I have some basic questions about the behavior of a charged particle in a static B-field.

1. Without a B-field, the particle has spin, with random orientation and spin frequency.

a) What determines its rotational angular velocity or spin frequency? Is it temperature?

b) What kind of energy does it have (Kinetic or Potential or both?)

c) How do you determine the energy?

2.So, from (1) above, we then apply a static B-field, and said particle then starts to align with the B-field.

a) Is this alignment instantaneous or not? If not, what governs its speed of alignment?

b) Does the proton's inherent potential/kinetic energy change due to the presence of the B- field? How so? In short, does it acquire or lose any energy because of the B-field?

I believe its new spin frequency is the Larmor frequency determined by its gyromagnetic ratio and magnitude of the B-field, right?

3. Now, from (2) above, the proton received an external energy tip pulse, as in standard NMR to tip the proton's magnetic moment. Let this pulse have energy E (= hf) and be applied for a duration of time T. I believe the tip angle = Larmor frequency * T, i.e THETA = 2 * pi * FLarmor * T degrees.

(a) But instead of the usual 90o/180o tips, I allow for much greater tip angles, e.g 3600o or 10 revolutions in this case but N complete 360o revolutions in general, and then remove the external tip pulse. How does the proton behave afterward? Has it accumulated energy over N revolutions and dissipate it (as the original RF or as a decaying FID?) over the same time interval T (or some other time interval)?

(b) What if I rotate the same above proton this time for N complete revolutions + 90o, finally ending up in the transverse X-Y plane. Has it accumulated energy over N revolutions + 90o, and start to de-phase it over a much shorter time interval T2* of the medium or the original T?

I'd appreciate all of you taking time away from your busy projects to help with my (naive?) questions above :-).

Thanks,

David