A question regarding excitation of electrons in atomic orbitals

Question

In Bohr's model of an atom, the formula used to find the energy between the 2 orbits and wavelength of emitted photon was valid only for single electron species like hydrogen.In the case of a multi-electron system like in the picture given above will the electron absorb a photon to go from 2s to 2p and also remitt a photon while dexciting from 2p to 2s.There are also elements like sulphur with two excited states thus showing variable covalency but how do the electrons not dexcite from higher energy orbital in a short time but give enough time gap to show two excitation states?Is the dexcitation and remission of photon a phenomenon which can only be seen when an electron goes from one shell to another like from n=1 to n=2 or can it also be seen when electron goes from orbitals and sub shells like 2s to 2p?Since there is an energy difference between the 2s and 2p sub shells there must be remission of photon on excitation but I did not find any online sources to verify this, so I need help.

Answer 1

The electron can go to any state allowed by the selection rules for the corresponding type of transitions considered (e.g. electric dipole transitions). So this means there are in general different decay channels available for the electron. Which channel it takes is a random process, with a statistical weight given by the corresponding decay probability in the respective levels (which depends on the transition frequency and the overlap integral for the two wave functions of the states involved in the transition). Of course, an electron in a given atom can lastly go only into one of the states available, but an electron in a different atom may go into a different state. This is why you can see more than one spectral line from an ensemble of many atoms. Having said this, in your example there is actually only one way the excited electron can go, namely where it came from.