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（他共同创立）过渡到多伦多大学。申请的资金将使这一研究计划得以继续，重点是原子解析动力学。这项研究计划是一项为期10年的努力的一部分，旨在应对科学领域的一些重大挑战，特别是在基本时空限制下直接成像化学和生物学。这个程序利用PI小组开发的超亮电子源技术，在真实的时间里照亮原子的运动。主要的挑战是将这种成像技术推向单分子极限，以观察原子水平上的单分子轨迹。这一目标现已实现。这个研究项目已经实现了化学中的一些梦想实验：1）获得结构转变的第一分子电影，2）具有保守立体化学的电环化的第一全原子分辨电影（键形成），3）有机和有机金属体系中的电子转移，4）经典的I3问题和晶格在定向化学中的作用，5）和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），实现了时空成像化学的基本限制。在对化学领域的影响方面，第一部原子电影说明了导致分子结构变化的许多可能的核运动，也称为化学，崩溃为几个关键的反应模式。正是这种发生在势垒交叉区域的维度的巨大减少使得化学可转移（关于：命名反应的经验发现）。这项工作为基于反应模式的化学提供了一个新的概念基础，该反应模式统一了结构和动力学，有助于更好地预测势垒交叉区域的核构型，从而更好地控制化学。发现反应模式的概念（降低的维度）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的空间成像。该计划的最终目标是将这些研究中揭示的分子结构-功能关系联系起来，以关闭化学和生物学之间的循环。

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.