For an atom, individual electron spins are added to get a total spin, and individual orbital angular momenta are added to get a total orbital angular momentum. These two then are added using angular momentum coupling to get a total angular momentum. For an atom with no nuclear magnetic moment, the magnitude of the atomic dipole moment, m atom , is then m atom = g J μ μ B j ( j + 1 ) where j is the total angular momentum quantum number, g J is the Landé g -factor, and μ B is the Bohr magneton. The component of this magnetic moment along the direction of the magnetic field is then m atom , z = − − m g J μ μ B .