THz Studies of Carrier Dynamics in Single-Walled Carbon Nanotubes and of Optical Activity in Organic Molecular Crystals

该奖项由化学学部实验物理化学项目资助，耶鲁大学Schmuttenmaer教授及其合作者和学生将进行两项相互关联的活动：来自单个单壁碳纳米管（SWCNTs）的太赫兹（THz）发射光谱；有机分子晶体和蛋白质中的太赫兹光学活性。SWCNTs受到广泛关注的原因之一是，与多壁CNTs不同，SWCNTs具有明确的电学性质。单个swcnts可以是金属的，也可以是半导体的，这取决于其手性向量的值（衡量管卷起的方式）。它们已被认为是进一步小型化电子产品的主要候选者，即碳基电子产品。此外，它们是研究一维（1D）系统现象的理想平台。多年来，降维系统提供了特殊的机会、挑战和魅力。他们的研究使我们对凝聚态材料的物理学有了更深入的了解。swcnts是最具吸引力的一维模型系统之一。拟议工作的另一个领域是研究太赫兹光学活性。旋光性是手性分子的基本性质。近年来，利用太赫兹时域光谱对有机分子晶体（OMCs）进行了大量的研究。这些研究的范围从氨基酸晶体和碳水化合物，到非法药物、药品和爆炸物。然而，分子体系的太赫兹振动圆二色性（VCD）或旋光色散（ORD）光谱在太赫兹区还没有报道过。这是一个未知的领域。了解SWCNTs高速导电的特性和机制是将其应用于先进电子或光电器件的关键一步。考虑到大量的科学家研究它们，似乎令人惊讶的是，还没有人描述它们的太赫兹辐射。太赫兹光活度的研究将具有很大的变革性，就像红外VCD通过打开光谱的红外区域来进行这类研究，从而改变了光活度的研究一样。太赫兹VCD将获得红外VCD无法获得的分子间模式信息。它将为计算谱提供严格的实验约束，无论是使用经验方法还是从头算方法。参与该项目的学生将受益于与来自不同领域的研究人员互动，即化学（Schmuttenmaer教授）和物理（Prober教授）。Prober教授和Schmuttenmaer教授在各个层面都有推广的记录，他们将继续这些活动，并在可能的情况下加强这些活动。

In this award, funded by the Experimental Physical Chemistry Program of the Chemistry Division, Professor Schmuttenmaer of Yale University and his collaborators and students will pursue two interrelated activities: 1. Terahertz (THz) emission spectroscopy from individual single-walled carbon nanotubes (SWCNTs), and 2. THz optical activity in organic molecular crystals and proteins.One of the reasons SWCNTs have received much attention is because they have well defined electrical properties, unlike multi-walled CNTs. An individual SWCNT can be either metallic or semiconducting, depending on the value of its chiral vector (a measure of the manner in which the tube rolls up). They have been recognized as prime candidates for further miniaturization of electronics, i.e., carbon-based electronics. In addition, they are an ideal platform for studying phenomena in one-dimensional (1D) systems. Systems of reduced dimension have provided special opportunities, challenges, and fascination for many years. Their study has given us a deeper understanding of the physics of condensed materials in general. The SWCNT is one of the most fascinating model 1D systems. Another area of the proposed work is to investigate THz optical activity. Optical activity is a fundamental property of chiral molecules. There has been a great deal of recent work using THz time-domain spectroscopy to characterize organic molecular crystals (OMCs). These studies have ranged from amino acid crystals and carbohydrates, to illicit drugs, to pharmaceuticals, to explosives. However, no one has ever reported the THz vibrational circular dichroism (VCD) or optical rotatory dispersion (ORD) spectrum of a molecular system in the THz region. It is uncharted territory. Understanding the characteristics and mechanisms in high speed conductivity in SWCNTs is a critical step toward their utilization in an advanced electronic or optoelectronic device. Given the huge number of scientists studying them, it might seem surprising that no one has yet characterized their THz emission.Studies of THz optical activity will be transformative much in the same way infrared VCD transformed studies of optical activity by opening the IR region of the spectrum to this type of study. THz VCD will obtain information about intermolecular modes that is inaccessible to IR VCD. It will provide rigorous experimental constraints on calculated spectra, whether empirical or ab initio methods are used.Students involved in this project will benefit by interacting with investigators from different fields, namely chemistry (Professor Schmuttenmaer) and physics (Professor Prober). Professors Prober and Schmuttenmaer have a track record of outreach at a variety of levels, and will continue these activities and strengthen them wherever possible.