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What determines if a photon is absorbed?

  1. Mar 21, 2013 #1
    Say it has xnm wavelenght. It hits an atom that reflects it, then another different atom absorbs it, why?

    Also what determines if particles like free neutrons or some hadrons will absorb a particular wavelenght?


    Why does gold absorb all wavelength except yellow and why does it also seem to reflect a small portion of the light(shine).

    Is the interactiom of photons with atoms and elemental particles well understood and explaind... with some laws. Ive tried reading some electrodynamics but havent gotten as far to see if a photon copulates with a particle or not or why it would.
     
  2. jcsd
  3. Mar 21, 2013 #2

    mfb

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    Quantum mechanics. Depending on your favorite interpretation:
    - It does not have any deeper reason and happens randomly.
    - Both processes happen.
    - It depends on (fundamentally unknown) internal states of the particles.
    That is the result of the band structure - gold is a good reflector for most visible light by the way, as most metals.
    It is, the laws are called quantum mechanics.
     
  4. Mar 21, 2013 #3

    So basically its mostly quantum mechanical equations... and the explainaition is "this equation says that this light is most likely to be reflected"
     
  5. Mar 21, 2013 #4

    mfb

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    Right.
     
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