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.

• Received 3 May 1976

DOI:https://doi.org/10.1103/PhysRevA.14.1296