questionposter Posted April 22, 2012 Posted April 22, 2012 (edited) I think you could do with a few preliminaries, because you're not making any sense. This is the basics, (we'll stick with one dimension) but hopefully you'll get the idea. Operators An operator which is denoted with a hat i.e [math]\hat{O}[/math] transforms a function, say [math]f(x)[/math] to another function. So if the function is [math]f(x)=2x^2[/math] and the operator is [math]\frac {d}{dx}[/math] then [math]\hat{O}f(x) = \frac{d}{dx}2x^2 = 4x[/math] There's a good tutorial on differentiation here, if the above doesn't make sense to you. Eigenfunctions and eigenvalues Considering the role of the operator above, we can move on to eigenvalue equations. These have the relationship... [math]\hat{O}f(x) = \lambda f(x)[/math] where [math]\lambda[/math] is a complex constant. So you can see, in order for it to be an eigenvalue equation, the operator has to return the same function multiplied by a constant. The constant is the eigenvalue, and [math]f(x)[/math] is the eigenfunction. So for instance [math]\hat{O}f(x) = \frac{d^2}{dx^2}(sin(bx)) = \frac{d}{dx}(b\, cos(bx)) = -b^2 sin(bx)[/math]. In this case, [math]-b^2[/math] is the eigenvalue, and the function has not changed, so [math]sin(bx)[/math] is an eigenfunction of the operator. The de Broglie wavefunction The de Broglie relationship for an electron in an isolated system i.e free from any disturbances (forces) is [math]\lambda_{dB} = \frac{h}{p}[/math]. Where [math]\lambda_{dB}[/math] is the de Broglie wavelength, h is Planck's constant, and p is momentum. You've probably seen a wave equation before, such as [math]f(x,t) = A\,cos(kx-wt)[/math]. Where A is the amplitude of the wave, k is the wave number, [math]k = \frac{2\pi}{\lambda}[/math] and w is the angular frequency [math]w = 2\pi f[/math] (f is the frequency i.e 1/T where T is the period). The x in the equation, just denotes the direction the wave is travelling. Now, wave functions are complex, so we can write [math]\Psi_{dB}(x,t) = A[cos(kx-wt) + i\,sin(kx-wt)]=A\,e^{i(kx-wt)}[/math] (see Euler's formula) Remembering the de Broglie relationship, this implies that [math]k = \frac{2\pi\,p}{h} = \frac{p}{\hbar}[/math] where [math]\hbar = \frac{h}{2\pi}[/math] Also the photon energy is [math]E=\hbar w[/math] so [math]w = \frac{E}{\hbar}[/math] The Hamiltonian function You're probably familiar with Newtons equation [math]F=ma[/math]. This can be reformulated, by noting that F relates to the gradient of the potential energy function V(x). So for an object moving in the x direction, we have [math]F_x = -\frac{\partial V}{\partial x}[/math] Look up partial differentiation, if you're not sure about what the RHS means. Further, the derivative of velocity is acceleration, and p=mv (i.e momentum equals mass times velocity) so [math]ma_x = \frac{d(mv_x)}{dt} = \frac{dp_x}{dt}[/math] therefore we have... [math]\frac{dp_x}{dt} = -\frac{\partial V}{\partial x}[/math] Now, kinetic energy in terms of the momentum of a particle is [math]E_k = \frac{p^2}{2m}[/math] The Hamiltonian function, is the sum of the kinetic energy and potential energy of a system, with a particle of mass m, and potential energy V(x), so... [math]H = \frac{p^2_x}{2m} + V(x)[/math]. Now [math]\frac{p^2_x}{2m}[/math] is not explicitly dependant on x, so [math]\frac{\partial H}{\partial x} = \frac{\partial V}{\partial x}[/math] So, recalling the reformulated Newtonian equation, we have [math]\frac{dp_x}{dt} = -\frac{\partial H}{\partial x}[/math] The Hamiltonian operator Now we need to convert an observable (in this case the energy of the system) into an operator. Recalling the de Broglie wave function, if we partially differentiate it twice, we get (1) [math]\frac{\partial}{\partial x}\Psi (x,t) = ik\Psi(x,t)[/math] (2) [math]\frac{\partial^2}{\partial x^2}\Psi (x,t) = (ik)^2\Psi(x,t) = -k^2 \Psi(x,t)[/math] Now to obtain the eigenvalues for kinetic energy and momentum, we multiply eq (1) with [math]-i\hbar[/math] and eq (2) with [math]-\hbar^2 / 2m[/math] so (1.1) [math]-i\hbar\frac{\partial}{\partial x}\Psi (x,t) = \hbar k\Psi(x,t)[/math] (2.2) [math]-\frac{\hbar^2}{2m}\frac{\partial^2}{\partial x^2}\Psi (x,t) = -\frac{(\hbar k)^2}{2m} \Psi(x,t)[/math] So, [math]p_x \Longrightarrow \hat{p_x} = -i\hbar\frac{\partial}{\partial x}[/math] and [math] E_k \Longrightarrow \hat{E}_k = -\frac{\hbar^2}{2m}\frac{\partial ^2}{\partial x^2}[/math] The arrow just indicates we're going from a classical variable to a quantum operator. Therefore the kinetic energy operator is simply [math]\frac{\hat p^2_x}{2m} = \frac{1}{2m} \left(-i\hbar \frac{\partial}{\partial x} \right)^2 = - \frac{\hbar^2}{2m}\frac{\partial ^2}{\partial x^2}[/math] So the Hamiltonian operator is (remembering the Hamiltonian function) [math]\hat{H} = \frac{\hat{p^2_x}}{2m} + \hat{V}(x) = -\frac{\hbar^2}{2m}\frac{\partial ^2}{\partial x^2} + V(x)[/math] The Schrodinger equation So finally, we're in a position to state the Schrodinger equation, which for a free particle could take the form [math]i \hbar \frac{\partial}{\partial t}\Psi (x,t) = \hat{E}_k \Psi(x,t)[/math] But for a bound particle, i.e there is a potential energy term, we require that [math]i \hbar \frac{\partial}{\partial t}\Psi (x,t) = (\hat{E}_k + \hat{V}(x)) \Psi(x,t)[/math] So using the kinetic energy operator, and the potential operator, this gives... [math]i \hbar \frac{\partial}{\partial t}\Psi (x,t) = -\frac{\hbar^2}{2m}\frac{\partial^2 \Psi(x,t)}{\partial x^2} + V(x) \Psi (x,t)[/math] more compactly... [math]i \hbar \frac{\partial}{\partial t}\Psi (x,t) = \hat{H}\Psi(x,t)[/math] Hopefully, this should give you a better understanding of operators, the Hamiltonian and wave functions (it's just a basic treatment). I'm not sure what your maths level is, but you can always ask if there's anything that you find confusing. Yes, I've seen that wikipedia article too, and wave-functions don't seem to be obsolete. It also doesn't seem operators can holistically describe an atom. on their own. Edited April 22, 2012 by questionposter
Royston Posted April 22, 2012 Posted April 22, 2012 (edited) Yes, I've seen that wikipedia article too, and wave-functions don't seem to be obsolete. What wikipedia article ? Have you quoted the wrong post ? That was written using my text books for reference. It also doesn't seem operators can holistically describe an atom. on their own. What do you mean it doesn't seem? I've just shown you explicitly what an operator is. Edited April 22, 2012 by Royston
Xittenn Posted April 22, 2012 Posted April 22, 2012 So you say this article about wave-particle duality is obsolete? My interpretation of what juanrga was saying is that although wave functions have--at a more rudimentary level--explained some of the phenomena associated with quantum mechanics, more modern approaches have been developed that make better sense of the available information, like with QFT. Now looking through Ryder's book on QFT I don't see any mention at all of wave like particles and the discussion is limited to particles, period. The book does not however offer an explanation for this. I found this on Wiki. I do however find it incredulous that anyone would offer Wiki as an argument for or against any point made in the context at present--especially against someone who has obviously spent some time considering more viable literature. How about offering up a more formal citation michel123456? I would like to point out that the wiki article I just submitted has zero citations to support its statements, which doesn't make it wrong, it just makes it weak. ---------------------------------------------------- I am finding more in Ryder's book on waves at closer look, maybe I'll find something relevant. --------------------------------------------------- 2.2 Klein-Gordon Equation "The interpretation of the Klein-Gordon equation as a single particle equation, with a wave function [math] \phi [/math], therefore also has to be abandoned." - Ryder the explanation is deeply mathematical and requires a chapter of discussion . . . 1
questionposter Posted April 22, 2012 Posted April 22, 2012 What wikipedia article ? Have you quoted the wrong post ? That was written using my text books for reference. I don't remember exactly what I looked up, but it was close to this. It's possible the book you looked in is what was cited on wikipedia. http://en.wikipedia.org/wiki/Hamiltonian_(quantum_mechanics) What do you mean it doesn't seem? I've just shown you explicitly what an operator is. And that operator still uses a wave function and probability density distribution. My interpretation of what juanrga was saying is that although wave functions have--at a more rudimentary level--explained some of the phenomena associated with quantum mechanics, more modern approaches have been developed that make better sense of the available information, like with QFT. Now looking through Ryder's book on QFT I don't see any mention at all of wave like particles and the discussion is limited to particles, period. The book does not however offer an explanation for this. I found this on Wiki. I do however find it incredulous that anyone would offer Wiki as an argument for or against any point made in the context at present--especially against someone who has obviously spent some time considering more viable literature. How about offering up a more formal citation michel123456? I would like to point out that the wiki article I just submitted has zero citations to support its statements, which doesn't make it wrong, it just makes it weak. ---------------------------------------------------- I am finding more in Ryder's book on waves at closer look, maybe I'll find something relevant. --------------------------------------------------- 2.2 Klein-Gordon Equation "The interpretation of the Klein-Gordon equation as a single particle equation, with a wave function [math] \phi [/math], therefore also has to be abandoned." - Ryder the explanation is deeply mathematical and requires a chapter of discussion . . . For the most part I like QTF, but I think it has to be more than a coincidence that so many aspects of a particle can be accurately described using wave mechanics.
