Geometrical implications of lateral interactions in chain systems: Li(1×2) and Li(1×4) on molybdenum (211)

The local geometries of Li adsorbed on the furrowed (211) surface of Mo have been investigated by a LEED-IV analysis using an energy of 30–180 eV. Adsorbate-induced lateral interactions mediated mainly through the substrate turn out to be mainly responsible for the formation of the low-coverage and Li(1×4) and Li(1×2) chain systems, which have been investigated quantitatively. While the adsorbate-induced vertical relaxations in the substrate have been found to remain small, the lateral relaxations reach values up to 0.15 Å. Especially for the Li(1×4) structure, these relaxations are correlated, forming wave-like regions of lateral compression and dilatation. They seem to be the consequence of adsorbate-induced Friedel oscillations of the electron density of the substrate, which screen the charge of the adatoms along the [1̄11]-channel direction of Mo(211). Furthermore, as concluded from the bond lengths determined by IV-LEED, the Limetal bond is much less ionic than that predicted by the Langmuir–Gurney model of chemisorption.