Nitrogen Buffer Gas Research Articles

Pressure Shifts of the Hyperfine Structure of Atomic Nitrogen

The hyperfine structure of atomic nitrogen in the ${(2p)}^{3}^{4}S_{\frac{3}{2}}$ electronic ground state has been investigated by the spin-exchange optical polarization method. The transmission of circularly polarized rubidium ${D}_{1}(5^{2}P_{\frac{1}{2}}\ensuremath{\leftrightarrow}5^{2}S_{\frac{1}{2}})$ 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 Average values found for the hyperfine interaction constants are: ${A({\mathrm{N}}^{14}),=+10450930\ifmmode\pm\else\textpm\fi{}8 \mathrm{cps}}{B({\mathrm{N}}^{14}),=+ 1\ifmmode\pm\else\textpm\fi{}5 \mathrm{cps}}{A({\mathrm{N}}^{15}),=\ensuremath{-}14645457\ifmmode\pm\else\textpm\fi{}5 \mathrm{cps}}$The quoted errors are based on the dispersion of the various extrapolated values of the zero-pressure intervals. In terms of the statistical variation of the data this error is equivalent to three standard deviations of the mean.The experimental pressure shifts are compared with a theory recently proposed by Adrian and an expression is derived for the Stark shift of the nitrogen hyperfine structure.