John Kassebaum <jak <at> k.yahoo.invalid>
2002-10-20 15:01:11 GMT
> First, NMR works with nuclear spins and
> dipole moments, not electrons. Second, NMR is a dynamic, not static,
> phenomenon. Third, what is described is nothing other than a bar
> magnet lining up with an external field.
> What he might have been thinking of is _electron_ paramagnetic
> resonance, but of course that's a dynamic effect too.
Hi Dr. Zimmerman,
Thanks for the feedback. I know NMR is a dynamic response. I guess these sentences were not really germain to
my argument anyway.
Just for clarity, my understanding of NMR is that a large static magnetic field (like a tesla or more) is
imposed on the imaging target which causes the atoms to align themselves with the imposed magnetic field.
Then a brief RF pulse is transmitted throught the target which causes the aligned atoms to 'ring'. Each
tissue or material transmits or damps out this ringing at different rates. By listening to the ringing,
and seperating the target's material regions into categories with similar ringing decay times, the
target can be imaged.
I think the are where I was imprecise was 'electrons ... have a magnetic moment'. I think I am imagining
Mill's orbitsphere here where the magnetic dipole moment is generated from the electron's orbital spin.
I think the accepted physics just uses the electron's spin here? On the other hand, maybe I am descibing
electron paramagnetic resonance.
I'd be happy to have any gaps or misunderstandings in my description cleared up if you would like to reply.
Thanks as always!