Crystallographic analysis of X-ray diffraction data
The ancient Greeks believed that Krystallos (crystal) was light frozen into ice and that it was so hard that it could never be melted. In later times, crystallography started as a science which studied the outer symmetry of crystals in order to try to explain the inner side of crystals. Father and son Bragg were the first ones that used X-ray diffraction (XRD) to study the inside of crystals and showed the periodic arrangement of atoms in a crystal.
Nowadays X-ray crystallography is used in many fields of chemistry, mineralogy and physics. Not only in the so-called crystalline state (ordered position of ions, atoms or molecules) but also in the amorphous and liquid states that do not have long-order periodicity.
Crystallography is the basic science underlying the determination of new structures, Rietveld analysis, pair distribution function analysis, texture analysis etcetera.
PANalytical’s XRD software solution
The needed steps for the crystallographic analysis of powder XRD data are all included in the PANalytical HighScore Plus software:
- Peak search and fitting the peaks with different (a)symmetrical functions
- Real and reciprocal space methods for indexing
- Unit cell refinement including zero offset or sample displacement
- Testing and ranking all possible space groups using the indexed peaks or the full profile
- LeBail and Pawley fits for lattice parameter refinement
- Symmetry explorer covering all standard and non-standard space group settings
- Charge flipping to discover the atom positions
- Fourier calculations to search for missing atoms
- Transformation between space groups with simultaneous modification of cell and structure data
- Automatic standardization of non-standard space group settings
- Cell reduction (Niggli cell) and finding the conventional cell with the highest possible symmetry
- Rietveld refinement including angle and distance calculations
- Plotting possibilities to visualize the structure.
PANalytical's XRD instrumentation solutions
Crystallographic analysis needs the highest quality diffraction data. PANalytical’s Empyrean Alpha-1 configured with a Ge monochromator (Johansson type) gives perfect Cu or Co Kα1-only Bragg-Brentano reflection geometry data for structure determination. Using a PreFIX hybrid monochromator, an α1-only parallel beam transmission geometry is created on Empyrean for transmission or capillary work. Our advanced detectors can be used for fast data collection.