ABSTRACT
The interaction of electromagnetic radiation, the energy inherent in light, with matter is useful in many ways to determine both the identity of compounds and their concentration in mixtures. The electromagnetic spectrum, shown in Figure 3.1, ranges from high energy y-rays to very low energy radio waves. Many regions of the spectrum are used for obtaining information about material samples. Because of the wide range of energies involved, the methods used in the various spectral areas seem quite different, but they all are based on similar principles.
