swansont Posted June 10, 2013 Share Posted June 10, 2013 Would the electron repel the photon as if it had the same charge? And is it impossible for free electrons to absorb photons? No. There's nothing like electrostatic repulsion going on. Free electrons can't absorb photons. Either energy or momentum would not be conserved; it's a nice little exercise for those learning this level of physics to show this. Link to comment Share on other sites More sharing options...
Sato Posted June 10, 2013 Author Share Posted June 10, 2013 No. There's nothing like electrostatic repulsion going on. Free electrons can't absorb photons. Either energy or momentum would not be conserved; it's a nice little exercise for those learning this level of physics to show this. Oh okay, unfortunately I do not think I am at that level yet. If it's not like that, then what causes the photon to scatter away from the electron? Link to comment Share on other sites More sharing options...
swansont Posted June 11, 2013 Share Posted June 11, 2013 Oh okay, unfortunately I do not think I am at that level yet. If it's not like that, then what causes the photon to scatter away from the electron? Photons interact electromagnetically, and electrons do as well. Link to comment Share on other sites More sharing options...
Sato Posted June 11, 2013 Author Share Posted June 11, 2013 Photons interact electromagnetically, and electrons do as well. Oh okay, and it's a concrete law of electromagnetism that unbound electrons will repel photons? Link to comment Share on other sites More sharing options...
swansont Posted June 11, 2013 Share Posted June 11, 2013 Oh okay, and it's a concrete law of electromagnetism that unbound electrons will repel photons? Repel is not a word I would use, because this does not take place like electrostatic repulsion, which varies with distance (1/r^2). Electrons scatter photons. Compton scattering happens http://en.wikipedia.org/wiki/Compton_scattering Link to comment Share on other sites More sharing options...
Sato Posted June 11, 2013 Author Share Posted June 11, 2013 Repel is not a word I would use, because this does not take place like electrostatic repulsion, which varies with distance (1/r^2). Electrons scatter photons. Compton scattering happens http://en.wikipedia.org/wiki/Compton_scattering I have read through that article as well as others on the topic of scattering theory but my comprehension rate was not very high, I think due to the concentration of jargon on the wikis. How would you describe it? Link to comment Share on other sites More sharing options...
swansont Posted June 11, 2013 Share Posted June 11, 2013 I have read through that article as well as others on the topic of scattering theory but my comprehension rate was not very high, I think due to the concentration of jargon on the wikis. How would you describe it? The photon scatters off of the electron. In this case it's not that different from marbles colliding. But since there's a photon, its energy change shows up as a wavelength change, and it depends on the scattering angle. If you're not at the level where you can show how the scattering violates absorption would violate conservation of energy or momentum, it's really hard to have any substantive discussion. 1 Link to comment Share on other sites More sharing options...
Sato Posted June 11, 2013 Author Share Posted June 11, 2013 The photon scatters off of the electron. In this case it's not that different from marbles colliding. But since there's a photon, its energy change shows up as a wavelength change, and it depends on the scattering angle. If you're not at the level where you can show how the scattering violates conservation of energy or momentum, it's really hard to have any substantive discussion. Oh okay, I understand. Thank you for your help! Link to comment Share on other sites More sharing options...
ACG52 Posted June 11, 2013 Share Posted June 11, 2013 . If you're not at the level where you can show how the scattering violates conservation of energy or momentum, it's really hard to have any substantive discussion. Did you mean doesn't violate conservation of energy or momentum? Link to comment Share on other sites More sharing options...
swansont Posted June 11, 2013 Share Posted June 11, 2013 . Did you mean doesn't violate conservation of energy or momentum? Good catch, I meant absorption. Fixed. Link to comment Share on other sites More sharing options...
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