Could IR and Raman be measured simultaneously? IR and Raman are measured using two different machines. Looking at the nature of excitation and at the way data is collected, it seems that these two measurements could be done simultaneously (or with some short time separation). Is that so?


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 A: Assuming you are trying to do vibrational Raman and IR then these two experiments are done in completely different frequency regions. This can be seen in your diagram where the arrows in the Raman experiment are much longer (higher frequency) than the arrows in the IR experiment. Because of this you would need two different light sources to get both spectra.
However, there are other options. If you are interested in vibrational modes that are both IR and Raman active, a vibrational sum frequency generation (SFG) experiment can be done. This uses a broadbandwidth IR pulse and a narrow bandwidth visible pulse to excite and up convert the signal of vibrational modes via a IR absorption followed by an Anti-Stokes Raman process. This gives signal at the sum of the absorbed IR frequency and the narrowband visible frequency. There are caveats to this though. SFG only works when the oscillators (molecules you're studying) are aligned with each other. This happens at surfaces, in external electric fields, or in crystals. 
