Infrared spectroscopy covers a range of techniques that occur within the infrared region of the electromagnetic spectrum. The Fourier transform infrared (FTIR) spectrometer is the common lab instrument for conducting a variety of techniques that are based on absorption spectroscopy.
The infrared segment of a given electromagnetic spectrum comprises three regions i.e. the far-infrared, near-infrared and mid-infrared regions named through their respective relation to the visible spectrum.
The near IR comprises higher energy raging from 14000–4000 cm−1 (0.8–2.5 μm wavelength). Near infrared can ignite harmonic and overtone vibrations. The mid-infrared, on the other hand, has energy that varies within 4000–400 cm−1 (2.5–25 μm) while the far infrared rages approximately 400–10 cm−1 (25–1000 μm).