Powder Diffraction Crystallography Educational Materials

The APS provides on-line materials related to learning to perform crystallographic analysis from powder diffraction.

Introductory Materials

An Introduction to Crystallography: A series of lectures and handout notes given by Dr. Cora Lind for her Chem 4980/6850/8850: X-ray Crystallography course at the University of Toledo (Ohio). These lectures introduce concepts in crystallography, such as the lattice, symmetry, single-crystal and powder diffraction, crystal structure determination and refinement.
Getting Started with Rietveld: A Flash movie presentation reviewing background concepts needed for Rietveld analysis and introducing how the Rietveld method works.
Space Groups: A primer on topics significant for powder diffraction: A Flash movie presentation discussing space group naming, subgroup transforms and their importance in phase transformations, and how space groups are input to GSAS, as well as common errors made in settings.
A Casual Introduction to Least-squares Fitting: A [mostly] descriptive approach: A non-rigorous introduction to linear algebra, linear and non-linear least squares and related concepts.

GSAS-II

GSAS-II is an open-source Python package appropriate for all types of crystallographic studies, from simple materials through macromolecules, using both powder and single-crystal diffraction and with both x-ray and neutron probes. GSAS-II handles all the steps in diffraction analysis, including data reduction, peak analysis, indexing, Pawley fits, small-angle scattering fits, and structure solution in addition to structure refinement. It can be used with large collections of related datasets for repeated (sequential) refinements and for parametric fitting to these results.

GSAS-II home page: The home page provides information for downloading and installing GSAS-II, citation information, how to report bugs, how to join the mailing list, etc.
Tutorials for learning GSAS-II: The best way to learn to use GSAS-II is to work through some of the 60+ tutorials.

Mini-symposium: A Century of Powder Diffraction

Powder diffraction was developed independently in 1916 by Peter Debye and Paul Scherrer in Germany and Alber Hull in the U.S. To commemorate the 100th anniversary, a half-day symposium on historical developments in powder diffraction as well as contemporary APS work was held on November 11, 2016. Speakers included: David Cox (Brookhaven National Laboratory, Retired), Tim Fawcett (International Centre for Diffraction Data) Pete Chupas, Andrey Yakovenko, Saul Lapidus, Olaf J. Borkiewicz, Robert B. Von Dreele (affiliation is Advanced Photon Source, Argonne unless otherwise noted). Talks are available on-line: see program.

Mini-symposium: Honoring Bob Von Dreele on his 80th Birthday

In cooperation with the ACA, IUCr, ICDD, LANSCE and NCNR, we celebrated Bob Von Dreele’s 80th birthday with a set of talks and remembrances at NIST in Gaithersburg, MD (USA) on Monday, December 4, 2023.

Both pre-recorded videos and live talks were presented. All content was placed on the American Crystallographic Association’s History Portal (via a special YouTube playlist. Also of note is a short (and fairly modest) autobiographical sketch about Bob’s work which can also be found in the ACA’s History Portal.

The full program with a list of talks and links to the presentations is available on the GSAS-II web site.