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

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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.