The development of Laue techniques for single-pulse diffraction of chemical complexes: time-resolved Laue diffraction on a binuclear rhodium metal-organic complex

A modified Laue technique suitable for time-resolved diffraction is described in which profile-independent integration is used, the RATIO method is applied and multi-crystal data are normalized to a common scale. The method is applied in single-pulse pump–probe studies of a binuclear Rh complex, showing Rh—Rh bond shortening of 0.136 (8) Å on excitation.

Kinematic diffraction on a structure with periodically varying scattering function

The correlation of external modulation with diffraction response as a tool to assess the selective diffraction signal and to recover partial phase information is described.

Using molecular-dynamics simulations to understand and improve the treatment of anharmonic vibrations. I. Study of positional parameters

Molecular-dynamics simulations are used to compare and relate three different types of positional parameters that are of interest to structural scientists.

Using molecular-dynamics simulations to understand and improve the treatment of anharmonic vibrations. II. Developing and assessing new Debye–Waller factors

Numerical data sets obtained from a series of molecular-dynamics simulations have been used to assess two new anharmonic Debye–Waller factors.

Addressing the amorphous content issue in qu­antitative phase analysis: the certification of NIST standard reference material 676a

A novel method is used to determine the amorphous content in the certification of NIST standard reference material (SRM) 676a (corundum). Extrapolation of diffraction measurements from mixtures with Si powders of varying surface-to-volume ratio show that approximately 1% by weight of SRM 676a is amorphous.

Estimation of the variance in any point of an electron-density map for any space group

The variance in any point of the electron-density map is estimated for any space group, whether centric or acentric. Calculations may be performed no matter how poor the structure model.

Linear transformations of variance/covariance matrices

The linear transformation of standard uncertainties involves the full variance/covariance matrix. A method based on the vec operator is described for the case of second-rank tensors, e.g. anisotropic displacement parameters. This method is also applicable for the calculation of equivalent isotropic displacement parameters (U_equiv), the comparison of refinements in different space-group settings and the calculation of standard uncertainties of eigenvalues.

Anomalous extinction of X-rays diffracted in strongly deformed crystals

The extinction concept is extended for very thin non-ideal crystals. It is shown that for a large gradient the integrated reflected intensity exhibits a prominent extinction minimum caused by X-ray interbranch scattering.

Relaxation of the resolution requirements for direct-methods phasing

Small changes in the `shake-and-bake' procedure of direct-methods phasing can extend the minimal resolution for successful applications from 1.2 toward 1.5 Å. These changes also permit the solution of macromolecular structures that are twice as large as those previously solved by these methods.

The similarity types of primitive parallelohedra in E^d, 2 ≤ d ≤ 5

The similarity types of parallelohedra are defined and a complete classification of the primitive parallelohedra in E^d, 2 ≤ d ≤ 5, is given.

High-resolution study of (222, 113) three-beam diffraction in Ge

Good agreement between the high-resolution experimental results for (222, 113) three-beam diffraction in Ge and computer simulations based on the dynamical multiple diffraction theory are presented.

Seitz notation for symmetry operations of space groups

Seitz notation is provided for the symmetry-operations subtables of International Tables for Crystallography, Volume A, Space-Group Symmetry.

Ninth Ewald Prize