Theory of nuclear spin-lattice relaxation of spin-polarized hydrogen on liquid-helium-coated surfaces due to magnetic particles in the substrate

A theory is presented for the nuclear spin-lattice relaxation rate 1/T1 for electron-spin-polarized H atoms on or near a liquid-He-coated surface due to magnetic particles in the substrate below the He film. The H-atom motion is assumed to be free-particle-like for atoms on the surface, while atoms in the gas are assumed to be reflected elastically by the surface. 1/T1 is found to exhibit a minimum at low temperatures due to two competing …