Band formation and quadrupole interaction of one-dimensional adsorbate structures: Xenon chains on hydrogen-modified Pt(110)

Using angle-resolved photoemission, we investigated the electronic valence- band structure of one-dimensional (1D) Xe chains adsorbed on a hydrogen-mod ified Pt(110)-(1x2) surface. By varying the Xe coverage, the Xe-Xe next-nei ghbor distance within the chains can be modified, which results in similar band structures but with different widths of up to 800 meV. For these 1D sy stems, the Xe-5p(3/2) states show a reversed energetic ordering with respec t to two-dimensional Xe adlayers. Numerical band-structure calculations and analytical considerations show that the Pt substrate affects the Xe valenc e bands negligibly. The energetic ordering of the Xe states can be explaine d in terms of the electric quadrupole interaction along the chains. [S0163- 1829(99)51832-8].