michel123456 Posted April 23, 2012 Posted April 23, 2012 (edited) (...) I do however find it incredulous that anyone would offer Wiki as an argument for or against any point made in the context at present--especially against someone who has obviously spent some time considering more viable literature. How about offering up a more formal citation michel123456? (...) Juanrga made the following statement: It was correct to discuss about a supposed "wave-particle duality" about 70 years ago I was surprised, that's all. There is a huge litterature about wave-particle duality. I am not aware of any information making the concept obsolete. The main article in Wiki is http://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality a random article from Nature http://www.nature.com/nature/journal/v401/n6754/abs/401680a0.html Edited April 23, 2012 by michel123456
juanrga Posted April 23, 2012 Posted April 23, 2012 (edited) So you say this article about wave-particle duality is obsolete? The part explaining the origins of the term and the history seems correct, but I have not checked the details. The rest is not only obsolete but even incorrect. If you take a look to the Talk page of the wikipedia article, you can find that already a pair of years ago Wiki-editors did comments such as: Early quantum physicists are forced to use classical concepts such as "newtonian particle" and "Fresnel wave" to describe quantum objects in contradictory manner because they had no other concepts. [...] duality is only of historical interest. [...] Sources, speaking on the "duality", either obsolete or are popular, educational, or philosophical literature. Serious contemporary theoretical sources don't mention about duality, they use more effective approaches, almost all based on PI. There is a good analogy with the notion of so-called "relativistic mass", which served its in the interpretation of relativistic effects in terms of Newtonian physics, but in the modern 4-dimensional formulation only creates a confusion Yes, I think that their analogy with "relativistic mass" is a good one. You find many old references, and some recent low-quality ones talking about a supposed relativistic mass, but any modern and rigorous reference does not even mention it except, maybe, in the introductory chapter about the history of the subject. I guess a Hamiltonian operator can still account for a bit of it, but what about the exact matches of nodal surfaces both in atomic orbitals and in the double slit experiment that can be accurately described by wave mechanics? How does a Hamiltonian operator account for those without wave mechanics? Also, can't these operators be set equal to a wave function? I problem that I see with your operators is that they are nothing more than shortcuts, they could only have been created with previous knowledge, and that previous knowledge was wave mechanics. People found out from experiments that there can only be specific results that work, so instead of constantly trying to re-create those results from scratch, they simply created operators specifically designed for creating those results since the results an operator generates are the only possible results (if the correct information in put in), where-as with a sine wave there's millions of possible ways to combine them, but you can still create an accurate model of an atom using them if you do a ton of work. You are mixing up it all. Wave mechanics also uses operators! Atomic orbitals and the double slit experiment can be accurately described by quantum mechanics (aka I mean the Dirac ket formulation). I already explained how wavefunctions can be obtained from kets under a determined representation |x> (I repeat the inner product <x|Psi>), and I also explained to you that representation is not universal (i.e. there are quantum situations where wavefunctions do not work). Any quantum chemistry student is taught that atomic orbitals are only crude approximations that do not account for electron-electron correlation. One electron in a multi-electronic atom or in a molecule cannot be found in a 1s, 2p, or a 4d orbital, for instance. If you assume the contrary and compute observables as energy you get values in disagreement with observations. I only want to remark, finally, that orbitals (even for Hydrogen atom) are not observables (unlike properties as mass, energy, momentum, spin...) but only mathematical constructs and that the nodes of the orbitals have the same ontological status. Interesting: This page was last modified on 22 April 2012 at 05:27. quoted from the linked wiki page. There is nothing interesting about that. The page was automatically modified by one Wiki-bot that corrected a word in French "particule --> corpuscule". Look to the change done by the bot http://en.wikipedia....oldid=488482596 2.2 Klein-Gordon Equation "The interpretation of the Klein-Gordon equation as a single particle equation, with a wave function [math] \phi [/math], therefore also has to be abandoned." - Ryder the explanation is deeply mathematical and requires a chapter of discussion . . . More concretely, the solutions to both the Klein-Gordon and the Dirac equations are operators defined in a dummy spacetime [math] \hat{\psi}(x,t) [/math]. However, if you go to very old textbooks you find all their authors trying to interpret those solutions as wavefunctions. Such interpretation is not possible and gives lots of paradoxes. A random article from Nature http://www.nature.co...s/401680a0.html The experiment is fine. The interpretation flawed. It is, more or less, if the buckyball does not behave as a ping-pong ball then we found a duality! Some people believes that particle is a synonym for classical particle. Edited April 23, 2012 by juanrga
