N14-N15Hyperfine Anomaly

Abstract

The optical transmission of an optically oriented sodium vapor in spin-exchange equilibrium with atomic nitrogen has been used to measure the zero-field hyperfine splitting of ${\mathrm{N}}^{14}$ and ${\mathrm{N}}^{15}$. The ground state of atomic nitrogen is ${}_{}{}^4{}_{}{}^{}S_{\frac{3}{2}}^{}{}_{}{}^{}$. For ${\mathrm{N}}^{14}$, which has $I=1\mathrm{}$, $\Delta {\nu }_{\frac{5}{2}\to \frac{3}{2}}=26.12721\mathrm{}\pm 0.00018 \mathrm{Mc}/sec,$ $\Delta {\nu }_{\frac{3}{2}\to \frac{1}{2}}=15.67646\mathrm{}\pm 0.00012 \mathrm{Mc}/sec.$ For ${\mathrm{N}}^{15}$, which has $I=\frac{1}{2}$, $\Delta \nu =29.29136\mathrm{}\pm 0.00016 \mathrm{Mc}/sec.$