A charge-flipping algorithm to handle incomplete data

G. Oszlányi, András Süto

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Missing data are a general hindrance for all iterative, dual-space methods of structure determination. Charge flipping is no exception; its real-space perturbation may turn out to be too strong if the amount of diffraction data is not sufficient. To handle this situation, we introduce a variant of the basic algorithm which combines the original charge-flipping density modification in real space, the reflector of the Fourier-modulus projection in reciprocal space and the parameterless iteration scheme of averaged alternating reflections (AAR). This simple algorithm is a balance of increased perturbations and full negative feedback, with the extra freedom that it can be fine-tuned by a different treatment of different unobserved reflections. The efficiency of the method was tested using several single-crystal data sets and varying the amount of missing data at both high and low resolution. The results prove that many small-molecule structures can be solved by utilizing significantly less data than is standard in current crystallographic practice.

Original languageEnglish
Pages (from-to)284-291
Number of pages8
JournalActa Crystallographica Section A: Foundations of Crystallography
Volume67
Issue number3
DOIs
Publication statusPublished - May 2011

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Charge density
Diffraction
Single crystals
Feedback
perturbation
negative feedback
Molecules
reflectors
iteration
projection
high resolution
single crystals
diffraction
molecules
Datasets

Keywords

  • ab initio structure determination
  • charge-flipping algorithm

ASJC Scopus subject areas

  • Structural Biology

Cite this

A charge-flipping algorithm to handle incomplete data. / Oszlányi, G.; Süto, András.

In: Acta Crystallographica Section A: Foundations of Crystallography, Vol. 67, No. 3, 05.2011, p. 284-291.

Research output: Contribution to journalArticle

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