Compared with X-rays, electron diffraction faces a crucial challenge: dynamical electron scattering compromises structure solution and its effects can only be modelled in specific cases. Dynamical scattering can be reduced experimentally by decreasing crystal size but not without a penalty, as it also reduces the overall diffracted intensity. In this article it is shown that nanometre-sized crystals from organic pharmaceuticals allow positional refinement of the hydrogen atoms, even whilst ignoring the effects of dynamical scattering during refinement. To boost the very weak diffraction data, a highly sensitive hybrid pixel detector was employed. A general likelihood-based computational approach was also introduced for further reducing the adverse effects of dynamic scattering, which significantly improved model accuracy, even for protein crystal data at substantially lower resolution.

中文翻译：

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减少动态电子散射揭示氢原子


与 X 射线相比，电子衍射面临着一个严峻的挑战：动态电子散射会损害结构解决方案，并且其效应只能在特定情况下进行建模。可以通过减小晶体尺寸来通过实验减少动态散射，但并非没有代价，因为它也会降低整体衍射强度。本文表明，来自有机药物的纳米尺寸晶体可以对氢原子进行位置细化，甚至在忽略细化过程中动态散射的影响的情况下也是如此。为了增强非常弱的​​衍射数据，采用了高灵敏度混合像素检测器。还引入了基于通用可能性的计算方法，以进一步减少动态散射的不利影响，这显着提高了模型精度，即使对于分辨率低得多的蛋白质晶体数据也是如此。