Laser Spectroscopy of New Fullerene and Metallofullerene Optical Materials

摘要9632993赖特这项研究致力于了解不同种类的富勒烯、它们的非线性性质和它们的电子结构之间的关系。这项拟议的工作将包括创建新的衍生品和材料的例子，这些例子可以被探索，以了解与其他部分的相互作用如何改变电子和光学性质。显然，中性富勒烯没有有趣的非线性，富勒烯和富勒烯衍生物家族中最有趣的成员是带电离子、电荷转移络合物和面内金属富勒烯。未来的研究将继续包括两个重要部分：新型富勒烯材料的合成、提纯、制备和表征，以及这些材料的新型光学性质的测量。光学测量的核心将集中在使用多共振四波混频光谱的能力来识别导致非线性的态，探测电子态之间的跃迁和耦合，并确定由于具有允许电荷转移跃迁的面内金属或外部部分而引起的新态的特征和有用性。基于富勒烯和金属富勒烯的材料的光学性质引起了人们的极大兴趣，因为它们的稳定性、非线性、电荷转移特性以及通过改变价态、笼子的大小、面体内离子的数量和类型来控制它们的性质的能力。衍生化，以及与其他富勒烯的连接。可能的材料包括电荷转移盐、纳米表面结构和薄膜、沸石和聚合物材料。开发新的光学材料需要了解富勒烯性质的变化如何影响材料的光学和电子传输性质。在之前的授权期内的工作已经清楚地表明，中性富勒烯不会成为使光子学领域具有竞争力的神奇的非线性材料。它们的非线性比现场工作人员希望和测量的要小得多。然而，阴离子的非线性性是很大的，通过这里提出的想法和通过形成突出极化率的衍生物，它们可以得到相当大的改善。富勒烯也是一种不同寻常的耐人寻味的材料，因为它能够通过操纵笼子中的碳数、价态、面内金属离子和形成富勒烯衍生物来设计它们的电子结构。除了作为非线性材料的前景外，富勒烯的正常电子和电荷转移状态也是许多有趣的潜在应用的核心，包括光折变、光导、光伏、空穴燃烧存储和激光材料。在此授权期内，该计划将重点研究带电富勒烯和面内金属富勒烯不同价态的电子结构特征。

Abstract 9632993 Wright This research is concerned with understanding the relationship between the different kinds of fullerenes, their nonlinear properties, and their electronic structure. The proposed work will involve creating examples of the new derivatives and materials that can be probed to understand how the interaction with other moieties changes the electronic and optical properties. It is clear that the neutral fullerenes do not have interesting nonlinearities and that the most interesting members of the fullerene and fullerene derivatives family are the charged ions, charge transfer complexes, and the endohedral metallofullerenes. The proposed research will continue to have two important parts: synthesis, purification, preparation, and characterization of new fullerene-based materials and measurement of the novel optical properties of these materials. The heart of the optical measurements will concentrate on using the capabilities of multi-resonant four wave mixing spectroscopy to identify the states that are responsible for the nonlinearities, to probe the transitions and coupling between electronic states, and to determine the character and usefulness of the new states that are caused by having endohedral metals or external moieties that allow charge transfer transitions. %%% There is great interest in the optical properties of materials that are based on fullerenes and metallofullerenes because of their stability, nonlinear properties, charge transfer characteristics and the ability to manipulate their properties through changes in the valence state, the size of the cage, the number and type of endohedral ions. the derivatization, and the linking with other fullerenes. The possible materials include charge transfer salts, nano-scale surface structures and films, zeolytes, and polymeric materials. Development of new optical materials requires an understanding of how changes in the nature of the fullerene affect the material's optical and electr on transfer properties. Work during a prior grant period has made it clear that the neutral fullerenes will not be the magic nonlinear material that will make the field of photonics competitive. Their nonlinearities are much smaller than the workers in the field had hoped for and measured. Nevertheless, the nonlinearities of the anions are substantial and they may be improved considerably by the ideas presented here and by forming derivatives that accentuate the polarizability. The fullerenes are also unusual and intriguing materials because of the ability to engineer their electronic structures by manipulating the number of carbons in the cage, the valence state, the endohedral metal ion and by forming fullerene derivatives. In addition to their promise for nonlinear materials, the normal electronic and charge transfer states of fullerenes are central to many interesting potential uses including photorefractive, photoconductive, photovoltaic, hole burning storage, and laser materials. The program during this grant period will focus on the electronic structures characteristic of the different valence states of the charged fullerenes and the endohedral metallofullerenes.