Molecular polarizabilities in aqueous proton transfer reactions.
J Chem Phys
; 131(23): 234507, 2009 Dec 21.
Article
en En
| MEDLINE
| ID: mdl-20025335
ABSTRACT
Dipole polarizabilities of individual ions and molecules are computed from first principles in three condensed-phase systems pure water, pure hydrofluoric acid, and an equimolar mixture of water and hydrofluoric acid in which HF is mostly ionized. We find that the polarizability of fluorine and oxygen centers varies linearly with the value of the bond order, which measures the local degree of advancement of the ionization reaction F-H+H(2)O<==>[F(delta-).H.(delta+)OH(2)]<==>F(-)+H(3)O(+). This observation explains the validity of the Lorentz-Lorenz formula for mixtures of acids and water and could have important practical consequences concerning the construction of empirical polarizable reactive force fields. Our results are consistent with the Mulliken charge-transfer picture of proton transfer reactions. The present results also suggest that the average isotropic polarizability of a chemical entity changes substantially only when that entity is involved in charge-transfer processes.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Chem Phys
Año:
2009
Tipo del documento:
Article
País de afiliación:
Canadá