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Shape transform phasing of edgy nanocrystals
Author(s) -
Chen J. P. J.,
Donatelli J. J.,
Schmidt K. E.,
Kirian R. A.
Publication year - 2019
Publication title -
acta crystallographica section a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.742
H-Index - 83
ISSN - 2053-2733
DOI - 10.1107/s205327331900113x
Subject(s) - diffraction , phaser , coherence (philosophical gambling strategy) , coherent diffraction imaging , optics , interference (communication) , phase retrieval , materials science , lattice (music) , nanocrystal , symmetry (geometry) , physics , crystallography , computational physics , algorithm , molecular physics , fourier transform , chemistry , computer science , nanotechnology , mathematics , quantum mechanics , geometry , telecommunications , channel (broadcasting) , acoustics
Diffraction patterns from small protein crystals illuminated by highly coherent X‐rays often contain measurable interference signals between Bragg peaks. This coherent `shape transform' signal introduces enough additional information to allow the molecular densities to be determined from the diffracted intensities directly, without prior information or resolution restrictions. However, the various correlations amongst molecular occupancies/vacancies at the crystal surface result in a subtle yet critical problem in shape transform phasing whereby the sublattices of symmetry‐related molecules exhibit a form of partial coherence amongst lattice sites when an average is taken over many crystal patterns. Here an iterative phase retrieval algorithm is developed which is capable of treating this problem; it is demonstrated on simulated data.