Optical Rotatory Dispersion of Helical Polymers

It is shown that for every transition in its individual residues, a helix has two transitions whose moments are respectively parallel and perpendicular to the screw axis. The largest contributions to the rotational strengths of these bands are equal and opposite in the two cases. As a result, their net effect on the optical activity contains a term proportional to the interval between the two upper states. This term shows abnormal dispersion and its magnitude and sign are more easily interpreted than any other component of the rotatory power.