The conversion of light into usable chemical and mechanical energy is pivotal to several biological and chemical processes, many of which occur in solution. To understand the structure–function relationships mediating these processes, a technique with high spatial and temporal resolutions is required. Here, we report on the design and commissioning of a liquid-phase mega-electron-volt (MeV) ultrafast electron diffraction instrument for the study of structural dynamics in solution. Limitations posed by the shallow penetration depth of electrons and the resulting information loss due to multiple scattering and the technical challenge of delivering liquids to vacuum were overcome through the use of MeV electrons and a gas-accelerated thin liquid sheet jet. To demonstrate the capabilities of this instrument, the structure of water and its network were resolved up to the $3\text{rd}$ hydration shell with a spatial resolution of 0.6 Å; preliminary time-resolved experiments demonstrated a temporal resolution of 200 fs.

中文翻译：

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液相兆电子伏特超快电子衍射

将光转换为可用的化学能和机械能对于几种生物和化学过程至关重要，其中许多过程发生在溶液中。为了理解介导这些过程的结构-功能关系，需要一种具有高时空分辨率的技术。在这里，我们报告用于研究溶液中结构动力学的液相超大型电子伏特（MeV）超快电子衍射仪的设计和调试。通过使用MeV电子和气体加速的薄液体射流，可以克服由于电子的浅穿透深度和多重散射导致的信息丢失以及将液体输送至真空的技术挑战所带来的限制。为了演示该仪器的功能，$3\text{rd}$水化壳，空间分辨率为0.6Å；初步的时间分辨实验表明时间分辨率为200 fs。