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Author McCarthy, M. I. ♦ Schenter, G. K. ♦ Scamehorn, C. A. ♦ Nicholas, J. B.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CHEMISTRY ♦ MATERIALS SCIENCE ♦ PHYSICS ♦ MATHEMATICS, COMPUTERS, INFORMATION SCIENCE, MANAGEMENT, LAW, MISCELLANEOUS ♦ INTERFACES ♦ DYNAMICS ♦ WATER ♦ MAGNESIUM OXIDES ♦ ELECTRONIC STRUCTURE ♦ HARTREE-FOCK METHOD ♦ MOLECULAR MODELS ♦ MONTE CARLO METHOD ♦ SIMULATION ♦ POTENTIAL ENERGY
Abstract A pairwise additive potential energy expression for the water/MgO interaction was obtained by fitting the parameters to ab initio electronic structure energy data, computed using correlation-corrected periodic Hartree-Fock (PHF) theory, at selected adsorbate/surface geometries. This potential energy expression was used in molecular dynamics and Monte Carlo simulations to elucidate the water/MgO interaction. Energy minimization reveals a nearly planar adsorbate/surface equilibrium geometry (-15{degree} from the surface plane with the hydrogens pointing toward the surface oxygens) for an isolated water on perfect MgO (001), with a binding energy of 17.5 kcal/mol; subsequent PHF calculations on this system confirmed that this is a potential minimum. Rate constants for desorption (k{sub desorb}), intersite hopping (k{sub hop}), intrasite rotation (k{sub rot}), and intrasite flipping (k{sub flip}) were estimated for an isolated water on the surface using simple transition state theory. The motion of a single water on the surface is described by an effective diffusion constant computed from the surface rate constants combined with Monte Carlo simulations. The structure of the liquid water/MgO interface was determined from simulations with 64 and 128 water molecules on the surface. Results are presented. 48 refs., 9 figs., 4 tabs.
ISSN 00223654
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-10-17
Publisher Place United States
Journal Journal of Physical Chemistry
Volume Number 100
Issue Number 42


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