Effect of nonadditive forces on the binding of closed-shell adsorbates on closed-shell substrates. I. Ar/Ar(100)

A local-density approach, introduced by Gordon and Kim, is used to assess the effects of nonpair forces on the binding of closed-shell atoms on closed-shell surfaces. The nonpair effects enter the kinetics, exchange, and correlation contributions to the potential. Calculations are performed for an Ar atom bound at various sites on a (100) Ar surface. These effects modify the binding energies by as much as {~} 12% and the barrier to surface mobility by {~} 70%. The magnitude of these deviations indicates a real need for further first-principles calculations.