On the problem of band spread in the UV spectrometry

Discussion in 'Science' started by Doberman1, Jul 10, 2015.

  1. Doberman1

    Doberman1 New Member

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    Because the UV wavelengths are so much shorter than infrared, the superimposition of vibration and rotation of the molecules is much more pronounced with the result that bands in the UV spectra are very much broader and spread out than in an infrared spectrum that features distinctly sharp lines. In other words, the distance displaced by the molecule during its rotational and vibrational cycles is sufficient to affect UV wavelengths to exhibit a significant frequency spread, but has a barely perceivable frequency spread in the infrared range due to longer wavelengths involved.
    if the Einstein’s General Theory of Relativity was correct and light propagation occurred according with the relativist laws of time frames of reference, such frequency spread then should not take place, since the light emitted by molecules at a given specific frequency should reach us always and regardless of that molecule’s vibration or rotation, with that same precise frequency. What happens instead from our velocity frame of reference, is when, during its rotational cycle, the molecule recedes from us, its apparent wavelength increases while the frequency decreases, and vice versa when the molecule vibrates in the direction towards us. That’s what causes the frequency spread. From the molecule’s velocity frame of reference however, the frequency and wavelength of the light emitted never changes.
    To demonstrate a common misconception regarding these differences in resolution in molecular spectra which seems to vary with the wavelengths of radiation emitted, I would like to quote from Roberts, Gilbert, Rodewall, Wingrove page 119:
    “The diffusiveness of the spectrum is a consequence of the fact that electronic transitions can occur from a variety of vibrational and rotational levels of the ground electronic state into a number of different such levels of the excited electronic state. Thus, although the transitions themselves are quantized and therefore should appear as sharp “lines”, the fact that closely spaced vibrational-rotational levels give rise to closely spaced lines causes coalescence of the discrete absorptions into a band envelope to produce the broad bands observed experimentally.”
    The problem with this interpretation lies in the statement that “electronic transitions can occur from vibrational and rotational levels of the ground electronic state into a number of different such levels.” The phenomenon is not caused by electrons jumping between the ground and excited orbits, but instead what seems to take place is for the distance displaced by the atom in a molecule during its vibrational and rotational cycles to superimpose itself against the wavelength of a constant parameter specific for a given molecule, given off by electrically or electromagnetically excited electrons.

    Let's say you have a vibrating molecule relative to you - a stationary observer. This molecule gives off a beacon at regular time intervals - longer intervals if it's an "infrared" beacon, and shorter intervals if it sports a "UV" beacon. Then of course the quasi-Doppler rules apply. When the molecule is accelerating towards you, the acceleration in the velocity of the molecule relative towards you will add to the velocity of the beacon signal's wavefront and you will get a higher frequency signal. If the same molecule accelerates away from you then the acceleration will subtract from the velocity of the beacon signal and each subsequent beacon wavefront will travel slower towards you and hence the time interval between the beacons will increase. Alternatively, a true Doppler effect may apply where the beacon wavefront always travels at the same velocity towards you, but the beacon wavefronts will reach you more frequently if the molecule is accelerating towards you and less frequently if the molecule accelerates away from you. Either way, this is what creates the frequency spread in the spectrum of the molecule. But then, and this is the key, this spread can be more - or less pronounced depending on what light we are dealing with. The effect will be more pronounced if the molecule gives off radiation in the ultraviolet range because the increase and decrease in time interval between individual beacons given off which results from the max and min velocity of the molecule relative to you, is a much greater fraction of the time interval between the individual beacon signals in the "UV" range than it is in the "IR" range. Hence the vibration of a molecule will induce a much greater frequency spread in the UV light than in the IR light of a vibrating molecule.

