Probing the dynamics of ³He atoms adsorbed on MCM-41 with pulsed NMR

We report measurements of the nuclear spin-spin and spin-lattice relaxation times for ³He adsorbed on MCM-41 for temperatures 0.08 < T < 1.2 K. Deviations from Curie behavior are observed at low temperatures. The relaxation times exhibit a two-component behavior representing the differing dynamics of the mobile quasi-free molecules in the center of the tubes compared to the adsorbed layer on the walls. The amplitudes of the two components provide an accurate measure of the number of fluid-like molecules traveling in the center of the nanotubes. (paper)