物理化学学报 >> 1991, Vol. 7 >> Issue (04): 449-455.doi: 10.3866/PKU.WHXB19910414

研究论文 上一篇    下一篇

测定晶体结构的系统试差法的研究(II)系统位相超解方程得改进

侯永庚; 马志梅; 傅亨   

  1. 中国科学院化学研究所,北京 100080
  • 收稿日期:1990-01-18 修回日期:1990-12-10 发布日期:1991-08-15
  • 通讯作者: 侯永庚

Studies of Trial and Error Methof for Crystal Structural Determinations(II)——Modifications of the Super-Solution Phase Eqation

Hou Yong-Geng; Ma Zhi-Mei; Fu Heng   

  1. Institute of Chemistry, Academia Sinica, Beijing 100080
  • Received:1990-01-18 Revised:1990-12-10 Published:1991-08-15
  • Contact: Hou Yong-Geng

摘要: 本文证明了|E(k)E(h-k)|的大小是由结构决定的。与原点无关, 在这种认识的基础上, 提出了用归一化结构振幅|E|估量它的三种模式。特别是通过四位相结构不变量的二级Noighborhood~[1,2]原理解决三位相不变量间的匹配问题而算出的|E(k)E(h-k)|_(QE), 这是在没有位相数据的情况下对它的理想的估量。予期它能改进系统试差法中位相超解方程的功能, 提高测得位相的准确性。

关键词: 位相方程, 结构不变量, 直接法

Abstract: In this paper, it is demonstrated that |E(k)E(h-k)| is a structure invari ant. On the basis of this knowledge, three models, which can be used to estimate the value of |E(k)E(h-k)| from normalized structure amplitudes |E|, are proposed. In particular, |E(k)E(h-k)|_(QE), which is deduced from the second neighborhood principle of quartet structure invariants, is an ideal estimation of |E(k)E(h-k)| with known phase lacks. It is expected that |E(k)E(h-k)|_(QE) will improve the function of super-solution phase equation in systematical trial and error method and increase the accuracy of the phase values to be determined.

Key words: Phase equation, Structure invariant, Direct method