Spectroscopy provides most of the information about the energy levels in atoms and molecules. This information is obtained by studying the absorption and emission of electromagnetic radiation by matter.
In this chapter we will study the rotational and vibrational spectra of diatomic and polyatomic molecules, electronic spectra, and nuclear magnetic resonance spectra.
Spectroscopy has application in all fields of chemistry:
- It allows the determination of angles, bond lengths, conformations and vibration frequencies in molecules.
- Organic chemistry uses magnetic resonance spectroscopy to determine the structure of organic compounds.
- In kinetics, spectroscopic methods are used in order to know the variation of a reactant or product over time.
- Analytical chemistry used spectroscopy to determine the composition of a sample.
- It is even possible to know the composition of distant planets and stars by studying the light that reaches us.