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Question on Changes of energy, such as the transition of an electron from one orbit

  1. Aug 23, 2012 #1
    Question on "Changes of energy, such as the transition of an electron from one orbit

    I am not educated on quantum physics or any of the math fields of this science, but always found the subject fascinating. I have a question about some of the wave/particle posted Q/A's and the quantum leap references I've read online. Now mind you I am not knowledgeble at all about these things. With that being said I was curious about something I read.
    This was the curiosity for me "Changes of energy, such as the transition of an electron from one orbit to another around the nucleus of an atom, is done in discrete quanta. Quanta are not divisible. The term quantum leap refers to the abrupt movement from one discrete energy level to another, with no smooth transition. There is no ``inbetween''.

    I had to cut and paste that in so that you would have a base of reference for my question. My question is this "No inbetween" state. Could there be a point of movement, since these things appear to be in constant motion, where it slips through a hole in time/space (another dimension) and as it bumps into another like element, causes displacement (like dropping a rock into water) and so in some other place in this fabric a different electron (?) pops out in a different orbiting position? I don't know, if I'm visualizing this wrong, but to me it seems like all is moving in time and space like a mesh or fabric with lots of holes and through those holes are different dimensions and as one thing from this place, ours pops through into some other dimension it causes displacement and makes one of those things to pop up on a different position in the orbit. So it appears from our perspective there was no "in between". Is this possible or not?
    My apologies if I sound like an idiot, but it really is a curiosity to me. I am not afraid to admit I am ignorant and curious to learn and understand. Really I have no other persons to talk to when I wish to question things like this. I am sure someone here can answer this question easily. Thank you.
     
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  3. Aug 23, 2012 #2

    Bill_K

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    Re: Question on "Changes of energy, such as the transition of an electron from one or

    Shyelude, All interactions in quantum mechanics are local, which means they take place at a single point. There is no case in which a particle disappears at point A and reappears at point B.

    When we talk about an atomic orbit, we don't mean a little circular path like a planet going around the sun. Think of an atomic orbit as a cloud, a region in which the electron may be found. The electron has a definite energy, but not a definite position. When an electron in an atom "jumps" from one orbit to another, it can do so because the two orbits overlap. The transition happens at a single instant, at a single point.
     
  4. Aug 23, 2012 #3
    What causes an electron in an atom "jumps" from one orbit to another

    Thank you so much for answering my question. I really appreciate you taking the time to respond. I have always had a natural curiosity about many things and so I like to read, listen and ask questions and learn.

    So I can visualize all of this in my mind (as small as it may be) this mass of electrons, like a cloud, has structure? What causes the jump from one orbit to another due to overlapping? If the orbits overlap do they always jump or is it a random event? Also, when the jump occurs is there any significant changes due to the change in orbit? Since you are able to say this event occurs, has it been observed and measured? You don't have to answer these questions if you don't wish to. I am sure these are questions less interesting to you than a grade school child would ask. And thank you so much again for not talking too far over my head. That was very nice of you and I am grateful.

    If you do have the inclination to respond back on these additional questions I would be most appreciative. I would probably have more questions at that point and you can always tell me to go away and I would respect that. Thanks again for your time and knowledge:)
     
  5. Aug 23, 2012 #4
    Re: Question on "Changes of energy, such as the transition of an electron from one or

    Hi.

    Electrons in atoms spontaneously drop from orbits of higher energy into orbits of lower energy. Just like a ball rolling spontaneously down the hill, speeding up. When an electron drops from an orbit of higher energy into orbit of lower energy, that means electron had higher energy first, and now it has lower energy.

    Where did the energy go? Energy was radiated out in form of a photon. Those quanta of energy You spoke about: those are photons, particles of light in laser beams.

