Getting more from your diffraction pattern: the atomic pair distribution function

Knowledge of the atomic scale structure is an important step towards understanding and possibly predicting the properties of materials. In case of crystalline materials, conventional structure determination is based on the analysis of the intensities and positions of Bragg reflections. It should be noted, that the study of Bragg reflections only reveals the long range average structure of the material. However, many real materials of technological importance are not perfect crystals or not crystalline at all. In this case the diffraction pattern will show diffuse scattering which contains information about two-body interactions or the local atomic arrangements to a deeper understanding of the properties of the material.

One method to reveal the local structure is the analysis of the atomic pair distribution function (PDF). The PDF is obtained via Fourier Transform of a properly normalized total powder diffraction pattern. This technique has long been used to study amorphous materials and liquids but can also be applied to crystalline or partly crystalline materials.

In this presentation I will give an overview of the PDF technique1 and discuss its application to a variety of amorphous, nanophase and disordered crystalline materials.

[1] For more information on the PDF technique and related software visit: http://www.totalscattering.org

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