Phenomenological Theory of Exchange Currents in Nuclei

On the assumption that the interaction between nuclear particles involves a space exchange operator, it is shown that an addition must be made to the conventional current density for the nucleons in order to establish the equation of continuity within the nucleus. A general expression is found for this exchange current and the corresponding exchange magnetic moment. This phenomenological theory has application to the calculation of magnetic moments of nuclei and to the calculation of transition probabilities for the absorption and emission of radiation by nuclei. In this paper, application is limited to the exchange moments of ${\mathrm{H}}^3$ and ${\mathrm{He}}^3$. It is found that the exchange moments are six or seven times too small to account for the observed moments. In view of results obtained by Villars, it is concluded that the important contributions to the magnetic moment are directly related to the properties of the field (meson field) which describes the nuclear interaction, so the exchange moment may be of use for obtaining direct information concerning the nature of this field.