    This perceived effect in a vacuum however may operate in conjunction not with the true Doppler rules which apply to sound waves which in turn are distortions in the air medium, and here the sound waves always travel at a constant speed relative to the air medium, not relative to you or the emitter. You just may happen to be stationary relative to the air medium. The light in the vacuum however knows no medium. Hence Einstein would be vindicated if the frequency spread results from the difference in min and max velocity of the vibrating molecule, where the wavefronts always travel with the same velocity but are only pushed closer and further apart, and proven wrong if the spread results from the difference in min and max acceleration of the molecule relative to you.
     
  2. Doberman1

    Doberman1 New Member

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    https://www.youtube.com/watch?v=ZtaKWt26dNs

    To illustrate the point further, the way doppler is explained here at 22:00 minutes has to do with sound waves where the sound wavefronts are squeezed together due to velocity of the emitter since the waves preceding the emitter cannot exceed a certain velocity which is limited by the medium (air). The narrator then incorrectly makes the parallel between the sound waves and the light waves. Light waves are not energy disturbances in the medium and have nothing to do with the medium. Light waves don't need a medium because light is self-propagating. We see a doppler effect in light from a moving emitter relative to us because the light's velocity relative to us is a sum of c plus the emitter's velocity, simple. The light which is procurred from a moving emitter relative to the observer has its peaks and valleys crossing a given point faster, and hence the higher frequency and the shorter wavelength of light as experienced by the observer.

    Maxwell never said the light speed cannot exceed the value of c. Technically, he only showed that light will travel at velocity c relative to its emitter.
     
  3. 10A

    10A Chief Deplorable Past Donor

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    Considering inertial reference frames, light travels at C (in a vacuum) no matter what the velocity of the emitter. If an emitter is moving at velocity u, the velocity of light emitted is NOT u+C. Maxwell died long before Special Relativity came along, and his equations say nothing of the speed limit of light. The speed of an electromagnetic wave is governed by values of the permittivity and permeability of free space in his equations.

    Light also travels at different velocities inside different media, depending on the permittivity and permeability of the medium i.e. travels a bit slower in air and a lot slower in liquids and solids.
     
  4. Anders Hoveland

    Anders Hoveland Banned

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    The mechanism of electromagnetic waves being slowed down through media is similar to the concept of a dielectric constant, for anyone who is familiar with capacitors. Such simple non-conductors like plastic and glass have interactions with electromagnetic fields. Another fascinating part of this phenomena is that the temporary absorbance and remittance of a photon in a media does not necessarily affect it's entanglement, besides how the photon itself was slowed down, it is as if the media never interacted with the photon.
     
  5. Doberman1

    Doberman1 New Member

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    I don't know. The Doppler equivalence between the sound and light is always held as true.

    But this does not hold air because the medium has everything to do with the Doppler effect of the sound (pitch) and nothing of the light (red/blueshift) . When the emitter is moving in the same direction as the sound waves it emitted then of course those latter will be compressed since the velocity of sound is limited by the relative velocity of the medium remembering that the medium is responsible for the properties and propagation of sound by distributing the energy provided by the emitter. Light does not carry such limitations in the vacuum (infinite permeability), while when the light travels through a medium which has nothing to do with light propagation, if the velocity of light exceeds c by a certain amount relative to this medium, the energy of interaction between light and the medium will cause light to convert to particles.
     
  6. Doberman1

    Doberman1 New Member

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    The permeability of space is an invented concept to have the math in the General Theory of Relativity hold together. It's an added complication and entirely hypothetical to prove a failed theory.
     
  7. 10A

    10A Chief Deplorable Past Donor

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    Permeability of free space was introduced 30 years before General Relativity, and like many constants, it's artificial based on what units we use. We could choose the permeability of free space to be 1, and adjust other units accordingly.

    I'm unfamiliar where the permeability of free space enters General Relativity. Special Relativity I can see, but please enlighten me on how permeability enters General Relativity? Does permittivity of free space enter General Relativity too?
     
  8. 10A

    10A Chief Deplorable Past Donor

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    I don't understand why you say Doppler equivalence between sound and light is always held to be true, then you say it isn't. Of course it isn't true, and so the Doppler equivalence between light and sound is not always held as true.

