
Fourier Transform Infrared Spectroscopy
(FTIR)*
9
The vibrational motions of the chemically
bound
constituents of matter have fre-
quencies
in the infrared regime. The oscillations induced by certain vibrational
modes provide a means for matter to couple with an impinging beam of infrared
electromagnetic radiation and to exchange energy with it when the frequencies are
in
resonance. In the infrared experiment, the intensity of a beam of infrared radia-
tion is measured before (7
0
) and after (/) it interacts with the sample as a function
of light frequency, {w;}. A plot of I/I
0
versus frequency is the "infrared spectrum."
The identities, surroundin ...