Pachucki, KrzysztofKomasa, Jacek2010-03-182010-03-182004Phys. Rev. Lett. 92, 213001 (2004)1079-7114http://hdl.handle.net/10593/199Complete relativistic and quantum electrodynamics corrections of order α2 Ry and α3 Ry are calculated for the ground state of the beryllium atom and its positive ion. A basis set of correlated Gaussian functions is used, with exponents optimized against nonrelativistic binding energies. The results for Bethe logarithms lnk0(Be)=5.750 34(3) and lnk0(Be+)=5.751 67(3) demonstrate the availability of high precision theoretical predictions for energy levels of the beryllium atom and light ions. Our recommended value of the ionization potential 75 192.514(80)   cm-1 agrees with equally accurate available experimental values.en-USberyllium atomrelativistic correctionsquantum electrodynamics correctionsBethe logarithmsIonization potentialCorrelated Gaussian functionsArtykuł