It depends on the scope of your study. XRD is mostly used as a supporting characterization technique, to FTIR. But most of the times their analysis usage is different. When you are carrying out certain studies for your samples, then it becomes important to verify or support those results with the help of other complementary studies. If you think you need to support only on FTIR studies, and XRD is not that valuable for your study then you can do away with it. It all depends on what you want to showcase as your results and you have sufficient information supporting that.

Hope this helps.

Dear Hassan, considering your doubt I believe that FTIR data gives information about the chemical nature of the materials and also some details about interaction. These interactions may offer support to discuss some mechanical properties; however, FTIR is not a quantitative technique, and the analysis history matters. Also, different from XRD, FTIR does not give information about the structure (amorphous, crystallinity, crystal size, etc.). It is common to make an associative discussion correlating FTIR and XRD data. Usually, these techniques give complementary data. Regards, André.

I believe I have understood your questioning.

The x-ray diffraction technique is absolute, depicting atomic positions, and the diffractogram can be refined, and correlated with symmetry groups, which will define a crystalline system. In IR spectroscopy you can correlate with symmetry groups, as long as your material is perfectly defined by a point symmetry group, and then calculate the terms allowed in IR and Raman.

Generally, researchers portray FTIR only in its qualitative perspective, however it is possible to determine the vibrational modes active in IR and Raman, using group theory. Being able to compare the theoretical calculations with those observed experimentally. That, as mentioned by colleagues above, should be used in a complementary way to support your hypotheses and strengthen your interpretation of the phenomenon / material.

Approaches used in some works:

https://www.nature.com/articles/s41467-019-12442-9

https://www.researchgate.net/publication/269995431_Practical_Group_Theory_and_Raman_Spectroscopy_Part_I_Normal_Vibrational_Modes#fullTextFileContent

Dear Hassan,

I totally agree with all responses.

It is depending on what kind of topic you want to write and deliver to the readers.

For example, if you want to focus on "investigation of elastic property of your sample using FTIR spectroscopy", then you can focus on that. You can do scanning with the ATR-FTIR (for surface chemistry analysis) and KBr-FTIR (for bulk chemistry analysis). and compare the results. In addition you can do post analysis with multivariate analysis, such as principal component analysis, and you can do semi-quantitaive analysis by calculating the ratio of specific functional groups related to the elastic property of your sample. Many journals focus on spectroscopy such as Journal of Applied Spectroscopy (Springer), Journal of Spectroscopy (Hindawi), Spectroscopy Letters (Taylor & Francis), Vibrational Spectroscopy (Elsevier), and etc.

In case of XRD analysis, you can focus on investigation of crystalline and amorphous domains of your sample with regard to its elastic property. You can calculate the d-spacing value and predict the crystallinity of your sample using different curve-fitting models such as Gaussia, Lorentz, etc. You can compare the results and write the stories. Specific journals are available in this field such as Crystal Research and Technology (Wiley), Journal of Crystal Growth (Elsevier), Acta Crystallographica (Wiley), etc.

Best regards,

Muhammad Adly Rahandi Lubis

Respected Sir,

With the help of XRD, you can find the structure of the material, even you can also find size of the nanoparticles. You can also define that which derivative do you get at the end of the synthesis process.And with the help of FT-IR technique, you can find the chemical functional group of the particular material. If you need any further help then please feel free. Hope my information would be helpful to you. Thank you.