1959 Articles

Variational Calculations of Energy and Fine Structure for the 2³P State of Helium

Traub, Joseph F.

ERV accurate calculations of the energies of the 1s2 1S and 1s2s3S states of helium have been made recently. It is now possible to consider the contributions of relativistic and electrodynamic effects to the observed ionization energies in a meaningful way. These small effects must still be added to the large calculated nonrelativistic energy, however, before a comparison with experiment can be made. In the 3P states, the spin-dependent part of the theoretical electromagnetic interaction of the two electrons can be compared directly with observed fine-structure splittings. Recent improvements in the experimental accuracy of the fine-structure measurements, 45 particularly the direct observation of the splittings as radio-frequency transitions, have made such a comparison possible to an order of accuracy including higher order electrodynamic corrections to the usual fine structure formulas.