Feynman didn't understand many things, judging from all the errors in his Lectures. All "spooky" quantum effects are nothing else but statistics and only people who don't know statistics thoroughly enough (which applies to the majority of scientists) claim otherwise.
No laws of physics are broken in photoluminescence
. When one finds that the laws of physics are broken, in 99.99% of cases it means that they do something wrong (e.g. don't take into account all important factors), in 0.01% of cases that they discover something new and in 0% cases that they are Collector. And when people give you meaningless percentage estimations, they are from finance - I'm just mocking you
The selection rules
dictate which electron transitions are "allowed" and which are "forbidden". The rules result from the properties of wave function of states betweeh which the transitions are being considered. You calculate a so called transition momentum integral
which is basically the probability of such a transition. Theoretically this probability is zero is when the states have different multiplicity
, i.e. the transition would require changing the spin of electron - it's simply energetically unfavourable. However, the complete energetic calculation should include a lot of effects other than the properties of the single electron states, e.g. spin-orbit interaction
, many-body interactions between the molecule atoms and electrons, etc. (just like there are some exceptions to Hund's rules
in the periodic system of elements). The corrections are usually second order, but can induce a non-zero probability of the "forbidden" transition
is due to such a "correction", and it's usually mainly the spin-orbit interaction (which is due to the specific features of the crystal symmetry) - what happens is the change in spin angular momentum
compensates for the change in orbital angular momentum
due to the transition. The unusually long phosphorescence duration (the materials can shine for hours) is related to the fact that the probability of this "forbidden" transition is very small (the correction is a higher order effect and generates just a very small transition momentum/probability - the electron "leaks" is density very slowly from its initial state to the final state).
It's actually chemistry, not physics. Quantum chemistry. I completed a BSc course in chemistry and even planned of continuing in this particular specialisation. It was many years ago, but the above problem is quite basics.
(Keywords in bold)