ACTIVE-SITES OF PT SURFACES FROM AB-INITIO CLUSTER MODEL MOLECULAR ELECTROSTATIC POTENTIAL MAPS

The electrostatic potential distribution above the Pt(100), Pt(110) an d Pt(lll) surfaces has been studied using finite cluster model represe ntations of the surfaces and their ab initio Hartree-Fock electron den sities. From the different distributions it is seen that electrostatic effects are not substantial for Pt(100), minor but significant for Pt (110) and quite important for Pt(lll). The minima of the electrostatic potential always appear at the more coordinated sites, four-fold for Pt(100) and Pt(110) and threefold for Pt(lll), indicating that, up to first order, electrophilic adsorbates will prefer to approach the high coordinated surface sites. Copyright (C) 1996 Elsevier Science Ltd