Reflections on the magnetic pair distribution function

The recent application of the total scattering method to magnetic systems is discussed. The ability to determine the magnetic pair distribution function opens the door to the study of local order in magnetic systems ranging from multiferroics to dilute magnetic semiconductors.

Magnetic pair distribution function analysis of local magnetic correlations

An analytical expression for the magnetic pair distribution function is derived. Examples and discussion of its utility for investigating magnetic structure are provided.

Symmetry groups of single-wall nanotubes

An approach to the determination of the symmetry groups of structural analogs of single-wall carbon nanotubes using ideas in color symmetry theory is described. The line group structures of the symmetry groups of BN, BC₃, BCN and BC₂N nanotubes are identified. An extension of the method to address nanotubes with non-hexagonal symmetry is also presented.

Double antisymmetry and the rotation-reversal space groups

It was found that there are 17 803 types of double antisymmetry space groups. This is four fewer than previously thought. When rotation-reversal symmetry and time-reversal symmetry are considered, this implies that there are 17 803 distinct types of symmetry that a crystal may exhibit.

Experimental determination of core electron deformation in diamond

Based on benchmark synchrotron powder X-ray diffraction data, the subtleties in the electron density of diamond are explored. A contraction of the core density inherently linked to covalent bond formation is experimentally observed.

Atomic order in the spinel structure – a group-theoretical analysis

Group-theoretical methods of the Landau theory of phase transitions are used to investigate the structures of ordered spinels. All types of ordered spinels are established.

Darwin's approach to X-ray diffraction on lateral crystalline structures

Darwin's dynamical theory of X-ray diffraction has been developed for lateral crystalline structures having rectangular cross section. This approach allows one to calculate rocking curves as well as reciprocal-space maps.

Statistical analysis of multipole-model-derived structural parameters and charge-density properties from high-resolution X-ray diffraction experiments

A comprehensive analysis of various properties derived from multiple high-resolution X-ray diffraction experiments is reported. The study indicates the precision and reliability of the analysed quantities and their usefulness in charge-density studies of organic molecules.

Early Days of X-ray Crystallography