HYPERFINE STRUCTURE OF HELIUM THREE

Relativistic contributions to the hyperfine structure of Helium 3 are re-examined in order to resolve the inconsistencies in the published values. The orbit-orbit and diamagnetic screening contributions are recomputed. They are each found to contribute less than one part per million, contrary to published values. A new value is obtained for the relativistic velocity correction by comparing the hyperfine structure computed using non-relativistic Hartree-Fock wave functions with that computed using recently available relativistic Hartree-Fock wave functions. The resulting correction is 318 ppm compared with a previously published result of 327 ppm calculated by perturbation theory. A review of all contributions to the hyperfine structure including nuclear structure corrections is presented. New values of the hyperfine structure splitting of Helium 3 in the 1S2S state and of the ratio of this splitting to the hyperfine structure splitting of the Helium 3 ion in the 1S and 2S states are calculated and compared with experiment. Comparison with experiment suggests that the relativistic velocity correction is 323 ppm and that the total nuclear structure correction is 185.8 ppm.