Absorption by chiral molecules

Optically active compounds are commonly characterized by their specific rotation [a], measured in solution [see Eq. (1-18)]. 

Commonly, for the sake of comparison, the molar ellipticity [6 ] = 100 Ofcd in units of deg cm dmol is recorded, where c is the concentration in mol and d is the optical path length. If, in the case of polymers such as proteins, the molar concentration is related to the molar mass of the residue, i.e. to the repeating (base) unit, the mean residue weight ellipticity [0]mrw is obtained. 

In recent years, circular dichroism spectroscopy has been widely applied in investigations concerning the molecular structure of chiral polymers. It is a powerful tool for revealing the secondary structures of biological macromolecules, for instance of polypeptides, proteins, and nucleic acids in solution. An 

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