In this lecture I discuss the use of perturbation theory to study the fine structure of hydrogenic spectra. I show that the degeneracy of the Kepler problem is partly lifted by the first order fine structure corrections - so thatthat in addition to the principal quantum number n, the energy shifts depend on the total angular momentum quantum number j. I then go on to . explain the effect this has on the spectrum In particular I explain the fine structure of the Lyman and the Balmer series.
