The Hyperfine Structure of Hydrogen and Deuterium

The hyperfine structure separations, ${\nu }_{\mathrm{H}}$ and ${\nu }_{\mathrm{D}}$, 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 ${\nu }_{\mathrm{H}}=(1420.4051\mathrm{}\pm 0.0002)\times {10}^6 invsec, {\nu }_{\mathrm{D}}=(327.38424\mathrm{}\pm 0.00008)\times {10}^6 invsec.$