Matter and Electromagnetic Energy

Probably one of the most faseinating phenomena in science is the interactions of light, electromagnetic radiation, with matter. The essential nature of matter, the nature of the forces acting between the parts of atoms, between the atomic components of molecules, is revealed by such phenomena. It produces a cosmic arithmetic that relates the energy changes associated with changes in atomic and molecular structural states. These phenomena provide the basis for one of the most widely used methods of chemical analysis colorimetric and spectrophotometric analysis. 

The mighty and mysterious quantum theory explains the interaction of light and matter in terms of well-defined energy states that characterize an atom or molecule. When the atom or molecule absorbs energy to enter a higher energy state, the energy used is 

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