The information is not enough. But you can try to Optimize the peak shape parameter (like the percentage of G-type and L-type etc) and Debye-Scharrer factor.

@Sihan Zhang . My Chi2 value is 2.3 but Rexp 30.5 and Rwp 20.2. how can I reduce the R values

Dear Shovon Mondal

It probably has something to do with the quality of the data. A high Rexp value suggests that the data quality is poor. This could be due to the intensity of the pattern being lower than 10,000 counts, or the pattern is recorded at an angle lower 2θ (e.g. 5-70° for inorganic materials). The parameter/data ratio may be low. As the fit is quite good, the Rwp is high becuse the Rexp is high. I would recommend re-collecting the diffraction pattern again with a longer counting time and at the highest possible 2θ angle.

Some peaks are also observed that do not have a Bragg position. It is not critical, but it is good if it is possible to find the phases related to them.

Best regards

Analio Dugarte-Dugarte

If you could please share your files, in this case XRD data (xy, raw, dat, etc) and the structural model employed (cif mol, xyz, etc). Just to analyze and revise if some issues could be present for this particular refinement.

Best regerds, Hiram

Looking at the blue line that shows the differences between the model with the parameters you set for the profiles and the experimental data, it seems that some of the reflections are not well matched (e.g., around 33° and 48°). As mentioned before, I would also recommend extending the measurement range to 10°-120° (assuming λ = 1.54 Å) to obtain better data for model refinement. For these data, I suggest first refining the parameters of the unit cell and the profiles (perhaps using a tutorial for FullProf or another program and refining the parameters step by step in the correct order), and only then proceeding with the structural refinement. Good luck!