questionposter Posted April 23, 2012 Posted April 23, 2012 You are mixing up it all. Wave mechanics also uses operators! Atomic orbitals and the double slit experiment can be accurately described by quantum mechanics (aka I mean the Dirac ket formulation). I already explained how wavefunctions can be obtained from kets under a determined representation |x> (I repeat the inner product <x|Psi>), and I also explained to you that representation is not universal (i.e. there are quantum situations where wavefunctions do not work). Any quantum chemistry student is taught that atomic orbitals are only crude approximations that do not account for electron-electron correlation. One electron in a multi-electronic atom or in a molecule cannot be found in a 1s, 2p, or a 4d orbital, for instance. If you assume the contrary and compute observables as energy you get values in disagreement with observations. I only want to remark, finally, that orbitals (even for Hydrogen atom) are not observables (unlike properties as mass, energy, momentum, spin...) but only mathematical constructs and that the nodes of the orbitals have the same ontological status. I don't understand, do you actually think by wave mechanics I mean only wave mechanics and nothing to do with actual quantum mechanics? Because wave mechanics is how quantum mechanics was originally coming about, and the Uncertainty Principal I don't think can only be described with wave mechanics for instance even though you can infer it by adding multiple probable frequencies and seeing it take place. Also, I don't know what you mean by "we can'y observe a multi-electornic atom" when there are special labs specifically designed with electron microscopes and guns to determine with accuracy the actual structure of a molecule or atom.
juanrga Posted April 23, 2012 Posted April 23, 2012 (edited) I don't understand, do you actually think by wave mechanics I mean only wave mechanics and nothing to do with actual quantum mechanics? Because wave mechanics is how quantum mechanics was originally coming about, and the Uncertainty Principal I don't think can only be described with wave mechanics for instance even though you can infer it by adding multiple probable frequencies and seeing it take place. Also, I don't know what you mean by "we can'y observe a multi-electornic atom" when there are special labs specifically designed with electron microscopes and guns to determine with accuracy the actual structure of a molecule or atom. When you repetitively ignore what is being said to you, whereas attribute to me nonsensical stuff as "we can'y observe a multi-electornic atom", which I have never said [*], then the discussion makes no sense... [*] What I said was: Any quantum chemistry student is taught that atomic orbitals are only crude approximations that do not account for electron-electron correlation. One electron in a multi-electronic atom or in a molecule cannot be found in a 1s, 2p, or a 4d orbital, for instance. If you assume the contrary and compute observables as energy you get values in disagreement with observations. Edited April 23, 2012 by juanrga
michel123456 Posted April 23, 2012 Posted April 23, 2012 The part explaining the origins of the term and the history seems correct, but I have not checked the details. The rest is not only obsolete but even incorrect. That is quite disturbing. I know wiki is not the best of the best, but "obsolete" and "incorrect" is a harsh judgment. If you take a look to the Talk page of the wikipedia article, you can find (...) i can find tons of interesting things in the talk pages, but when those things are not reflected in the main page, there must be a reason to it. Interesting:This page was last modified on 22 April 2012 at 05:27. quoted from the linked wiki page. There is nothing interesting about that. The page was automatically modified by one Wiki-bot that corrected a word in French "particule --> corpuscule". Look to the change done by the bot http://en.wikipedia....oldid=488482596 the interesting part is that the page was updated the same day you said it was obsolete. That looks to me as a page under 100% application. (...)Some people believes that particle is a synonym for classical particle. What do I have to believe? That an electron (and matter) has a duality? Or not?
Xittenn Posted April 23, 2012 Posted April 23, 2012 Juanrga made the following statement: I was surprised, that's all. There is a huge litterature about wave-particle duality. I am not aware of any information making the concept obsolete. The main article in Wiki is http://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality a random article from Nature http://www.nature.com/nature/journal/v401/n6754/abs/401680a0.html These are probably not the best sources to be citing in this situation. Quaint little slideshow, with many slides and a lot of text, on some of the history! Why was this important to the OP? How does it affect the electron orbit?
