Electrons jumping energy levels

Discussion in 'Physics & Math' started by AntonK, Mar 16, 2003.

  1. AntonK Technomage Registered Senior Member

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    I've wondered this for a good long time now. We all from HS physics or chemistry know that an electron can gain energy from some quanta of light and jump energy levels. This electron will usually then jump back down to its previous energy level and release a quanta of light at some frequency.

    My questions is, during this "jump" from energy level to energy level does the electron physically move as we think of things moving in the macro world, or does is simply stop existing in one lergy level and start existing in a higher energy level? Seems to make sense (being as ive grown up in a macro world as we all have) that it would move physically like we think of motion. But it doesnt make sense since that would mean it could theoretically stop and be in an intermediate energy level. Could anyone illumate this for me?

    -AntonK
     
  2. James R Just this guy, you know? Staff Member

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    AntonK:

    In an atom, it is wrong to think of an electron as a kind of mini billiard ball which orbits the nucleus like the planets orbit the sun. An electron is really a kind of fuzzy probability wave which surrounds the nucleus.

    When the electron energy changes, it does so in a single "quantum leap" which changes the form of the electron wave function. You can think of it as the electron physically moving to a "higher" orbit in the atom, but that is not a particularly accurate view of what actually happens.
     
  3. AntonK Technomage Registered Senior Member

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    I've heard this before. My question is, when an electron is free, as in a cathode ray tube, can it be thought of as a "billiard ball" then? I mean, mathematically it is nice to think of it as a probability cloud, but in reality there is something there right? I mean just because we can't know both velocity and position, it does have both. Right?

    -AntonK
     
  4. blobrana Registered Senior Member

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    There is a line of thought that says that the probability cloud stretches to all parts of the universe, and that when we <b>see </b>an electron `<i>moving</i>` through space it is rather like watching a film. ( forgetting about Heisenberg)
    The individual `<i>frames</i>` give an illusion of continuous action.

    I think that the probability cloud analogy is good to envisage the electron shells but i rather prefer the virtual electrons (<i>ones created from the space/time energy</i>) theory to describe the movement of an electron through space...

    But both ideas are interchangeable ...
     
  5. James R Just this guy, you know? Staff Member

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    27,054
    AntonK:

    <i>My question is, when an electron is free, as in a cathode ray tube, can it be thought of as a "billiard ball" then?</i>

    How an electron looks depends largely on what kind of experiment you do to detect it. Certainly, electrons in CRTs behave a lot like billiard balls in that they have fairly well-defined positions.

    <i>I mean, mathematically it is nice to think of it as a probability cloud, but in reality there is something there right? I mean just because we can't know both velocity and position, it does have both. Right?</i>

    Actually, no. To a certain extent, an electron has a range of possible velocities and positions, but Heisenberg's uncertainty principle says that the more accurately we know the velocity the less accurately we can know the position, and vice versa. This isn't a problem with our measuring apparatus, but something deeper. In fact, it makes no sense in quantum physics to talk about exact positions and velocities of particles simultaneously.
     

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