Crystallography of Quasiperiodic Crystals

A unified description is given of modulated crystals and quasicrystals based on higher-dimensional crystallography.

Maximum Entropy and Bayesian Statistics in Crystallography: a Review of Practical Applications

The applications of the maximum entropy and Bayesian methods to problems in X-ray, neutron and electron crystallography are reviewed.

Growth and Polytype Transformation of AgI-Doped and Undoped PbI₂ Crystals

Significant results on (a) polytype formation in undoped and AgI-doped single crystals of lead iodide and (b) polytype transformation in them on prolonged storage of several months are reported and analysed.

The Symmetry of Three-Beam Scattering Equations: Inversion of Three-Beam Diffraction Patterns from Centrosymmetric Crystals

It is shown that, for a centrosymmetric crystal and within the range of validity of the three-beam approximation, the phases as well as the magnitudes of the three structure amplitudes can be measured uniquely and directly from the geometry of the intensity distributions in the discs of a convergent-beam diffraction pattern. Separate proofs are given in terms of Lie groups, Dirac projector operators and Bloch waves.

MEM Analysis of Electron-Density Distributions for Silicon and Diamond using Short-Wavelength X-rays (W Kα 1)

The electron-density distributions of silicon and diamond with high resolution were synthesized by the maximum-entropy method using short-wavelength X-rays (W Kα 1).

X-ray Back-Diffraction Profiles with an Si (111) Plate

An experimental study is presented of the profiles backward and forward diffracted by a thin Si (111) crystal plate using synchrotron radiation.

Position-Resolved Measurement of the Polarization State in the Forward-Diffracted X-ray Beam

The polarization state inside the transmitted 0 beam in the Laue case of X-ray diffraction was determined with high local resolution. Calculations according to the dynamical theory were used to explain the experimental data.

Discrete Hilbert Transforms and the Phase Problem in Crystallography

By means of discrete Hilbert transforms, the autocorrelation function (the Patterson for a single unit cell) has been incorporated into the analysis of the crystallographic phase problem.

A Tangent Formula Derived from Patterson-Function Arguments. IV. The Solution of Difference Structures Directly from Superstructure Reflections

The direct-methods solution of the difference structure of a superstructure using only the intensities of superstructure reflections is shown. This result may be relevant for determining the internal structure of reconstructed surfaces by direct methods.

Direct Methods for Intergrowth Compounds. III. Solving the Average Structure in Multidimensional Space

A direct-methods procedure is presented for the determination of a composite crystal. The crucial step is the definition of normalized structure factors for the different reflection groups.

Novel regular quinquehedral packing obtained by the local approach

The derivation of novel regular three-dimensional packing with a square-pyramidal coordination polyhedron is briefly described within the local approach.

Optimizing bond lengths in a model using Patterson methods prior to the solution of the structure

A method is described that allows the refinement of bond lengths in a partial model using Patterson-method calculations. The information has uses in fragment building prior to structure solution.