论文标题
单晶X射线衍射可以独特地确定结构吗？
Can single crystal X-ray diffraction determine a structure uniquely?
论文作者
论文摘要
衍射技术广泛用于确定晶体结构，是现代科学和技术的基础之一。所有相关的结构确定方法均基于以下假设：完美的单晶X射线衍射（SXRD）都可以独特地确定结构。但是，由于SXRD中的结构因子阶段丢失，并且在粉末X射线衍射（PXRD）中丢失了更多信息，因此该假设仍然值得怀疑。在这项工作中，我们发现具有某些特征的结构可以具有其姐妹结构，其pxrd甚至SXRD模式完全相同。开发了一个计算机程序来搜索ICSD数据库，并确定了约1000个结构具有此特征。原始结构及其姐妹结构可以具有不同的空间组，拓扑，晶体系统等，有些甚至可能有多个姐妹。我们的研究表明，需要特殊谨慎，因为具有合理的原子位置和实验衍射强度的完美匹配的结构仍然是错误的。
The diffraction technique is widely used in the determination of crystal structures and is one of the bases for the modern science and technology. All related structure determination methods are based on the assumption that perfect single crystal X-ray diffraction (SXRD) can determine a structure uniquely. But as the structure factor phases are lost in SXRD and even more information is lost in powder X-ray diffraction (PXRD), this assumption is still questionable. In this work, we found that structures with certain characteristic can have its sister structure with exactly the same PXRD or even SXRD pattern. A computer program is developed to search the ICSD database, and about 1000 structures were identified to have this characteristic. The original structure and its sister structures can have different space groups, topologies, crystal systems etc. and some may even have multiple sisters. Our studies indicate that special caution is needed since a structure with reasonable atomic positions and perfect match of experimental diffraction intensities could still be wrong.
