I + (H2O)2 â HI + (H2O)OH Forward and Reverse Reactions. CCSD(T) Studies Including Spin-Orbit Coupling.
J Phys Chem B
; 120(8): 1743-8, 2016 Mar 03.
Article
en En
| MEDLINE
| ID: mdl-26562487
The potential energy profile for the atomic iodine plus water dimer reaction I + (H2O)2 â HI + (H2O)OH has been explored using the "Gold Standard" CCSD(T) method with quadruple-ζ correlation-consistent basis sets. The corresponding information for the reverse reaction HI + (H2O)OH â I + (H2O)2 is also derived. Both zero-point vibrational energies (ZPVEs) and spin-orbit (SO) coupling are considered, and these notably alter the classical energetics. On the basis of the CCSD(T)/cc-pVQZ-PP results, including ZPVE and SO coupling, the forward reaction is found to be endothermic by 47.4 kcal/mol, implying a significant exothermicity for the reverse reaction. The entrance complex I···(H2O)2 is bound by 1.8 kcal/mol, and this dissociation energy is significantly affected by SO coupling. The reaction barrier lies 45.1 kcal/mol higher than the reactants. The exit complex HI···(H2O)OH is bound by 3.0 kcal/mol relative to the asymptotic limit. At every level of theory, the reverse reaction HI + (H2O)OH â I + (H2O)2 proceeds without a barrier. Compared with the analogous water monomer reaction I + H2O â HI + OH, the additional water molecule reduces the relative energies of the entrance stationary point, transition state, and exit complex by 3-5 kcal/mol. The I + (H2O)2 reaction is related to the valence isoelectronic bromine and chlorine reactions but is distinctly different from the F + (H2O)2 system.
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01-internacional
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MEDLINE
Idioma:
En
Revista:
J Phys Chem B
Asunto de la revista:
QUIMICA
Año:
2016
Tipo del documento:
Article
Pais de publicación:
Estados Unidos