What Are the Rules for Electron Absorption and Emission in Atoms?

DeG
Messages
23
Reaction score
0
This is my understanding; please, correct me if I'm wrong.
If you bombard an atom with em-waves they will never break loose electrons until a certain threshold frequency. At this point the intensity of the light (or the amount of photons) striking the atom is proportional to the number of electrons ejected. The additional energy in the photon, beyond the energy required to break the bond, goes into kinetic energy of the electron. Electrons also absorb and emit specific frequencies of light when jumping between specific orbitals.
Does the threshold frequency only apply to breaking an electron loose, i.e. out of the atoms orbitals, and does this mean they can absorb any frequency above the threshold? Do the emission/ absorption frequencies only happen at discrete, exact values (versus a distribution of values)? Can they absorb higher energy photons, jump orbitals, then take the remaining energy as kinetic or even re-emit it as a lower frequency photon?
Thanks
 
Physics news on Phys.org
I am not an expert, but I will take a shot at answering your questions.

does this mean they can absorb any frequency above the threshold?

Yes. Only bound particles are restricted to carrying specific amounts of energy.

Do the emission/ absorption frequencies only happen at discrete, exact values?

No. The uncertainty principle dictates that a process with a known amount of time has an uncertain amount of energy. Spectral lines are not infinitely thin. Instead, there is a very small range in which the energy can be absorbed/emitted.

Can they absorb higher energy photons, jump orbitals, then take the remaining energy as kinetic or even re-emit it as a lower frequency photon?

If the electron is still bound, no. The energy of a photon emitted or absorbed can only be equal to the difference between two energy levels in the atom.

It actually took me some research to find these answers, so I hope you like them.
 
Nice, thank you very much. That all makes a lot of sense.
 
DeG said:
Nice, thank you very much. That all makes a lot of sense.

You're welcome. I guess I should also add that, while the electron can't absorb a fractional amount of energy from a photon, the atom as a whole can, since the atom itself is not bound.

https://www.physicsforums.com/showthread.php?t=515982
 
From the BCS theory of superconductivity is well known that the superfluid density smoothly decreases with increasing temperature. Annihilated superfluid carriers become normal and lose their momenta on lattice atoms. So if we induce a persistent supercurrent in a ring below Tc and after that slowly increase the temperature, we must observe a decrease in the actual supercurrent, because the density of electron pairs and total supercurrent momentum decrease. However, this supercurrent...
Hi. I have got question as in title. How can idea of instantaneous dipole moment for atoms like, for example hydrogen be consistent with idea of orbitals? At my level of knowledge London dispersion forces are derived taking into account Bohr model of atom. But we know today that this model is not correct. If it would be correct I understand that at each time electron is at some point at radius at some angle and there is dipole moment at this time from nucleus to electron at orbit. But how...

Similar threads

Back
Top