Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Optical Emission - due to Acceleration or Oscillation

  1. Feb 11, 2005 #1
    Three Interconnected Questions:

    1. When an atom is excited by a visible photon (KE=1 eV), does the probability (radial) density increase for the valence electrons or not?

    2. If the probability density has increased outward, then what normally causes the excited state to begin the process of photon emission?

    3. Once the excited atom has been "iritated" by some means, what is the cause of the photon emission - Choice A: electric dipole oscillation, or Choice B: some acceleration or deceleration process, or Choice C: another explanation which is...
     
    Last edited by a moderator: Feb 11, 2005
  2. jcsd
  3. Feb 11, 2005 #2

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Let's take them slowly.First question:what is radial density...?Is it the PROBABILITY DENSITY...?If so,why would that happen??I'd say that the electron is ejected (just like in the photoelectric effect).

    Daniel.
     
  4. Feb 11, 2005 #3
    Sorry. Got my X-ray and visible wires crossed. Let's drop KE down to <1 eV. I edited my original post. Also changed radial to probability.
     
    Last edited by a moderator: Feb 11, 2005
  5. Feb 11, 2005 #4

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    The question is still the same...?What would the principles to account for an increase in (radial) probability distribution...?

    Daniel.
     
  6. Feb 11, 2005 #5

    reilly

    User Avatar
    Science Advisor

    When an atom absorbs a photon, it necessarily makes a transition to a more energetic state. Given that the average radius for an atomic state grows with energy, it most likely is the case that the radial probability's max does grow after absorbtion. But, the devil is in the details, and to be sure, you'll need to do some computations, or check in Condon and Shortley's The Theory of Atomic Spectra, a bible in its field. (The issue of photon absorbtion in multi-electron atoms is somewhat tricky.)
    Regards,
    Reilly Atkinson
     
  7. Feb 11, 2005 #6
    Maybe you can make clear what you mean with this question.
    The probability density for WHAT exactly will increase?

    That's a good question. I personally don't know how
    one can explain spontaneous emission in an intuitive way.
    To my knowledge the spontaneous emission is not contained in usual quantum mechanics. The process of spontaneous emission comes into play
    if you quantize the electromagnetic field, that is you introduce the photons.

    As I stated above, I don't know why spontaneous emission occurs, that is I can't give you an intuitive explanation. All I know is that you can
    describe the emission formally in second quantization by bosonic and fermionic annihilation and creation operators (maybe you know about that stuff).
     
  8. Feb 12, 2005 #7
    WHAT=electron

    I did not say "spontaneous" emission. My 3rd "interconnected" question uses the word "iritated" which defines the type of emission - ie stimulated by not in a coherent way.
     
  9. Feb 12, 2005 #8
    Is the energetic state one of a near continuum of available quantum states or is it a restructuring of the original electron state?
     
  10. Feb 12, 2005 #9
    That is the question isn't it. Does extra energy promote the electron that has "absorbed" the energy (for t <10(-18) sec or so) into a new quantum state which is farther from the nucleus, or does the energy directly modify the wave function (quantum state) of electron which stays at its original distance from the nucleus?
     
    Last edited by a moderator: Feb 12, 2005
  11. Feb 12, 2005 #10

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    The last view is highly classical...Hence incorrect.If the electron aquires energy (from a photon or more),then its quantum state will be modified and therefore its initial radial probability distribution (r^{2}R_{nl}(r)) will be modified as well.Under such transition,the electron will certainly end up in a nonstationary state.

    Daniel.
     
  12. Feb 12, 2005 #11
    OK. What is the nature of this nonstationary state?
     
  13. Feb 13, 2005 #12

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    What do you mean...?Since the time-dependent SE is (for this case of interaction with external Em field) totally unsolvable,u cannot know it...There are other quantities which are computed in the theory of time-dependent perturbations (i'm assuming the time-dependent Hamiltonian to be of perturbative nature).

    Daniel.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Optical Emission - due to Acceleration or Oscillation
  1. Atmospheric emission. (Replies: 1)

  2. Photon emission? (Replies: 2)

  3. Stimulated emission (Replies: 7)

Loading...