Calculations of magnetic moments for three-electron atomic systems

The first fully correlated calculations of the magnetic moment in lithium are presented. Relative to the free-electron value, the Zeeman g(J) factor for the ground state lithium g(J)/g(e) - 1 is calculated to a computational accuracy of 200 parts in 10(9), including relativistic and radiative corrections of orders alpha (2) alpha (2)m/M and alpha (3). The isotope shifts in g(J) are predicted precisely for various isotopes. The extensions to the first excited S state of lithium and the ground state of Be+ are made.