Femtosecond Laser for Mapping Atomic Motions with Ultrabright Electrons

Pi的小组已经达到了成像化学的基本时空限制，并发现了导致过渡态区域降维的基本物理学，使化学成为一个可转移的概念。通过开发能够实时照亮原子运动的超亮电子源，这个长期存在的化学梦想实验得以实现。这种超亮电子源依赖于使用飞秒激光的光注入来触发感兴趣的化学物质，并产生具有足够电子的完全定时的飞秒电子探针脉冲，以实现单发结构确定。在这方面，所要求的飞秒激光系统对于国际和平研究所的研究计划的继续至关重要。它是仪器的核心，构成了一个名副其实的分子电影摄像机，用于在原子细节水平上捕捉行动中的化学。 在这方面，拟议研究的主要重点将是发展反应模式基础，作为理解化学的新概念框架。我们控制想要的化学过程障碍的能力在很大程度上仍然是经验的。化学是动态的。我们需要一个动态的基础来对化学进行分类并寻找趋势。随着Pi小组的分子电影相机的发展，我们现在可以直接观察到化学中涉及的远离平衡的原子运动，在100fs的时间尺度上，即在成像化学的基本时空极限上，其运动优于0.01。到目前为止，我们已经观察到从经典的3原子系统到越来越大的系统的过程，一直到像蛋白质这样复杂的系统，所涉及的化学在很大程度上是通过几个关键模式的位移沿着反应坐标传播的。这种实验推导出的反应模式基础将在化学概念化中将结构和动力学统一起来，以指导理论。下一阶段的研究将专注于开发专门为探索不同化学反应而设计的样品，从电子转移、质子互易化、电环化反应到双分子过程来回答这个问题。这些研究，从小分子系统到生物系统，将有助于理解化学到更高水平的复杂性，最终导致生命物质的产生。 应该指出的是，在成功地在德国汉堡建立了一个新的马克斯·普朗克研究所作为基于这一研究计划的研究伙伴关系的一部分之后，国际和平研究所已经过渡回多伦多大学。由于马克斯·普朗克关于保留设备供内部使用的政策，不可能移动国际在汉堡开发的实验室中的激光设备。如果没有所要求的飞秒激光，这项计划就不可能在目前的水平上继续下去。

The PI's group has achieved the fundamental space-time limit to imaging chemistry and has unearthed the basic physics that leads to the reduction in dimensionality in the transition state region that makes chemistry a transferable concept. This long held dream experiment in chemistry was achieved through the development of ultrabright electron sources capable of literally lighting up atomic motions in real time. This ultrabright electron source depends on the use of photoinjection using femtosecond lasers for both triggering the chemistry of interest and in generating perfectly timed femtosecond electron probe pulses with sufficient electrons to enable single shot structure determination. In this respect, the requested femtosecond laser system is essential for continuation of the PI's research program. It is the heart of the instrumentation that constitutes a veritable molecular movie camera for capturing chemistry in action at the atomic level of detail. In this regard, the primary focus of the proposed research will be on the development of a reaction mode basis as a new conceptual framework for understanding chemistry. Our ability to control barriers to desired chemical processes is still largely empirical. Chemistry is dynamic. We need a dynamic basis for categorizing chemistry and looking for trends. With the development of the “Molecular Movie Camera” by the PI's group, we can now directly observe the far-from-equilibrium atomic motions involved in chemistry with better than 0.01 on 100 fs timescales, i.e. at the fundamental space-time limit to imaging chemistry. To date, we have observed for all systems from classic 3 atom systems to processes of larger and larger systems, all the way to systems as complex as proteins that the chemistry involved is largely propagated along the reaction coordinate by the displacement of a few key modes. This experimentally derived reaction mode basis, to guide theory, will unify structure and dynamics in conceptualizing chemistry. The next phase of the research will focus on developing samples specifically designed to probe different chemical reactions, from electron transfer, proton tautomeization, electrocyclization reactions, to bimolecular processes to answer this question. These studies, from small molecular systems to biological systems, will help understand the scaling of chemistry to higher levels of complexity that ultimately led to living matter. It should be noted that the PI has transitioned back to the University of Toronto after successfully co-founding a new Max Planck Institute in Hamburg Germany as part of a research partnership based on this research program. It was not possible to move the laser equipment in the labs the PI developed in Hamburg due to Max Planck policies on retaining equipment for internal use. Without the requested femtosecond laser, there is no prospect for continuation of this program at the current level.