ARITVE - Glass structure modelling software
NEW : Y2K version
ARITVE models glass structures by a Rietveld-type approach (RDM = Rietveld
for Disordered Materials method). A crystalline model is selected, then
the corresponding calculated diffraction pattern (possibly neutron + X-ray)
is compared to experimental data after broadening the reflection line profiles
by microstrain effect. Atomic coordinates, cell parameters and microstrain
are refined up to the best possible agreement (which may be eventually
satisfying or not, according to the selected model). The package is 15-years-old
and has been slightly modified and recently re-used in order to simulate
the structure of glassy SiO2 (J.
Non-Cryst. Solids, 183, 1995, 39-42), NaPbM2F9,
Full details are in the manual including
other references for previous applications (for instance Pb2M2F9
and BaZr2F10 fluoride
glasses and amorphous FeF3,xHF).
A comparison of RDM and RMC (Reverse Monte Carlo) methods is to
Executing the test files (SiO2) with ARITVE for 90 refinement
cycles takes 2 minutes on a Pentium II 333Mhz (WINDOWS 95).
PC (WINDOWS 95/98/NT) as 32 bits executable
together with FORTRAN source code (GNU Public License). Version updated
December 27, 1999 : 4 programs gathered in one, simplifying the user's
role. Current limits are : 3 interference functions can be fitted simultaneously,
60000 (hkl) per pattern, 20000 overlapping (hkl) at a given diffracting
angle, 1200 intensity data points per pattern, 70 refined parameters, 4
different atom-type in your sample.
Other versions can be easily built up from the Fortran source code which
does not contain graphism in itself. However, the program prepares files
for specific Rietveld viewers (DMPLOT...).
Armel Le Bail
Laboratoire des Fluorures - CNRS ESA 6010
Université du Maine - Av. O. Messiaen
72085 Le Mans Cedex 9, FRANCE