Sulphur adsorption on Cu{110} : a SEXAFS study

Polarization-dependent SEXAFS measurements have been performed for various phases formed by sulphur adsorption on Cu(110). At low coverage, a diffuse c(2 × 2) LEED pattern is observed. Upon increasing S coverage, splitting of the (12, 12) spot occurs, initially in the 〈001〉 direction and subsequently in the 〈110〉 direction. The SEXAFS results show that, independent of the S coverage, the adatoms occupy the two-fold hollow site on the Cu{110} surface with a SCu bond length of 2.37 ± 0.03 A. S adsorption is associated with an expansion of the first interplanar distance in copper. The splitting of the half-order beams is attributed to the formation of antiphase domain boundaries.