Using Rietveld refinement you cannot only refine crystal structure data but also perform a quantitative phase analysis (details see below). This is especially adventageous if more accuracy of the analysis results (phase amounts) compared to the standard RIR method is required.
In order to perform this analysis, you first have to finish the qualitative analysis of the phases in your sample. Afterwards, simply run the "Rietveld (FullProf)" command in the "Quantify" menu, or press the combination <Ctrl+Alt+R> on your keyboard. Match! will run an automatic Rietveld refinement calculation using the parameter sequence defined in the currently selected preset for automatic Rietveld refinement.
If the refinement was successful, the amounts in the match list will be replaced by the ones obtained from the Rietveld refinement, and the pie chart graphics will be displayed. The corresponding information will also be included in the report.
Please note:Each time a Rietveld refinement calculation has converged, the amounts of the individual phases resulting from the calculation are copied back into the match list, so that the results of the quantitative analysis are updated there. Hence, the values in the "Quant. (%)" column in the match list may change each time a Rietveld/FullProf calculation has been run successfully.
The quantitative analysis using Rietveld refinement in FullProf works by applying the equation defined by Hill and Howard [1], modified by including the particle absorption contrast factor defined by Brindley [2] (to account for microabsorption effects), to the scale factors obtained from the refinement.
Hence, the better the agreement between experimental profile and the one calculated from the Rietveld model, the better (more accurate) will be the scale factors and hence also the result of the quantitative analysis.
[1] R.J. Hill & C.J. Howard, "Quantitative phase analysis from neutron powder diffraction data using the Rietveld method", J. Appl. Cryst. 20, 467-476 (1987). https://doi.org/10.1107/S0021889887086199
[2] G.W. Brindley, "The effect of grain or particle Size on x-ray reflections from mixed powders and alloys, considered in relation to the quantitative determination of crystalline substances by x-ray methods", Phil. Mag. 36 (256), 347-369 (1945). https://doi.org/10.1080/14786444508520918