Experiments on the2P3State of Helium. II. Measurements of the Zeeman Effect

Abstract

A series of Zeeman resonances has been measured in the $2{}_{}{}^3{}_{}{}^{}P$ state of ${\mathrm{He}}^4$, using the optical-microwave atomic-beam magnetic-resonance technique. The results were analyzed in terms of relativistic and motional contributions to the Zeeman effect, and are presented in the form of corrected $g$ factors: $g_{S^{\prime }}=g_S-(76.0\mathrm{}\pm 2.4)\times {10}^{-6\mathrm{}}$, $g_{L^{\prime }}=g_L+(3.8\mathrm{}\pm 9.0)\times {10}^{-6\mathrm{}}$, and an additional factor $g_x=(4.0\mathrm{}\pm 25.0)\times {10}^{-6\mathrm{}}$. These are compared with theoretical calculations using quasi-hydrogenic radial wave functions which give $g_{S^{\prime }}=g_S-(79.9\mathrm{}\pm 3.5)\times {10}^{-6\mathrm{}}$, $g_{L^{\prime }}=g_L+(1.1\mathrm{}\pm 1.5)\times {10}^{-6\mathrm{}}$, and $g_x=-(3.2\mathrm{}\pm 4.4)\times {10}^{-6\mathrm{}}$. The values of the experimental $g$ factors are $g_S^1=2.002\mathrm{}2432\pm 0.0000224$, and $g_L^1=0.\mathrm{}999867\pm 0.000009$. The validity of the theory and the consistency of the data are discussed. The experimental results were used to reduce the quoted uncertainty in a previously reported fine-structure measurement. The new result is $E\left(2\mathrm{}{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}\right)-E\left(2\mathrm{}{}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}\right)=2291.\mathrm{}196\pm 0.005$ MHz.