    Infinite permeability in a vacuum means you couldn't make a magnetic field in a vacuum, and then light or radio or any other electromagnetic phenomena wouldn't travel in space (c = 0). Clearly a vacuum does not have infinite permeability, but very small permeability.

    The velocity of light never exceeds c, no matter what the speed of the medium, and in any medium other than a vacuum it slows down.
     
  9. Doberman1

    Doberman1 New Member

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    Actually, what I said is there is no permeability of space, only the light's interaction with the medium, which does provide resistance manifested as the refraction of light, or in the more energetic cases, conversion of light into particles. In the vacuum, there is no medium and no resistance. And there will always be a magnetic field as long as you have a charged particle in motion, as in the radio waves by having an electron accelerated up and down the wire by reversing the direction of current.
     
  10. 10A

    10A Chief Deplorable Past Donor

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    Well there is permeability of free space. If there were no permeability at all light would travel at infinite speed, which wouldn't make sense since by definition waves are time dependent.

    Light is particles (photons), no conversion needed.
     
  11. Doberman1

    Doberman1 New Member

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    I think it's easiest to understand the Doppler in terms of the number of wavefronts that pass through a given point, the observer, per unit time. With both light and sound the Doppler is due to the motion of the emitter, and because as a result more wavefronts pass the observer per unit time. However the difference arises on the following point. In sound the Doppler is created due to the shortening of the distance between the wavefronts while the velocity of these wavefronts remains unchanged. In the light, more wavefronts pass the observer per unit time not because the distance between the wavefronts changed, which in fact remained the same, but because the velocity of the wavefronts increased relative to the observer. This results in a higher pitch and the blueshift respectively.
     
  12. Doberman1

    Doberman1 New Member

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    Also keep in mind that if the high energy light, say in the X-ray or the gamma ray range passes close enough to a nucleus of an atom (say that of a medium) then it will convert into particle pairs. A light from a moving emitter will be blueshifted from the perspective of the encountered nucleus and will convert even more readily. That's why light can travel in excess of c, but is rarely detected because we don't sit in the vacuum but are surrounded by medium of all sorts, from the atmosphere to the solar wind. Or rather, any blueshifted light we detect travels in excess of c relative to us, but we have no way to measure its speed directly since we can only measure its frequency i.e. the number of "wavefronts" passing us per unit time. And much of the highly blueshifted light will never reach us (unless it starts out as radiation in the radio or the microwave range in the emitter's velocity frame of reference) since it always converts into particle pairs once it encounters any medium in our velocity frame of reference.
     
  13. Doberman1

    Doberman1 New Member

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    It should be noted that although the speed of light from a stationary emitter (emitter and observer found in the same velocity frame of reference) has been determined since Ole Romer did his experiment, the speed of light with red or blueshift was never measured.
     
  14. Doberman1

    Doberman1 New Member

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    Actually, it's better to think of the doppler of light in terms of a wavetrain. The emitter in a manner of a locomotive is pushing a wavetrain ahead of it, and the faster it goes, the more waves will cross the observer in allocated time. However, the observer can only detect the number of waves crossing it per second i.e. the frequency, and not the speed of the wavetrain.
     
  15. Doberman1

    Doberman1 New Member

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    With the General Theory of Relativity you would have all these other complications, such as the shortening of the waves and time adjustments. Without these added complications, the wavetrain model works more neatly - is much more coherent.
     
  16. Doberman1

    Doberman1 New Member

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    Actually on a further note, and I don't know why I keep making such obvious mistakes, the total frequency of doppler light as experienced by the observer is the sum of the described two effects, since the emitter acting as a locomotive model pushing a wavetrain ahead of it accounts only for the additional frequencies responsible for the doppler itself. So the total frequency of the doppler light as experienced by the observer will be the number of the waves/wavefronts the emitter produces in a second, plus the number of waves in a wavetrain that the moving emitter pushes past the observer per second (or another way to put it, the number of waves which are squeezed out of the space occupied by the wavetrain connecting the emitter and the observer, when the emitter is moving).
     
