Section4: An assembly of non-interacting spins. Real systems consist of many nuclear spins. In a static magnetic field, B =B z k , there is a degeneracy of spin states. Population difference, n , is given by BOLTZMANN STATISTICS:. Boltzmann equation. Many spin system:.
An assembly of non-interacting spins
Many spin system:
All spins have the same precession frequency,wl=gBz
BUT random phases.
So Mx and My = 0, and net magnetisation is in z-direction.
4) An ensemble of spins
4.2 Effect of B fields on ensemble of spins
(p 31 & p258 Levitt)
4.3 Bloch equations
4.4 The NMR Signal
4) The NMR Spectrometer