# Fine structure of hydrogen

1. Oct 28, 2012

### copernicus1

Griffiths writes that the formula for the hydrogen energy levels taking fine structure into account "breaks the degeneracy in $l$" but "still preserves degeneracy in $j$." I'm confused by this, because the formula he gives (Eq. 6.67 in the textbook) depends on $j$. How can the system be degenerate in $j$ if the energies depend on $j$?

2. Oct 28, 2012

### Staff: Mentor

"The system is degenerate in j" = "different states with the same j have the same energy"
States with different j can have a different energy, even with the same l.