Femtosecond Laser for Mapping Atomic Motions with Ultrabright Electrons

用超亮电子绘制原子运动的飞秒激光器

• 批准号: RTI-2021-00188
• 负责人: Miller, RJDwayne
• 金额: $ 10.93万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=718814
• 关键词: Femtosecond; Laser; Mapping; Atomic; Motions

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.

PI的团队已经实现了成像化学的基本时空限制，并发现了导致过渡态区域维数降低的基本物理学，使化学成为一个可转移的概念。 这个长期以来的化学梦想实验是通过超亮电子源的发展实现的，它能够在真实的时间内照亮原子的运动。 这种超亮电子源依赖于使用飞秒激光器的光注入的使用，用于触发感兴趣的化学反应和产生具有足够电子的完美定时的飞秒电子探测脉冲，以实现单次发射结构确定。 在这方面，所要求的飞秒激光系统是必不可少的继续PI的研究计划。 它是仪器的核心，构成了一个名副其实的分子电影摄像机，用于在原子水平上捕捉化学反应的细节。 在这方面，拟议研究的主要重点将是发展一种反应模式基础，作为理解化学的新概念框架。我们控制所需化学过程障碍的能力在很大程度上仍然是经验性的。化学是动态的。我们需要一个动态的基础来分类化学和寻找趋势。随着PI小组开发的“分子电影相机”，我们现在可以直接观察化学中涉及的远离平衡的原子运动，其时间尺度优于100 fs的0.01，即在成像化学的基本时空限制。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，所涉及的化学反应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。这个实验得出的反应模式的基础上，指导理论，将统一结构和动力学概念化化学。研究的下一阶段将专注于开发专门设计用于探测不同化学反应的样品，从电子转移，质子互变异构，电环化反应到双分子过程，以回答这个问题。这些研究，从小分子系统到生物系统，将有助于理解化学向更高层次复杂性的扩展，最终导致生命物质。 应该注意的是，PI在成功地共同创立了德国汉堡的新马克斯普朗克研究所后，已经过渡回多伦多大学，作为基于该研究计划的研究伙伴关系的一部分。由于马克斯·普朗克关于保留设备供内部使用的政策，PI在汉堡开发的实验室中无法移动激光设备。 如果没有所要求的飞秒激光，则在当前水平上不存在继续该项目的前景。