    So, what are those orbits? Well, electrons and other elementary particles are peculiar objects... One can try measure and detect their exact position in space, and every time a measurement is performed - one finds a different answer. This means that particles, although being detected at one particular more-or-less well determined point, have a chance to be detected elsewhere instead. So, it can be in two points in space? No. It can't. It takes two different measurements to detect it in different positions. So, there is a probability that Your experiment will detect a particle at some spot. It is not certain. When You put Your ball in a corner, the ball just stands still, not going anywhere. The same is not true for electrons. If You put an electron in a corner, there is a probability that electron will the next second be elsewhere. And what if we put electron in a corner and tell him to be still? Well, will it remain in a corner? No. That's the point here: there is a chance it will move around. So it teleports? No, of course not. There is a time difference between two measurements. Enough time for electron to walk around to another position.

    And what if electron is at a lower orbit and then jumps to an orbit of higher energy? Well, there has to be some sort of kick in order to lift electron up. That kick is, again, a photon. You must hit an electron with a photon. Only then will electron jump into a higher orbit.

    So how do orbits overlap? Well, if electron is one orbit, it is not in the other orbit. It cannot be measured in two orbits at the same time. And since electron's position has probability to be anywhere, really, this means orbit is not like orbits of planets. Orbit is more like all the positions electron could possibly be measured at. However, when detected, electron is at a single point: well, not quite single point, but within some small region of space. So, when in lower orbit, there is a chance it is anywhere. The highest chance is that it is on a certain path. This path is just the spot, where in its neighborhood will electron be detected most frequently. Each measurement will give different result, though, different position, so no fixed orbit in planetary manner. And when in higher orbit: same story. Orbit can be anywhere with some probability. So yes, orbits do overlap. But when in one orbit, that's it: electron is not in any other orbit at that moment, when we measure it.

    Do we know those probabilities of electron being at the spot? Oh, yes we do. That's called psi function. Err, to be more precise, probability density function is modulus of psi squared. You might have heard about psi function. Yep, it has information on the probability of finding electron at any spot. So psi can tell us where electron is? No. It tells us the probability that electron will be detected at some particular spot. No-one in universe can tell You where electron is.

    Why so? Well, when You measure electron's position, You hit it with light. When light hits electron, electron reflects this light and shines for that moment. So detectors then detect light being reflected, and we say then: "Aha, there You are"! Wait, so we actually measured exact position of electron just now? Not really. Photon that just hit electron, itself is a particle and its position is unknown. We can just say: somewhere near that point it was.. But once hit by a photon, electron is kicked away... and is no longer at previous position. So, You see, we don't really know its position after all...

    Wait, but when light is reflected from a ball, nothing happens to a ball. Just stands still... That's because ball is very very big and photon is very very small. Same with positions of planets. Too big to detect uncertainty in position.

    So what changes when electron jumps into different orbit? Its energy changes, of course. Anything else? Oh yes. Its spin may change, its angular momentum may change, there are quantum numbers that describe everything that may change for an electron for each orbit. When You vary those numbers for each orbit, You get: Mendeleev periodic table of chemical elements.

    I hope this helps a bit. Please do ask if You have some other questions on this peculiar subject.

    Cheers.
     
  6. Aug 23, 2012 #5
    Uncertainty principle?

    So can you measure this electron's movement into another orbit (probability) and the energy it has released in the form of a photon is what you have as an indication
    of the movement or no...location/existence, right? But then if I understand, that once you hit it, then it shoots off somewhere else and you cannot locate the same one again?
    Is there ever a way to know if it is the SAME one you were trying to observe? Oh and that point of the observing and the outcome changing, I do remember reading the some theory on that a long time ago. Something about an uncertainty principle. Is there a way of making a marker for the electron hit so that when it moves, to parts unknown, you can find the same one again? I'm still processing so my apologies if I make you repeat something over. It almost reminds me of those pens at pizza/game places that have all the multi colored balls that the kids jump in and try finding one of the ones you were playing with when it gets lost in the pack of other balls in that huge pen. Except I can imagine a pen like that with air in it and all the balls moving around the room. I will process this some more. I know it sounds strange but I have a tendency to visualize things. I just needed to make sure I am understanding things in the right direction because this gets my brain juices excited all at once. So I have to slow down and make my notes. Thanks again
    and I will get back with more questions.
     
