Theoretical study of water coverage on MgO surfaces

Ab initio and semiempirical calculations have been performed on an (MgO)(16 ) cluster model in order to study the effects of water coverage on pure MgO (100) surfaces. The geometries of various adsorbed water molecules have be en optimized and the binding energies, charge transfer, and preferential si tes of interaction analyzed. We have used Mulliken and natural bond populat ion analysis methods in order to analyze charge distributions and the direc tion of charge transfer processes. We have also investigated the effects of low and high coverage on energy gaps, density of states, self-consistent f ield (SCF) orbital energies, and stretching frequencies. (C) 1999 John Wile y & Sons, Inc.