THE HYPERFINE STRUCTURE OF HYDROGEN AND DEUTERIUM

The hyperfine structure separations, ${\ensuremath{\nu}}_{\mathrm{H}}$ and ${\ensuremath{\nu}}_{\mathrm{D}}$, of the ground states of hydrogen and deuterium have been measured by the atomic beam magnetic resonance method. In both cases the determination depends essentially on a measurement with high precision of the frequency of a very nearly field independent line at weak fields and the measurement with reduced precision of the frequencies of one or more field dependent lines. The design of the apparatus and the conditions under which the experiment was performed were such as to permit the accumulation of a large body of significant data and the determination of precise values for the hfs separations by statistical analysis of the data. We find ${\ensuremath{\nu}}_{\mathrm{H}}=(1420.4051\ifmmode\pm\else\textpm\fi{}0.0002)\ifmmode\times\else\texttimes\fi{}{10}^{6} invsec, {\ensuremath{\nu}}_{\mathrm{D}}=(327.38424\ifmmode\pm\else\textpm\fi{}0.00008)\ifmmode\times\else\texttimes\fi{}{10}^{6} invsec.$From these results and the very accurately known ratio of the proton and deuteron magnetic moments, we find $\ensuremath{\Delta}=(1.703\ifmmode\pm\else\textpm\fi{}0.008)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4},$ where ${(\frac{{\ensuremath{\nu}}_{\mathrm{H}}}{{\ensuremath{\nu}}_{\mathrm{D}}})}_{\mathrm{exp}}=(\frac{{\ensuremath{\nu}}_{\mathrm{H}}}{{\ensuremath{\nu}}_{\mathrm{D}}})[1\ensuremath{-}\ensuremath{\Delta}] \mathrm{and} (\frac{{\ensuremath{\nu}}_{\mathrm{H}}}{{\ensuremath{\nu}}_{\mathrm{D}}})$ is calculated from the ratio of the magnetic moments of the proton and deuteron under the assumption that these particles are point dipoles which interact with the electronic magnetic field.