Chlorine Adsorption on the Ag(110) Surface: STM and DFT Study
Adsorption of molecular chlorine onto the Ag(110) surface has been studied with low-temperature scanning tunneling microscopy, low-energy electron diffraction, and density functional theory calculations (DFT). At a coverage of 1/2 ML, chlorine forms a p(2 × 1) structure, which, with a further increase in coverage, transforms into a p(3 × 1) structure consisting of dimer rows. DFT modeling shows that both p(2 × 1) and p(3 × 1) phases can be explained by the adsorbate induced added-row reconstruction rather than formation of a simple overlayer. The p(2 × 1) phase consists of – Cl–Ag–Cl–Ag– rows, in which silver atoms occupy hollow sites. The p(3 × 1) structure contains a basement formed by a double Ag row and chlorine atoms decorating both of its edges. The increase of Cl coverage up to 0.78 ML leads to the formation of the quasi-hexagonal phase of chlorine atoms chemisorbed on the unreconstructed silver (110) surface. At further chlorine adsorption, the formation of stripes with an average period ≈25 Å aligned parallel to the 〈001〉 direction occurs as a result of the reconstruction, in agreement with DFT calculations.