Hyperfine Splittings of Hydrogen and Tritium. II

The spin-exchange optical polarization method was used to remeasure the zero-field hyperfine splittings of atomic hydrogen and atomic tritium. The transmission of circularly polarized rubidium resonance radiation through a flask containing rubidium, atomic hydrogen, or atomic tritium, and a buffer gas was monitored as a function of the frequency of an applied radio-frequency field. Measurements were made for hydrogen in helium, neon, molecular hydrogen, and argon buffer gases and for tritium in neon and argon buffer gases. The values of the hyperfine splittings obtained are $\Delta \nu \left(\mathrm{H}\right)=1\mathrm{}420405749.1\pm 6.0$ cps; $\Delta \nu \left(\mathrm{T}\right)=1\mathrm{}516701476.8\pm 6.0$ cps. The assigned limits of error represent the range of disagreement of the zero-pressure extrapolations in the different buffer gases. The fractional pressure shifts [pressure shift in cps/mm Hg divided by the hyperfine splitting in kMc/sec] for hydrogen in helium, neon, molecular hydrogen, and argon are 4.80±0.09, 2.88±0.05, -0.56±0.10, and -4.77±0.12, respectively. Those for tritium in neon and argon are 3.24±0.09 and -5.05±0.15, respectively.