juanrga Posted April 23, 2012 Posted April 23, 2012 (edited) That is quite disturbing. I know wiki is not the best of the best, but "obsolete" and "incorrect" is a harsh judgment. i can find tons of interesting things in the talk pages, but when those things are not reflected in the main page, there must be a reason to it. the interesting part is that the page was updated the same day you said it was obsolete. That looks to me as a page under 100% application. What do I have to believe? That an electron (and matter) has a duality? Or not? Then you will find disturbing that the own Wiki-editors use terms as obsolete to refer to the article that you linked. When I said that your link was obsolete, I did mean that its scientific content was obsolete. This fact is not changed by a Wiki-bot who automatically fixed a typo in a French word. You can open a Word document, write some scientific nonsense, then use the automatic spell-checker, and the resulting doc (now without typos) will continue to be scientific nonsense. About your three questions. I will repeat the quote from the Talk page of the article that you linked, because it explains the situation very well. It explains why about 1930 physicists lacked the adequate concepts and invented new words as duality. How those new words have now only historical interest, and how serious modern resources do not even mention duality. The quote also gives a beautiful analogy with the obsolete concept of relativistic mass. It was invented in the early years, when relativistic theory was in its infancy, but it is not used in serious and modern resources. Early quantum physicists are forced to use classical concepts such as "newtonian particle" and "Fresnel wave" to describe quantum objects in contradictory manner because they had no other concepts. [...] duality is only of historical interest. [...] Sources, speaking on the "duality", either obsolete or are popular, educational, or philosophical literature. Serious contemporary theoretical sources don't mention about duality, they use more effective approaches, almost all based on PI. There is a good analogy with the notion of so-called "relativistic mass", which served its in the interpretation of relativistic effects in terms of Newtonian physics, but in the modern 4-dimensional formulation only creates a confusion Edited April 23, 2012 by juanrga
questionposter Posted April 23, 2012 Posted April 23, 2012 (edited) When you repetitively ignore what is being said to you, whereas attribute to me nonsensical stuff as "we can'y observe a multi-electornic atom", which I have never said [*], then the discussion makes no sense... [*] What I said was: I'm not ignoring anything, your not addressing how many aspects of an atom can be accurately described by wave mechanics, all you do is keep saying there's new math, when even a Hamiltonian operator uses wave functions, although I suppose that might just be for using Schrodinger's equation. It makes no sense what-so-ever that particles are not like waves in any shape or form given the observable evidence. I have no problem with wave mechanics not being the only thing, but it's definitely involved. Do you think a little marble follows the uncertainty principal? Because I sure don't. Do you think a little marble interferes with itself? Makes no sense that way. All the modern quantum operators were derived from that data anyway. Tell me one other thing in the universe that makes an interference pattern besides a wave. One electron in a multi-electronic atom or in a molecule cannot be found in a 1s, 2p, or a 4d orbital, for instance. 1s2 2s2 2p1 - Boron I think you were triyng to say orbitals in chemistry are inaccurate. Modern quantum mechanics uses perturbation theory anyway yet not everything in QM has an exact answer. Even modern QM is an approximation. In other words, there's' room for interpretation, which is exactly why you have things like string theory which to me don't seem likely, but have caught on, whereas wave-mechanics doesn't seem likely to you but has also caught on. http://en.wikipedia....antum_mechanics wave-particle duality seems to be pretty fundamental for QM. Dirac equations can end up with many of the same results as quantum wave mechanics and Schrodinger's equations, but still has some loose ends. In fact, the wave mechanics of Schrodinger and the operators and linear systems you seem to like are actually the same thing. I wouldn't be surprised if the math you like was developed by Heisenberg. Edited April 24, 2012 by questionposter
esbo Posted April 24, 2012 Posted April 24, 2012 (edited) I have been looking at the structure of the atom lately and wondered what makes the electron orbit? You would think if a proton is positively charged and a electron is negatively charged that the two would eventually stick together. I realize in theory that the orbiting electron like a planet never lets this happen. But what makes an electron orbit in the first place and when an electron goes from one atom to another how does it automatically orbit in a way that it does not collide with the proton or neutron? I am not interested in theories (there are way to many of them flying around), but in proof + experiments on what is going on. Thanks. Yea there is a force of attraction between and electron, but there is the same force of attraction between the earth and the moon, so would you ask why the earth is not pulled into the moon? It's basically the same question except the force is gravity not electro static but it is essentially the same 'problem'. So the answer is the electron is falling towards the electron just as the moon is falling towards earth, without that falling the moon would fly off into space or the electron would fall away from the proton. I guess it the electron did hit the proton it would become a neutron, however once it is an electron in orbit it will never hit the proton same as the moon will never hit the earth. Even using that model, say another planet passed by earth and pulled the moon away, is it likely the moon would crash into that planet? I think that is fairly unlikely. A hydrogen atom is 100,000 time the size of the nucleus so the chances of it hitting are tiny. Who is to say they do not hit, can we detect one neutron in 100,000 hydrogen atoms? I don't really need another model to understand why it does not hit really, even if I am technically incorrect accord into current