Why does total angular momentum cause energy splitting in Lyman Hydrogen series?

[Goodver]

I have read that Lyman series of Hydrogen atom occur on the n = 2 level, and it is due to electron orbital coupling.

Suppose I understand what is an electron-orbital coupling, and that one gets 3/2 and 1/2 total angular momentum for n = 2 level.

But, from quantum mechanical derivation of the orbitals of Hydrogen atom, the energy level depends only on n quantum number, and that p orbitals caused by possible set of m numbers are degenerate.

How total angular momentum causes energy splitting, if electron-orbital coupling is due to spin and angular momenta which are degenerate?

Thank you.

 

[DrClaude]

Relativity. The degeneracy is present in the non-relativistic Hamiltonian, where the only potential term is the Coulomb interaction. Spin-orbit coupling comes from a relativistic correction.