First principles calculation of the energy and structure of two solid surface phases on Ir{100}

The structure and energetics of the hexagonal reconstruction of Ir(100) hav e been determined with first principles density functional theory calculati ons based on the local-density approximation with the generalised-gradient correction. The results reproduced the experimentally determined surface bu ckling and show the presence of some lateral displacement of the reconstruc ted (1 x 5) phase with respect to the ideal hexagonal close packed structur e. The (1 x 5) phase is found to be 0.06 eV/(1 x 1 area) more stable than t he (1 x 1)phase. The reconstruction is analysed by examining surface bondin g. (C) 1998 Elsevier Science B.V. All rights reserved.