ABSTRACT
This chapter is devoted to the mechanisms of spin relaxation. It is
explained how the combination of quantum-mechanical properties
with classical Brownian dynamics determines the relaxation behav-
ior of spin systems. Relaxation processes are described as a result
of transitions between spin states (energy levels) induced by local
magnetic fields stochastically fluctuating in time due to rotational
and translational dynamics of molecules. The derivations are first
conducted on the level of “kinetic equations” describing changes
in populations of spin states. Then progressively, the quantum
mechanical formalism of spin relaxation phenomena is introduced.
