Münster 1997 – wissenschaftliches Programm
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CP: Chemische Physik
CP 19: Poster zur Sitzung CP 8(Fortführung am Do, 9:30-10:30)
CP 19.1: Poster
Mittwoch, 19. März 1997, 18:30–19:45, FBH
DISCUS, a Program for Diffuse Scattering and Defect Structure Simulation — •Thomas Proffen1 and Reinhard B. Neder2 — 1Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia — 2Institut für Kristallographie und Mineralogie, LMU M/"unchen, Theresienstrasse 41,80333 München, Germany
The authors present the program package DISCUS (version 3.0), so far mainly used in the crystallography community. DISCUS is a tool for the analysis of diffuse scattering and for defect structure simulations. The model structure can be created from an asymmetric unit of a unit cell or a complete structure can be read from a file. A FORTRAN-77 style interpreter including IF statements and loops combined with predefined defect types like thermal displacements, waves, microdomains, stacking faults and general symmetry operations, allows to create all sorts of defect structures. The program allows to calculate neutron as well as X-ray intensities including anomalous scattering. The program also allows to subtract the contribution of the average structure. The calculation of the inverse and difference Fourier transform as well as the Patterson function are also implemented. A model structure can be "fitted" to observed diffuse scattering data by Reverse Monte Carlo (RMC) simulations. The RMC segments allows to model displacive as well as occupational disorder. The program is mainly written in FORTRAN-77 and the source code is available via World Wide Web (http://www.kri.physik.uni-muenchen.de/geo/crystal/discus/discus.html).