Homogeneous sphere packings with triclinic symmetry

All homogeneous sphere packings with triclinic symmetry have been derived by studying Wyckoff positions P 1a and P 2i.

Refinement of crystal structural parameters and charge density using convergent-beam electron diffraction – the rhombohedral phase of LaCrO₃

Atom positions and anisotropic Debye–Waller factors of the rhombohedral phase of LaCrO₃ have been refined simultaneously with the low-order structure factors for the first time, using the structure analysis method of convergent-beam electron diffraction (CBED).

Determination and refinement of disordered crystal structures using evolutionary algorithms in combination with Monte Carlo methods

An evolutionary algorithm for the determination and refinement of disordered crystal structures is presented and applied to a real world problem.

Reconstruction of the form of a particle from its three-dimensional asymptotic form factor

The leading asymptotic term of the three-dimensional form factor of a homogeneous, finite, smooth, strictly convex and centrosymmetric particle uniquely determines the form of the latter.

Direct-method-aided phasing of MIR diffraction data from proteins

Direct-method-aided MIR phasing (DMIR) has been proposed based on the direct method of breaking the phase ambiguity intrinsic in protein SIR data.

Extinction effect and Borrmann effect of resonant dynamical scattering in the Bragg case

The article presents the distinction between the extinction effect and the Borrmann effect on the basis of the X-ray resonant dynamical theory and also discusses the complex dispersion surface.

The generalized F constraint in the maximum-entropy method – a study on simulated data

A new type of constraint is proposed for use in the maximum-entropy method. It leads to much reduced artifacts in the reconstructed electron-density maps. Tests are performed with simulated data for oxalic acid dihydrate.

On the computation of structure factors by FFT techniques

A rule is given to efficiently calculate molecular scattering factors and crystal structure factors by fast Fourier transform techniques.

The crystallographic fast Fourier transform. I. p3 symmetry

An algorithm for computing the discrete Fourier transform of data with threefold symmetry axes is presented. This algorithm is straightforward and easily implemented. It reduces the computational complexity of such a Fourier transform by a factor of 3.

Kinematic and dynamical CBED for solving thin organic films at low temperature; experimental tests with anthracene

Low-dose, low-temperature convergent-beam electron diffraction (CBED) patterns from thin organic crystalline films have been used for measurement of structure-factor amplitudes and phases. CBED patterns from thicker regions affected by multiple scattering give structure-factor signs, which are varied for best fit.

The method of joint probability distribution functions applied to SIR–MIR and to SIRAS–MIRAS cases

SIR–MIR and SIRAS–MIRAS cases are studied via the method of joint probability distribution functions.

Crystal structure solution of proteins by direct methods: an automatic procedure for SIR–MIR and SIRAS–MIRAS cases

An automatic procedure for solving protein structures via direct methods applied to SIR–MIR and SIRAS–MIRAS cases is described

Report of a Subcommittee on the Nomenclature of n-Dimensional Crystallography. II. Symbols for arithmetic crystal classes, Bravais classes and space groups

Specific symbols for R-irreducible groups in 4 and higher dimensions, centrings, Bravais classes, arithmetic crystal classes and space groups (space-group types) are recommended by the Subcommittee on the Nomenclature of n-Dimensional Crystallography in this Second Report. The relationship with higher-dimensional crystallographic groups used in the description of aperiodic crystals is briefly discussed.

On the real crystal octahedra

A real crystal octahedron is defined as any polyhedron bounded, at least, by some of four pairs of parallel planes being in a standard crystallographic orientation with arbitrary distances between them. All the combinatorially non-equivalent shapes (30 in total) are found and characterized by 2-subordination symbols, automorphism group orders and symmetry point groups. The results are discussed with respect to the diamond crystal morphology.

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