Diffraction analysis of perovskite-like oxides containing irregular intergrowths

An approach is proposed providing the means for determining stacking fault properties by analysis of the relative positions of selected pairs of X-ray diffraction peaks.

Modifications in the correlation function in poly(vinyl alcohol)/silica hybrid wet gels

Small-angle X-ray scattering was used to study modifications in the correlation function in tetraethoxysilane-derived poly(vinyl alcohol)/silica hybrids. An additional scattering at low q was found to overlap the fundamental mass-fractal scattering from the basic silica. The fraction of both contributions to the total correlation function was estimated; this is the first time that such a study has been carried out for mass-fractal structures.

Structural changes in nanocrystalline mackinawite (FeS) at high pressure

The high-pressure behavior of nanocrystalline mackinawite (FeS) has been studied by X-ray total scattering experiments and pair distribution function analysis. A pressure-induced structural phase transition has been observed at about 3 GP and from the tetragonal mackinawite structure to orthorhombic FeS-II.

Simulation of powder diffraction patterns of mixed-layer compounds in the restacked binary nanosheet system Ti_0.91O₂–MnO₂

The matrix method for diffuse scattering was effectively used to simulate powder X-ray diffraction patterns of misfit mixed-layer compounds in a restacked binary nanosheet system.

Multiple-wavelength anomalous dispersion techniques applied to powder data: a probabilistic method for finding the substructure via joint probability distribution functions

A joint probability distribution function method is described for finding the anomalous scatterer positions from two-wavelength powder data.

Single-crystal diamond: a potential gem in neutron instrumentation

It is shown theoretically that single-crystal diamond would be the ultimate neutron monochromator material if it were available as large mosaic crystals. Present chemical vapour deposition growth techniques are capable of preparing single crystals with a suitable mosaic spread and should be further developed with the aim of producing neutron monochromators.

Mounting powder samples for sub-Kelvin neutron diffraction

The problems associated with cooling powder samples below 1 K are discussed. Two strategies for mounting neutron powder diffraction samples are described and evaluated.

Post-processing intensity measurements at favourable dose values

An investigation of the usefulness of higher-order least-squares fits in the post-processing of intensity measurements is presented.

Phase transitions and ferroelectricity in NaSb₃F₁₀

Atomic coordinate analysis allows the property of ferroelectricity, previously unsuspected in a material, to be recognized if its crystal structure is known. An earlier such prediction that NaSb₃F₁₀ is ferroelectric is unambiguously confirmed.

Synthesis and physical properties of ferrocene derivatives. XXI. Crystal structure of a liquid crystalline ferrocene derivative, 1,1'-bis­[3-[4-(4-methoxyphenoxycarbonyl)phen­oxy]propyloxycarbonyl]ferrocene

The title 1,1′-disubstituted ferrocene derivative exhibits a nematic phase only, and the rod-like shape of the molecule favors liquid crystalline behavior. C—H⋯π, π–π and T-stacking interactions play a major role in stabilizing the molecular packing arrangement and the mesomorphism.

Disordered materials studied using neutron polarization analysis on the multi-detector spectrometer, D7

The technique of neutron polarization analysis spectroscopy on a multi-detector instrument is described.

Strain profiles in thin films: influence of a coherently diffracting substrate and thickness fluctuations

A simple model-independent method is proposed to retrieve strain profiles in thin films using X-ray diffraction. The dynamical diffraction from the substrate as well as the film thickness fluctuations are explicitly taken into account.

Effect of pressure on the superionic argyrodite Ag₇GeSe₅I

The effect of pressure on both the structure and the electrical conductivity of the superionic Ag₇GeSe₅I phase has been studied at room temperature (i) by powder X-ray diffraction from 0.1 MPa to 10 GPa, (ii) by single crystal X-ray diffraction from 0.1 MPa to 2 GPa and (iii) by impedance spectroscopy from 0.1 MPa to 1.5 GPa. The decrease in conductivity of about one order of magnitude, when the pressure increases up to 1.5 GPa, can be explained by the compression of the cell.

Instrument-independent specification of the diffraction geometry and polarization state of the incident X-ray beam

Conventions are proposed to encode information about the diffraction geometry and polarization properties of the incident X-ray beam in an unambiguous and economical way. The use of these definitions is beneficial in the analysis of polarization-dependent phenomena in X-ray diffraction.

Examination of whewellite kidney stones by scanning electron microscopy and powder neutron diffraction techniques

The techniques of synchrotron radiation micro-X-ray fluorescence, neutron diffraction and scanning electron microscopy have been applied to the study of different whewellite kidney stones.

Indexation and misorientation analysis of low-quality Laue diffraction patterns

A template-matching-based indexing scheme for Laue diffraction patterns is implemented, and a method is proposed for misorientation determination within a diffracting volume from smeared/split Laue patterns. The methodologies developed are illustrated using micro-Laue patterns obtained from a fatigue crack-wake.

An inexpensive automatically operated device for the flash annealing of crystals of macromolecules

A small, inexpensive and automatically operated device for the flash annealing of crystals of macromolecules is presented. Operation of the device is completely integrated within the ESRF beamline control graphical user interface for macromolecular crystallography experiments, mxCuBE, and the device can thus be controlled either from the beamline control cabin or by users accessing the beamline remotely.

A hands-free capillary system for protein crystallography from crystallization to data collection

This paper presents a hands-free protein crystallography system in which all aspects of crystallographic experiments from crystallization to diffraction data collection are performed within a modified X-ray glass capillary.

Spherical harmonics preferential orientation corrections and structure solution from powder diffraction data – a possible avenue of last resort

An approach is described where structure solution may be attempted from powders with preferential orientation. Based on spherical harmonics, it does not assume any orientation direction but is stable during simulated annealing. The approach relies on a macro keyword already present in TOPAS, but could be implemented in other simulated annealing codes.

ACDP – a Java application for data processing and analysis of protein circular dichroism spectra

ACDP is a Java application for processing protein circular dichroism spectra. Three different algorithms for secondary structure deconvolution have been implemented, and spectra can be analysed without the need for data reformatting.

Computer-controlled high-temperature single-crystal X-ray diffraction experiments and temperature calibration

Additional hard- and software allows computer-controlled temperature-dependent X-ray studies and temperature calibration using a Stoe IPDS II with the Heatstream attachment. The presented software is open source and therefore can easily be adapted to other diffractometer platforms with similar gas flow heaters.

Maria Przybylska (1923–2008)

Notes for authors 2009

Forthcoming meetings and short courses