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Electron 'orbits' question

  1. Oct 12, 2008 #1
    I was reading the faq and it said this

    It turns out that the picture of electrons moving in circular orbits around the nucleus isn’t correct either(*). The solution here is the implementation of Quantum Mechanics via the Schrödinger Equation and the concept of wavefunction. By applying such formalism, the “electron” occupies a volume of space simultaneously, so that it is “smeared” in a particular geometry around the nucleus. While there are no more “orbits”, we do use the term “orbitals” to indicate the shape of such geometry. However, this term should not be confused to mean an orbiting electron similar to our planets in the solar system. By describing the system in terms of the QM wavefunction, it creates stable states for the nucleus+electrons system that matches very well with experimental observation of standard atomic spectra.

    Since there are no more “orbits” in the conventional sense, the problem of electrons radiating due to an accelerated motion is no longer meaningful. It explains why we have stable atoms.

    To read more in detail: http://scienceworld.wolfram.com/phys...rogenAtom.html

    (*) By saying that “an electron orbits the nucleus”, one is already implicitly assuming that one can track the position and momentum of that electron in an atom over a period of time. We have no such ability, and for those who know a bit about the Heisenberg Uncertainty Principle (HUP), one can already tell that such a statement violates this principle.

    Now my question is does this imply the electron is actually in many places at once? i.e. merging with space and time?
  2. jcsd
  3. Oct 12, 2008 #2
    merging with space and time?
  4. Oct 12, 2008 #3
    This is a question to which different people will give different answers. For example, the theory of Bohm would imply that the electron does trace a kind of orbit, but a very intricate one, which isn't at all like a circle or an ellipse. The Many Worlds theory would have the electron trace different orbits in different worlds, and there are also interpretations of quantum theory where the electron becomes a sort of cloud, existing in many places at once.

    Quantum theory says that one cannot precisely know both the speed and the location of an electron. If one is content to know both at a certain imprecision, the precision in speed which is needed to ensure that the electron does not escape from the atom and the precision in location which is needed to ensure that the electron resides there in the first place, multiplied together, are equal to Planck's Constant (or some fraction thereof). Neither can therefore become more precise (and this is the reason that atoms have the size they have; if things could become more precise, atoms could contract to a smaller size, because the electrons could spiral in towards the nucleus, and shed electromagnetic radiation to lose some of their energy). Therefore: we cannot know whether the electron is in the left hemisphere or the right one, and we cannot know whether it is presently moving towards or away from the plane separating these hemispheres.
  5. Oct 13, 2008 #4
    This would seem to imply the the electron is in many places at once, like it is 'diffusing' into a quasi-unified surface, like a ball melting into a flat puddle and yet appearing at many points around the center of the atom instantaneously, as if it was a unified surface.
  6. Oct 13, 2008 #5
    You are asking in effect "Is the electron a wave or a particle?" and the answer is YES...The double slit experiment explanation with electrons will clarify my ambiguous "yes" further.

    It appears yes the electron is in many places simultaneously....while position and momentum are covariables which cannot be measured simultaneously with ever increasing precision, so too energy and time cannot be either...so with a particle of finite life, there is a fundamental uncertainty in its energy....so in a sense both space and time are 'smeared", but the smearing is related to the particular measurments we perform...
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