Dear Lakshmi

There are some good free databases in the internet for spectroscopy. If you already have an idea of what you can have in your material, you can search for the components, or you can use a generic table with the different chemical links and their respective range of wavelength.

You can find more information here:

https://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi

https://m.chemicalbook.com/ProductIndex_EN.aspx

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.horiba.com/fileadmin/uploads/Scientific/Documents/Raman/bands.pdf&ved=2ahUKEwisysCu3InhAhVi2OAKHVehCMEQFjAAegQIBBAB&usg=AOvVaw0GpLEiVcqoU68Rm1_uW0S1

I have more links I can send you later if needed.

Best regards

Joao

Spectrabase.com is also an excellent source.

Either compare peaks with literature or fit peaks theoretically

try www. Spectrabase.com