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Is Simulating Electron Energy Drops Possible?

  1. Oct 11, 2007 #1
    Is there any way that science can simulate an energy drop that an electron would give? So that a spectroscope would think it's seeing a particular element, when in fact it is simply a synthesized energy transmission?

    Maybe taking some free electrons and somehow getting them to absorb and emit at a specific energy level? Though I'm not sure how would be done since they are not bound by anything; but just wondering.

    Also, along those same lines, is it possible to force an electron to a shell which is between orbital shells?
  2. jcsd
  3. Oct 11, 2007 #2


    Staff: Mentor

    Sure, all you need is a transmitter of the right frequency.
  4. Oct 11, 2007 #3
    If you could simulate a particular energy output from an electron, then would it fool your eyes as well?
  5. Oct 11, 2007 #4
    In principle it would be impossible to replicate the full spectrum of any (even quantum) source exactly. Among electrons undergoing transitions, one must consider the effects of magnetic fields, relativity, virtual fields (as well as electron-electron and nuclear interactions?) to name a few.

    Within reason, however, it would be a lot more practical to mimic a atomic transition than most any other signal, by virtue of its comparatively simple and discrete waveform. Speculation: one might isolate an emission line and then manipulate it (by blue or redshift) according to the frequency needed. Maybe an accelerator would do the job? The eyes are easy to fool next to the fantastic spectrographs used today.
  6. Oct 12, 2007 #5

    Claude Bile

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    Yes, you can write a series of gratings (or a single super-structured grating) into a length of optical fibre whose reflection spectrum matches the desired emission spectrum. If you were to launch a broadband source down the fibre, the reflection would mimic the desired emission spectrum.

    Astronomers do something similar, they pass light through gratings that reject certain wavelengths that correspond to OH transitions for example, to filter them out of the spectrum before analysis.
    You can introduce additional energy levels in an ordinarily forbidden zone (through the addition of dopants in a Semi-conductor for example). You can't get a stable state to my knowledge between energy levels without adding an intermediate allowed energy state.

  7. Oct 12, 2007 #6
    Claude Bile - How do they generate the energy transmissions. You said that they "write a series of gratings"; but I'm not sure what you mean.

    As far as introducing "additional energy levels in an ordinarily forbidden zone", wow, I've never heard of that being possible before. How is that represented in Quantum mechanics when they can only calculate the traditional energy states?
  8. Oct 14, 2007 #7

    Claude Bile

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    Sorry about that, I should have been more specific - I was referring to Bragg gratings, which are regions of periodic refractive index change and act basically as mirrors for a particular wavelength or wavelengths, while allowing other wavelengths to pass through.

    With regard to the additional energy levels - I should specify that by "ordinarily forbidden zone" I meant that with regard to the original, undoped Semiconductor lattice. Quantum mechanics does indeed predict the existence of these extra energy levels if the presence of dopants in the lattice are accounted for.

  9. Oct 15, 2007 #8
    Ok, so you can kind of pick and choose which wavelengths you can allow to pass through. Interesting. So if they applied it to light coming from the sun they could set the grating up so that it only allowed the light emitted by hydrogen through? Interesting. Though that's light being emitted by electrons ultimately right? Is there a way to emit an energy signature which mimics the energy signature emitted by an electron (without having electrons in the picture)?

    I'm pretty new in my studies with Quantum Mechanics, so I'm sure I'll learn more about what is allowed and what is not, so I'll look for more info then. Thanks again for the help.
  10. Oct 15, 2007 #9
    I'm not sure I completely understand what you're asking or that I'm qualified to answer, but I'm aware of such a thing as Electron Energy Loss Spectroscopy (EELS) which may be relevant to what you're asking. Google it if you're interested.
  11. Oct 15, 2007 #10

    Claude Bile

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    The vast majority of light is emitted by electrons, but the emission can be due to different mechanisms. In the technique I mentioned, the emission mechanism is a cascaded nonlinear process in a length of optical fibre, which is a different mechanism to spontaneous emission, which would normally comprise an atomic emission spectrum.
    Light does not carry around an intrinsic signature that has information about what emitted it. All we can do is look at the spectral content of the source, and make estimates based on that. It is entirely feasible to have two sources with the same spectral content that emit via two completely different mechanisms, and we could not tell the sources apart by the knowledge of their spectra alone.

  12. Oct 15, 2007 #11
    AcidBathSDMF - Thanks for the info. It looks like that's a way they can tell what kind of matter they are looking at by shining light onto objects and measuring the 'scattering angel' for the electrons. So in a sense you're simply creating your own scenario where you can view a spectroscopy to determine just what you're looking at. Science has some neat stuff.

    Claude Bile - So you're describing a method which would be like a domino effect with a single photon, or would it be a bunch of photons?

    But you can measure the wavelength of the light and find out where it matches on the electromagnetic spectrum still right? I know that's not really a "signature"; but that's one aspect of what I was wondering about. Thinking about it more though there are many things that can give off energy, and you could get a color; but it might be emitted using a different method.

    Are there any non-electron methods of giving off a photon? ie. any quark or quark-composed particles that cause photon emissions during certain interactions?
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