Calculated bond properties of K adsorbed on graphite

The properties of the chemical bond of K adsorbed on a graphite(0001) surfa ce have been studied for different coverages, by means of a full-potential slab method. Specific modifications of the Hamiltonian are performed in ord er to make it possible to study K on graphite in the disperse phase (dilute limit). It is found that K forms a metallic state when covering a graphite surface with a (2 x 2) coverage. For a (3 x 3) coverage as well as in the disperse phase K is found to form an ionic bond with graphite. It is shown that in the disperse phase, the hybridization between the K 4s level and gr aphite is weak. Our findings are consistent with recent experiments. Furthe rmore the cohesive energies of K adsorption on graphite are found to be lar ger in the (2 x 2) coverage compared to the (3 x 3) coverage. [80163-1829(9 8)03743-6].