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Ab initio study of the reaction mechanism of water dissociation into the ionic species OH − and H 3 O +
Author(s) -
Cárdenas R.,
LagúnezOtero J.,
FloresRivero A.
Publication year - 1998
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1998)68:4<253::aid-qua3>3.0.co;2-u
Subject(s) - chemistry , dissociation (chemistry) , ionic bonding , ab initio , enthalpy , transition state , ab initio quantum chemistry methods , configuration interaction , molecule , computational chemistry , atomic physics , thermodynamics , ion , physics , catalysis , biochemistry , organic chemistry
A reaction mechanism of water dissociation is proposed where solvent effects are accounted for via a minimum stable model that considers the interaction of five water molecules. It is based on the fully self‐consistent field (SCF) optimized structures of the reactant, product, and transition state, the calculations being at the Hartree–Fock and configuration interaction level [Møller–Plesset second‐order perturbation (MP2) and coupled‐cluster single and double excitations (CCSD)]. They were performed with four different basis sets that included polarized and diffuse orbitals. The dissociative mechanism leads to the ionic species OH − +H 3 O + as stable products and upon analysis of the energy hypersurface, a transition state is found which yields an activation barrier of 21.2 kcal/mol. This value is in good agreement with the experimentally determined enthalpy for the reaction. The contribution of the aggregation energy is emphasized. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 68: 253–259, 1998