Optical Activity as a Two-State Process

Abstract

The phenomenon of optical activity is analyzed as a quantum two‐state process with transitions between photon states of perpendicular plane polarizations, but with the same momentum. The matrix element connecting the two states is computed using quantum electrodynamics. The Rosenfeld—Condon formula for the angle of optical rotation is derived without recourse to Maxwell's equations. The relationship between refractive index and molecular polarizability is also derived using quantum electrodynamics. The theory is extended to obtain the difference between refractive indices of an optically active medium with respect to right and left circularly polarized light and the difference is related to optical rotation.