First-principles calculation of structural stability of alkali-atom adsorbed metal surfaces

Structural stability of alkali-atom adsorbed metal surface systems, Al(001) -Na and Al(001)-Li at coverages of 1/2 and 1/4, is studied in terms of a fi rst-principles plane-wave pseudo-potential approach within the local densit y approximation. Optimized structural parameters and adsorption energies ca lculated at the 1/2 coverage are quite consistent with our previous all-ele ctron approach. Mechanism of the structural stability is discussed by compa ring the optimized structure and adsorption energies at the different cover ages of 1/2 and 1/4. (C) 2001 Elsevier Science BN. All rights reserved.