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arXiv 0810.3811cond-mat.mtrl-sci
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用电子衍射中的动力学散射求解晶体相问题

Solving the Crystallographic Phase Problem using Dynamical Scattering in Electron Diffraction

Christoph T. Koch

摘要:

从单晶的运动学X射线或电子衍射图案求解晶体结构需要记录比结构中的原子多得多的衍射光束,因为结构因子的相位只能从这样的数据中检索,如果原子可以被解析为尖锐的峰值对象。本文提出了一种方法,利用多重散射对衍射强度中的结构因子相进行编码的事实来解决晶体学相问题。检索的振幅和相位的电子结构因子从衍射图案记录与不同的入射角将被证明。没有对散射势本身做任何假设。特别是,衍射数据的分辨率不需要足以分辨原子,使得这种方法对于二维蛋白质晶体和其他光束敏感复杂结构的电子晶体学具有潜在的意义。

英文摘要:

Solving crystal structures from kinematical X-ray or electron diffraction patterns of single crystals requires many more diffracted beams to be recorded than there are atoms in the structure, since the phases of the structure factors can only be retrieved from such data if the atoms can be resolved as sharply peaked objects. Here a method is presented by which the fact that multiple scattering encodes structure factor phases in the diffracted intensities is being used for solving the crystallographic phase problem. The retrieval of both amplitudes and phases of electron structure factors from diffraction patterns recorded with varying angle of incidence will be demonstrated. No assumption about the scattering potential itself is being made. In particular, the resolution in the diffraction data does not need to be sufficient to resolve atoms, making this method potentially interesting for electron crystallography of 2-dimensional protein crystals and other beam-sensitive complex structures.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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