H{sub 2}O dissociation at low-coordinated sites on (MgO){sub n} clusters, n = 4, 8

Journal Article · Thu Nov 21 04:00:00 EST 1996 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/jp961108x· OSTI ID:437381

Anchell, J L; Hess, A C ^[1]

---

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

We invest the interactions on one and two H{sub 2}O molecules at three-coordinated sites of (MgO){sub 4} and (MgO){sub 8} clusters. Energies of adsorption are calculated and compared to similar work involving periodic and embedded cluster systems. The cluster model results predict that H{sub 2}O chemidissociates without a barrier directly onto adjacent three-coordinated sites. The chemidissociation energy per water molecule is observed to be greater upon the dissociation of two neighboring water molecules compared to the dissociation of a single water molecule: a positive cooperativity effect. Correlation energy treated at the MP2 level of theory reduces the predicted chemidissociation energy by approximately 10 kcal/mol, and it is found that the MP2 single-point energies evaluated at the RHF-optimized geometries, MP2//RHF, differ from the energy of the MP2-optimized structures by approximately 1 kcal/mol. 26 refs., 3 figs., 3 tabs.

• DOE Contract Number: FG06-89ER75522; FG06-92RL12451
• OSTI ID: 437381
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 47 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
99 GENERAL AND MISCELLANEOUS
ADSORPTION
CALCULATION METHODS
DISSOCIATION
HARTREE-FOCK METHOD
MAGNESIUM OXIDES
MOLECULAR STRUCTURE
SOLID CLUSTERS
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
WATER