%0 Journal Article
%T PROCEDURE FOR SOLVING THE PROBLEM OF PHASE DEGENERATION RESULTING FROM DIRECT METHODS<br>直接法中相位退化问题的处理
%A FAN HAI-FU
%A QIAN JIN-ZI
%A <br>范海福
%A 千金子
%J 物理学报
%D 1981
%I 
%X 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.
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=47EA7CFDDEBB28E0&jid=29DF2CB55EF687E7EFA80DFD4B978260&aid=042BF54C0FCB74675A9E4BDA518A9B7D&yid=AA64127AB7DEB65D&vid=340AC2BF8E7AB4FD&iid=94C357A881DFC066&sid=65FC738C50B41E43&eid=ED9DF3402785F68D&journal_id=1000-3290&journal_name=物理学报&referenced_num=0&reference_num=0