theory. So with that basic model you would expect the electron to orbit all the time and would be very surprise it it hit the nucleus. You seem to be under the impression a collision is likely, which is understandable as there is a force of attraction, but the 'trick' is unless it is aimed directly at the centre it will accelerate towards the proton, but it will be going so fast it will over come the force of attraction and loop round into and orbit which will never collide with the proton. Now if you want an experiment it woudl be hard to do wouldn't it? Basically you would need a particle accelerator firing electrons at protons. Then you are in the realm of sub atomic physics and strange particles etc.. http://www.emsb.qc.ca/laurenhill/science/quark.html In 1935, the Japanese physicist, Hideki Yukawa, first proposed the existence of a particle responsible for a strong force. The discovery of the pi meson confirmed his hypothesis and won him the Nobel Prize in 1949. But the existence of quarks was only confirmed about 20 years later by Taylor, Friedmman and Kendall, who fired high energy electrons from a linear accelerator at protons and neutrons. Strangely, electrons were deflected at large angles. Sixty years earlier, Rutherford had obtained similar deflection angles upon firing helium nuclei at gold foil. The trio's results suggested that neither the proton nor the neutron was a solid sphere. Two up quarks and a down quark of charge +2/3 and -1/3, respectively, make up the proton, and two downs and an up make up a neutron. [note] to any over zealous mods (I know they exist sometimes) I am just throwing out some ideas out for discussion not presenting a paper to the Royal Society, please don't pull me up on 'the rules' or whatever. I am just putting out a model which like all models, is wrong. Edited April 24, 2012 by esbo -2
questionposter Posted April 24, 2012 Posted April 24, 2012 (edited) Yea there is a force of attraction between and electron, but there is the same force of attraction between the earth and the moon, so would you ask why the earth is not pulled into the moon? It's basically the same question except the force is gravity not electro static but it is essentially the same 'problem'. So the answer is the electron is falling towards the electron just as the moon is falling towards earth, without that falling the moon would fly off into space or the electron would fall away from the proton. I guess it the electron did hit the proton it would become a neutron, however once it is an electron in orbit it will never hit the proton same as the moon will never hit the earth. Even using that model, say another planet passed by earth and pulled the moon away, is it likely the moon would crash into that planet? I think that is fairly unlikely. A hydrogen atom is 100,000 time the size of the nucleus so the chances of it hitting are tiny. Who is to say they do not hit, can we detect one neutron in 100,000 hydrogen atoms? I don't really need another model to understand why it does not hit really, even if I am technically incorrect accord into current theory. So with that basic model you would expect the electron to orbit all the time and would be very surprise it it hit the nucleus. You seem to be under the impression a collision is likely, which is understandable as there is a force of attraction, but the 'trick' is unless it is aimed directly at the centre it will accelerate towards the proton, but it will be going so fast it will over come the force of attraction and loop round into and orbit which will never collide with the proton. Now if you want an experiment it woudl be hard to do wouldn't it? Basically you would need a particle accelerator firing electrons at protons. Then you are in the realm of sub atomic physics and strange particles etc.. http://www.emsb.qc.c...ence/quark.html [note] to any over zealous mods (I know they exist sometimes) I am just throwing out some ideas out for discussion not presenting a paper to the Royal Society, please don't pull me up on 'the rules' or whatever. I am just putting out a model which like all models, is wrong. That's just completely and utterly wrong. Electrons can't orbit at all because orbiting requires constant acceleration and if an electron did that it would radiate all of it's energy away, and I did some research http://hyperphysics....base/uncer.html And if you look at the 3rd box, the energy needed to force an electron in the nucleus is massive, I can see why it would take a huge particle accelerator. There's a few theories for particles not falling into the nucleus. Some of them depict them as fields just simply don't exist in a way to interact in the nucleus, some picture them as waves who's probabilities don't exist enough in the nucleus nucleus, some theories view electrons as having odd extra-dimensional properties that make it move in dimensions we can't see. Gravity and electro-magnetism are not the same thing, they have completely different equations and different force carrier particles. Edited April 24, 2012 by questionposter
Xittenn Posted April 24, 2012 Posted April 24, 2012 [note] to any over zealous mods (I know they exist sometimes) I am just throwing out some ideas out for discussion not presenting a paper to the Royal Society, please don't pull me up on 'the rules' or whatever. I am just putting out a model which like all models, is wrong. Esbo, it is intuitive to say what you have just said. It is however common knowledge within Modern and Theoretical Physics that what you have stated is by today's standards incorrect. In fact the reason that QM exists is because we do not observe what you have just describe. In terms of particle interactions if this were true we would observe in experiments what is known as the Ultraviolet Catastrophe, which I will leave for you to research as there are ample discussions on the topic already. In brief observations with respect to blackbody radiation, as well as the photo-electric effect demonstrate that electrons occupy quantized energy levels around the nucleus, quite unlike what is observed with gravitational orbits. ** I was the one who gave you at the very least the first neg rep, I think it is savy that if you are to post in a thread like this you come prepared with at least a basic knowledge--as a minimum standard. I note this as you directed your comment to the mods after I had done so, and it wasn't them!
