When does photon emisson occurs ?

[yaxlei]

Hello,

Imagine having exited an electron and it went on a higher energy atom orbit. Is it possible to predict when the electron will emits a photon to lower his energy? If it's hazardous , does it follow a probabilistic model like a gaussian curve or smth like that?

ty for your answers!

[studiot]

4 hours ago, yaxlei said:

Hello,

Imagine having exited an electron and it went on a higher energy atom orbit. Is it possible to predict when the electron will emits a photon to lower his energy? If it's hazardous , does it follow a probabilistic model like a gaussian curve or smth like that?

ty for your answers!

It's complicated by the fact that the electron in general doesn't return to the ground state by the same sequence of energy levels it jumped up.
Some transitions are forbidden, for spin and other reasons.
This is why for instance luminescence occurs and the difference in timing accounts for the difference ebtween phosphorescence and luminescence.

Well would all appreciate full English words in your answer.

[mathematic]

I'm not absolutely sure, but I believe the time distribution for decay is exponential.

[swansont]

For a simple two-level system it is exponential. As studiot has stated, for many-state systems there are extra factors to consider

In addition, you can "reset the clock" by interrogating the atom and confirming it hasn't decayed, keeping it in the excited state for much longer (the quantum Zeno effect). You can also inhibit or enhance the decay by putting the atom in a cavity that changes the density of states into which the emitted photon would couple. If there are no photon modes supported, the atom doesn't decay at all. 

[studiot]

10 hours ago, mathematic said:

I'm not absolutely sure, but I believe the time distribution for decay is exponential.

negative exponential.