Location and Schedule

8:00 – 8:30 AM: Software installation.

8:30 – 9:00 AM (1 lecture, 1 practice/worked examples session): Introduction to X-ray diffraction from single crystals and powders. Results from diffraction experiments and CIF files. Identification of crystalline phases in powders.

9:00 – 9:30 AM (1 lecture, 1 practice/worked examples session): Lattice. Unit cell parameters. Atomic coordinates. Bragg’s law. Finite symmetry elements and operations. Crystal systems. Bravais lattices. Reciprocal lattice. Miller indices. Qualitative size relationships for direct and reciprocal lattices.

9:30 – 10:30 AM (1 lecture with examples): “Advanced Materials Characterization Using Powder Diffraction Techniques and the Powder Diffraction File^TM”. Thomas Blanton.International Centre for Diffraction Data (ICDD).

10 min break

10:40 AM – 1:00 PM (2 lectures, 2 practice/worked examples sessions): Crystal structure solution and refinement overall procedure and free-distribution software. Indexing powder diffraction patterns. Quadratic formulas. Figures of merit. Indexing practice using free-distribution software (EXPO2014, DICVOL, and McMAILLE). Asymmetric unit. Infinite symmetry elements and operations. Combination of symmetry operations. Proper and improper symmetry elements and operations. Point groups and space groups of symmetry. International Tables for Crystallography. Systematic absences. Practice determining the space group symmetry of powder patterns using EXPO2014 and CHEKCEL software.

Slides and video: Instrumentation and data collection. Laboratory X-ray powder diffraction (XRPD) with Bragg-Brentano optics. Introduction to X-ray sources, monochromatization, and detectors. Selection of the scan mode, range, step size, and counting time. Synchrotron X-ray powder diffraction. Data aberrations and systematic errors in laboratory diffractometers.

1:00 PM – 2:00 PM – Lunch break.

2:00 PM– 3:50 PM (2 lectures, 2 practice/worked examples sessions): Structure factors. Fourier transform.  Phase problem. Atomic scattering factor, occupancy factor, Debye-Waller factor, atomic displacement parameters. Powder diffraction step intensities and integrated intensities of the reflections. Peak profile functions in X-ray powder diffraction. Exact and partial overlap. Whole pattern decomposition methods and extraction of integrated intensities. Practice on the extraction of integrated intensities using EXPO2014.

10 min break

4:00 PM– 5:30 PM (1 lecture, 2 practice/worked examples sessions): Brief overview of the direct methods. Direct-space methods to solve crystal structures from powders. Parameterization of the crystal structure solutions. Global optimization algorithms. Available software and overall structure solution steps.Crystal structure solution of 2-ethoxybenzamide, phentolamine, divanillin, and Cu(CN)-2-aminopyrazine.

Tuesday, December 2

9:00 – 10:35 AM (1 lecture, 2 practice/worked examples sessions): An introduction to the Rietveld method. The residual. Rietveld agreement factors and criteria of fit. Linear and non-linear least squares minimization. Normal equations. Rietveld refinement strategy. Variances and covariances. Constraints and restraints. Practice on a Rietveld fit of LaB₆ line shape standard and the generation of a parameter file for GSAS-II software (laboratory X-ray powder diffractometer). Rietveld refinement of 2-ethoxybenzamide with GSAS-II. Soft bond length and bond angle restraints. Refinement of atomic positions and atomic displacement parameters. Visualization of the structure (Mercury software) and generation of a CIF file.

10 min break

10:45 AM – 12:20 PM (2 practice/worked examples sessions): Rietveld refinement of phentolamine using GSAS-II. CIF preparation and validation (PLATON software).

12:20 PM – 1:20 PM – Lunch break.

1:20 – 2:50 PM (2 lectures, 1 practice/worked example): The Cambridge Structural Database, software, and uses.

2:55 PM– 3:25 PM(1 lecture): Crystal Explorer software software and uses.