Recent Studies of the Circular Dichroism and Optical Rotatory Dispersion of Biopolymers

When electromagnetic radiation interacts with matter, a number of changes result both in the light and in matter. The intensity of the light at given wavelength may be reduced due to absorption; the velocity of light may change, dependent on the wavelength, upon interaction with the medium due to refractive index dispersion (scattering). If the incident light is plane polarized, a change in the plane of polarization may occur, again dependent on wavelength [optical rotatory dispersion (ORD)]. Also, the radiation may become elliptically polarized at the absorption bands; this phenomenon is termed circular dichroism (CD). While normal absorption and dispersion occur with any molecule, ORD and CD require not only polarized light but also molecular systems with built-in asymmetry or dissymmetry.