Journal of Applied Crystallography

Volume 41, Part 5 (October 2008)

research papers

J. Appl. Cryst. (2008). 41, 846-853 [ doi:10.1107/S0021889808024643 ]

Helium cryostat synchrotron charge densities determined using a large CCD detector - the upgraded beamline D3 at DESY

W. Morgenroth, J. Overgaard, H. F. Clausen, H. Svendsen, M. R. V. Jørgensen, F. K. Larsen and B. B. Iversen

Abstract: A 165 mm Mar CCD detector has been fitted on a large Huber four-circle diffractometer together with a helium cryostat at beamline D3 at Hasylab, DESY in Hamburg. This setup allows fast collection of accurate, short-wavelength, very low temperature X-ray diffraction data for charge-density analysis. As a test example, diffraction data have been collected in 10 h on a hydrogen-bonded network system with 15 unique atoms, and the electron density was modelled with the multipole formalism in an X-N procedure using matching-temperature neutron diffraction data collected at Institut Laue Langevin, Grenoble in France.

Keywords: experimental electron density distribution; He cooling; synchrotron radiation; X-N refinement; atomic displacement parameters.