Berlin 2008 – scientific programme
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O: Fachverband Oberflächenphysik
O 62: Metal Substrates: Adsorption of Inorganic Molecules
O 62.3: Talk
Thursday, February 28, 2008, 10:00–10:15, MA 042
Insight into water molecules bonding on 4d metal surfaces — •Javier Carrasco1, Angelos Michaelides1,2, and Matthias Scheffler1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany — 2London Centre for Nanotechnology and Department of Chemistry, University College London, London WC1E 6BT, United Kingdom
H2O-metal interactions are of capital importance to a wide variety of phenomena in materials science, catalysis, corrosion, electrochemistry, etc. Here we address the nature of the bond between water molecules and metal surfaces through a careful systematic study. Specifically, the bonding of isolated H2O molecules to a series of close-packed transition metal surfaces—Ru(0001), Rh(111), Pd(111) and Ag(111)—has been examined in detail with density functional theory (DFT). Aiming to understand the origin behind energetic and structural trends along the 4d series we employ a range of analysis tools, such as decomposition of the density of states, electron density differences, and inspection of individual Kohn-Sham orbitals. The results obtained allow us to rationalize the bonding between water and transition metal surfaces as a balance of covalent and electrostatic interactions. A frontier orbital scheme based on so-called two-center four-electron interactions between molecular orbitals of H2O— mainly 3a1 and 1b1—and d band states of the surface proves incisive in understanding these systems.