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Titolo:
Prediction of the Gibbs energies and an improved equation of state for water at extreme conditions from ab initio energies with classical simulations
Autore:
Sakane, S; Liu, WB; Doren, DJ; Shock, EL; Wood, RH;
Indirizzi:
Univ Delaware, Dept Chem & Biochem, Newark, DE 19716 USA Univ Delaware Newark DE USA 19716 pt Chem & Biochem, Newark, DE 19716 USA Univ Delaware, Ctr Mol & Engn Thermodynam, Newark, DE 19716 USA Univ Delaware Newark DE USA 19716 Engn Thermodynam, Newark, DE 19716 USA Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA Washington Univ St Louis MO USA 63130 anetary Sci, St Louis, MO 63130 USA
Titolo Testata:
GEOCHIMICA ET COSMOCHIMICA ACTA
fascicolo: 21, volume: 65, anno: 2001,
pagine: 4067 - 4075
SICI:
0016-7037(200111)65:21<4067:POTGEA>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR-DYNAMICS; UPPER-MANTLE; THERMODYNAMIC MODELS; MAGNESIUM SILICATES; TRANSITION ZONE; OCEANIC-CRUST; LIQUID WATER; H2O; PRESSURES; TEMPERATURES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
58
Recensione:
Indirizzi per estratti:
Indirizzo: Wood, RH Univ Delaware, Dept Chem & Biochem, Newark, DE 19716 USA Univ Delaware Newark DE USA 19716 Biochem, Newark, DE 19716 USA
Citazione:
S. Sakane et al., "Prediction of the Gibbs energies and an improved equation of state for water at extreme conditions from ab initio energies with classical simulations", GEOCH COS A, 65(21), 2001, pp. 4067-4075

Abstract

The hydration free energies of water at two state points (2344 K and 1.0 g/cm(3) and 2000 K and 1.8 g/cm(3)) were calculated using the ABC-FEP method(Wood et al., 1999) that combines interaction energies calculated from ab initio quantum mechanics with configurations sampled from classical simulations. We start with a calculation of the Gibbs energy of an approximate classical water model by a standard simulation method. Next, the difference inGibbs energy of the approximate model potential and more accurate ab initio interaction potential was obtained using the free energy perturbation method. At 2000 K and 1.8 g/cm3, it was necessary to derive a better classicalmodel from the ab initio results due to the inaccuracy of the classical model at short distances. The estimated accuracy of the predicted free energies is +/- 15 kJ/mol. The calculated results are used to examine the predictive capability of previously proposed classical simulations and equations of state. The equation of Pitzer and Sterner (1994) was reparameterized using the available experimental data and the newly calculated data points. Copyright (C) 2001 Elsevier Seience Ltd.

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Documento generato il 02/07/20 alle ore 22:37:38