Hyperfine Structure ofHe3+andHe3

The ratio of the hfs of ${\mathrm{He}}^{3+}$ to ${\mathrm{H}}^1$ is calculated by taking into account all effects other than the radiative mass corrections, $\frac{\alpha m}{M}$ (hfs), which contribute a relative correction to hfs greater than ${10}^{-6\mathrm{}}$. This includes the effect of nuclear structure and internal motion, and also of interaction currents calculated according to various models. Following A. Bohr, structure effects are calculated in the adiabatic approximation, and corrections for nonadiabaticity are included. Nuclear orbital hfs is evaluated by a perturbation theory which proceeds from a nonadiabatic approximation, and a rather simple general expression is obtained for the evaluation of the effect of interaction currents. Corrections are obtained to the hfs of the ${\mathrm{He}}^3{}_{}{}^3{}_{}{}^{}S$ atomic state, as calculated with a nonrelativistic wave function for a point nucleus of infinite mass. These corrections include both the nuclear structure effects for which the analysis of ${\mathrm{He}}^{3+}$ applies, and the relativistic and reduced mass effects characteristic of the two-electron atom.