Can an electron absorb multiple photons at once?

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    Electron Photons
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Discussion Overview

The discussion centers around the possibility of an electron absorbing multiple photons simultaneously or sequentially to transition between energy levels and subsequently emitting a photon. The scope includes theoretical considerations, quantum electrodynamics (QED), and references to experimental findings.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant proposes that an electron can absorb two photons simultaneously to jump to a higher energy level and emit a higher energy photon.
  • Another participant agrees that the energy difference between the electron's ground state and excited state can correspond to the sum of two photon energies.
  • A different participant questions the existence of references supporting the absorption of multiple photons, specifically six or ten at once.
  • One reply references a publication discussing five-photon absorption in a fluorophore, suggesting that similar principles may apply to electrons.
  • Another participant cites QED formalism, stating that simultaneous absorption of two photons is not possible due to the absence of a corresponding vertex in Feynman rules.
  • Further clarification is sought regarding whether an electron can absorb multiple photons sequentially, with the possibility of emitting one photon after several absorptions being raised.
  • One participant notes that while two-photon absorption is possible, conservation laws may limit the likelihood of multiple photon absorption events.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of simultaneous versus sequential photon absorption by electrons. There is no consensus on the maximum number of photons that can be absorbed or the conditions under which this occurs.

Contextual Notes

Limitations include the need for conservation of angular momentum and energy in photon absorption processes, as well as the increasing unlikelihood of higher-order absorption events.

big_bounce
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Hello all

Is that possible a electron absorbs two photons at the same time to jump to a higher energy level and then emission one higher energy photon and back to before level ?

example : electron absorbs 2 photon by energy 10 and 20 eV and jump up from 2 to 3 energy level and emission a 30 eV photon and back to 2 energy level ?
 
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Yes, it is possible.
The energy difference from the electron in its ground state and excited state corresponds to the sum of the two photon energies.
 
Last edited:
I didn't see in any reference that said a electron can absorbs six or ten photons at same time and emission one equal photon .
Do you see in any reference ?
 
You were asking about two photons before. Why are you now asking about six or ten?
 
Are five photons sufficient? Right now in the advanced online publication of Nature Photonics:
"Frequency-upconverted stimulated emission by simultaneous five-photon absorption" by Q. Zheng et al. (Nature Photonics (2013) doi:10.1038/nphoton.2012.344). Not an electron, but a fluorophore, but I suppose the concept is what matters.

And yes, in principle that works also for higher photon numbers, but please do not ask for a reference about 347-photon absorption.
 
big_bounce said:
Is that possible a electron absorbs two photons at the same time to jump ... ?
According to the details of the QED formalism = Feynman rules it's not possible at the same time b/c there is no vertex with two photon lines.
 
jtbell said:
You were asking about two photons before. Why are you now asking about six or ten?

Because my purpose and my main question was that can electron absorbs many photons and release a equal photon ? and i think maybe my question was unclear . sorry for my English

Number is not important for me !
I want to know electron can absorbs several photons at the same time and emission one equal photon .
if a electron can absorbs two photon why not absorbs 6 or 347 or ... ?
 
tom.stoer said:
According to the details of the QED formalism = Feynman rules it's not possible at the same time b/c there is no vertex with two photon lines.

How about at several time ?

example : electron absorbs one photon and jump from first to second level energy and then absorbs another photon and jump from second to third level and then absorbs another photon and jumps to fourth level and then emission one equal photon and back to first level ? is that possible ?
 
You need to try to ask your questions a bit more specifically. I'm guessing that you are talking about an electron that is bound to an atom right? In this case two-photon absorption is possible (and higher order as well), see for example the wiki page: http://en.wikipedia.org/wiki/Two-photon_absorption. The main restriction which may limit multiple photon absorption events in atoms is conservation of angular momentum/spin. But as long as that is fullfilled (together with energy conservation) there is no reason why they can't happen. Just note that higher order processes are more unlikely.
 

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