First-principles calculation of the interaction energy of (√3 x √3)R30° Xe/Pt(111)

Calculations of the energy of the interaction between Xe and Pt(111) in the (root 3 x root 3)R30 degrees structure are reported. A density functional approach is used with a slab geometry and a pseudopotential formalism. Exchange-correlation effects are treated within the local density approximation and the generalized gradient approximation. The local density approximation gives a well depth comparable to that obtained from experiment whereas the generalized gradient approximation gives very weak binding. Both approximations predict that the on-top site is the most favourable position for the adsorption of Xe atoms. The binding mechanism is discussed in terms of the charge density and the local density of states.