# Principle Quantum Number - Transition

1. Dec 1, 2009

### cpmiller

1. The problem statement, all variables and given/known data
Is the following transition allowed?

[4,3,0,1/2] -> [4,2,1, -1/2]

If so, find the energy involved and whether the photon is absorbed or emitted for the hydrogen atom.

2. Relevant equations

Selection rules for allowed transitions:
$$\Delta$$n = anything
$$\Delta$$l =$$\pm$$1
$$\Delta$$ml = 0 or $$\pm$$1

3. The attempt at a solution

$$\Delta$$ n = 4-4 = 0
$$\Delta$$ l = 3-2 = 1
$$\Delta$$ml = 0-1= -1

So all of the transitions are allowed, but it doesn't quite make sense to me.

There is no energy involved, because $$\Delta$$ n = 0, which means that this electron just suddenly spontaneously decided to be in a different configuration, can it do that?

(I also checked and it looks like both of the states are allowed...)

Can it do that, am I missing something?