issue contents
September 2002 issue
research papers
The basic crystallography of confined structures has been established
The least path criterion (LPC) has been suggested for unique indexing in a two-dimensional decagonal quasilattice while using redundant pentagonal basis vectors.
A general method for determining subgroups of any group is explained. Application to crystal family holohedries of 5D space permits the 955 point groups in this space belonging to 32 crystal families to be found.
Basic principles for the Weigel–Phan–Veysseyre system of crystallographic point groups of any dimensional space are explained. As an application, the 196 point groups belonging to 15 crystal families are given a WPV symbol.
A hybrid Monte Carlo sampling algorithm is applied to the problem of crystal structure determination from powder diffraction data.
Different extrapolation procedures are examined using γ-ray diffraction data. The wavelength dependence predicted by the standard theory of extinction is confirmed.
Topologies of total charge densities obtained from crystalline molecular-orbital calculations are compared to those obtained from the multipole refinement of the structure factors obtained from the same densities.
The equations determining the best discrete-valued approximation to a given electron or scattering-length density function are reported.
The feasibility of building a database of theoretical atomic deformation density parameters applicable to the construction of the densities of biomacromolecules and to the interpretation of their X-ray diffraction data is discussed.
Intensity profiles measured with synchrotron radiation are compared with theoretical intensity distributions. Expressions for the integral width as well as the full width at half-maximum are presented.
A model for the X-ray rocking-curve width of sagittally bent Laue crystals has been developed and verified.
The substitution of boron atoms for copper was studied by combining high-resolution electron microscopy (HREM) and electron diffraction. The boron atoms were determined to be located at the `chain' Cu sites.
short communications
The symmetry point groups for all combinatorially non-isomorphic simple 12- and 13-hedra (7595 and 49566, respectively) are contributed in the paper for the first time.
A revised proof is given that the root-mean-square deviation between more than two vector sets after optimal superposition induces a metric. This corrects an error in a previous manuscript [Kaindl & Steipe (1997>). Acta Cryst. A53, 809].
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