  17. Doberman1

    Doberman1 New Member

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    Copyright of P. Sz.
     
  18. Aleksander Ulyanov

    Aleksander Ulyanov Well-Known Member

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    I really can't follow this much but I still have three questions

    1. What is the point of this thread, if any? Pointless threads are okay here, AFAICT, (Matter of fact, many think I post a lot of them) but I'm just wondering.

    2. You are aware that when two light beams approach and pass each other at 186,000 miles per second their relative speeds to each other are STILL 186,000 mps. I don't know much about Relativity but I believe every source I have ever read says that is true, (and some of the posts here seem to be implying that isn't so, but I probably just misunderstood.)

    3. Had Michael Faraday had more training in mathematics could he have come up with Maxwell's Equations? and could someone else, or maybe even him, have then gone on to anticipate Einstein's theory?
     
  19. Doberman1

    Doberman1 New Member

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    So convincingly prove it.
     
  20. 10A

    10A Chief Deplorable Past Donor

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    Einstein already did, and hundreds if not thousands after him, both experimentally an in practical applications.

    If you don't accept Einstein's work, I look forward to your award for the Nobel Prize in Physics when you convincingly refute him and the rest of the physics community.
     
  21. 10A

    10A Chief Deplorable Past Donor

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    1. To point out ideas that have been proven false over 100 years ago I suppose.

    2. Comparing the relative speeds of two light beams approaching each other is nonsensical really. Light beams can't measure each other, they can't "see" each other. When you talk about observations like this it is important to explain the state of the observer and the relative state(s) of what is being observed, and how those observations are measured.

    3. Faraday's work was an integral part of Maxwell's equations, and that wasn't the least of his work. He was a great scientist. Maxwell couldn't have done what he did without Faraday, and Einstein couldn't have done what he did without Faraday and Maxwell, and none of them could have gone as far as they did without Newton. Faraday's biggest problem, as you point out, was he didn't have the mathematical knowledge to express his discoveries. If he had a mathematical education, I have no doubt we'd be talking about Faraday's equations rather than Maxwell's equations.

    Faraday simply didn't live long enough to anticipate Einstein's work. Einstein certainly built upon Faraday and Maxwell, but also Lorentz, Poincare, Michelson, Fitzgerald, and others. Special Relativity was ready to be discovered, in my opinion. It was a just a matter of time. Any of those guys could have formulated it (but they didn't, only Einstein did). Einstein's great achievement was General Relativity. It took him 10 years to figure it out and to this day we haven't explored all the possible solutions.
     
  22. Doberman1

    Doberman1 New Member

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    Light cannot attain infinite speed relative to its emitter because for that to happen it would require infinite energy. For the photon to achieve an infinite speed its electric and magnetic fields would need to change from zero to max and back to zero an infinite cycles per second. But actually, the frequency of light corresponds more to the motion of the charged particle that set it off, at least in the radio range. Thereafter you have electrons changing energy by changing orbitals.
     
  23. 10A

    10A Chief Deplorable Past Donor

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    Of course light doesn't attain infinite speed relative to its emitter, it attains 299,702 km/sec relative to its emitter, no more no less (in a vacuum).

    You seem to be confusing speed with frequency. Light travels at the same speed in a vacuum no matter what the frequency.
     
  24. Doberman1

    Doberman1 New Member

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    Now you're deviating away from your original postulate, that light could travel with infinite speed were it not for the limits of permeability of the vacuum. That's what you said.
     
  25. 10A

    10A Chief Deplorable Past Donor

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    No, what I said was IF there was no permeability light would travel and infinite speed. I also sad that would make no sense, it wouldn't be a wave any more. Since there is vacuum permeability talking about it being zero is meaningless.
     

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