Whats the difference between FTIR and Raman Spectroscopy?

Question

Carter Allen · Accepted Answer

In IR, the electrons gets excited to higher energy level before falling to original ground level state. Therefore, the wavelength that gets scattered or reemitted is the same wavelength as the ...

original monochromatic light source. This is called elastic scattering. There is one more scattering that should be included in the comparison, which is Rayleigh scattering, similar to IR, Rayleigh also excites electrons, but it excites it to an unobservable quantum state called a virtual state. It is still elastic scattering. In Raman scattering, the excitation is assymetrical. It is called inelastic scattering.
But the problem with inelastic scattering is that its signal is faint. So the original signal must be filtered out in order to detect the signal

Ruby Allen · Answer

undefined The main difference between FTIR (Fourier Transform Infrared Spectroscopy) and Raman Spectroscopy is the type of molecular vibrations they analyze. FTIR measures changes in dipole moments, while Raman measures changes in polarizability. Additionally, FTIR requires the sample to absorb infrared light, while Raman measures scattered light. FTIR provides information on functional groups and bond types, while Raman is more sensitive to molecular symmetry and can be used to identify crystalline structures.