esbo Posted April 24, 2012 Posted April 24, 2012 That's just completely and utterly wrong. Electrons can't orbit at all because orbiting requires constant acceleration and if an electron did that it would radiate all of it's energy away, and I did some research http://hyperphysics....base/uncer.html And if you look at the 3rd box, the energy needed to force an electron in the nucleus is massive, I can see why it would take a huge particle accelerator. There's a few theories for particles not falling into the nucleus. Some of them depict them as fields just simply don't exist in a way to interact in the nucleus, some picture them as waves who's probabilities don't exist enough in the nucleus nucleus, some theories view electrons as having odd extra-dimensional properties that make it move in dimensions we can't see. Gravity and electro-magnetism are not the same thing, they have completely different equations and different force carrier particles. Well as I said all theories are completely and utterly wrong when it comes to this sort stuff, so I can equally say the theories you describe are completely and utterly wrong but that does not get he discussion anywhere does it? I said we were in the realm of particle physics and I never said gravity was the same as electromagnetic force just that they were both force. I was just illustration a few points that even in the classical model the chances of hitting a proton are remote. Anyway it goes on to say that that energy cannot be confined in the nucleus because a nucleus cannot contain that energy but it does not say what happens. Furthermore as you cannot say where the electron is due to the uncertainty principle how can you say it does not orbit? How can you be so sure? You cannot say where the electron is so how can you say it is not orbiting? That's a contradiction? So I think you have to accept that according to the link you provided you cannot be certain the electron is not orbiting, so you are wrong on that aren't you? You are happy to call me 'completely and utterly wrong' so perhaps you will be big enough to admit you are 'completely and utterly wrong' on that. - I doubt it some how, I really do.... Esbo, it is intuitive to say what you have just said. It is however common knowledge within Modern and Theoretical Physics that what you have stated is by today's standards incorrect. In fact the reason that QM exists is because we do not observe what you have just describe. In terms of particle interactions if this were true we would observe in experiments what is known as the Ultraviolet Catastrophe, which I will leave for you to research as there are ample discussions on the topic already. In brief observations with respect to blackbody radiation, as well as the photo-electric effect demonstrate that electrons occupy quantized energy levels around the nucleus, quite unlike what is observed with gravitational orbits. ** I was the one who gave you at the very least the first neg rep, I think it is savy that if you are to post in a thread like this you come prepared with at least a basic knowledge--as a minimum standard. I note this as you directed your comment to the mods after I had done so, and it wasn't them! Well thanks for your courteous response I think one or two of you may have misread my post because you seem to missed where I said "even if I am technically incorrect accord into current theory" so some (one) of the attacks on me for being wrong are a bit over the top because I was the first to admit I was wrong. So for Questionposter to say I am completely and utterly wrong he must be saying I am right, as I said I was wrong? I will leave it for others to work that one out!!! Thanks for the negative rep, I don't take much notice of reputations myself, I am rather more concerned with facts and models and science than personal reputations, it is a very unscientific method to just correctness of someone by their reputation, that is why I do not use it myself but each to their own, it takes all sorts as they say. I do have a basic knowledge. I have A level physics at grade B, which would get me onto most university physics courses, that is more than most. You say you do not observe what I describe but to be fair you are not sure what you are observing, so how can you say, "well it is not that" when you can't say what it is? See the problem is the scientist do all these experiment and work out all these various laws and then find they do not actually fit together very well
Xittenn Posted April 24, 2012 Posted April 24, 2012 I do have a basic knowledge. I have A level physics at grade B, which would get me onto most university physics courses, that is more than most. You say you do not observe what I describe but to be fair you are not sure what you are observing, so how can you say, "well it is not that" when you can't say what it is? See the problem is the scientist do all these experiment and work out all these various laws and then find they do not actually fit together very well Some pieces fit better than others. Electrons are not observed falling into nuclei and dismissing this fact dismisses all of known modern physics. You are however correct that it is not understood how electrons move about in their orbits and you are very good to question this. I hope you do well in your studies and find answers to the questions you are asking. I'm posting a paper that has been submitted online by a professor from the University of Iceland, it addresses some aspects of the topic. It is a paper that I find very difficult to understand, but I believe I can learn from it at least a little for now. Have fun esbo! Spin and orbital angular momentum
