issue contents

ISSN: 2053-2733

July 2012 issue

Highlighted illustration

Cover illustration: The sequence of constructing the cartwheel pattern of the first-level hierarchy of the quasi-periodic pattern on the interior walls of the courtyard of the Madrasa of al-'Attarin (1323), Fez, Morocco [Al Ajlouni (2012). Acta Cryst. A68, 235-243].

research papers

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Crystal-field effects in the non-standard amino acid L-homoserine were investigated. Benchmark results from periodic B3LYP calculations are well reproduced by point-charge models. Basis-set representations of the electron density show subtle features further away from the nuclei, which cannot be retrieved by the Hansen/Coppens multipole model.

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The propagation of electron vortices in crystals is studied numerically. It is found that angular momentum is exchanged between the probe beam and the crystal lattice.

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An extension is proposed to the rigid-bond description of atomic thermal motion in crystals.

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The multipolar electron distribution of the title compound was compared with a spherical-charge modelling of the atoms, bonding density and lone pairs.

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An algorithm for the calculation of the variance of electron-density maps via fast Fourier transform is proposed. A study of the related features is described.

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A rigorous method is proposed to describe and classify the topology of entanglements between periodic networks if the links are of the Hopf type. The catenation pattern is unambiguously identified by the so-called Hopf ring net, which consists of barycentres of catenating rings with edges corresponding to the Hopf links.

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The interaction of a scalar wave with a single Si crystal is treated using Ewald's self-consistent field method. The reflectivities of allowed and forbidden reflections in the Bragg geometry valid for both coplanar and non-coplanar cases are derived. It is shown that there exists a very narrow reflectivity peak of the forbidden reflection.

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Based on a self-consistent wave approximation for solving the integral wave equation, the grazing-incidence small-angle X-ray scattering from a random rough surface is considered to test the applicability of the optical theorem.

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The triplet structure invariant is probabilistically estimated when a model structure with imperfect isomorphism is available.


books received

Acta Cryst. (2012). A68, 523
doi: 10.1107/S0108767312016534
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