Single conformation spectroscopy and dynamics of multichromophore networks

化学系化学结构、动力学和机理（CSDM-A）项目将资助普渡大学的Timothy Zwier教授和他的合作者研究影响大分子自我折叠方式的细微分子间相互作用。Zwier教授和他的团队利用复杂的技术将这些分子转化为气相，并结合灵敏的光谱方法，正在进行实验，以揭示使这些分子具有特定几何形状的单一构象的微妙力量。待研究的分子包括多肽以及可能用于电子材料的分子。从这些研究中获得的知识将为理论和计算化学家提供基准，以测试新的计算方法准确预测产生特定构象的微妙分子间力的能力。该项目的一个独特之处在于与许多合成和理论化学家以及中西部主要本科院校的教师和学生的合作。Zwier教授和他的研究小组使用各种方法，包括激光解吸（中性）和电喷雾电离（离子），在气相中制作中性和带电形式的大型构象柔性分子的低温样品。使用各种能够分离单个构象的光谱的激光光谱方法来询问物种的光谱。正在研究的特定种类包括：形成螺旋的肽，形成平行和反平行β -片的肽，参与形成缠结网络的富含谷氨酰胺或天冬酰胺的肽，以及被认为在淀粉样蛋白原纤维形成中起作用的特定六肽。除了多肽，Zwier和他的团队正在研究分离的环对苯乙烯（纳米环）的光谱，预计它们具有有趣的振动耦合。Zwier研究小组正在与各种各样的研究人员合作，从合成化学家到理论化学家和计算化学家。通过与一些小型文理学院的教师和本科生的合作，这项研究的影响显著扩大，包括霍普学院、卡拉马祖学院和威斯康星大学欧克莱尔分校。

With this award, the Chemical Structure, Dynamics and Mechanisms (CSDM-A) Program of the Division of Chemistry is funding Professor Timothy Zwier of Purdue University and his collaborators to investigate the subtle intermolecular interactions that influence the ways in which large molecules fold up on themselves. Using sophisticated techniques to get these molecules into the gas phase, combined with exquisitely-sensitive spectroscopic methods, Professor Zwier and his group are doing experiments that will unravel the delicate forces that hold single conformations of these molecules in their specific geometries. Molecules to be studied include peptides as well as molecules that may find use in electronic materials. The knowledge obtained from these studies will provide theoretical and computational chemists with benchmarks for testing the ability of new computational methods to accurately predict the subtle intermolecular forces that give rise to particular conformations. A unique element in this project is the collaboration with a number of synthetic and theoretical chemists as well as with faculty and students at primarily undergraduate institutions in the Midwest.Professor Zwier and his research group make low-temperature samples of neutral and charged forms of large, conformationally-flexible molecules in the gas-phase using a variety of methods including laser-desorption (neutrals) and electro-spray ionization (ions). The species' spectra are interrogated using a variety of laser spectroscopic methods that are capable of separating the spectra of individual conformers. Specific species that are being examined include: peptides that form helices, peptides that form parallel and anti-parallel beta-sheets, glutamine- or asparagine-rich peptides that are involved in the formation of tangled networks, and specific hexapeptides that are believed to play a role in the formation of amyloid fibrils. In addition to the peptides, Zwier and his group are studying the spectra of isolated cycloparaphenylenes (nano-hoops) that are predicted to have interesting vibronic coupling. The Zwier research group is collaborating with a wide variety of researchers from synthetic chemists to theoretical and computational chemists. The impact of this research is significantly broadened through the collaboration with a number of faculty and undergraduate students from small liberal arts colleges, including Hope College, Kalamazoo College and the University of Wisconsin - Eau Claire.