esbo Posted April 24, 2012 Posted April 24, 2012 (edited) Some pieces fit better than others. Electrons are not observed falling into nuclei and dismissing this fact dismisses all of known modern physics. You are however correct that it is not understood how electrons move about in their orbits and you are very good to question this. I hope you do well in your studies and find answers to the questions you are asking. I'm posting a paper that has been submitted online by a professor from the University of Iceland, it addresses some aspects of the topic. It is a paper that I find very difficult to understand, but I believe I can learn from it at least a little for now. Have fun esbo! Spin and orbital angular momentum Well I did go to uni but to study electronics, I would rather have done physics maths or chemistry as find the pure subjects much more interesting but I though electronics would have been better jobs wise, maybe it was initially but not any more really I went into computer programming in the end, but that went downhill after a while. I had little interest in electronics and found most of it to be 'rubbish'. I could possibly do another degree but I don't think that is gonna happen for a number or reason not least cost. I do sometimes discuss stuff on forums from time to time but it is usually not long before I get my knuckles raped by the mods (lol) so I don't bother with it so much these days. Science forums seem to be particularly bad for this, free speech seems to have gone out the window a long time ago. That paper is a bit too long and mathematical for me to look at at the moment, it is difficult to follow stuff in mathematical symbols unless you know where it is going. So just to go back to the particle experiment, what does happen when you fire a high energy election at a proton? That's the kind of thing which is easier to discuss. Again the following is probably wrong, but when you fire an electron you create a current so we are getting towards thing like the left hand motor rule. http://en.wikipedia.org/wiki/Fleming%27s_left-hand_rule_for_motors So I said this is all a bit wrong because maybe it is the corkscrew rule but what I am getting at which is probably don't wrong anyway is that if you fire an electron at a proton, don't you get a force at right angles which would make it impossible to hit the proton anyway? Again as I said probably all wrong but can someone see what I am getting at and explain why I am wrong, preferably start from where I am at rather than from somewhere else, if you see what I mean. Anyway I will leave it at that for now. Edited April 24, 2012 by esbo
Xittenn Posted April 24, 2012 Posted April 24, 2012 AFAIK the electron can achieve ground state but if they were both at rest they wouldn't combine. Now if you shoot an electron at a proton at high energy nothing will happen, or nothing in respect to what you might be thinking. The energy for a reaction is unfavorable, but if it did react it would form a neutron as the combination of an electron and a proton is a neutron and neutrons decay into an electron and a proton. Maybe if there was a bombardment of electron antinutrinos, because one is emitted in neutron decay as well! I see you added some thoughts, the fields will not create this sort of repulsion no; at least not that I'm aware of!
esbo Posted April 24, 2012 Posted April 24, 2012 Moving electric particles tend to create fields which produce force at right angles to the direction of movement that's how motors work. So I am just wondering about how that affects things, might not work if they are moving head on though.
esbo Posted April 24, 2012 Posted April 24, 2012 (edited) However if the object and target are not absolutely head on there may be this force causing the target to me missed. I am not sure whether the size of the force is proportional to the speed (which would make things worse) But I am now. http://www.regentsprep.org/Regents/physics/phys03/cdeflecte/default.htm If the charge on the electron were greater, the force would be greater. If the speed of the electron were greater, the. force would be greater If the magnetic field strength were greater, the force on the electron would be greater. If the mass of the electron were greater, it would have no effect on the force, but the circular path would be larger. Edited April 24, 2012 by Cap'n Refsmmat fix bbcode borkage
juanrga Posted April 24, 2012 Posted April 24, 2012 Well as I said all theories are completely and utterly wrong when it comes to this sort stuff That is not a correct approach to scientific theories. A scientific theory is something which has been experimentally confirmed [*], therefore it cannot be wrong. [*] Yes I know that currently some physicists and cosmologists abuse of the term and name "theories" to certain pseudo-philosophical speculations and hypothesis.
Cap'n Refsmmat Posted April 24, 2012 Posted April 24, 2012 That is not a correct approach to scientific theories. A scientific theory is something which has been experimentally confirmed [*], therefore it cannot be wrong. Karl Popper would like to have a word with you. Experimental confirmation means a theory has been tested to be valid in one particular set of circumstances. There is no logical guarantee that it will be correct anywhere else, to any arbitrary level of precision. There is no logical way to demonstrate that a theory is always correct under any circumstance, and so I don't think you can conclude that theories "cannot be wrong."
michel123456 Posted April 24, 2012 Posted April 24, 2012 (edited) Then you will find disturbing that the own Wiki-editors use terms as obsolete to refer to the article that you linked. Only ONE editor used the term "obsolete" Some other editor wrote: I have no argument about the relative merits of the viewpoints, but I don't see any source saying that because of PI, duality is only of historical interest. And many sources that still talk about duality, not in a historical context. Dicklyon (talk) 22:33, 17 September 2010 (UTC) from the same talk page. I'd like to get some confirmation (or infirmation) from other knowledgeable members. Also the particular wiki article has been peer reviewed, and the word "obsolete" does not appear once on the main page. Wave–particle duality has had a peer review which is now archived. It may contain ideas you can use to improve this article. from the talk page introduction. Edited April 24, 2012 by michel123456
Cap'n Refsmmat Posted April 24, 2012 Posted April 24, 2012 I'd like to get some confirmation (or infirmation) from other knowledgeable members. The associate dean of our college, a particle physicist, dedicates a week or two in his introductory modern physics course to the idea of wave-particle duality. I wouldn't say nobody serious uses the term "wave-particle duality" any more.
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