Principle of FTIR Spectrometers

It is beyond the scope of this chapter to describe Fourier transform infrared spectroscopy in detail. Recent papers by Pons et Pons, and Habib and Bockris have reported the use of FTIRS for in situ spectroelectro-chemical studies. 

FIGURE 18. Schematic diagram of the FTIR spectrometer used by Pons.  

FIGURE 19. Principle of obtaining an interferogram with a Michelson interferometer (a) Light intensity of the different monochromatic waves issued from the IR source as a function of the relative displacement x of the moving mirror (b) constructive and destructive recombination of the reflected beams, leading to an interferogram with a maximum intensity when the waves are in phase (x = 0). 

The second term of this expression is known as the interferogram function  

By performing a Fourier transformation on f (x), it is possible to obtain the spectrum  

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