ABSTRACT
The energies associated with the fundamental vibrational modes of a chemical
compound lie within the range of 400-4000 cm21, a spectral region corresponding
to midinfrared (mid-IR) electromagnetic radiation. Transitions among vibrational
energy levels can be observed directly through their absorbance in the infrared
(IR) region of the spectrum or through inelastic scattering of incident energy via
the Raman effect. Overtones and combination bands of vibrational modes are
observed in the near-infrared (NIR) region of the spectrum (4000 to 13,350 cm21).
