# How does the Orbital Electron Rotate Permanently without Energy Supply?

1. Oct 28, 2005

### kevinajay

Is there anyone who knows the answers of these two long-standing questions?

1. How can the orbital electron rotate permanently without energy supply?

2. How can the orbital electron keeps its position without merging into its nucleus when an external pressure applied on it if its kinetic energy balances delicately with its potential energy?

I found a very innovative theory about the questions:

How do you think?

Last edited by a moderator: Oct 28, 2005
2. Oct 28, 2005

### Physics Monkey

Your first question is answered by quantum theory. The "orbits" of the electron in Hydrogen are quantized. The only way an electron can change its energy is by jumping between levels and emitting light. Once the electron sits in the ground state of atom, the lowest energy state, it can't go down anymore because of quantum effects. For more complicated atoms, all the discrete states up to a certain energy are filled, and the atom is stable because of the Pauli exclusion principle which tells you that no two electrons can be in the same quantum state.

To answer your second question, remember that as you compress the atom you are applying an additional force, but the force from the nucleus also gets stronger as the electron moves further in. The system will find a new equilibrium and the electron will not collapse into the nucleus in general. In practice, you could alter the orbit with electric and magnetic fields, but the electron isn't going to crash into the nucleus.

We have known the answers to these questions for many years. There is no confusion even though Dr. Yoon seems to suggest that there is. The confusion lies with him, not with modern atomic theory which is very well founded and well verified experimentally. Dr. Yoon is what we call a crackpot.

Last edited: Oct 28, 2005
3. Oct 28, 2005

### Gokul43201

Staff Emeritus
While this is hardly an answer to the question, recall the revolution that Newton brought to understanding of motion at constant velocity over that achieved by Galileo.

There are several levels at which one can answer this. One of these has been given to you by PM above. For another picture altogether (a different regime), consider the formation of degenerate neutron matter, as is found in a neutron star.

4. Oct 29, 2005

### lightgrav

Extra Energy (as from a supply) would only be needed if the orbital electron radiated.
so - why doesn't it radiate?
Its charge density function doesn't change with time - it is spread out over the "orbit". radiation/(absorption) occurs only as the charge density changes.
Sorry, very few 3rd semester intro courses introduce the Bohr model well.

"orbital electron" is probably not a very good phrase, but it is still in use.
Remember - pressure and balancing are FORCE ideas, not ENERGY ideas.
Real balancing occurs near a STABLE equilibrium - it is not "delicate" in the sense of being unstable; it is seldom even very sensitive.

5. Nov 11, 2005

### Bass Boy

Electron Orbit

Why is it stated that the orbit of an electron can not change??
Is this incorrect or only relevent to force aplied??
I am confused on this. It would seem that if you applied additional
"excitment" to the electron, say in Hydrogen, that it would change in some manner.
Could such "excitement" be used to bring in the orbit of the electron??
Or would there be an equall force applied keeping it in a stable orbit??

6. Nov 12, 2005

### marlon

Ok, this is classic one. people, please STOP talking about an electron's orbit. Using such a language implies that we know the way an electron travels. This is NOT the case.

Secondly, you are referring to the Bohr-model of circular orbits in momentum space, not spatial space. the coordinates are not x,y,z here by the elementary quanta of the L-operator [1]. The only "spatial" notion you can use within this context is the fact that the electron-waves must form closed standing waves along one of the circles.

Thirdly, when talking about an eletcron's position we can only talk in terms of orbitals and corresponding probabilities of finding an electron in such an orbital.

If you guys realize these common misconceptions, most of your questions will solve themselves. It is very important that you all interprete QM and its fundamental concepts in the correct manner.

Err, you guys do know that the Bohr model is hopelessly incomplete, right ?

regards
marlon

[1] Check out this Look for the QM physics section and then the Bohr model.

Last edited: Nov 12, 2005
7. Dec 1, 2005

### StanWilson

You'd better to read "Quantum Physics: Illusion or Reality?" by Alastair Rae, and "Natural Science Founded on A New Atomic Model" by Hansik Yoon in oder to get some answers to your question.

