Mapping Atomic Motions with Ultrabright Electrons: Fundamental Space-Time Limits to Imaging Chemistry

PI正在从德国的马克斯·普朗克研究所(他与人共同创立)过渡回多伦多大学。所要求的资金将使这项研究计划得以继续，重点放在原子解析的动力学上。这项研究计划是一项为期10年的努力的一部分，目的是应对科学中的一些重大挑战，特别是直接将化学和生物学想象在基本的时空限制上。这个程序利用圆周率小组开发的超亮电子源技术，实时照亮原子运动。主要的挑战是将这种成像技术推向单分子的极限，以便在原子水平上观察单分子的轨迹。这一目标现在已经达到。*这个研究计划已经实现了化学中的一些梦寐以求的实验：1)获得了第一个结构转变的分子电影，2)第一个完全原子分辨的具有保守立体化学(键形成)的电环化电影，3)有机和有机金属系统中的电子转移，4)经典的I3问题和晶格在指导化学中的作用，5)第一个全原子分辨的化学反应(通过解决图像重建中的相位问题)，这达到了时空成像化学的基本极限。就对化学领域的影响而言，最早的原子电影表明，导致分子结构变化的无数可能的核运动，也被称为化学，崩溃到只有几个关键的反应模式。正是这种在跨越障碍区域发生的巨大降维使化学可转移(Re：命名反应的经验发现)。这项工作为化学产生了一个新的概念基础，它基于统一的结构和动力学的反应模式，以帮助更好地预测跨越势垒区域的核配置，从而更好地控制化学。反应模式的概念(降维)被发现在复杂性上扩展到生物分子的水平。随着电子源、探测器和纳米流体设备的最新进展，PI的团队正在接近获得单分子轨迹的原子分辨率生物分子的原子真实空间成像。该计划的最终目标是连接这些研究中揭示的分子结构-功能关系，以关闭化学和生物学之间的环路。**

The PI is transitioning back from the Max Planck Institute in Germany (he co-founded) to the University of Toronto. The requested funds will enable continuation of this research program with a focus on atomically resolved dynamics. This research program is part of a 10-year effort to meet some of the grand challenges in science, notably to directly image chemistry and biology at fundamental space-time limits. This program exploits the ultrabright electron source technology developed by the PI's group to literally light up atomic motions in real time. The major challenge is to push this imaging technology to the single molecule limit to observe single molecule trajectories at the atomic level. This objective is now in reach.******This research program has achieved some of the dream experiments in chemistry: 1) obtaining the first molecular movies of structural transitions, 2) first full atomically resolved movie of electrocyclization with conserved stereochemistry (bond formation), 3) electron transfer in organic and organometallic systems, 4) the classic I3 problem and effect of the lattice in directing chemistry, 5) and the first full atomic resolved chemical reaction (via solving the phase problem in image reconstruction), which achieved the fundamental limits in space-time imaging chemistry. In terms of impact on the field of chemistry, the very first atomic movies illustrated that the numerous number of possible nuclear motions leading to changes in molecular structure, also known as chemistry, collapse to just a few key reaction modes. It is this enormous reduction in dimensionality that occurs in the barrier crossing region that makes chemistry transferable (re: the empirical discovery of named reactions). This work has led to a new conceptual basis for chemistry based on reaction modes that unifies structure and dynamics to help better predict the nuclear configurations of the barrier crossing region and thereby better control chemistry. The concept of reaction modes (reduced dimensionality) is found to scale in complexity to the level of biological molecules. With recent advances in electron sources, detectors, and nanofluidic devices, the PI's group is closing in on obtaining atomic resolution to single molecular trajectories atomic real space imaging of bio-molecules in action. The ultimate objective of this program is to connect molecular structure-function relationships revealed in these studies to close the loop between chemistry and biology. **