Solving the Sayre equations for centrosymmetric structures with a genetic algorithm

Authors: Zhou, Yi; Su, Wu-Pei

Source: Acta Crystallographica Section A, Volume 60, Number 4, July 2004 , pp. 306-310(5)

Publisher: Wiley-Blackwell

Buy & download fulltext article:

OR

Price: $48.00 plus tax (Refund Policy)

Abstract:

Sayre's equations give a set of relationships that exist among the structure factors of an equal-atom structure. In order to obtain the correct phases of the structure factors, a genetic algorithm is used to minimize a least-squares residual of Sayre's equations. In the genetic algorithm, a phase is treated as a gene and the whole set of phases is considered as a chromosome. Every chromosome is relaxed to a nearby local minimum by quenching after being produced from a previous generation. Trial calculations for a structure containing 92 non-H equal atoms with synthetic data and another structure containing 62 non-H equal atoms with real data are presented. Compared to simulated annealing, a genetic algorithm is a more efficient means of global optimization.

Keywords: Sayre equations; genetic algorithm

Document Type: Research Article

DOI: http://dx.doi.org/10.1107/S0108767304010001

Publication date: July 1, 2004

Related content

Tools

Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content

Text size:

A | A | A | A
Share this item with others: These icons link to social bookmarking sites where readers can share and discover new web pages. print icon Print this page