  7. Aug 23, 2012 #6
    Re: Question on "Changes of energy, such as the transition of an electron from one or

    Hi.

    Exactly. If You want to see the transition from one orbit to another, You must hit electron with photon small enough to locate electron precisely in-between in a very short interval of time. This means: the photon must be very powerful. So You are kicking electron far away now. You are observing electron transiting to who knows where. Not the orbit You would like to observe it go.

    So, uncertainty principle. When You measure any property of any elementary particle, You get many data, all different, on the same property, from many measurements. All this data fits into a probability distribution. Say, like this:

    325px-Standard_deviation_diagram.svg.png

    Now, uncertainty of measuring something can be bigger or smaller. Consider this graphics:

    350px-Normal_Distribution_PDF.svg.png

    Blue distribution is narrow. It is very sharp in the middle. The height of it measures the likeness the particle will have desired property with exactly that value. Well, it's a bit more complicated than that, but one may say so vaguely. So property will most likely have the middle value.

    Orange curve is wide. Property measurements will yield spread values.

    Uncertainty of measurement is width of this curve somewhere near the middle height. So, blue curve has small spread or small uncertainty. Orange curve has big spread or big uncertainty.

    Uncertainty in measuring property [itex]p[/itex] is denoted [itex]\Delta p[/itex]. If uncertainty is zero, [itex]\Delta p =0[/itex], then curve is sharp as needle and measurement will always measure one and the same value again and again.

    Now, the tricky part... As You may have noticed, when we measure position of a particle, we have to kick it with a photon. So, we give it some additional impulse. So position and impulse are connected. In physics we don't say connected, because we have a special name just for this kind of being connected. We say: impulse and position are canonically conjugate variables. So, when we measure one, the other is disturbed, too. As argued earlier, one cannot measure position precisely, exactly because of this phenomenon. So how exactly can we measure them, then? Well, data from measurements will spread, and there will be uncertainties. We know how exactly are those uncertainties connected: Heisenberg uncertainty relation!

    [itex]\Delta p \Delta x \geq \hbar /2[/itex]

    What does it mean? Can we have [itex]\Delta p =0[/itex]? Then we would be 100% certain about impulse [itex]p[/itex]. Try it. If [itex]\Delta p =0[/itex], then [itex]\Delta x [/itex] must be... Well, infinitely large, because only [itex]\infty \times 0[/itex] can produce some finite number, such as [itex]\hbar /2[/itex]. So, if we know impulse of this electron here exatcly, then its position is... Where did it go? Where is it... Under the table? It was right here, I just measured its impulse... Yes, it's gone. Where? Uncertain. How uncertain? Infinitely.

    About the marker. If You measure particle's position at the marker, then.. You will have uncertaities :wink:

    Ah, yes, we can describe this mathematically precisely: it's called quantum mechanics.

    I hope this helps a bit.

    Cheers.
     
    Last edited: Aug 23, 2012
  8. Aug 23, 2012 #7
    Re: Question on "Changes of energy, such as the transition of an electron from one or

    Ok by Mathematical equations you calculate the probability of an electron in it's orbit. You mentioned higher orbit and lower orbit. What is the difference? Is there a different mathematical equations you use to determine probablitiy of location in the context of a lower or higher orbit? And you mentioned higher energy and lower energy. Is that relative to being in higher orbit or lower orbit? What is the significants of the higher energy and lower energy in an electron? You mentioned that when an electron jumps to a differnt
    orbit it's spin may change or it's angular momentum. What is the significants of this and how does it relate to the other electrons within it's environment?

    So you hit it with a photon and it causes it to bounce to a different place unknown. You have the evidence of it's existence near that spot by the energy released by the event, correct? But then, I guess my question again is can you find the same one you hit or is that impossible at this point in our human abilities to determine?

