Electron Orbits and Spin

I was just pondering over something about electrons. As we know electrons are sub-atomic particles that spin in the orbit of a nucleus(up and down) and each revolution would signify an electron vibration. If the electron's vibration were to increase or decrease, what would happen to the atom and what kind of effects would you observe.

[edit on 26-1-2005 by Indigo_Child]

I'm not entirely sure what you mean by "electron vibration". It is true that the position of an electron within an orbital is not precisley defined (Heisenberg's uncertainty principle), and so is mathematically represented by the wavefunction phi. phi^2 is related to the "density" of the electron cloud, which in real terms refers to the "probability" of finding an electron at any given location in its orbitals. Because classical theory postulates that an electron should lose energy as they orbit the nucleus, and because atoms still seem to work, it was postulated by, among others, Bohr (look up his absolutley brilliant analysis of the spectral lines of hyrdogen) that the electrons have to resonate with themselves, and that their wavelength has to be a multiple of hbar/2, so that they reinforce themselves. If this were to change, then the atom would probably collapse... I'm not too sure, but I'm thinking that the electrons would either fly off or impact the nucleus, which would probably cause at least some form of radioactive decay. Problem is, electrons like staying where they are... I doubt you'd be able to have a non-integral path length.

"spin" is an intrinsic property of electrons that describes their angular momentum and various other quantum properties. Fermions, which are regular matter, incl. electrons, have half-integer spin (1/2 for electrons). This means, roughly, that you have to rotate an electron through 720 deg. to preserve symmetry. In any case, the spin number (Ms) can have two values, + or -. It roughly represents the fact that the electron rotates about itself, and creates a magnetic field, as it is a moving charge. This is why things like iron can be ferromagnetic, as all the spins for some reason align and add up to one big magnetic field.

Hope this sorta answers your question...

I was assuming something to the effect that if an electron was spinning faster in it's orbit it would probably cause the atom to collapse. However, as you said, according to classical theory, the electron should be losing it's energy. Does this mean the electron is independent of the nucleus?

Therefore, if it revolved around it's orbit faster, then would it have an affect on the nucleus, or no effect? I am visualizing two scenoris;

The electron flies off and hits the nucleus or just continues to orbit at it's new velocity. If this is the case, it would cause a change in the magnetic field, and how would this affect the symmetry of the atom?

Further, is it the spin that causes the electron to move?

[edit on 26-1-2005 by Indigo_Child]

I do not think electrons "revolve" around the nucleas in the way you are describing indigo. Are you saying revolve, as compared to a planet revolving around the sun? If so, I could be wrong, but as I understand it, they don't exactly revolve. They move from place to place, and orbit to orbit, without the possibility of being observed in between them. If they revolved, as a planet would for say, we would be able to precisely locate them rendering the uncertainty principle wrong. (I may be way off here) There have been theories of a single electron.

I will try to exoplain my thoughts better here. Uncertainty dictates that position and direction can never be measure precisely at the same time. If one is more precisly measured, the other suffers less accuracy as a result. Therefore an electron can't be orbiting, because that would mean that we would have to know its position and direction at the same time to establish an orbit. Rather they just exist in orbitals. They may even jump from orbital to orbital. Electrons go from place to place without ever being in between them as far as we are concerned.

Then again I probably do not understand what you are saying, and I am not sure if I am correct or not, so this is probably meaningless.

Indigo, your still thinking in terms of Rutherford's theory of electrons - which has been proven wrong. He proposed that electrons revolved around the nucleus..like planets to stars.

Electrons occupy 'clouds' usually the denser the graph of these clouds the more certain you are to locate the electron in that region at a certain time.

This is basically the study of chemistry, tons of different types of bonds and such between electrons making 'cloud' regions around the nucleus and how they can be manipulated.

