Y. T. Struchkov, 1926–1995

Direct Methods and Powder Data: State of the Art and Perspectives

The various problems that have to be faced when direct phasing procedures are applied to powder data are described.

Planar Facet Interface: Overlapping Volume and Scherrer Constant Expressions

For a powder sample, the overlap function is a cubic function when the interface consists of planar facets. The explicit expressions of the Scherrer constants are reported.

Molecular Geometry of Incommensurate Structures

Molecular geometry calculations in the superspace framework of incommensurate structure analysis are presented in detail.

The Map Correlation Coefficient for Optimally Superposed Maps

The comparison of ab initio generated phase sets requires preliminary map alignment. A space-group-symmetry-specific algorithm for optimal origin and enantiomorph choices is proposed.

Anharmonic Motion vs Chemical Bonding: on the Interpretation of Electron Densities Determined by X-ray Diffraction

Anharmonic motions and effects of chemical bonding of heavy atoms result in nearly identical features of difference electron-density maps, which vary similarly with temperature except at very low temperatures. Examples are K₂PtCl₆ and Si.

A Relativistic n-Beam Dynamical Theory for Fast Electron Diffraction

From the Dirac equation with periodic scalar potential, an n-beam dynamical formula of high-energy diffraction by a crystal is developed by the matrix representation.

On Integrating the Techniques of Direct Methods with Anomalous Dispersion: the One-Phase Structure Seminvariants in the Tetragonal System

Traditional direct methods are combined with anomalous scattering techniques for their potential applications to mediun/large molecules.

The Double Shear Geometry and Associated Rational Orientational Relationships

A new classification of coincidence lattices is derived from the factorization of transition matrices into a product of shear transformations.

The Two-Channel Maximum-Entropy Method Applied to the Charge Density of a Molecular Crystal: α-Glycine

As the effects of chemical bonding are small compared to the dynamic range of the total density, the two-channel maximum-entropy method is applied to the deformation density of α-glycine. The molecular dipole moment is reasonably well preserved in the reconstruction provided a non-uniform informative prior density is used.

The Crystal Structure and Optical Activity of Tellurium

The Schwinger scattering of neutrons has been used to determine the sense of rotation of the helices of atoms in a crystal of tellurium. Its optical activity shows that the rotation of the plane of polarization of infrared radiation traversing the crystal parallel to the triad axis is in the same sense as the rotation of the helices.

Theoretical Structure Factors and Electron Density of Magnesite(MgCO₃)

Theoretical structure factors F_q of rhombohedral magnesite (MgCO₃) have been computed by quantum-mechanical periodic Hartree-Fock methods and compared with observed |F_o| (literature data) and conventional F_c (independent-spherical-atom model) values. Difference electron-density maps have been calculated on the most important sections.

New Developments in Direct Shape Determination from Small-Angle Scattering. 2. Uniqueness

The low-resolution shape restoration from small-angle scattering data is shown to be unique if the number of shape parameters is 1 to 1.5 times the number of Shannon channels covered by the data set.

The Non-Resonant Magnetic X-ray Scattering Cross Section of MnF₂. 1. Medium X-ray Energies from 5 to 12keV

A new set-up for magnetic X-ray diffraction is described and the form of the non-resonant magnetic X-ray scattering cross section is investigated for the model system MnF₂.

The Non-Resonant Magnetic X-ray Scattering Cross Section of MnF₂. 2. High-Energy X-ray Diffraction at 80keV

A new method for the microscopic investigation of magnetic materials, namely the non-resonant diffraction of high-energy X-rays (E > 80 keV), is discussed and experimental results for MnF₂ are reported.

Corrections to Atomic Scattering Factors for High-Energy Electrons Arising from Atomic Vibrations

The potential used to calculate electron diffraction intensities depends on the amplitudes of atomic vibrations. This paper provides a method for calculating this potential.

Debye–Waller Factors and Absorptive Scattering Factors of Elemental Crystals

Debye-Waller factors are given for 66 elemental crystals and absorptive scattering factors are given for 44 elemental crystals over the temperature range 1 to 1000 K.

Dynamical RHEED Calculations from the Surface of a Semi-Infinite Crystal

A slab method is developed for dynamical RHEED calculations from the surface of a semi-infinite crystal.

The Locked Translation Function and Other Applications of a Patterson Correlation Function

A Patterson correlation function has been used to define a locked translation function and to refine rotational parameters of a search atomic model.

Direct Phasing in Protein Electron Crystallography – Phase Extension and the Prospects for Ab Initio Determinations

The Sayre equation is evaluated as a technique for phase extension or ab initio phase determination, using electron crystallographic data from a bacterial porin.

The SAS Maximal Principle: a New Approach to the Phase Problem

When single-wavelength anomalous acattering (SAS) diffraction intensities are available, the phase problem may be formulated as one in global optimization. This formulation permits a substantial strengthening of the traditional techniques of direct methods, particularly in the case that data are available at low resolution only.

Comment on Contrast of HOLZ lines in energy-filtered convergent-beam electron diffraction patterns from silicon by Lehmpfuhl, Krahl & Uchida (1995)

Contrary to statements in the recent literature, there is no evidence for strong anisotropy in the Debye–Waller factor for silicon at room temperature.

X-ray topography of a lysozyme crystal

White and monochromatic X-ray topographic methods are used to image defects in protein crystals.

International Tables for Crystallography Volume B. Corrigenda and Addenda to the First Edition (1993)

Keywords for the World Database of Crystallographers

Crystallography by W. Borchardt-Ott