Surface relaxation of the platinum (100)-(1 × 1) surface at 175 K

Abstract

Abstract Backscattering of MeV 4He+ ions in conjunction with nuclear microanalysis has been used to study the effect of adsorbed gases on the interplanar spacing between the outermost Pt layers of the Pt(100)−(1 × 1) surface at 175 K. For the “almost clean” surface, the spacing is found to be within ~0.2% of the bulk spacing: i.e. the surface is unrelaxed. Similar measurements on CO- or H2-covered surfaces, however, show that monolayer adsorption of either gas produces a small outward relaxation of ~0.015 nm (i.e. 0.8%). The results also suggest that the surface Debye temperature is considerably lower than that of the bulk.