Topas is a powerful suite of software written by Alan Coelho for the analysis of powder diffraction data. Some highlights of our research enabled by Topas are given here. Bruker market the original version of topas which comes with a full graphical user interface. An academic-only version is available from Alan Coelho for a few hundred euros depending on the number of licenses purchased.
The academic version is run by editing a text based input file which allows you access to all the features of topas. In Durham we’ve been using “jedit” which is a freely downloadable editor to work with topas input files. jedit has a powerful macro language that lets you customise it to work with input files. The files can be colour-coded to make them easy to view. You can also run programmes from within jedit which allows you to control topas and its ancillary programmes from within the editor. jedit macros considerably speed up the writing/editing of topas input files. If you want to use our jedit menus then final responsibility for the suitability of the resulting .inp files lies with you.
- There are some videos on using topas on my YouTube channel. There’s a jEdit setup/tips playlist here; and an introduction to Rietveld refinement here. Supporting datafiles are here.
- More information on using jedit with topas is here.
- Information on how to install and set up jedit for use with topas is here.
- How to register as a jedit/topas user so you receive updates is here.
- Some examples on getting started with jedit are here.
- More detailed step by step tutorials on Rietveld, Pawley, Indexing, Structure Solution and using Time of Flight data are here.
- A much more extensive library of tutorials is here.
- The latest set of durham jedit menus and update information are here.
- The topas wiki with lots of help, on line manual, forums etc is here.
- The topas academic macro library is on the topas wiki.
- Information on performing distortion mode (isodisplace) Rietveld refinement is here and here. New: refine occupancies as well as coordinates!
- Information on stacking fault refinements is here.
- Information on exhaustive symmetry searching refinements is here.
- Information on using a Genetic Algorithm (GA) to solve either nuclear or magnetic structures using a symmetry mode approach.
Topas allows you to:
- analyse constant wavelength and energy dispersive X-ray data
- analyse constant wavelength and time of flight neutron data
- perform Rietveld/Pawley/individual reflection fitting
- index powder diffraction data
- solve structures by simulated annealing
- perform isodisplace distortion mode refinements