Theory of Magnetic Rotation Spectra

Abstract

A general theory is developed for optical and magneto‐optical rotation in the case of resonance, that is, if the frequency v of the primary light is equal to an absorption frequency v_k of the system. It is concluded that for this case optical and magneto‐optical rotatory power are physically meaningless quantities since they cannot be measured; instead the total intensities of the emission lines in optical rotation spectra or magnetic rotation spectra should be considered. General formulas for these intensities are derived from the quantum theory of radiation fields by making use of a perturbation method that was introduced by Heitler and Ma for the description of damping phenomena. An important feature of the method is the introduction of a damping constant which causes our results to remain finite for v=v_k; this was not the case in the older theories. The possibility of measuring optical rotation spectra is mentioned: it is predicted that they may be observed in dilute gases of optically active molecules. No applications of the general theory to specific molecules are given.