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

在这个由化学系实验物理化学项目资助的奖项中，耶鲁大学的Schmutenmaer教授和他的合作者和学生将从事两项相互关联的活动：1.单个单壁碳纳米管(SWCNTs)的太赫兹(THz)发射光谱；2.有机分子晶体和蛋白质中的THz光学活性。SWCNTs受到广泛关注的原因之一是，它们具有与多壁碳纳米管不同的明确的电学性质。单个SWCNT可以是金属的，也可以是半导体的，这取决于它的手性矢量的值(衡量管子卷起的方式)。它们已被认为是电子产品进一步小型化的主要候选者，即碳基电子产品。此外，它们是研究一维(1D)系统中现象的理想平台。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物质的物理学有了更深入的了解。SWCNT是最吸引人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的光学活性。旋光性是手性分子的一种基本性质。最近已经有大量的工作利用太赫兹时间域光谱来表征有机分子晶体(OMC)。这些研究的范围从氨基酸晶体和碳水化合物，到非法药物，到药物，再到爆炸物。然而，还没有人报道分子体系在太赫兹波段的振动圆二色谱(VCD)或旋光色散(ORD)谱。这是一个未知的领域。了解单壁碳纳米管的高速电导特性和机理是将其应用于先进电子或光电子器件的关键一步。考虑到研究它们的科学家数量巨大，还没有人描述它们的太赫兹发射似乎令人惊讶。太赫兹光学活性的研究将具有很大的变革性，就像红外VCD通过将光谱的IR区域开放给这类研究来改变光学活性的研究一样。太赫兹VCD将获得IR VCD无法获得的有关分子间模式的信息。它将对计算的光谱提供严格的实验限制，无论是使用经验方法还是从头计算方法。参与该项目的学生将从与来自不同领域的研究人员的互动中受益，即化学(Schmutenmaer教授)和物理(Prober教授)。Prober教授和Schmutenmaer教授有在不同级别进行外联的记录，并将继续开展这些活动，并尽可能加强这些活动。

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.