XRS X-ray Rietveld System
The programs
XRS-82,
EXTRAC,
DLS-76 and the supporting program
KRIBER are available at www.kristall.ethz.ch/LFK/software/xrs
Supported operating systems are:
- Unix
- LINUX (Linux executables in file /pub/xrs-dist/linuxexe were
kindly provided by Bernt Karasch of Ruhr-Universität Bochum,
Germany. To run XRS-82 you also need the script `xrs' and some data files
available in xrs-dist.tar.Z or xrs-dist.zip)
- VMS
- DOS
- OS/2
The X-ray Rietveld System (XRS) comprises a collection of programs for
crystal structural analysis with powder diffraction data. It provides
routines at all levels of the analysis - examples are Fourier transforms
and least-squares refinements, and also programs to aid in the
interpretation and publication of the refined results.
For details see xrs82/README and xrs82/manual/README and
[1] for additional useful reading.
A program to extract integrated intensities from powder diffraction data.
This is done in a way described by A. Le Bail et al.
[2] Individual
intensities are extracted from the powder pattern by using a (..) cell-
constrained whole pattern fitting program. The main originality of this
program is that the individual F(obs) are not refined in a least-squares
sense, they are estimated from an iterative procedure based on the very
simple principle which gives the so called `F(obs)' in all Rietveld-type
refinement programs. The idea behind EXTRAC was first introduced
in [3].
EXTRAC is not a stand-alone program since it was derived from the XRS-82
program CRYLSP. To run EXTRAC you need modules from XRS-82. For details
see extrac/README and extrac/manual/README.
A program for the simulation of crystal structures by geometric refinement.
For downlowding and/or the on-line DLS-76 Manual
click here.
KRIBER is an interactive program to
- calculate distances and angles,
- generate input files for the program DLS-76 and for the
program LOADAT of the X-Ray Rietveld System XRS-82, and
- calculate coordination sequences and loop configurations.
For details see in subdirectory kriber/vms:
program_description.txt,
worked_example.txt and
input_manual.
Further information
XRS-82, EXTRAC and DLS-76 represent old-fashioned FORTRAN-style programs.
None of them will ever win a competition for the most user-friendly
program. But all the programs do their job and have been used to refine
several zeolite structures, including ZSM-5 and VPI-5.
You will find example input and output files for XRS-82, EXTRAC and
DLS-76, but - sorry - no tutorial. The information included should be
adequate to work your way through. In addition, feel free to ask
for help on specific problems. We can not guarantee to help, but we
will try.
References
- [1] R.A. Young (editor) (1993).
The Rietveld Method, Oxford University Press, UK.
- [2] A. Le Bail, J.L. Fourquet,
U. Bentrup (1992). J. Solid State Chemistry 100,
151-159.
- [3] A. Le Bail, H. Duroy,
J.L. Fourquet (1988). Mat. Res. Bull. 23, 447-452.
Ralf Grosse-Kunstleve. rwgk@cci.lbl.gov