issue contents

ISSN: 2053-2733

January 2002 issue

Highlighted illustration

Cover illustration: Electrostatic equilibrium of simultaneous Coulomb attraction and core repulsion for an ensemble {\cal F}=(X_1^-,X_2^-); the conjoint centroids, shown in yellow, characterize force-free positions of the fragment inside the unit cell. For comparison, the pure Coulomb equilibrium is shown in the background. See Mädler, Behrends & Knorr [Acta Cryst. (2001). A57, 20-23].


Acta Cryst. (2002). A58, 1-3
doi: 10.1107/S0108767301014908

research papers

Acta Cryst. (2002). A58, 4-11
doi: 10.1107/S0108767301013800
link to html
The orbital ordering effect of the Mn2+ ion on the structure factors of an LaMnO3 crystal have been calculated. Lower-order structure-factor measurement methods such as Bragg X-ray and the QCBED method are discusssed and compared.

Acta Cryst. (2002). A58, 12-20
doi: 10.1107/S0108767301014957
link to html
Kinematical intensity profiles are compared with dynamical, as well as extinction-corrected, intensity distributions. Primary-extinction correction factors are discussed.

Acta Cryst. (2002). A58, 21-26
doi: 10.1107/S0108767301014714
link to html
Thanks to a new interpretation of the direct-methods modulus sum function, its relation to other existing phase-refinement functions can be easily visualized. The behaviour of the modulus sum function has been optimized by analysing the effect of the two most important control parameters on a selection of test structures.

Acta Cryst. (2002). A58, 27-32
doi: 10.1107/S0108767301015173
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Lattice parameters are determined from harmonic emission reflected from crystalline targets irradiated by short femtosecond laser pulses.

Acta Cryst. (2002). A58, 33-41
doi: 10.1107/S0108767301015963
link to html
A detailed analysis of multiple diffraction data collected by the stereoscopic multibeam imaging technique from a tetragonal lysozyme crystal is reported. The proposed procedures provide a practical way of reconstructing diffraction profiles for experimental phase determination for macromolecular crystals.

Acta Cryst. (2002). A58, 42-46
doi: 10.1107/S0108767301015537
link to html
A new optimization algorithm, the guided simulated annealing method, for use in X-ray crystallographic studies is presented.

Acta Cryst. (2002). A58, 47-53
doi: 10.1107/S0108767301016609
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Topological properties of the geodesics of a net allow an algebraic calculation of the generating function for its coordination sequences.

Acta Cryst. (2002). A58, 54-59
doi: 10.1107/S0108767301016221
link to html
Analysis of X-ray integrated intensities measured as a function of crystal thickness revealed that the two correlation lengths in the theory are absolutely required to interpret the variations of the intensities. It is shown that X-ray diffraction is more sensitive to the two correlation lengths than γ-ray diffraction.

Acta Cryst. (2002). A58, 60-65
doi: 10.1107/S0108767301016658
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Algorithms for the treatment of special positions in three-dimensional crystallographic space groups are presented.

Acta Cryst. (2002). A58, 66-71
doi: 10.1107/S0108767301016579
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An analysis of the normal modes of vibration of a cubic perovskite that have condensed out to produce phases with tilted octahedra is presented. A Landau expansion of the excess free energy is presented involving the seven distinct modes found in the possible structures.

short communications

Acta Cryst. (2002). A58, 72-74
doi: 10.1107/S0108767301016476
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The inclusion of low-resolution reflections and taking into account a bulk-solvent correction improves drastically the signal in molecular replacement searches for the molecular position.

Acta Cryst. (2002). A58, 75-76
doi: 10.1107/S0108767301016725
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A theorem is introduced and applied to determine the latent symmetry of composite systems.

Acta Cryst. (2002). A58, 77-78
doi: 10.1107/S0108767301017688
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A simple tiling of Euclidean space by infinite tiles with all hexagonal faces is described and related to a dense cylinder packing with symmetry Ia{\bar 3}d. Some related structures with the same symmetry are also described.

addenda and errata

Acta Cryst. (2002). A58, 79
doi: 10.1107/S0108767301018372

international union of crystallography

book reviews

Acta Cryst. (2002). A58, 117
doi: 10.1107/S0108767301015720

books received

Acta Cryst. (2002). A58, 118
doi: 10.1107/S0108767301015719

international union of crystallography

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