Ultrafast streak camera system for mapping atomic motions with ultrabright electrons

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，用于触发感兴趣的化学反应和产生完美定时的飞秒电子探测脉冲。所要求的用于超快条纹照相机的rf部件和激光系统将使得可以采用单个长电子脉冲（几皮秒）来在单次激发中的光激发之后对整个时变结构信息进行编码，即，单镜头全分子电影。时间分辨率将在10 fs域中，这是足够的，并且沿着信噪比的显著增加将使得可以直接观察电子分布变化的效果，其中激发比核运动更快。这一观测提供了电子密度梯度或力，这些力负责将大量可能的核排列和波动坍缩为几个关键的反应模式。我们有机会将电子和核的自由度分开，以充分理解导致不同类别反应机制的广义性质的维度的巨大减少的机制。所要求的仪器有望揭示物理学，使化学能够在复杂性方面一直扩展到生物系统，并使化学成为一个可转移的概念。所要求的仪器是必不可少的，以进入这个新的领域的时空分辨率，同样重要的是实现灵敏度，观察化学的本质。值得注意的是，PI在成功共同创立了德国汉堡的新马克斯普朗克研究所和汉堡大学的超快成像中心后，于2020年过渡回多伦多大学。他从2010年到2020年借调到马克斯普朗克是基于上述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所需的激光设备。如果没有所要求的设备，就没有推进PI计划以实现直接成像化学基本驱动力的宏伟目标的前景。

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 photo injection using femtosecond lasers for both triggering the chemistry of interest and in generating perfectly timed femtosecond electron probe pulses. The requested rf components and laser system for the ultrafast streak camera will make it possible to employ a single long electron pulse (a few picoseconds) to encode the entire time-varying structural information after photoexcitation in a single shot, i.e., single shot full molecular movies. The time resolution will be in the 10 fs domain, which is sufficient and along with the dramatic increase in signal to noise ratio will make it possible to directly observe the effect of changes in electron distribution with excitation faster than nuclear motions. This observation provides the electron density gradients or forces responsible for collapsing the enormous number of possible nuclear permutations and fluctuations to just a few key reaction modes. We have the opportunity to separate the electronic and nuclear degrees of freedom to come to a full understanding of the mechanism leading to the enormous reduction in dimensionality responsible for the generalized properties for the different classes of reaction mechanisms. The requested instrumentation holds the promise to reveal the physics that has enabled chemistry to scale in complexity all the way to biological systems and makes chemistry a transferrable concept. The requested instrumentation is essential to enter this new domain in space-time resolution, and equally important to achieve sensitivity, for observing the very essence of chemistry. It should be noted that the PI has transitioned back to the University of Toronto in 2020 after successfully co-founding a new Max Planck Institute in Hamburg Germany and the Centre for Ultrafast Imaging for the University of Hamburg. His secondment to the Max Planck from 2010 to 2020 was part of a research partnership based on the above research program. It was not possible to move the needed laser equipment in the labs the PI developed in Hamburg due to Max Planck policies on retaining equipment for internal use. Without the requested equipment, there is no prospect for advancing the PI's program to realize this grand objective to directly imaging the fundamental driving forces for chemistry.