Lateral interaction energy derived from Frumkin isotherm for c(2 x 2) Br/Ag(100)

The structure of the bromide adlayer on Ag(100) and the adsorption isotherm have been determined by using in situ surface x-ray scattering techniques and chronocoulometry. Bromide adsorbed on Ag(100) forms a fourfold-hollow-site lattice gas and the adsorption saturates at 1/2 monolayer in a c(2 x 2) structure. The Frumkin isotherm has been employed to fit the experimentally obtained isotherm. Using the experimentally determined electrosorption valency, the lateral interaction energy of 220 meV/atom at full coverage is obtained.