ADSORPTION-KINETICS AND GROWTH OF POTASSIUM ON CU(100)

Measurements of the helium atom scattering reflectivity during growth, adsorption-desorption equilibrium and isothermal desorption of K on C u(100) are reported. An orientational order-disorder phase transition is observed between 123 and 223 K in the submonolayer condensed phase. AdsorPtion-desorption isotherms have been obtained for a range of tem peratures between 263 and 448 K The data indicate a Stranski-Krastanov growth mode for this system, with the formation of 3D clusters after one monolayer, and give a heat Of adsorption of about 1 +/- 0.1 eV per atom near the completed first monolayer. The form of the isotherms su ggests repulsive adsorbate interactions in this coverage and temperatu re regime.