ECM 25

Aug 212009
 

The 25th European Crystallographic Meeting was held in the Harbiye Museum and Cultural Centre in the beautiful city of Istanbul.  It was a very eventful week, and contributions to the conference made by Chem. Cryst. include:

N. David Brown, James Haestier, Mustapha Sadki, Amber L. Thompson & David J. Watkin
A Further Improved Structure Matching Algorithm (Poster)

James Haestier
Handling of Cell Errors and their Effect on Derived Parameters (Poster)

Mustapha Sadki
New Modelling for Disordered Atoms in Free-form Based Hybrid Refinement and Visual Representation (Poster)

Mustapha Sadki
The Application of Novel Modelling and Refinement Strategies to Crystallography (Presentation)

Amber L. Thompson & David J. Watkin
Absolute Configuration Determination – Is there More Information in the Data? (Poster)

David J. Watkin, Richard I. Cooper & Amber L. Thompson
CRYSTALS:  Refinement and Validation Tools (Poster)

David Watkin
The Future of Small Molecule Software (Session Chair)

Dr. Jeppe Christensen

Aug 212009
 

Dr. Jeppe ChristensenJeppe’s specialist areas are crystallographic instrumentation, experiment design, weak diffraction, twinning and modulation. He is also very knowledgeable about software and the theoretical basis of crystallography. Formerly beamline manager at the Swedish synchrotron facility MAX IV Laboratory, where he operated the small molecule and powder diffraction beamline, Jeppe is currently Research Officer in the Dynamical Structural Science group at the Research Complex at Harwell where he is involved in the development of time resolved crystallography.

Handling Cell-Parameter Errors in Crystallographic Data

Aug 012009
 

J. Appl. Cryst. (2009), 42, 798-809.    [ doi:10.1107/S0021889809024376 ]

A new method is presented for handling errors on crystallographic data. In single-crystal diffraction experiments, two variance-covariance matrices are present, one for the cell parameters and the second for the refined parameters (atomic coordinates and anisotropic displacement parameters). These two matrices can be combined so that errors on derived parameters, such as bond distances, bond angles and TLS tensors, may be calculated more simply. The new method works for all space groups but there are limitations on its application to triclinic space groups. The method allows errors to be transformed between space groups.

Publisher copy: IUCr