8. Dec 2, 2005

### Staff: Mentor

In my opinion, introductory courses should not discuss the details of "Bohr orbits" at all, because that implants or reinforces the erroneous concept of electrons moving in deterministic classical trajectories around the nucleus. A detailed analysis of Bohr orbits should be left to a later study of the historical development of QM, after the student is well acquainted with QM as we know it today.

When I teach that material in our second-year "intro modern physics" course, I say that Bohr's important contribution (from a modern perspective) was the concept of discrete atomic energy levels. I use the Balmer/Rydberg formula for the wavelengths of the hydrogen spectrum to get the energy levels for hydrogen in terms of the empirical Rydberg constant. I describe Bohr's circular orbit picture (and the later elliptical-orblt version) quickly and qualitatively, with about the same amount of detail that I give to Thomson's "plum pudding" model. I emphasize that the correct derivation of the energy levels in terms of fundamental constants wasn't found until "real" quantum mechanics came on the scene several years later. I don't do things like find the velocity of the electron in Bohr's circular orbits, or assign any homework invoving such things.

9. Dec 2, 2005

### erickalle

Hopelessly?
If we can’t visualise electrons in orbits how are we explaining the ionisation potentials of i.e. the electrons nearest to the nucleus?
These potentials can be worked out from Wi=1/2me*(Z*Vo)^2 . Vo=constant=~2.1877E6.
Especially when I take in account a heavier relativistic mass of the electron I get good results. How to apply relativity but not imagine a speeding mass?
The Bohr model gives me at least some idea.

10. Dec 2, 2005

### marlon

First of all, how does the fact that we cannot "visualise electrons in orbits" contradict with the fact that we can study the energetics of an atom with tremendous accuracy ?

It is true that Bohr's model was the first big step towards the current QM picture because of the L-quantization but you do need to acknowledge its manifest flaws. That was my point.

But to some extent, hopelessly is perhaps a bit of an overstatement and i do agree with your point on the ionization potential.

I am sorry but i do not really understand what you mean by this. Could you clarify, please.

regards
marlon

11. Dec 3, 2005

### McQueen

Bohr’s theory ( or the old quantum theory as it is now called ) suffered from internal contradictions : in order to determine the radius of the orbit , it was necessary to make use of relations of different kinds- the classical relation
$$m\frac {e^2}{r^2_n}$$ and the quantum relation
$$mv_nr_n=n\hbar$$ . The Heisenberg Uncertainty relation
$$\Delta\p_x\Delta\x \geq \hbar$$ illustrates why the electron does not spiral into the nucleus. If the electron is localized at a definite point x , then its momentum will have an arbitrarily large uncertainty. If on the contrary the electron is in a state with a definite value of $${p_x}$$ then it cannot be localized exactly. This also illustrates the fact that the electron is not one of the constituents of the nucleus. What strikes me however is that no-one has yet referred to the virtual transitions of electrons from orbit to orbit through the process of self interaction (i.e the absorption and emission ) of virtual photons. This is the result of another Heisenberg Uncertainty relation which can be stated as
$$\Delta{E}\Delta{t}\geq\hbar$$. Thus an electron can move from $$E_1\longrightarrow{E_2}\longrightarrow{E_1}$$ if it satisfies the relation :
$$\frac{\hbar}{\Delta_t}\geq ({E_2}{-} {E_1})$$. This theory of virtual transitions through the absorption and emission of virtual photons is a continuous process.The statement that the electron occupies level $$E_1$$ should be understood specifically as incessant transitions from the original state to others with an inevitable return every time to the starting level. Virtual transitions don’t require an expenditure of energy. It is only when the electron absorbs a real photon that an actual transition is considered to have been made.

Last edited: Dec 3, 2005
12. Dec 3, 2005

### ZapperZ

Staff Emeritus
I'm not sure why you are addressing PM's comment using the outdated Bohr's model. Why aren't you using the standard QM approach that we teach to every physics undergraduate students? Is there something wrong with that?

Secondly, I don't need to cause a "real" transition only when "electron absorbs a real photon". I can bombard an atom with electrons and cause such an excitation. Your fluorescent light bulb works this way. What this means is that how you excite an atom is irrelevant. If you can sneeze at it to cause a transition, then that works too. I also don't think you should be using "virtual transition" as an explanation for this, especially since you are still using the Bohr model. Keep in mind the rules against over speculative posting.

