Photoelectric Effect and Conservation of Momentum

[/0]

It's something I've never really noticed until recently, but superficially it seems that the photoelectric effect violates conservation of momentum.

I mean your classic diagram for the photoelectric effect goes like this:



The photon comes in from above, and the electron shoots back up! Wouldn't you expect the electron to be pushed down, due to conservation of momentum?

Anyone have any ideas why this is?

[Mao]

That is, assuming the metal doesn't move.

Are you sure the metal will remain perfectly stationary?

[/0]

I don't think the metal needs to move. It's just the interactions of one photon and one electron (delocalised).

Besides, isn't the photoelectric effect supposed to be a special case of compton scattering, which strictly adheres to conservation laws?

[Mao]

Apparently, the metallic lattice absorbs the recoil momentum. http://www.physicsforums.com/archive/index.php/t-73979.html

[QuantumJG]

It's something I've never really noticed until recently, but superficially it seems that the photoelectric effect violates conservation of momentum.

I mean your classic diagram for the photoelectric effect goes like this:

(Image removed from quote.)

The photon comes in from above, and the electron shoots back up! Wouldn't you expect the electron to be pushed down, due to conservation of momentum?

Anyone have any ideas why this is?

I'm doing a prac on this today.

The metallic lattice absorbs the recoil momentum as what Mao said.

We are starting to discuss in lectures what the wave-like nature of particles is and the Born interpretation, the next few lectures are going to be really mathematical!

[/0]

Lol yeah I did a prac on the photoelectric effect today. Got Planck's constant as , I'm just glad it's not negative XD

Oh yeah and in Quantum Mechanics we just finished talking about the 'old quantum mechanics' and now we're gonna discuss Schrodinger's wave equation! It's gonna be so awesome.

[Cthulhu]

Schrodinger's equation \o/ Fun stuff.

[QuantumJG]

In the prac we got h/e to be 3.177x10^{-15[/sub] Js/C.}

[/0]

wow gj, that's pretty close