Shimadzu IRAffinity-1 Instruction Manual page 26

Chapter 1 Principles, Description, and Functions of the IRAffinity-1
Equation 1.3 demonstrates that I(χ) is a Fourier cosine transform of spectrum B(σ). Thus, an inverse Fourier
cosine transform of I(χ) recovers the original spectrum B(σ).
+∞
∫
B σ ( ) I χ ( )
=
∞
–
While the conventional dispersive spectrometer directly determines the intensity of B(σ) at certain
wavenumbers, the FTIR detector observes the interferogram I(χ) which must be Fourier transformed to obtain
the spectrum.
IRAffinity-1
1-4
2πσχ χ δ ................................................................................................................... (1.4)
cos