Difference between photon and electron collisions with atoms

[Daveami]

Hi,

Would anyone be able to explain the main differences between the effect of electrons and photons colliding with atoms in the ground state.

As far as I understand they are very similar as both cause excitation and in some cases ionization.

Any help would be greatly appreciated.

Dave

 

[dulrich]

One difference is that the electron is charged while the photon is not. So the photon will collide with the atom based solely on its energy, while the electron will interact electromagnetically with the electrons.

In addition, a photon can be completely absorbed while an electron cannot.

 

[magnetic flux]

The photon could collide with an electron from the atom as described in the Compton effect, pushing the electron a little. The photon will loose some of its energy (therefore frequency as well) and fly off in another direction. An electron could bump into another electron as described as well, but they would not collide like you would think of two marbles, but rather electromagnetically, like dulrich already said.

But both can exite an atom, which might later emit a photon and glow. The electron collision resulting in light is something one finds in an x-ray cathode, or a regular gas lamp like a neon sign. The photon collision resulting in light would be all flouroscense, like one has in these bright colors and most glow-in-the-dark stuff as well.

 

[Daveami]

Brilliant, thank you both for your help!

 

[rdl]

Hello Dave,

Thank you for your question. The main difference between photon and electron collisions with atoms lies in the nature of the particles themselves. A photon is a particle of light, while an electron is a negatively charged subatomic particle. This difference in charge and mass leads to different interactions with atoms.

When a photon collides with an atom, it can either be absorbed or scattered. If it is absorbed, it can transfer its energy to the atom, causing it to become excited or even ionized. However, if it is scattered, it simply changes direction and does not transfer its energy to the atom.

On the other hand, when an electron collides with an atom, it can transfer its energy to the atom through a process called collisional excitation. This can result in the atom becoming excited or ionized. Additionally, the electron can also interact with the atomic nucleus, causing further changes in the atom's energy state.

In terms of energy transfer, photons tend to have a higher energy than electrons, so they are more likely to cause ionization. However, electrons can transfer their energy more efficiently due to their mass and charge, making them more effective at causing excitation and ionization in atoms.

I hope this helps to clarify the differences between photon and electron collisions with atoms. Let me know if you have any further questions.

Best,