A multi-temperature high-resolution diffraction study of a biologically important salt potassium uridine monophosphate, K(UMPH), is reported. Anharmonic motion in the uracil moiety was detected and verified by He-temperature X-ray diffraction experiments. The charge density distribution was modelled within the Hansen–Coppens formalism, while anharmonicity was taken into account using Gram–Charlier parameters.

This paper reports on the determination of charge density distributions from crystals compressed at high pressure. Although much less accurate than traditional charge density analysis, these studies provide valuable information because the electronic states of molecules confined in highly condensed space are not easily predictable by theory and therefore experimental validation is a must.

Errors on molecular properties including the topology of electron density and electrostatics are estimated from a sample of deviating models generated using the variance–covariance matrix issued at the end of the charge-density refinement.

The most recent research in charge spin and momentum density is presented and discussed.

Random noise added to theoretical structure factors for a cobalt carbonyl complex is shown to have a large influence on the resulting topological landscape with the potential disappearance of bond-critical points. Atoms in molecules (AIM) analysis of the experimental charge density shows evidence of all the bond-critical points while being highly sensitive to the chosen parameter set.

A spherical-electron-density database with additional spherical scattering centres located on bonds and lone-pair sites is created for charge-density modelling.

Local axes systems are generated for multipole orientation in order to take the symmetry of the atoms fully into account.

Results of experimental multipole refinement and theoretical density functional theory calculations show that donation of electron density from lone pairs of water molecules to 5d and 6s orbitals of Gd³⁺ produces a covalent admixture to predominantly ionic Gd—O(H₂) bonds.

The first comprehensive analysis of the sunitinib malate crystal structure and charge-density distribution in the context of sunitinib complexes with a series of protein kinases is reported. The aspherical atom databank approach, Hirshfeld surface analysis and quantum theory of atoms in molecules are used as a foundation for the investigations of interactions between an inhibitor and a protein.

Wavefront propagation studies show that apertures in the laser injection path into photoinjector electron guns result in spatial ripples in relay-imaged cut-Gaussian profiles. The effect on electron beam properties depends on the extent to which space charge washes out the corresponding ripples in the emitted electron bunch, but could significantly negatively impact the quality of the electron bunch.