Structure and dynamics of the water/MgO interface

Journal Article · Thu Oct 17 04:00:00 EDT 1996 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/jp961373i· OSTI ID:420842

McCarthy, M I; Schenter, G K; Scamehorn, C A; Nicholas, J B ^[1]

---

1. Pacific Northwest National Lab., Richland, WA (United States)

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.

• DOE Contract Number: AC06-76RL01830; FG06-89ER75522
• OSTI ID: 420842
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 42 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
66 PHYSICS
99 GENERAL AND MISCELLANEOUS
DYNAMICS
ELECTRONIC STRUCTURE
HARTREE-FOCK METHOD
INTERFACES
MAGNESIUM OXIDES
MOLECULAR MODELS
MONTE CARLO METHOD
POTENTIAL ENERGY
SIMULATION
WATER