搜索

x

留言板

尊敬的读者、作者、审稿人, 关于本刊的投稿、审稿、编辑和出版的任何问题, 您可以本页添加留言。我们将尽快给您答复。谢谢您的支持!

姓名
邮箱
手机号码
标题
留言内容
验证码

直接法中相位退化问题的处理

范海福 千金子

引用本文:
Citation:

直接法中相位退化问题的处理

范海福, 千金子

PROCEDURE FOR SOLVING THE PROBLEM OF PHASE DEGENERATION RESULTING FROM DIRECT METHODS

FAN HAI-FU, QIAN JIN-ZI
PDF
导出引用
  • 相位退化是直接法应用中的一大问题。所谓相位退化,系指非中心对称晶体结构因子的相位在推引或修正过程中收敛为中心对称类型的相位,属于P21、P41等空间群的晶体,常会出现这一情况。相位退化使相应的E图添加了一个对称中心,这使E图中“鬼峰”的数目大增,因而往往导致直接法的失败。本文提出一种两步处理方法:先将晶体当作中心对称求解以获得一个同时包含真正结构及其对映体的、中心对称的赝结构;然后在此基础上利用所谓分量关系式从赝结构解出真正的结构。此法经用已知结构的晶体检验,证明效果良好。
    A serious problem in the application of direct methods is the problem of phase degeneration. That is the phases of structure factors of a non-centrosymmetric crystal converge to a set of centrosymmetric phases. This would occur frequently in case of space groups P21, P41 etc. Phase degeneration gives rise to an additional centre of symmetry and hence a considerable number of spurious peaks in the resulting E-map leading often to the failure of direct methods. In this paper, a two step procedure of solving this ambiguity is proposed. In the first step, the crystal is treated as a centrosymmetric one and a mised image including both enantiomorphs is obtained, while in the second step, the actual structure is then derived from the mixed image by making use of the so-called "component relations". This method has been verified with a known structure and proved to be effective.
计量
  • 文章访问数:  6042
  • PDF下载量:  401
  • 被引次数: 0
出版历程
  • 收稿日期:  1980-06-10
  • 刊出日期:  2005-07-27

/

返回文章
返回