Effect of Radiation Damping on Dispersion

Abstract

Optical observables such as the polarizability,optical rotation, the Kerr and Faraday effects, and the Cotton—Mouton effect will become infinite whenever the incident frequency coincides with any of the natural frequencies of the system. Consideration of the finite lifetime of the initial states removes the singularities. For a completely isolated molecule, radiation damping would suffice to limit the lifetime; for laboratory systems the vibrational and rotational relaxation accomplish the same purpose and radiation damping is negligible for practical applications. The main point of the calculation has been to show explicitly what was previously (by Condon and by Moscowitz) surmised.