Results are reported for high frequency pulsed NMR studies of He-3 adsorbed
on hexagonal boron nitride. The commensurate coverage, corresponding to a
0.75 fraction of a monolayer was studies. The temperature dependence of the
nuclear spin-spin relaxation time was measured in the range of 0.1-2 K. Fr
om the relaxation times, the quantum mechanical exchange rates are calculat
ed for a triangular array of He-3 atoms.