    My apologies for my writing and questions being so disjointed, but so many thoughts are just popping into my mind at once and I need to get them out so I can ask you as many things as I can that are coming into my mind. And thanks again.
     
  9. Aug 23, 2012 #8
    Uncertainty principle

    Wow! that is truly fantastic! So, if I am to understand this last post, you have a set of criteria for determining a range for the event to occur within. Your mathematical equations set the stage for you to capture the process correct? So it's almost like a big spider web and then when you hit the electron you get a corresponding response in that web. You have just enough coverage in variables to make sure you have it correct?

    It seems there are a wide set of variables you have plugged into this in order to do these tests.
     
  10. Aug 23, 2012 #9
    orbits

    I see you had already addressed my question on how you determine where or how to find an electron in orbit. I had written those questions before I saw your graphs, which explain
    it to me very well.
     
  11. Aug 23, 2012 #10
    Re: Question on "Changes of energy, such as the transition of an electron from one or

    Hi.

    Yes, You can hit the same one. Actually, if You hit electron by photon, but very weak photon, then electron doesn't have enough energy to jump to a higher orbit. Photon just bounces back, reflects off electron. Electron stays in same orbit. One can do it again and again. This way one can, actually, construct a quantum computer... But that's another subject, I guess.

    Orbits: when bound, electron cannot be just anywhere. For instant, when in atom, electron is bound to nucleus. They are both bound by attractive force of electricity. So, yes, it can be measured anywhere, but the probability will favor the orbit. So can electron move to another orbit, but just very close to the original orbit? Do such close orbits exist? No. Electron cannot have have arbitrary energy when bound. This is directly connected to psi function. Psi function is a wave function. Probability of particles waves. And when a particle is bound, then it is confined to some region of space. And within a small region, waves will interfere with one another. So electron interferes with itself? Yes. Well... Yes, it's psi function does. It's like waves on rope stretched between 2 walls. Or guitar string. Or any wave confined to some region. Consider a guitar string, for instance. If You put a finger gently on string exactly in the middle of string, and You pluck string with other hand gently, it will make a beautiful sound, and this beautiful gentle sound will last for quite a while. If You move finger a bit and pluck string again while holding finger gently on it, there will be no sound at all. That's because string can wave freely when finger is exactly in the middle. It waves around this fixed point. When left part of string moves up, right part goes down. String can wave. If finger is moved a bit from the middle position, left part and right part of string are no longer of equal length. Left part wants to go up, but right part sometimes wants to go up, sometimes down, forcing the string to stop waving. Wave interferes with itself.

    So there is music in electrons :smile:

    So, if electron was moved out of orbit a bit, its probability function would wave out soon. Like a wave on a guitar string.

    And when You put a finger on a string gently, but not in the middle, but at the 1/4 of the string length, and then pluck it gently, it will sing again... left and right waves on string are supporting each other again. So is with electron in atom. When electron is moved from one orbit to another, probability function will not destroy itself, but will support itself. So we get orbits. Like different tones on a guitar string, really.

    I hope this helps a bit.

    Cheers.
     
  12. Aug 23, 2012 #11
    Re: Question on "Changes of energy, such as the transition of an electron from one or

    Hi.

    Yes, quantum theory is very predictive and very precise theory. Unlike astronomy, one can measure particle features with enormous precision.

    Cheers.
     
  13. Aug 23, 2012 #12
    Music of the universe

    I always knew music was all around us! I think about everything moving, vibrating. Some at different pitch/range. Funny you should pick guitar to describe the wave. I used to play the guitar when I was young. There are so many aspects of this science that are so logical and reasonable and simply beautiful. I guess I have picked your poor brain enough for now. I will be back and thank you so very much.
     
  14. Aug 23, 2012 #13
    Re: Question on "Changes of energy, such as the transition of an electron from one or

    Hi.

    You are most welcome. Looking forward to chatting with You about music in universe again.

    Cheers.
     
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