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B Question about photoelectric effect?

  1. Oct 11, 2016 #1
    I think that an electron only absorb a photon with energy corresponding to the energy levels in an atom.

    If the energy of a photon is higher than the energy between a specific energy level and infinity level (0 eV), it can also absorb the photon and the remained energy is changed to KE.
    Am I right?
  2. jcsd
  3. Oct 11, 2016 #2

    Let us examin/revisit the event of photo-emission...

    The energy of emitted photo electrons is directly proportional to the frequency of incident light.

    It has also been observed that there must be a minimum energy needed for electrons to

    escape from a particular metal surface and is called work function 'W' for that


    The work function can be expressed in terms of frequency as, W= h. frequency(0)

    the Photoelectric effect obey the equation,

    h.frequency of incident light = k.E. (max) + W
    on the above backdrop how you place your argument?
  4. Oct 11, 2016 #3
    Work function is for a metal solid, can't photoelectric effect occur on an atom scale?
  5. Oct 11, 2016 #4
    When one is devising experiments of getting photo electrons from atoms of a particular kind.....the atoms are in the form of a 'material' or layer of those atoms called 'Photo active surface/coatings'-

    the name photo electrons is derived by the mechanism of energy transfer from a photon quantum to a bound electron in the atom of the active material ;
    so basically its atomic absorption of photons - the work function has to be there as one is not having scattering of photon with a free atom ....
    the array of atoms are also bound in a structure with surface interaction potentials and the ejected electron has to cross it to be registered as a photo current.

    Moreover if one looks at Photo electron spectroscopy with variety of photon sources of higher energies
    like UV or X-ray sources the spectroscopy helps to unravel the atomic structure.

    There may be also "internal conversion" of emitted photons of an atom giving rise to photo electrons called "Auger electrons" but in each case the energy conservation has to be accounted for .
    For more details about the the spectroscopy and variety of mechanisms one can look up the wiki or XAS(X-ray photoelectrons ) sites
    Such as
    <https://en.wikipedia.org/wiki/Photoelectric_effect#Three-step_model> and some more....
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