Do electrons need specific energies to excite electrons

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Discussion Overview

The discussion centers on whether electrons require specific energy levels to excite other electrons in atoms, similar to how photons interact with atomic energy levels. The scope includes theoretical considerations of electron scattering and energy transitions in atomic systems.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that photons need specific energy levels to excite electrons, questioning if the same applies to colliding electrons.
  • It is noted that atomic energy levels are quantized, and for an electron to leave an atom in an excited state, it must give up a specific amount of energy.
  • One participant suggests that incoming electron energies may be particularly likely to result in excitation, leading to the investigation of electron scattering spectra.
  • Another participant highlights that while photons are neutral, electrons are charged, which introduces electromagnetic repulsion into their interactions with atoms.
  • It is mentioned that an electron can induce an energy-level transition by transferring kinetic energy corresponding to that transition, as illustrated by the Franck-Hertz experiment.
  • One viewpoint states that an incoming electron only needs to have kinetic energy greater than the energy difference between levels, rather than a specific amount, allowing it to transfer part of its energy to the atom.

Areas of Agreement / Disagreement

Participants express differing views on whether specific energies are required for electrons to excite other electrons, with some suggesting that only a minimum kinetic energy is necessary while others emphasize the importance of quantized energy levels.

Contextual Notes

There are unresolved aspects regarding the dependence on definitions of energy levels and the implications of electromagnetic interactions in electron-atom collisions.

GeneralOJB
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Photons need specific energy levels, equal to the difference between two energy levels to excite an electron in an atom. Is this the same case with electrons that collide with atoms?
 
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Atomic energy levels are quantized.
For a scattered electron to leave an atom in an excited state, then it must have given up a particular amount of energy. You want to know if some electron energies are particularly likely to leave an atom in an excited state.

You want to investigate electron scattering spectra.

Note: photons are absorbed by the atom - leaving it in an excited state.
If an electron were absorbed into the atom, it would have to enter a particular orbital - incedentally turning your atom into an ion.
In that context, your question is asking if some incoming electron energies are particularly likely to get the electron captured.

This would come under electron absorption spectra.
 
Is this the same case with electrons that collide with atoms?

As Simon points out, only certain energies are allowed...electron energies in an atom are quantized...and remain so...so in that sense yes.

What is different is that while photons are electrically neutral, electrons are not...so electromagnetic repulsion plays a role in behavior.
 
When an electron collides with an atom, it can induce an energy-level transition by giving up an amount of kinetic energy that corresponds to that particular transition. It can then continue on its way with a reduced amount of kinetic energy.

See for example the Franck-Hertz experiment.
 
Incoming electron is only required to carry a K.E. which is larger than the difference in energy levels but not required to be a specific amount. As it can give out part of its energy to the atom, unlike photon which can give either all its energy or nothing.
 

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