issue contents

ISSN: 2053-2733

January 2009 issue

Highlighted illustration

Cover illustration: Electron-density isosurface of silicon coloured with electrostatic potential (red for lowest and blue for highest), together with a convergent-beam electron-diffraction (CBED) pattern of silicon. The red regions between neighbouring atoms indicate that the electrostatic potential is lowered due to the excess (bonding) electrons. The electrostatic potential and electron density were determined using a CBED structure-refinement method [Ogata et al. (2008), Acta Cryst. A64, 587-597]. The figure was drawn using VESTA [Momma & Izumi (2008), J. Appl. Cryst. 41, 653-658].

research papers

Acta Cryst. (2009). A65, 1-4
doi: 10.1107/S0108767308031280
link to html
The mystery of observing films that are much thinner than the resolution limit of a reflectivity measurement is explained within the bounds of the kinematic approximation. Although never encountered in crystal structure determination (hence it is not widely known and even seems counter-intuitive to crystallographers), the phenomenon is in no way limited to reflectometry, which could not be described without invoking dynamic scattering theory.

Acta Cryst. (2009). A65, 5-17
doi: 10.1107/S0108767308031437
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The Debye–Waller factors of group IV, III–V, and II–VI semiconductors are calculated from ab initio force constants and fitted in the temperature range from 0.1 to 1000 K.

Acta Cryst. (2009). A65, 18-27
doi: 10.1107/S0108767308036222
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Tables of the abelianizations of all the n-dimensional space groups for n = 1, 2, 3 are provided. The exponent of the torsion subgroup of the abelianization of an arbitrary n-dimensional space group is shown to divide the order of its point group.

Acta Cryst. (2009). A65, 28-38
doi: 10.1107/S0108767308032728
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Multiple-scattering artifacts in soft X-ray diffraction can be completely removed using diffraction patterns recorded at two wavelengths.

Acta Cryst. (2009). A65, 39-45
doi: 10.1107/S0108767308038130
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In addition to the diverse parameter-retrieval algorithms commonly used for multilayer structure determination, a dynamic Newton–gradient-direction-type algorithm is proposed. It works well and provides the absolute minimum of the error functional even when the initial values of the search parameters are rather far from the true ones.

short communications

Acta Cryst. (2009). A65, 46-47
doi: 10.1107/S0108767308029772
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The analytical solution of the tilt-angle determination problem in fiber diffraction is presented.

Acta Cryst. (2009). A65, 48-50
doi: 10.1107/S010876730802936X
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A new method for the deconvolution of the interatomic vector set is presented.

book reviews

Acta Cryst. (2009). A65, 51
doi: 10.1107/S010876730802850X

international union of crystallography

Acta Cryst. (2009). A65, 52-75
doi: 10.1107/S0108767308024136

Acta Cryst. (2009). A65, 76-80
doi: 10.1107/S0108767308035587
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