John Evans Erice School 2024
Erice School 2024 Resources – John Evans
This page contains links to the resources that John mentioned in his lectures on Rietveld Analysis.
Topas tutorials – a wide variety of tutorials for TOPAS/jEdit.
Rietveld refinement in excel – a tutorial using excel to explore the fundamentals of least squares fitting, how to fit a Gaussian or Lorentzian peak, how to do a Pawley-like structure independent fit and how to do a Rietveld refinement. The related paper contains more information.
Least squares by hand – it’s worth trying to do a least squares fit by hand once in your life, even if just to appreciate the power of computers. This example goes through a simple linear least squares fit, and shows you how to work out standard uncertainties and correlation coefficients. It also explores constraints and restraints in Rietveld refinement.
Data used in the demo refinement – the .xye file used during lectures to demonstrate Rietveld refinement. A (deliberately bad) starting cif file of Y2O3 is here. For TOPAS the monochromator angle was 27.26 degrees and it was Cu Ka1 radiation.
Analysis of Y2O3 data in GSAS-2 – the data and an instrument parameter file to try the lecture demonstration in GSAS-2.
There are some videos on using topas on my YouTube channel.
The topas wiki with lots of help, on line topas manual (includes Rietveld equations), links to forum etc is here.
Lecture notes for Whole Pattern Fitting, Sequential & Parametric Fitting and Distortion Mode Analysis.
Mark Senn’s distortion mode glossary.
Branton Campbell and Harold Stokes ISODISTORT webpage. A parent WO3 Pm-3m parent cif file. A tutorial on the distortion mode refinment from the lecture.
Other tutorials on symmetry/distortion mode refinements are tutorial numbers 36-40.