State-Resolved Spectroscopy and Dynamics of Chemical Transients

通过该奖项，由化学结构，动力学和机制-化学系的一个项目资助，来自科罗拉多大学的大卫·J·内斯多夫教授正在使用最先进的基于激光和分子束的方法来表征在化学反应过程中反应物转化为产物时发生的短暂分子结构（“化学瞬变”）。这个实验计划的总体目标是开发工具来探测化学瞬变的分子结构和反应性。 该项目结合了荧光显微镜和激光加热方法，用于研究生物重要物种（例如，核酸、蛋白质等）。 荧光是一种过程，通过该过程，分子暴露于给定波长的光，然后分子发出不同波长的光（其“颜色”是该分子的特征）。 这项研究预计将对广泛的科学产生影响，研究活生物细胞和恒星的化学反应。参与该项目的研究生正在获得广泛的工具（激光和光学，电子和显微镜）的经验，这些工具在工业和先进制造业中具有很高的价值。这些研究的结果也为研究生参与国家专业会议、通过科学开放日进行外展、在当地高中进行指导以及为中小学生实施“CU Wizards”科学外展计划提供了宝贵的机会。该实验计划的总体目标有三个方面：i）利用量子态分辨共振增强多光子电离（REMPI）和3D速度图成像来研究化学可调气体-自组装单层界面处的非弹性和氢/氘（H/D）反应动力学，ii）开发和实现用于探测高蒸气压液体表面处的量子态分辨的蒸发/碰撞动力学的新颖光谱工具（例如，水）“微射流”和iii）利用时间分辨荧光显微镜和激光纳米浴缸加热方法的强大组合，用于在单分子水平上RNA的温度/粘度依赖性折叠/解折叠的基础化学物理研究。这项工作的智力优势来自各种基本问题的解决，涉及高活性的分子瞬变，从气溶胶化学在海洋边界层和新的质子耦合电子转移（PCET）促进H/D交换在气液界面，单生物分子的构象动力学。这项工作的更广泛的影响涉及培养研究生和本科生在化学物理的最先进的领域（例如，量子光学、脉冲和连续波激光器、等离子体、电子学、低噪声光子检测等），同时促进基础新研究知识的发现。

Through this award, funded by the Chemical Structure, Dynamics, and Mechanisms - A Program of the Division of Chemistry, Prof. David J. Nesbitt from the University of Colorado is using state-of-the-art laser- and molecular beam-based methods to characterize the short-lived molecular structures ("chemical transients") that occur as reactants are transformed into products during chemical reactions. The overall goals of this experimental program are to develop tools to probe the molecular structure and reactivity of chemical transients. This project combines fluorescence microscopy and laser heating methods for studying both the kinetics and energetics of folding/unfolding of biologically-important species (e.g., nucleic acids, proteins, etc). Fluorescence is a process by which a molecule is exposed to light of a given wavelength, the molecule then gives off light of a different wavelength (the "color" of which is characteristic of that molecule). This research is expected to have impacts on a wide range of science, examining the chemical reactions of both living biological cells and the stars. The graduate students involved in this project are gaining experience in a wide range of tools (lasers and optics, electronics, and microscopy) that are highly valued in industry and advanced manufacturing. The results of these studies are also providing invaluable opportunities for graduate student participation in national professional meetings, outreach through scientific open houses, mentoring at the local high schools, as well as operation of the "CU Wizards" Science Outreach Program for elementary and middle school students.The overall goals of this experimental program are threefold: i) exploit quantum state resolved resonance enhanced multiphoton ionization (REMPI) and 3D velocity map imaging for the study of inelastic and hydrogen/deuterium (H/D) reaction dynamics at chemically tunable gas-self assembled monolayer interfaces, ii) develop and implement novel spectroscopic tools for probing quantum state-resolved evaporation/collision dynamics at the surface of high vapor pressure liquid (e.g., water) "microjets" and iii) utilize the powerful combination of time-resolved fluorescence microscopy and laser nano bathtub heating methods for fundamental chemical physics studies of temperature/viscosity dependent folding/unfolding of RNA at the single molecule level. Intellectual merits of this work derive from the variety of fundamental problems addressed involving highly reactive molecular transients, ranging from aerosol chemistry at the marine boundary layer and to novel proton coupled electron transfer (PCET) promoted H/D exchange at gas-liquid interfaces, to the conformational dynamics of single biomolecules. The broader impacts of this work involve training graduate and undergraduate students in state-of-the-art areas of chemical physics (e.g., quantum optics, pulsed and continuous wave lasers, plasmas, electronics, low noise photon detection, etc.), while furthering the discovery of fundamental new research knowledge.