THE JOINT PROBABILITY-DISTRIBUTION OF ANY SET OF PHASES GIVEN ANY SET OF DIFFRACTION MAGNITUDES .2. PRACTICAL APPLICATIONS

被引:11
作者
BURLA, MC [1 ]
CASCARANO, G [1 ]
GIACOVAZZO, C [1 ]
机构
[1] DIPARTIMENTO GEOMINERAL, CNR, IST RICERCA SVILUPPO METODOL CRISTALLOG, I-70124 BARI, ITALY
来源
ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES | 1992年 / 48卷
关键词
D O I
10.1107/S010876739200518X
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
In the first paper in this series [Giacovazzo, Burla & Cascarano (1992). Acta Cryst. A48, 901-906], the conditional joint probability distribution function of n phases given p greater-than-or-equal-to n moduli was derived. The properties of the concluding formulae are checked here. It is found that the distribution is not maximized by the correct phases, mostly because of bias in the formulae. If the triplets are estimated via the P10 formula [Cascarano, Giacovazzo, Camalli, Spagna, Burla, Nunzi & Polidori (1984). Acta Cryst. A40, 278-283] instead of being estimated by the Cochran relationship [Cochran (1952). Acta Cryst. 5, 65-67], the situation is remarkably improved but further improvements are needed. A practical procedure is also described that successfully uses phase relationships to solve difficult structures.
引用
收藏
页码:906 / 912
页数:7
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