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Why electron doesn't fall on proton, quantum explanation

  1. May 16, 2015 #1
    According to Feynman's lecture in physics an electron doesn't fall on the proton because of the uncertainty principle. Now, if electron falls on the proton, it's position and momentum can be known so it leaves some place for it to move.

    But uncertainty principle is applicable for all particles, this includes proton. So even if Electron becomes stack with the proton, it will still follow uncertainty.
     
  2. jcsd
  3. May 16, 2015 #2
    Yes the electron is governed by the uncertainty principle, however that's not a very thorough explanation.You see, the electron encompasses an intrinsic angular orbit resided in quantized energy states, with the energy determined by the angular momentum (spin) about the nucleus, with energetic conservation stronger than the coulomb force between the electron and nuclei. The electron would need to obtain a threshold amount of energy in order to spiral into singularity or eject form it's atom or covalent bond (work function). The electron(s) move between energetic states by the spontaneous emission/absorption of photons (quanta) at specific frequencies in which are in direct proportion to the exerted energy E=hf (Planck-Einstein relation). It was discovered that all matter exhibits coexisting matter-wave properties λ=h/p=h/mv (De broglie relation). Wave properties of electrons are easier to observe with experiments than those of other particles because electrons have a lower mass and hence a higher De Broglie wavelength for typical energies. A particle is described mathematically as a complex-valued function, the wave function, commonly denoted by the Greek letter psi (ψ). Where the function squared modulus gives the probability that a particle will be observed near a location—a probability density (look up the Schrodinger eq. for the hydrogen atom).
     
  4. May 16, 2015 #3

    ZapperZ

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    Yes, it does. But as a consequence of the HUP, it will acquire such a huge momentum that it cannot be confined within that small volume of space. Thus, this is not something that is either stable, or can possibly occur.

    For a clearer explanation on why an electron doesn't crash into a nucleus, read our https://www.physicsforums.com/threads/why-dont-electrons-crash-into-the-nucleus-in-atoms.511179/ [Broken].

    Zz.
     
    Last edited by a moderator: May 7, 2017
  5. May 16, 2015 #4

    stevendaryl

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    One thing to keep in mind in talking about the possibility or impossibility of an electron falling into a nucleus is to consider a corresponding "atom" in which the nucleus is a positron (an electron's anti-particle). An electron and positron can orbit each other, just like an electron and proton can in a hydrogen atom. Such an atom is called "positronium".

    But for positronium, it is possible for the electron and positron to annihilate each other, so in some sense, the electron falls into the positron.
     
  6. May 16, 2015 #5

    ZapperZ

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    But it should be expanded further by elaborating that the electron cannot stay there, i.e. it is not a stable condition, because the e-p are transformed into something else. As a result, no more electron (and no more positron).

    Zz.
     
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