3D structure determination from electron-microscope images: electron crystallography of staurolite.
3D structure determination from electron-microscope images: electron crystallography of staurolite.
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从电子显微镜图像确定 3D 结构：十字石的电子晶体学。
DOI：
10.1107/s0108767392000850
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
O'Keefe,MA
中科院分区：
文献类型：
--
作者：
Wenk,HR;Downing,KH;Hu,M;O'Keefe,MA
通过高分辨率电子显微镜在许多晶体中获得了优于2 Å的分辨率。虽然这个分辨率足以解决原子间的间距，但传统上通过对比实验图像和对比计算来解释结构。这种方法的一个缺点是，图像是二维投影，其中的信息总是被原子的重叠所掩盖。由生物物理学家开发的用于研究蛋白质的三维电子晶体学已被用于研究橄榄石的晶体结构。结构因子的振幅和相位是通过高分辨率图像（LBL国家电子显微镜中心的Jeol ARM 1000）在不同方向从动态散射最小的薄区域实验获得的。从五个方向（包含59个独立反射，分辨率为1.38 Å）的图像中，构建了一个三维电子势图，可以清楚地分辨所有阳离子（Al, Si, Fe，包括部分占据的）和所有O原子。该方法在非均相晶体中x射线分析无法达到的小区域的晶体结构测定中具有很大的潜力。据估计，三维结构的确定应该是可能的区域只有大约10个单位胞宽，应该解决不仅原子位置，而且位置占用。该方法同样适用于空间群的确定。
Resolution of better than 2 Å has been obtained in many crystals by high-resolution electron microscopy. Although this resolution is sufficient to resolve interatomic spacings, structures are traditionally interpreted by comparing experimental images with contrast calculations. A drawback of this method is that images are 2D projections in which information is invariably obscured by overlap of atoms. 3D electron crystallography, developed by biophysicists to study proteins, has been used to investigate the crystal structure of staurolite. Amplitudes and phases of structure factors are obtained experimentally from high-resolution images (Jeol ARM 1000 at the National Center for Electron Microscopy at LBL), taken in different directions from thin regions where dynamic scattering is minimal. From images in five orientations (containing 59 independent reflections to a resolution of 1.38 Å), a 3D electron potential map is constructed which resolves clearly all cations (Al, Si, Fe, including those with partial occupancy) and all O atoms. This method has great potential in crystal structure determinations of small domains in heterogeneous crystals which are inaccessible to X-ray analysis. It is estimated that 3D structure determinations should be possible on regions only about ten unit cells wide and should resolve not only atom positions but also site occupancies. The method is also applicable to space-group determination.
晶体学中的傅里叶方法
影响因子：
7.3
作者：
G. N. Ramachandran;R. Srinivasan;R. Stewart
通讯作者：
R. Stewart