The Impact of Chirped Pulse Millimeter-Wave Technology on the Spectroscopy, Dynamics, and Manipulation of Molecules in Rydberg States

啁啾脉冲毫米波技术对里德堡态分子的光谱学、动力学和操纵的影响

• 批准号: 1058709
• 负责人: Robert Field
• 金额: $ 75.4万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2015-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1058709&HistoricalAwards=false
• 关键词: Impact; Chirped; Pulse; Millimeter; Wave

Professor Robert Field of MIT is supported by the Chemical Structure, Dynamics, and Mechanisms Program to develop experimental methods that exploit the interaction of Chirped Pulse millimeter wave (CPmmW) radiation with large Rydberg-Rydberg transition moments (kilo-Debye) in excited molecules. The CPmmW-based approach will enable the development of schemes for efficiently populating core-nonpenetrating Rydberg states, which are of special interest in part because of their enormous transition moments and relatively long lifetimes ( 1 microsecond). The crucial feature of CPmmW spectroscopy is that Rydberg-Rydberg transitions are detected directly via the Free Induction Decay (FID) signal that results when the CPmmW pulse polarizes all two-level systems that fall within the ca. 10 GHz wide spectral region of the chirp (10^5 resolution elements in a single 10 nanosecond duration CP). This NMR-like scheme is vastly superior to the single-resolution- element-at-a-time indirect detection schemes that are universally used in pulsed supersonic molecular beam spectroscopy. The interpretation of experimental spectra will be done in the context of Multichannel Quantum Defect Theory (MQDT), which is a beyond-Hydrogen, scattering-based framework for assembling, interpreting, and extrapolating all information about the electronic structure of a molecule. Its building blocks are channels, each comprised of an infinite number of electronic states, rather than Born-Oppenheimer potential energy curves. Although the quantum defect matrix elements provide a compact numerical description of structure and dynamics, the fundamental physical meanings encoded in these matrix elements remain obscure. The most ambitious objective of this project is to uncover the more compact physical representation that lies beyond the numerical MQDT matrix elements. Core-nonpenetrating Rydberg states are a neglected state of matter. Knowledge and exploitation of their unique properties will ignite research in areas ranging from fundamental science to practical applications. For example, MQDT can potentially provide a complete picture of the structure and dynamics of a molecule, which will be essential for the development of molecular electronic devices and quantum computing. Professor Field expects to continue providing assistance to spectroscopists, users of spectroscopic data, and creators of spectrum-based approaches in other areas of science. He has a passion for sharing his unique vision of how intramolecular dynamics is encoded in spectroscopic arcanae, and for devising elegantly simple experimental methods to interrogate and exploit molecules that are not amenable to simple, textbook conceptualization. Students and postdocs in the Field laboratory are challenged to design original experiments, build unconventional fit models for their unconventional spectra, and perform rigorous yet intuition-based quantum mechanical and quantum optics calculations. Members of Field's research group leave MIT with the confidence, instincts, and vision to formulate and solve both fundamental and applied problems.

麻省理工学院的罗伯特·菲尔德教授在化学结构、动力学和机制计划的支持下开发实验方法，利用啁啾脉冲毫米波 (CPmmW) 辐射与激发分子中的大里德堡-里德堡跃迁矩 (kilo-Debye) 的相互作用。 基于 CPmmW 的方法将有助于开发有效填充核心非穿透里德堡态的方案，这些方案因其巨大的转变时刻和相对较长的寿命（1 微秒）而受到特别关注。 CPmmW 光谱的关键特征是，里德堡-里德堡跃迁是通过自由感应衰减 (FID) 信号直接检测到的，该信号是当 CPmmW 脉冲极化落在大约范围内的所有两能级系统时产生的。 10 GHz 宽频谱区域的线性调频脉冲（单个 10 纳秒持续时间 CP 中的 10^5 分辨率元素）。 这种类似核磁共振的方案远远优于脉冲超音速分子束光谱中普遍使用的单分辨率单元素间接检测方案。 实验光谱的解释将在多通道量子缺陷理论（MQDT）的背景下完成，该理论是一种超越氢、基于散射的框架，用于组装、解释和外推有关分子电子结构的所有信息。 它的构建块是通道，每个通道都由无限数量的电子态组成，而不是玻恩-奥本海默势能曲线。 尽管量子缺陷矩阵元素提供了结构和动力学的紧凑数值描述，但这些矩阵元素中编码的基本物理意义仍然模糊。 该项目最雄心勃勃的目标是揭示数值 MQDT 矩阵元素之外的更紧凑的物理表示。 非核心里德堡态是一种被忽视的物质态。 对它们独特性质的了解和利用将激发从基础科学到实际应用等领域的研究。 例如，MQDT 可以提供分子结构和动力学的完整图像，这对于分子电子设备和量子计算的发展至关重要。 菲尔德教授希望继续为光谱学家、光谱数据的用户以及其他科学领域基于光谱的方法的创建者提供帮助。 他热衷于分享他对如何在光谱奥秘中编码分子内动力学的独特见解，并热衷于设计优雅简单的实验方法来询问和利用那些不适合简单的教科书概念化的分子。 现场实验室的学生和博士后面临的挑战是设计原创实验，为其非常规光谱建立非常规拟合模型，并执行严格但基于直觉的量子力学和量子光学计算。 菲尔德研究小组的成员带着制定和解决基本问题和应用问题的信心、本能和远见离开了麻省理工学院。