The energy of a molecule consists partly of translational energy, partly of rotational energy, partly of vibrational energy, and partly of electronic energy. For a first approximation these energy contributions can be considered separately. Electronic energy transitions normally give rise to absorption or emission in the ultraviolet and visible regions of the electromagnetic spectrum. Pure rotation gives rise to absorption in the microwave region or the far infrared. Molecular vibrations give rise to absorption bands throughout most of the infrared region of the spectrum. In this book we shall mainly be concerned with the interaction of electromagnetic radiation with molecular vibrations and rotations.  <...>

This book was inspired by the transition of Raman spectroscopy from a technically demanding research technique to a useful and practical method of chemical analysis. There are many fine texts and thousands of scientific articles on research in Raman spectroscopy, primarily oriented toward understanding the Raman effect itself and using Raman scattering to probe molecular structure and dynamics.