Last week I posted this question which was massively downvoted. The downvotes appear to be largely motivated by an observation I made which was not essential to the question, but which seems to have branded me as a quack in the eyes of the downvoters. Here is what I said:
It is common to talk about an atom absorbing a photon, transitioning to a higher energy state, and then re-emitting the photon. But none of this is directly observable. All you can really do is shine light on some atoms and measure the scattered radiation. You never actually observe "an atom/molecule in an excited state".
I still think this is correct. How would you possibly observe a hydrogen atom in a 2p state? You can infer that it must have been in that state when you detect a photon, but that's a little indirect isn't it?