= Spontaneous emission
{wiki}
Do electrons spontaneously jump from high orbitals to lower ones emitting photons?
Explaining this was was one of the key initial achievements of the <Dirac equation>.
Yes, but this is not predicted by the <Schrödinger equation>, you need to go to the <Dirac equation>.
A critical application of this phenomena is <laser>.
See also:
* https://physics.stackexchange.com/questions/233330/why-do-electrons-jump-between-orbitals
* https://physics.stackexchange.com/questions/117417/quantum-mechanics-scattering-theory/522220\#522220
* https://physics.stackexchange.com/questions/430268/stimulated-emission-how-can-giving-energy-to-electrons-make-them-decay-to-a-low/430288