NMR OBSERVATION OF DIFFUSION-BARRIERS FOR LITHIUM ADSORBED ON RU(001)

The diffusion of lithium on a Ru(001) surface has been studied with nu clear magnetic resonance techniques using the radioactive isotope Li-8 as a probe. As a function of substrate temperature and alkali metal c overage the nuclear spin-lattice relaxation measurements show the exis tence of two distinctly different diffusion barriers on the surface, v alued at 0.46 and 0.22 eV. The former is attributed to jumps from step to terrace sites, whereas the latter is the barrier between adjacent terrace sites. At 200 K the Li diffusion was observed from low to full coverage.