Unit cell refinement software

Table 17.15 Available unit cell refinement software.

Nearly all unit cell refinement programs assume that a list of peak positions will be provided in some form. A personal favorite for quick unit cell refinement is the graphical Celref for Windows software of Jean Laugier and Bernard Bochu. Celref also understands space groups and includes a facility to automatically match HKL positions to observed peaks. For use of internal standard, the XLAT software of Bernhard Rupp, despite its age, is very effective. However,... 

High time-resolution is afforded with energy dispersive diffraction (see above). While systematic errors are problematic, reliable structural refinements are possible for a limited class of experiment. The software and method to enable structure refinement using the Rietveld method and ED powder diffraction data are now well-established (Chen and Weidner 1997, Larson and von Dreele 1986). In a recent study of the partitioning of iron between the olivine and ringwoodite polymorphs of (Mg,Fe)2Si04, energy dispersive data were sufficiently accurate to allow derivation of unit cell volumes... 

C. Powder Indexing completes a comprehensive package of software modules for crystal structure determination from powder data. It is possible to establish unit cell and symmetry information, and use this to assist Rietveld refinement or crystal structure predictions. 

The structure of the compounds was probed by XRPD (Philips PW Diffractometer with graphite monochromator) The measured integrated intensities were used for the refinement of the unit cell dimensions, the atomic coordinates, the site occupancies and the isotopic thermal factor related to a crystallographic model developed by XRD123, a publically available software (internet address http //www.polito.it/Ulisse/Corsi/TLC/F0620/materiali). 

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