Direct phasing of finite crystals illuminated with a free-electron laser

Richard Kirian, Richard J. Bean, Kenneth R. Beyerlein, Miriam Barthelmess, Chun Hong Yoon, Fenglin Wang, Flavio Capotondi, Emanuele Pedersoli, Anton Barty, Henry N. Chapman

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


It has been suggested that the extended intensity profiles surrounding Bragg reflections that arise when a series of finite crystals of varying size and shape are illuminated by the intense, coherent illumination of an x-ray free-electron laser may enable the crystal's unit-cell electron density to be obtained ab initio via wellestablished iterative phasing algorithms. Such a technique could have a significant impact on the field of biological structure determination since it avoids the need for a priori information from similar known structures, multiple measurements near resonant atomic absorption energies, isomorphic derivative crystals, or atomic-resolution data. Here, we demonstrate this phasing technique on diffraction patterns recorded from artificial two-dimensional microcrystals using the seeded soft x-ray free-electron laser FERMI. We show that the technique is effective when the illuminating wavefront has nonuniform phase and amplitude, and when the diffraction intensities cannot be measured uniformly throughout reciprocal space because of a limited signal-to-noise ratio.

Original languageEnglish (US)
Article number011015
JournalPhysical Review X
Issue number1
StatePublished - 2015


  • Optics

ASJC Scopus subject areas

  • General Physics and Astronomy


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