使美国科学基础设施受益。

Laser vaporization studies have demonstrated the stability of a family of even-numbered carbon clusters ranging in size from about 38 to 150 atoms. It has been suggested that C60, the most prominent member of this family, has a hollow structure similar in shape and structure to a soccerball. MNDO calculations have confirmed the vibrational stability of this structure and have shown it to be energetically stable relative to silmilarly sized graphite chips and other competing structures. Additional MNDO calculations have indicated stability for spheroidal C40, C50, and C70 clusters. This project involves a systematic search for stable spheroidal structures for the remaining even-numbered carbon clusters. The MNDO caculations will be preceded by graph theoretical analysis to see which ring combinations are topologically possible, and by Huckel calculations to see which are likely to have closed shell electronic structures. Hollow carbon clusters of the type described above may play a role in the formation of soot and the transportation of other molecules in interstellar space, and may lead to novel lubricants. A fundamental understanding of these structures is needed and is addressed by this project. Moreover, the project will also benefit the infrastructure of U.S. science by providing exposure of talented undergraduates to advanced computing techniques and equipment.