Zz.

13. Dec 3, 2005

### McQueen

You are missing the WHOLE point . What about virtual transitions ???

14. Dec 3, 2005

### ZapperZ

Staff Emeritus
And you're missing a physics lesson. What about The Schrodinger Equation?

Or are you hijacking this thread to another topic other than the OP?

Zz.

15. Dec 3, 2005

### Staff: Mentor

Whose theory is this? I don't remember seeing it in any textbook. Can you provide a reference to a textbook or research paper that describes it?

16. Dec 3, 2005

### erickalle

The fact that when I include relativistic mass in my calculations the potentials are even closer to given value’s, reinforces my idea of a speeding particle round a nucleus. In the past I’ve been thought that we just have to accept particle and wave duality.
Another (cheeky) point. What does the Latin under your name translate to?
Thanks.
eric

17. Dec 3, 2005

### McQueen

I thought that the electron in the atom did not move at relativistic speeds , could you clarify , please.

18. Dec 3, 2005

### McQueen

Ok. Let me attempt an explanation. The original question by Kevinajay was
And
Where does Schrodinger’s equation come into all this ? Schrodinger’s equation can be used to consider the motion of a microparticle in a limited region of space or , in other words in a potential well . ( For example the motion of an electron in an atom} Such a motion is called finite and the electron is in a bound state. In this case the time-independent Schrodinger equation is used. :

$$-\frac{\hbar^2}{2m}\frac{d^2}{dx^2}\varphi_E\(x)+[U(x){-}E]\varphi_E\(x)=0$$

By solving the Schrodinger equation under certain boundary conditions imposed on the wave function and its first derivative , the spectrum of the values of the energy of the electrons and the wave functions of the stationary states can be found. So this is about eigen values. The question was how does the electron rotate permanently without energy supply. To which I had replied that this was achieved through constant “virtual” transitions using Hesienbergs Uncertainty relation , is there anything wrong with that ?. The original problem with transitions was that of quantum jumps. It had to do with the contradictions observed while considering the jump of an electron one orbit (energy level if you like ) to another . Whatever the speed of transition from one orbit ( energy level ) to another it had to last for some finite time. What is the energy of the electron in the intermediate time. Owing to which Schrodinger had made the famous remark those damned quantum jumps…. The contradiction regarding quantum transitions is overcome by making use of the idea of duality or more precisely the uncertainty relation and the super position of states. Take the two energy levels $${E_1}$$ and $${E_2}$$ this can be denoted as <1| and <2| respectively it is also possible to get the state : <f|= <f|1|> + <f|2><2| Mesurement of the energy of the electron in this state leads either to the result $${E_1}$$ or to the result $${E_2}$$ . According to this the microparticle can simultaneously occupy $${E_1}$$ and $${E_2}$$.
Such a state can only be explained through “virtual’ transitions.

19. Dec 3, 2005

### Physics Monkey

The particle doesn't "spiral into the nucleus" because there is a lowest energy state amongst the solutions of the Schrodinger equation. The notion that the particle has some path is itself flawed, and I don't understand why you acted as if I was making use of the Bohr model in my answer. I wasn't. Now, you can couple your atom to a classical radiation field or even go all the way and couple it to the full quantum radiation field. Either way, the atom is stable because there is a lowest energy state. If there was no lowest energy state then the atom wouldn't be stable regardless of any virtual transitions you might want to talk about. Adding all the complexity of the quantized radiation field gains you nothing in terms of explaining the basic stability of the atom (it does do a lot of other neat things for you, of course). Furthermore, as I said in my first post the electron moves between levels when it emits or absorbs light, be it real or virtual photons.

Last edited: Dec 3, 2005
20. Dec 3, 2005

### ZapperZ

Staff Emeritus
You sound as if you have never done Lagrangian/Hamiltonian mechanics, nor calculus of variation, where "stationary" solution is derived.

Secondly, what in the world is "U(x) - E"?

Thirdly, have you EVER worked though to the solution of one of these? Or did you just read about it somewhere on the 'net?

Fourth, please show citation for your "virtual" stuff, as was asked before. This will be the LAST time such a request will be made before this is deleted. Any further "theory" on this can only be sent to the IR section.

Zz.