Absorption and Emission Spectroscopy with Polarized Light

In the first part of this chapter we will illustrate circular dichroism and we will discuss the optical activity of chemical compounds with respect to light absorption which is at the basis of this technique. Moreover, we will introduce the phenomena that lie behind the technique of optical rotatory dispersion. We thought appropriate to include a brief description of linear dichroism spectroscopy, although this technique has nothing to do with optical activity. In the final part of the chapter we will introduce the basic principles of the luminescence techniques based on polarized (either circularly or linearly) excitation. The experimental approach to the determination of steady-state and time resolved fluorescence anisotropy will be illustrated. For all the techniques examined in this chapter the required instrumentation will be schematically described. A few examples of application of these techniques to molecular and supramolecular systems will also be presented.