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Titolo:
COOPERATIVE EFFECTS IN THE STRUCTURING OF FLUORIDE WATER CLUSTERS - AB-INITIO HYBRID QUANTUM MECHANICAL MOLECULAR MECHANICAL MODEL INCORPORATING POLARIZABLE FLUCTUATING CHARGE SOLVENT/
Autore:
BRYCE RA; VINCENT MA; MALCOLM NOJ; HILLIER IH; BURTON NA;
Indirizzi:
UNIV MANCHESTER,DEPT CHEM,OXFORD RD MANCHESTER M13 9PL LANCS ENGLAND
Titolo Testata:
The Journal of chemical physics
fascicolo: 8, volume: 109, anno: 1998,
pagine: 3077 - 3085
SICI:
0021-9606(1998)109:8<3077:CEITSO>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR-DYNAMICS SIMULATIONS; NONADDITIVE INTERMOLECULAR POTENTIALS; COMPUTER-SIMULATIONS; AQUEOUS SOLVATION; DIPOLE-MOMENT; ION SOLVATION; FORCE-FIELDS; BASIS-SETS; GAS-PHASE; CL IONS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
58
Recensione:
Indirizzi per estratti:
Citazione:
R.A. Bryce et al., "COOPERATIVE EFFECTS IN THE STRUCTURING OF FLUORIDE WATER CLUSTERS - AB-INITIO HYBRID QUANTUM MECHANICAL MOLECULAR MECHANICAL MODEL INCORPORATING POLARIZABLE FLUCTUATING CHARGE SOLVENT/", The Journal of chemical physics, 109(8), 1998, pp. 3077-3085

Abstract

A new hybrid quantum mechanical/molecular mechanical model of solvation is developed and used to describe the structure and dynamics of small fluoride/water clusters, using an ab initio wave function to model the ion and a fluctuating charge potential to model the waters. Appropriate parameters for the water-water and fluoride-water interactions are derived, with the fluoride anion being described by density functional theory and a large Gaussian basis. The role of solvent polarization in determining the structure and energetics of F(H2O)(4)(-) clustersis investigated, predicting a slightly greater stability of the interior compared to the surface structure, in agreement with ab initio studies. An extended Lagrangian treatment of the polarizable water, in which the water atomic charges fluctuate dynamically, is used to study the dynamics of F(H2O)(4)(-) cluster. A simulation using a fixed solvent charge distribution indicates principally interior, solvated states for the cluster. However, a preponderance of trisolvated configurations is observed using the polarizable model at 300 K, which involves only three direct fluoride-water hydrogen bonds. Ab initio calculations confirm this trisolvated species as a thermally accessible state at room temperature, in addition to the tetrasolvated interior and surface structures. Extension of this polarizable water model to fluoride clusters with five and six waters gave less satisfactory agreement with experimental energies and with ab initio geometries. However, our resultsdo suggest that a quantitative model of solvent polarization is fundamental for an accurate understanding of the properties of anionic water clusters. (C) 1998 American Institute of Physics. [S0021-9606(98)50432-1].

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Documento generato il 04/12/20 alle ore 06:12:59