Analysis of Molecular Structure with Electronic Spectroscopy
We have constructed a view of biochemical state space based predominantly on the ideas of a limited set of mechanical motions and the existence of electrical charge. Using just these basic concepts we have been able to develop useful descriptions of light and electromagnetic radiation and subsequently of atomic and molecular structure. These ideas are developed from the same core physical concepts. Therefore it is not surprising that a substantial interaction between electromagnetic radiation and matter will be found. A great deal of structural information can be gained by studying these interactions. In general we can explore structure of biological molecules by either focusing on either the quantum mechanical aspects or the wave-like nature of light. The first forms the basis of spectroscopic experimental methods and is the subject of this chapter and the second, the basis of light scattering (e.g., x-ray diffraction) and is the subject of Chapter 29.