The novel aspect of hydrogen atom: the fine structure and spin can be   derived by single component wavefunction
  The fine structure of hydrogen energy was calculated by using the usual momentum-wavefunction relation directly, rather than establishing the well-known Dirac wave equation. As the results, the energy levels are completely the same as that of the Dirac wave equation, while the wavefunction is single component that is quite different from Dirac's four component wavefunction, the most important thing is that the present calculation brings out electronic spin in a new way which has never been reported and indicates that the electronic spin is a kind of orbital motion. 
H. Y. Cui