Bethe Logarithms for the 11S, 21S, and 23S States of Helium and Helium-like Ions
Jonathan Baker, R C. Forrey, M Jeziorska, J D. Morgan
We have computed the Bethe logarithms for the 11S, 21S, and 23S states of helium to about seven figures using the method developed by Charles Schwartz and further developed by Forrey and Hill. Bethe logarithms for the helium-like ions Li+, Be++, O6+, and S14+ are also calculated for all three states in order to study the 1/Z behavior of the results. The Bethe logarithm of H* was also calculated with somewhat less accuracy. Our results for neutral helium correct the preliminary values of our Bethe logarithms used in the recent article by Drake and Martin and make changes on the order of about 1 MHz or less to the theoretical ionization energies in that work.