Pressure Shifts of the Hyperfine Structure of Atomic Nitrogen

The hyperfine structure of atomic nitrogen in the ${\mathrm{}\left(2p\right)\mathrm{}}^3{}_{}{}^4{}_{}{}^{}S_{\frac{3}{2}}^{}{}_{}{}^{}$ electronic ground state has been investigated by the spin-exchange optical polarization method. The transmission of circularly polarized rubidium $D_1(5\mathrm{}{}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}\leftrightarrow 5{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{})$ resonance radiation through a flask containing rubidium vapor, a buffer gas, and atomic nitrogen was observed as a function of the frequency of an applied radio-frequency field. Measurements were made at pressures ranging from 10 to 65 mm Hg in neon, argon, helium, and molecular nitrogen buffer gases. The extrapolated zero-pressure frequency intervals and their corresponding pressure shifts, as determined by the method of least squares, are