[sdiy] OT: The spin of electrons!

[Magnus Danielson]

karl dalen wrote:
> Does science know today what's causing the spin of the electron?

It's a fundamental property just as charge. However, as we combine 
particles into larger particles (say quarks into a proton) the spin 
values goes together. However, their interactions allow for different 
spin states.

> Are electrons resonance fix at a certain frequency or can you change
> it by the means of ESR or paramagnetic electroresonace?

The spin frequency of electrons is related to the electron as it is 
hooked into an atom electron shell. The difference in spin state 
manifest itself as different frequencies, which correlates to different 
energy levels. These energy levels is sensitive to things like magnetic 
fields. This effect is used in atomic clocks. Especially alkali metals 
like rubidium and caesium is being used, but also hydrogen.

> I'm not talking of alter spin direction by magnetization
> or an alternating AC field.
> 
> Speculates round that to much energy are needed to change the spin?
> I read that its possible to freeze the atom and a peculiar state
> of the atom appears but does the electrons spin also stop at this
> frozen state of the atom? I speculate that the rotation around atom
> has stopped but what about the spin?

The freezing of the atoms is really only relating to the atoms ability 
to move around. The spin itself does not change or go away, but our 
vision of it does. Lasercooling small balls of cesium or rubidium 
provides for very stable and accurate atomic clocks. The original model 
was on creating a form of "optical molass" for the atoms, but a slight 
detuning created (accidentily) what is now known as Sisyphus Effect 
(remember the old greek tale of a man rolling a stone uphill?). These 
people is taking it really cool, their thermometer is down to 
microkelvins. This just to see the spin effects free of thermal mayhem.

The movements of the electrons "around" the atom does not stop, neither 
do the spin. Just lowering the wild dance that the whole atoms do when 
being warm.

I do some spin-physics in the basement. Who could tell?

Cheers,
Magnus