Many-Body Approach to Hyperfine Structure in theP2State of Lithium

Abstract

The Brueckner-Goldstone (BG) many-body perturbation theory has been applied in a calculation of the hyperfine structure (hfs) of lithium in the excited $1s^{2}2p\left({}_{}{}^2{}_{}{}^{}P\right)$ state. This is the first complete calculation of hfs by the BG theory in a nonspherical system. Our result for $a_{\frac{1}{2}}$ is 45.86 Mc/sec in excellent agreement with the experimental result of 46.17 ± 0.35 Mc/sec. In addition, we obtained the value $a_{\frac{3}{2}}=-2.79\mathrm{}$ Mc/sec for which no direct experimental result is currently available. The contributions from each of the magnetic hyperfine interactions and also the electric quadrupole moment interaction are presented. This approach also makes possible an analysis of the relative importance of various physical effects in each case.