ONE-DIMENSIONAL XENON BAND STRUCTURES ON HYDROGEN MODIFIED AND STEPPED PLATINUM SURFACES

The adsorption of xenon on hydrogen modified Pt(110)-(1 x 2) and on Pt (997) has been studied using TPD, LEED, XPS, and ARUPS. On Pt(110)-(1 x 2) with preadsorbed hydrogen, a single xenon species forming one-dim ensional adsorbate chains in the [1 (1) over bar 0] direction is found . ARUPS shows well-resolved dispersion of the xenon 5p(1/2) and the sp lit 5p(3/2) bands in the [1 (1) over bar 0] azimuth, but no dispersion in the [001] direction, in agreement with the packing density. On Pt( 997) xenon decorates the close-packed steps in [1 (1) over bar 0] dire ction at low coverages. No dispersion of xenon bands is seen in ARUPS, indicating weak lateral adsorbate interaction along the chains as exp ected from the relatively large Xe-Xe distance of 5.6 Angstrom extract ed from LEED.