The gyromagnetic ratios of neon and argon in their metastable ${}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$ states have been measured by the atomic beam magnetic resonance method. The results are $g_J(\mathrm{Ne}, {}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{})=1.500888\mathrm{}\pm 0.000005$ and $g_J(\mathrm{A}, {}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{})=1.500964\mathrm{}\pm 0.000008$, in agreement with the less precise optical spectroscopic measurements. Theoretical values, including radiative and relativistic effects, are $g_J(\mathrm{Ne}, {}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{})=1.50088\mathrm{}$ and $g_J(\mathrm{A}, {}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{})=1.50095\mathrm{}$, in good agreement with the experimental values. In addition, the Zeeman transition frequency for neon has been measured as a function of magnetic field to obtain evidence that the magnetic moment of ${\mathrm{Ne}}^{20}$ is less than 4×${10}^{-4\mathrm{}}$ nuclear magneton and hence that the spin of ${\mathrm{Ne}}^{20}$ is probably zero.

• Received 24 May 1960

DOI:https://doi.org/10.1103/PhysRev.120.153