Applications
Unlike NMR, Infrared and UV-Visible spectroscopies, microwave spectroscopy has not yet found widespread application in analytical chemistry. However, it is a powerful technique that continues to be used for contemporary research around the world. It is a uniquely precise tool for the determination of molecular structure in gas phase molecules. It can be used to establish barriers to internal rotation such as that associated with the rotation of the CH3 group relative to the C6H4Cl group in chlorotoluene (C7H7Cl), for example. When hyperfine structure can be observed, the technique can also provide information on the electronic structures of molecules. Much of current understanding of the nature of weak molecular interactions such as van der Waals, hydrogen and halogen bonds has been established through rotational spectroscopy. When connected with radio astronomy, the technique has had a key role in establishing the chemical composition of the interstellar medium.
Read more about this topic: Rotational Spectroscopy