A lamellar model for the X-ray rocking curves of sagittally bent Laue crystals

A lamellar model was developed to predict the X-ray rocking curves of sagittally bent Laue crystals.

Extension of the time-dependent dynamical diffraction theory to `optical phonon'-type distortions: application to diffraction from coherent acoustic and optical phonons

A generalization of the time-dependent Takagi–Taupin equation which covers also `optical phonon'-type distortions and its perturbative analytical solution for the case of single-mode phonons.

On the enumeration of the simple 3-polyhedra

Enumeration of simple polyhedra.

Structure and stability of α- and β-Ti₂Se. Electron diffraction versus density-functional theory calculations

This paper presents scf-DFT calculations on α- and β-Ti₂Se including full structural relaxation. The results serve to validate recent results from selected-area electron diffraction obtained for the previously unknown β structure.

Three-periodic nets and tilings: regular and quasiregular nets

Five regular nets and one quasiregular net are identified and described.

The crystallographic symmetry test for the correctness of a set of phases

The use of the crystallographic symmetry as a new reliable criterion for the correctness of the phase extension process in the context of the TWIN variables algorithm.

Analysis of voids in crystal structures: the methods of `dual' crystal chemistry

The methods of the analysis of voids and cavities in crystal structures by means of Voronoi–Dirichlet polyhedra and of the graph theory are stated. The efficiency of the method is shown with the analysis of compounds of different chemical nature: simple substances, ionic structures, superionic conductors, zeolites, clathrates, organic supramolecular complexes.

The generalized pendulum analogy of the X-ray dynamical diffraction by one-dimensional regularly deformed crystals

The pendulum analogy has been generalized in a form suitable for the case of an off-Bragg position. It is shown that, by introducing a time variation of the pendula masses, this analogy can be used to simulate the X-ray dynamical diffraction by a one-dimensional regularly deformed crystal.

Domino phase-retrieval algorithm for structure determination using electron diffraction and high-resolution transmission electron microscopy patterns

The concept of direct methods is developed one step further using both the two-dimensional ED and HRTEM data sets in a domino fashion. The idea of the domino phase-retrieval procedure is to obtain the phase fit for the complex structure factors sequentially from low- to high-order ED and HRTEM data sets.

Average unit cell for Penrose tiling and its Gaussian approximation

A diffraction pattern for Penrose tiling has been calculated with the Gaussian approximation for the average unit cell. Analytical formulae have been derived and checked against numerical results.

On integrating the techniques of direct methods and SIRAS: the probabilistic theory of doublets and its applications

The joint probability distribution of two-phase structure invariants (doublets) is derived. This distribution leads directly to a formula for estimating individual phases when a heavy-atom substructure is known.

Report of the Executive Committee for 2001

Notes for authors 2003