Lateral interaction and structures in Cl adlayers on the Ag(111) surface

►Energies of lateral interaction for Cl on Ag(111) are determined from DFT. ► Structures and order-disorder transitions are studied via Monte Carlo simulations. ► The disordering of the (√3 × √3)R30° structure is abrupt. ► Antiphase domains of the honeycomb structure cancel the (2 × 2) LEED pattern.