Fick diffusion coefficients in ternary liquid systems from equilibrium molecular dynamics simulations / Xin Liu in Industrial & engineering chemistry research, Vol. 51 N° 30 (Août 2012)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 51 N° 30 (Août 2012) . - pp. 10247-10258 Titre : Fick diffusion coefficients in ternary liquid systems from equilibrium molecular dynamics simulations Type de document : texte imprimé Auteurs : Xin Liu, Auteur ; Ana Martín-Calvo, Auteur ; Erin McGarrity, Auteur Année de publication : 2012 Article en page(s) : pp. 10247-10258 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Modeling Dynamic model Molecular dynamics method Diffusion coefficient Résumé : An approach for computing Fick diffusivities directly from equilibrium molecular dynamics (MD) simulations is presented and demonstrated for a ternary chloroform―acetone―methanol liquid mixture. In our approach, Fick diffusivities are calculated from the Maawell―Stefan (MS) diffusivities and the so-called matrix of thermodynamic factors. MS diffusivities describe the friction between different molecular species and can be directly computed from MD simulations. The thermodynamic factor describes the deviation from ideal mixing behavior and is difficult to extract from both experiments and simulations. Here, we show that the thermodynamic factor in ternary systems can be obtained from density fluctuations in small subsystems embedded in a larger simulation box. Since the computation uses the Kirkwood―Buff coefficients, the present approach provides a general route toward the thermodynamics of the mixture. In experiments, Fick diffusion coefficients are measured, while previously equilibrium molecular dynamics simulation only provided MS transport diffusivities. Our approach provides an efficient and accurate route to predict multicomponent diffusion coefficients in liquids based on a consistent molecular picture and therefore bridges the gap between theory and experiment. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26201442 [article] Fick diffusion coefficients in ternary liquid systems from equilibrium molecular dynamics simulations [texte imprimé] / Xin Liu, Auteur ; Ana Martín-Calvo, Auteur ; Erin McGarrity, Auteur . - 2012 . - pp. 10247-10258. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 30 (Août 2012) . - pp. 10247-10258 Mots-clés : Modeling Dynamic model Molecular dynamics method Diffusion coefficient Résumé : An approach for computing Fick diffusivities directly from equilibrium molecular dynamics (MD) simulations is presented and demonstrated for a ternary chloroform―acetone―methanol liquid mixture. In our approach, Fick diffusivities are calculated from the Maawell―Stefan (MS) diffusivities and the so-called matrix of thermodynamic factors. MS diffusivities describe the friction between different molecular species and can be directly computed from MD simulations. The thermodynamic factor describes the deviation from ideal mixing behavior and is difficult to extract from both experiments and simulations. Here, we show that the thermodynamic factor in ternary systems can be obtained from density fluctuations in small subsystems embedded in a larger simulation box. Since the computation uses the Kirkwood―Buff coefficients, the present approach provides a general route toward the thermodynamics of the mixture. In experiments, Fick diffusion coefficients are measured, while previously equilibrium molecular dynamics simulation only provided MS transport diffusivities. Our approach provides an efficient and accurate route to predict multicomponent diffusion coefficients in liquids based on a consistent molecular picture and therefore bridges the gap between theory and experiment. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26201442

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