I had started to learn rietveld refinement using fullprof software and there I come to know about the profile matching method. Can you guide me about this?
Profile matching is just the refinement of your lattice parameter and peak shape. But in the Rietveld refinement, crystal structure of the material is refined, after that thermal ellipsoid diagram is generated.
In the past, the traditional method of analyzing powder diffraction diagrams was first to extract the 2-theta positions of the peaks and estimate their intensities and sigmas (the errors) on an arbitrary scale. Once this list was established, the data was used to identify the lattice parameters and identify the compound(s) or possibly to resolve the structure on the basis of the observations.
Hugo Rietveld, a Dutch material scientists came with a new idea which revolutionized the powder diffraction field by first considering the full diffraction diagram from the lowest possible theta value to the highest one. Rietveld introduced different shape functions to approximate the shape of the peaks and the refinement of the structure is based on the full diffraction diagram. i.e. not only the peaks but the complete diagram. The Rietveld method is now used wherever a powder diffraction diagram is analyzed.
H. M. Rietveld, A profile refinement method for nuclear and magnetic structures. Appl. Cryst. (1969). 2, 65-71 [ doi:10.1107/S0021889869006558 ]
There is an annual FullProf tutorial course (see link). There is information uploaded onto YouTube and a manual available which should assist along with previous Researchgate Q+A which could assist.
http://www.ill.eu/fr/presse-et-infos/events/fpschool-2015/
https://www.youtube.com/watch?v=65j8gu04vCM
www.psi.ch/sinq/dmc/ManualsEN/fullprof.pdf
https://www.researchgate.net/post/How_to_use_FullProf_Suite_toolbar_for_Rietveld_refinement_of_XRD_data
The full profile can be adjusted without prior knowledge of the structure (needs only good starting cell and profile parameters) . In some cases, in particular when the structural model is very crude, it is advisable to analyse first the pattern with the profile matching method in order to determine accurately the profile shape function, background and cell parameters before running the Rietveld method.
1. The Rietveld method uses structure factor to calculate the intensity of the profiles in the pattern matching while the profile matching analysis (also known as Le-Bail method) uses arbitrary values of the intensity for fitting the diffraction profiles.
2. The Rietveld method is more precise in comparison to Le-Bail but knowledge of unit cell and positional coordinates of the atoms are required.
In profile matching analysis you don't need these information, thus it is more convenient for beginners.
Article Whole powder pattern decomposition methods and applications:...
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