RUI: High-Resolution Electronic Spectroscopy of Transition Metal-Containing Free Radicals in the Gas Phase

该奖项由化学部化学结构、动力学和机理计划资助。它将支持明尼苏达州圣保罗Macalester学院的Thomas D.Varberg教授和他的本科生研究人员的工作，他们记录和分析含有过渡金属原子的气相自由基的电子光谱。这些分子将用脉冲和连续波激光在可见光区用激光激发光谱进行研究。光谱分析将给出主要分子常数的精确值，包括振动、旋转、精细和超精细结构。这种分析将更详细地描述每个分子的电子态和化学键的性质，并提供准确的跃迁频率，对其他领域的科学家有用。研究的目标分子包括硫化金、氢化钽、氧化钽和氟化汞等双原子分子，以及乙炔锌和乙炔铜等线性多原子分子。了解含有过渡金属的分子的结构、成键和光谱是很重要的，原因有几个。例如，化学家们已经学会了如何制造被称为胶体的金原子的小簇，然后将这些胶体与终止于硫原子的长链有机分子反应。由此产生的金纳米粒子可能是用于数据存储、超快开关和量子电子学的设备的构建块。该NSF奖将支持对双原子分子金硫化物的基本测量，作为对金-硫键最简单形式的研究，金-硫键位于更复杂的纳米颗粒结构的核心。此外，许多工业上有用的有机化合物化学反应利用过渡金属来催化或加速所需产品的形成。在这些催化反应中，金属-碳键形成，然后在将体系从反应物转化为产物的过程中断裂。由NSF奖支持的实验将研究自然界中发现的一些最简单的金属-碳键，其结果将有助于化学家理解更大系统中的这种键。所有这些研究都将由Macalester学院的本科生进行，这将向这些年轻的科学家介绍物理化学的现代研究，并为他们在化学、化学物理和工程方面的研究生培训做准备。

This award has been funded by the Chemical Structure, Dynamics, and Mechanisms A Program of the Division of Chemistry. It will support the work of Prof. Thomas D. Varberg and his undergraduate student researchers at Macalester College in St. Paul, Minnesota as they record and analyze the electronic spectra of gas-phase free radicals that contain a transition metal atom. These molecules will be studied using laser-excitation spectroscopy in the visible region, with both pulsed and continuous-wave lasers. Spectral analyses will yield accurate values for the principal molecular constants, including the vibrational, rotational, fine, and hyperfine structures. Such analyses will characterize in some detail the nature of each molecule's electronic states and chemical bonding, as well as provide accurate transition frequencies that are of use to scientists in other fields. The molecules targeted for study include diatomic molecules such as gold sulfide, tantalum hydride, tantalum oxide and hafnium fluoride, and linear polyatomic molecules such as zinc acetylide and copper acetylide. Understanding the structure, bonding and spectroscopy of molecules that contain a transition metal is important for several reasons. For example, chemists have learned how to make small clusters of gold atoms known as colloids and then react these colloids with long-chain organic molecules that terminate in a sulfur atom. The resulting gold nanoparticles are possible building blocks for devices to be used for data storage, ultrafast switching and quantum electronics. This NSF award will support fundamental measurements on the diatomic molecule gold sulfide as a study of the simplest form of the gold-sulfur bond, which lies at the heart of the more complex nanoparticle structures. Furthermore, many industrially useful chemical reactions of organic compounds utilize transition metals to catalyze, or speed up, the formation of the desired product. In these catalyzed reactions, a metal-carbon bond is formed and then later broken in transforming the system from reactant to product. Experiments supported by this NSF award will study some of the simplest metal-carbon bonds found in nature, the results of which will help chemists understand such bonding in larger systems. All of these studies will be carried out by Macalester College undergraduate students, which will introduce these young scientists to modern research in physical chemistry and prepare them for graduate training in chemistry, chemical physics, and engineering.