DGK Arbeitskreis Experimentelle Methoden

DGK Ph.D. student/young scientist course Rietveld and Pair distribution function (PDF) analysis workshop 2025

March 31st – April 4 th , 2025

Announcement (PDF)

Max Planck Institute for Solid State Research
Heisenbergstraße 1
D-70569 Stuttgart Germany

in cooperation with
the universities of Tübingen and Stuttgart
and the committee Teaching of Crystallography of the German Society for Crystallography

http://www.fkf.mpg.de/xray

Course description:
In crystallography, the Rietveld method revolutionized the way in which we study the structure of
materials to understand their properties. It is the aim of this intensive course to impart the Rietveld
method in theory and practice. Using selected examples the entire process from profile fitting using
fundamental parameters towards crystal structure determination and refinement will be explained. Now
more than ever, it is important to consider structure characterization methods for nanostructured and
amorphous materials that diffract poorly. This workshop will serve as an introduction to the pair
distribution function (PDF) method, a technique for determining the local structure in disordered
materials. We will cover the basic theory of the method, data processing, and an in-depth tutorial on
structure refinement implemented in TOPAS v.7.

In particular, the following topics will be covered:

• Basics of powder diffraction and Rietveld Refinement
• The profile of a Bragg reflection
• Determination of the Instrument Resolution Function (IRF) for powder diffractometers
• Whole Powder Pattern-Fitting techniques (WPPF)
• The intensity of a Bragg reflection
• Correction factors for diffraction angles and intensity
• Methods to develop a starting model for crystal structure determination
• Penalty-functions, constraints, restraints
• Rigid Bodies (RB) (flexible polyhedra, molecules, z-matrices)
• Strategies for structure determination, global optimization in direct space, Charge-Flipping (CF)
• Difference-Fourier-analysis in combination with Rietveld refinement
• Isotropic and anisotropic microstructural parameters
• Quantitative Phase Analysis (QPA)
• Different methods for quantifying the amorphous content
• Alternative ways of describing crystal structures
• Sequential and parametric Rietveld refinements
• Stacking faulted superstructures
• The making of Rietveld-Plots for publication
• Basics of total scattering and pair distribution function analysis
• Obtaining the pair distribution function from total scattering data
• Determining and accounting for effects of instrumental resolution
• Small-box crystal structure refinement
• Modelling nanoparticle structures and particle size distributions
• Simulated annealing and large-box approach

Place and Time:
Meeting point on Monday March 31st
, 2025 at 8:30 am in front of the lecture hall 2D5 of the MPI-FKF
(Heisenbergstraße 1). Please be there in time.Duration of the course approx. 9.00 am – 4:00 m (Friday 9.00 am – 12:00 am)

More detailed schedule to follow.

Main tutors:
Sebastian Bette, Robert E. Dinnebier, Matin Etter, John Evans, Paolo Scardi, Maxwell W. Terban

Language:
Lectures and exercises in English.

Computer:
No computers can be supplied by the organizer. For the exercises, a contemporary laptop with a current
Windows version with administrator rights is necessary. The licenses of Topas will be supplied using WiFi. A
sufficient number of power outlets will be supplied. Bring an adapter if needed.
Due to the large number of participants, there is no time for individual installation support.

Information:
More information will become available at: http://www.fkf.mpg.de/xray

All programs and course material need to be downloaded and installed before the course. Installation
instructions will be sent in due time.