# Selection rules for Hydrogen

1. Oct 16, 2015

### temp050505

Good afternoon,

Does the selection rules have a condition on $\Delta n$ ? I have not found a website or a book that show transitions between $2S_{1/2}$ and $2P_{3/2}$, that's why I was wondering if $\Delta n = 0$, with respect to the other selection rules, are allowed transitions.

2. Oct 16, 2015

### blue_leaf77

$\Delta n = 0$ is not a restriction for a transition to occur, in fact when one takes spin-orbit effect into account the levels of constant $n$ split further and transitions among them can happen.

3. Oct 16, 2015

Thanks !