On the Optical Rotary Dispersion of Polymers

The ``time-dependent Hartree'' method is used to obtain the optical rotary power of a polymer. The resulting equation for the susceptibilities are solved by a normal mode method in both the weak and strong coupling limit. First-order perturbation theory gives in a very simple way the Moffit—Kirkwood—Fitts equation. The time-dependent Hartree approximation is shown to satisfy both the f-sum rule, and the rotational-strengths sum rule. The susceptibilities of the polymer in an optically inactive medium are formally obtained, and a cumulant expansion is suggested. The relation of the time-dependent Hartree approximation to the classical theory of macroscopic electrodynamics and to exciton theory is discussed. The nature of the approximations used in the theory is discussed, as well as their range of validity.