Spin-orbit effects splits !? Hi AllL the spin-orbit effect splits the 3P-->3S transition in sodium(which gives rise to the yellow light of sodium vapor highway lamps) into two lines 589.0 nm corresponding to 3P sub 3/2-->3S sub 1/2 and 589.6nm corresponding to 3P sub 1/2 --> 3S sub 1/2. How can I use these wavelengths to calculate the effective magnetic field experinced by the outer electron in the sodium atom as a result of its orbital motion ??