大学化学 >> 2024, Vol. 39 >> Issue (3): 94-102.doi: 10.3866/PKU.DXHX202310035

所属专题： 晶体化学教学

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粉末X射线衍射法解析晶体结构的三种常用方法简介

马宏伟1, 李晖2,*()   

  1. 1 北京理工大学分析测试中心, 北京 122488
    2 北京理工大学化学化工学院, 北京 122488
  • 收稿日期:2023-10-10 录用日期:2023-12-25 发布日期:2024-01-12
  • 通讯作者: 李晖 E-mail:lihui@bit.edu.cn
  • 基金资助:
    国家自然科学基金项目(21471017)

Three Methods for Structure Determination from Powder Diffraction Data

Hongwei Ma1, Hui Li2,*()   

  1. 1 Analysis and Testing Center, Beijing Institute of Technology, Beijing 122488, China
    2 School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 122488, China
  • Received:2023-10-10 Accepted:2023-12-25 Published:2024-01-12
  • Contact: Hui Li E-mail:lihui@bit.edu.cn

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摘要：

介绍了X射线粉末衍射法解析晶体结构的三种常用方法：直接法、模拟退火法和电荷翻转法的基本原理和处理方法。直接法是典型的倒易空间法，利用倒易空间的衍射强度建立初始结构；模拟退火法则在实空间产生随机模型并进行全局优化获得初始模型；电荷翻转法为双空间迭代法，分别在倒空间和实空间进行微扰并在二者间进行傅里叶循环得到结构模型。文中以三个实例Ba3BPO7，MgSO4·2.5H2O以及MgSO4∙2H2O的结构解析分别进行简要说明。

关键词: 晶体结构分析, X-射线粉末衍射, 直接法, 模拟退火, 电荷翻转

Abstract:

This paper provides a concise overview of three commonly employed methods for the determination of crystal structures from powder diffraction data, each exemplified with a specific case study. The first method is the single-crystal-like direct methods, leveraging reciprocal space information to construct the structure model. The second approach involves simulated annealing, which performs a global optimization of randomly generated models in real space to identify the structure. The third is the charge flipping method in which modifications to structure factors in reciprocal space and charge densities in real space are made, leading to the determination of the structure model through Fourier cycling switching back and forth between the two spaces. The presented examples are Ba3BPO7, MgSO4·2H2O and MgSO4·2.5H2O, respectively.

Key words: Crystal structure analysis, X-ray powder diffraction, Direct methods, Simulated annealing, Charge flipping