Photoelectric Effect

[enslam]

I'm having some trouble understanding some parts of the photoelectric effect.
I get the part about how the photon transfers some/all of its energy to excite and electron and emmit it from the atom but wouldn't this make the atom become unstable because it dosen't have a full outer shell.

[PRodQuanta]

It's called ionization.
Paden Roder

[Chi Meson]

Originally posted by enslam
I'm having some trouble understanding some parts of the photoelectric effect.
I get the part about how the photon transfers some/all of its energy to excite and electron and emmit it from the atom but wouldn't this make the atom become unstable because it dosen't have a full outer shell.

It's not "some/all" . THe photon can only transfer all of its energy to one electron. THis was the breakthrough of Einstein for which he received the Nobel Prize.

The atoms in a contucting material will all have a "free electron." THis is an electron that is very loosely attached to a nucleus. So loose, in fact, that all free electrons will float around and through the material. When these electrons get hit by a photon, they receive a jolt of energy. IF the energy is more than the "work function" of the metal, then the electron will leaver the metal.

If the metal is grounded, it can easily suck up a replacement electron from the earth. If the metal is not grounded, then it will require more and more energy for each subsequent photo-electron to be emitted.

[Chi Meson]

I don't think my last post answered your question.

The atom does not become chemically unstable, because conductors (usually metals) do not have a full outer shell to begin with. In fact metals (OK chemsts out there, I'm talking generally here) are usually trying to get rid of one or two electrons. In a lump of metal, those free electrons are being essentially ignored by their nuclei, so in a sense, the atoms are accustomed to being without an electron.

Some folks don't like to anthropomorphize, but it's really close to a long weekend and I like the image of a lost electron wandering from house to house when BAM! it's struck by a speeding photonmobile, and the little electron is knocked clean out of its world.

[VBPhysics]

I like the image of a lost electron wandering from house to house when BAM! it's struck by a speeding photonmobile, and the little electron is knocked clean out of its world.

That is quite possibly the best interpretation of the PE that I have ever heard in my life. Can I have permission to reprint this?

[Chi Meson]

Originally posted by VBPhysics
That is quite possibly the best interpretation of the PE that I have ever heard in my life. Can I have permission to reprint this?

You're not joking? Be my guest.

[1100f]

BTW, although, historically, the explanation of the photoelectric effect was that light was made of photons with each photon having an energy of \hbar\omega. This gave the basis of the quantum mechanics. However, if we solve the Schrodinger equation of a charged particle in an attractive potential (which will give bound states with discrete ebergy levels) in the presence of a classical oscillating electromagnetic field (light) with frequency \omega, there will be transitions between difernt energy levels only if the energy difference between the two levels will be \hbar\omega. So that in fact, the PE can be explained ,in the framework of quantum mechanics, even if light is not made of photons but is a classical wave.