Calculated anisotropies for the quenching radiation in the hydrogen isoelectronic sequence

Abstract

Accurate values of the Lamb shift can be derived from measurements of the anisotropy in the angular distribution of the radiation accompanying the electric field induced $2s$-$1s$ transition of hydrogen. Calculations of the anisotropy, including relativistic and hyperfine structure corrections, are presented for the hydrogenic ions up to ${\mathrm{S}}^{15+}$. The data enable the calculation of the Lamb shift from a measured value of the anisotropy.