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DIFFRACplus TOPAS
New: TOPAS Version 4
TOPAS defines a new generation of profile and structure analysis software by seamlessly integrating all currently employed profile fitting techniques as well as related applications:
- Single Line Fitting
- Indexing (LSI and LP-Search methods)
- Whole Powder Pattern Decomposition (Pawley and Le Bail methods)
- Ab-initio structure determination in direct space from powder and single crystal data
- Rietveld structure refinement
- Quantitative Rietveld analysis
For applications, which do not require the full features of TOPAS, an additional variant has been developed: TOPAS P.
TOPAS P is designed for profile analysis of powder data without reference to a crystal structure model. This includes Single Line Fitting up to Whole Powder Pattern Fitting, Whole Powder Pattern Decomposition (Pawley and LeBail methods), and Indexing (LSI-Index and LP-Search methods).
TOPAS is built around a general non-linear least squares system written specifically to integrate various types of powder diffraction and single crystal analyses. This includes the ability to refine on any number of powder patterns (lab and synchrotron X-ray, CW and TOF neutron data) as well as single crystal data sets simultaneously.
Characteristic to TOPAS is a number of highly remarkable innovations leading to analytical capabilities not available in any other software package:
- Improved direct profile fitting techniques
- Convolution based description of virtually any observed profile shapes including anisotropic line broadening
- A fundamental parameters approach for describing observed profile shapes
- Improved minimization routines
- Rietveld refinement without the need of a parameters turn-on sequence
- Ab-initio structure determination from powder step intensity data using simulated annealing
- New indexing methods based on iterative use of least squares (LSI) and Monte-Carlo based whole powder pattern decomposition (LP-Search)
Most notably are TOPAS' capabilities to determine and refine very large and disordered structures; several of the largest structure solved to date from powder diffraction data have been solved with TOPAS. Not unexpectedly, TOPAS also performed best in the international Structure Determination by Powder Diffractometry Round Robin 2 sdpd.univ-lemans.fr/sdpdrr2/results/.
Driven by innovation - it's outstanding and unique fundamental parameters approach, function minimization routines and structure determination capabilities are just a few examples, of how TOPAS is at the leading edge in powder diffraction. Consequently, with an impressive base of more than 2000 users, TOPAS is the most successful commercial profile analysis program available on the market. Moreover, as a result of its unique analytical capabilities, TOPAS has become the industry standard for quantitative phase analysis in industrial areas such as the cement and mining industries.
Also available: TOPAS BBQ for fully automated environments.