The electron is totally independent of the nucleus - the fact that atoms have an electron cloud orbiting them is just a nice fact that prevents everything from going to hell... the electromagnetic force is incredibly strong. If just one-tenth of one percent of the charge in your body was to become unbalanced, its effect on a similar amount of charge would produce enough force to lift something with the weight of... the earth. In any case, electrons in atoms have a variety of differently shaped "orbits". Like seapeople says, it's not planets around a sun - just a mathematical function that describes the probability of finding a particular electron in a particular place. Quantum mechanics is really just statistics. Seapeople is right about electrons jumping from orbit to orbit - they correspond to different energy levels of an electron. Electrons with more and more energy keep on rising in orbital until they are torn free of the atom and fly off - this is essentially what happens in a solar energy panel. Loss of electrons causes things to be ionized - not so much of a problem if you're a metal, because metals share lattice electrons in their crystalline structure, but ionized gases and such will become magnetic and can conduct electricity.

As a side note, orbitals are the reason lasers work. An electron is pumped by a photon to higher energy level, and so jumps to a higher, unstable, orbital. A little while later, it reemits that energy in the form of a new photon. Imagine this repeated billions of time in rapid succesion with trillions and trillions of atoms (there are 6.602 e 22 atoms in 12 grams of carbon...) and you have a laser.

And no, the spin does not affect the movement of electrons - that's due to the electromagnetic force - all the spin does is model the rotational motion of the electron about its own axis, like the earth... what that does is cancel out the loss of energy predicted by classical theory.

Yes you are right, according to QM, they are moving in orbitals that is difficult for me to visualize, so I am using Bohrs model, and representing the electron as a planet orbitting a sun.

According to the QM model there are 7 energy states(orbitals) and 4 different kinds of angular momentium, s, p, d and f. However, is this actually been empirically proven, or is just theoretical?

Further, is there a fixed electron velocity? If they are falling to different states of energy, then surely their velocity would increase or decrease(or not?)

[edit on 26-1-2005 by Indigo_Child]

Spin is somewhat of a misnomer. Electrons do not rotate about a nucleus. The term spin is used to describe differing 'states' of electrons occupying the same orbital. Much in the same way that quarks can come in different colors and flavors.

The spin of an electron can be changed via a magnetic field. It doesn't result in the collapse of the atom. It results in the spins being aligned with the magnetic fields. This is the basis the basis for the measurements obtained via Electron Paramagnetic Resonance (EPR) spectroscopy.

To my knowledge properties such as angular momentum don't exist at the quantum level.

Originally posted by Indigo_Child
Yes you are right, according to QM, they are moving in orbitals that is difficult for me to visualize, so I am using Bohrs model, and representing the electron as a planet orbitting a sun.

According to the QM model there are 7 energy states(orbitals) and 4 different kinds of angular momentium, s, p, d and f. However, is this actually been empirically proven, or is just theoretical?

Further, is there a fixed electron velocity? If they are falling to different states of energy, then surely their velocity would increase or decrease(or not?)

[edit on 26-1-2005 by Indigo_Child]

Like the previous posters said, velocity is not an accurate term, and no one will be able to explain this effect using that terminology.

Electrons do lose energy and "drop" to lower orbitals. There are a finite number of allowed energy positions, but this is dependant upon the atom. Simple atoms like Hydrogen have only a few allowed positions (before enough energy is deposited in the electron that it leaves to nucleus), complex ones have many, many more. It is in fact still not possible to theoretically determine the allowable positions for atoms above atomic number 10 or so. Spin is also not spin in the literal sense. It is just a theoretical property that allows two electrons of the same energy to occupy the same space at the same time (as long as they have different spin).

Nothing in Quantum mechanics has been proven in any way. As far as we know there is something much more complex (or simpler) that is at play that we do not understand. Our mathematical capabilites and available computing power have made extensive testing of fundamental QM on many of the complex compounds (large atoms, etc.) that we deal with on a day to day basis.

All this talk reminds me of one of my favorite physics jokes:
"Two identical fermions walk into a bar - but not the same bar"