Question about energy needed by electron to change energy levels

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Discussion Overview

The discussion centers around the energy transitions of electrons between energy levels in an atom, specifically addressing the conditions under which an electron can move to a higher energy level upon absorbing a photon. The scope includes theoretical considerations of energy absorption, photon interactions, and the implications of excess energy.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that if a photon has energy greater than the required energy difference for an electron to transition to a higher energy level, the electron may not move to that level.
  • One participant suggests that the electron will remain in its initial state if the energy does not match the required transition energy, even if the photon energy exceeds it.
  • Questions arise about the fate of the excess energy from the photon if the electron does not transition, with some participants speculating that the photon may scatter rather than be absorbed.
  • Another participant introduces the concept of momentum and energy conservation in the context of scattering processes, suggesting that the photon may transfer some energy to the electron as kinetic energy without causing a state change.
  • There is a mention of Compton scattering as a possible mechanism for the interaction between the photon and the electron.

Areas of Agreement / Disagreement

Participants express differing views on whether an electron can transition to a higher energy level when the incident photon has excess energy. Some assert that the electron will remain in its initial state, while others explore the possibility of scattering and energy transfer without a state change. The discussion remains unresolved regarding the exact outcomes of such interactions.

Contextual Notes

Participants do not reach a consensus on the implications of excess photon energy, and there are unresolved questions about the specific mechanisms of energy transfer and scattering processes.

Who May Find This Useful

This discussion may be of interest to those studying atomic physics, quantum mechanics, or anyone exploring the interactions between light and matter.

songoku
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TL;DR
This learning material is high - school level

Let say hypothetically there are 2 different energy levels in an atom, n =1 state and n = 2 state and at n = 1 the electron has energy level of 5 eV and at n = 2 the electron has energy level of 8 eV.

What happens to the electron, when at n = 1 there is photon of energy 4 eV falls on it? Will it move to n = 2 state or will it stay at n = 1?
Electron can move from lower energy level to higher energy level when it absorbs energy equal to the difference between the energy levels based on equation: ##hf = \Delta E##

If the incident photon has lower energy compared to ##\Delta E##, then electron won't move to higher energy level. But what about if the incident photon has higher energy compared to ##\Delta E##?

1. Will the electron still move to n = 2 by only absorbing 3 eV from the photon and "ignoring" the remainder 1 eV? If yes, what happens to the remainder 1 eV?

2. Or maybe the electron just stay at n = 1 because the energy of photon does not match the required energy to move to n = 2, even tough the energy is more than required?

Thanks
 
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songoku said:
Will it move to n = 2 state or will it stay at n = 1?

It will stay at n = 1.
 
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PeterDonis said:
It will stay at n = 1.
So what happens to the photon carrying the 4 eV energy? Will the photon disappear and all the energy is dissipated as heat inside the atom or the photon will just bounce off the electron and moving away carrying all the 4 eV energy or maybe something else?

Thanks
 
songoku said:
So what happens to the photon carrying the 4 eV energy?

Remember, that you must conserve momentum and energy of the atom+photon system! This is a scattering process.
 
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etotheipi said:
Remember, that you must conserve momentum and energy of the atom+photon system! This is a scattering processs
Are you maybe referring to Compton scattering? The photon will hit the electron and then move at certain angle to conserve momentum, and some of energy of initial photon will be transferred to electron (as KE of the electron) so the scattered photon will have lower energy compared to initial photon?

This means that the electron will move (because it gains KE) but will not change state?

Thanks
 
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songoku said:
So what happens to the photon carrying the 4 eV energy?

It doesn't get absorbed. It might scatter off the atom.
 
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Thank you very much PeterDonis and etotheipi
 

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