The Lamb Shift of Helium

Abstract

Using carefully selected oscillator strengths the logarithm of the average excitation energy, measured in rybdergs, appropriate to the Lamb shift is computed to be 4.37 ± 0.03. Taken together with recent calculations by Pekeris, the theoretical value of the ionization potential of helium is 198310 674 ± 0.025 cm-1 compared with 1983 10.82 ± 0.15 cm-1, the experimental value.