Nuclear magnetic relaxation in adsorbed helium-3 monolayers and other two-dimensional systems

The general theory of nuclear magnetic relaxation in homogeneous adsorbed systems is developed in a way which takes account of the specific features of two-dimensional motion. It is shown that the reduced dimensionality has the effect of decreasing the relaxation times from their naively expected values by as much as a few orders of magnitude, and of causing T1 and T2 to be unequal even in the presence of fast atomic motion. The theory is in close agreement with observed relaxation times of adsorbed helium-3. (author)