Rietveld analysis of powder XRD data
The Rietveld refinement method uses a non-linear, least-squares algorithm to fit the whole powder XRD pattern with a parameterized structural model that is based on the crystal structure data of the phases that are present in the sample. By optimizing the agreement between the calculated and observed pattern, versatile information about the sample can be obtained. Rietveld analysis requires high-quality XRD data acquired with a high resolution, good counting statistics and appropriate step size.
Revealing composition, structures, and more
- Quantitative, standardless phase analysis even of complex mixtures with severe overlap of diffraction peaks in the XRD pattern. Quantification can be done with an accuracy of +/- 0.5%
- Crystal structure refinement (cell parameters, atomic positions and Debye-Waller factors)
- Size-strain analysis for nanocrystalline materials based on the peak profiles
- Investigations of solid solutions
- Analysis of texture effects
Intrumentation and software solutions
PANalytical's Empyrean multipurpose XRD platform allows collection of the highest quality diffraction data suitable for Rietveld analysis. It can be configured with incident beam monochromators such as a focusing monochromator of the Johansson type (Alpha-1 geometry) or with a hybrid monochromator in a parallel-beam, transmission geometry. Our hybrid PIXcel detectors enable fast data collection.
The X'Pert³ Powder X-ray diffraction system combined with a hybrid monochromator and the X'Celerator detector, or configured in classical Bragg-Brentano geometry, offers a cost-effective alternative to the Empyrean. Both instruments allow diffraction measurements to be performed under non-ambient conditions, such as increased temperature or humidity.
For high-volume production control in a rugged environment CubiX³ systems are the best choice. They are often used in automated environments.
The PANalytical software package HighScore Plus supports Rietveld refinements, Pawley and Le Bail fits. It offers extensive automation, scripting and reporting options.