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All matter has energy levels?

  1. May 6, 2013 #1
    Im wondering if all matter have discrete energy levels because electron and nuclei have discrete energy level. my thought is that as mass increases the separation of the energy levels decease, so because mass is so large at our scale the separation of energy levels is so infinitely small and see it as a continuous scale?
    Tell me if my way of thinking is completely wrong, its just a thought.
  2. jcsd
  3. May 6, 2013 #2


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    Have you never heard of the conduction and valence bands of metals, semiconductors, and insulators? There are no "discrete" energy levels there.

  4. May 7, 2013 #3
    Of course there are - the conduction band of a metal in the usual treatment comes about from a potential well with periodic b.c.s, with discrete spacing. That's why you can have a density of states - if the levels were truly continuous, you could cram as many electrons as you want into any small energy interval. Without a finite number of states below a certain energy, things like a fermi sphere could not exist.

    We can treat the levels as quasi-continuous just because there are so many of them and because they are so close to each other that the distance between two adjacent levels is extremely small.
  5. Sep 20, 2013 #4
    No i have not heard of the conduction and valence bands of metals, semiconductors, and insulators.
    This is only a thought and was asking if my way of thinking is completely wrong and if I should neglect this thought.

    So I'll ask this again. should I neglect this thought or is there some truth behind it?
  6. Sep 20, 2013 #5


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    There is probably a grain of truth to any statement. You would be well served to learn more from existing theory, as ZapperZ suggests, before you randomly speculate with non-specific conjecture.

    Theory and experiment go hand in hand, there is plenty written on the rules about electron orbitals in an atom. Check out those. :smile:
  7. Sep 20, 2013 #6
    Wikipedia has a decent, short explanation:

    One basic distinction between discrete quantum theory and continuous relativity is the 'quantum of action' or Planck's constant, h, a cornerstone of quantum theory, that pops up in many situations....but not in relativity.

    Last edited: Sep 20, 2013
  8. Sep 20, 2013 #7
    it's ok as a start....as stuff gets bigger and bigger the relative size of 'discrete' interactions generally loses significance. A next step to think about energy levels is along these lines:

    A truly free electron has an interaction potential that is not spatially localized, so there is a continuous spectrum of states; that means the electron can interact with photons of any energy. There is no "h" involved. Such an idealized free particle can have continuous energy transitions.

    In the real world there are no completely "free" particles; every particle interacts with something, so there are always some degrees of freedom present beyond the "free particle" ones. An electron bound in an atom has a spatially confined interaction potential, so its spectrum of states is discrete; that means the electron can only interact with photons that have the right energy to kick it from one of the discrete states to another...."h" is important.

    A decent analogy: consider a vibrating violin string....certain frequencies resonate....these are like 'standing waves' of electrons in the Wikipedia description I gave in the prior post. Remove the fixed ends and tension....the darn string won't vibrate! In fact this analogy works ok for string theory, too, where 'particles' are extended two dimensional 'strings'....and increased tension correlates with increased particle mass.
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