Density functional study of the adsorption of K on the Ag(111) surface

TL;DR

This study uses density functional theory to analyze how potassium atoms adsorb onto the Ag(111) surface, revealing site preferences, charge transfer, and structural details consistent with experimental data.

Contribution

It provides a detailed first-principles analysis of K adsorption on Ag(111), including site energetics, charge transfer, and structural effects, which advances understanding of surface interactions.

Findings

Fcc, hcp, and bridge sites are nearly degenerate at lower coverage.

Substrate rumpling significantly affects top adsorption sites.

Small charge transfer from K to Ag substrate, larger at lower coverage.

Abstract

Full-potential gradient corrected density functional calculations of the adsorption of potassium on the Ag(111) surface have been performed. The considered structures are Ag(111) (root 3 x root 3) R30degree-K and Ag(111) (2 x 2)-K. For the lower coverage, fcc, hcp and bridge site; and for the higher coverage all considered sites are practically degenerate. Substrate rumpling is most important for the top adsorption site. The bond length is found to be nearly identical for the two coverages, in agreement with recent experiments. Results from Mulliken populations, bond lengths, core level shifts and work functions consistently indicate a small charge transfer from the potassium atom to the substrate, which is slightly larger for the lower coverage.