Self-diffusion coefficient and viscosity of methane and carbon dioxide via molecular dynamics simulations based on new ab initio-derived force fields

Beitrag in einer Fachzeitschrift
(Originalarbeit)


Details zur Publikation

Autor(en): Higgoda U, Hellmann R, Koller TM, Fröba AP
Zeitschrift: Fluid Phase Equilibria
Verlag: ELSEVIER SCIENCE BV
Jahr der Veröffentlichung: 2019
Band: 481
Seitenbereich: 15-27
ISSN: 0378-3812
Sprache: Englisch


Abstract

In the present study, the self-diffusion coefficient and viscosity of methane (CH4) and carbon dioxide (CO2) were studied by molecular dynamics (MD) simulations in the superheated vapor, gaseous, and supercritical state. The parameters used for the MD simulations are based on new molecular force fields (FFs), which were derived from previously developed, highly accurate pair potentials based on ab initio-calculated interaction energies in the limit of zero density. Using these optimized rigid all-atom FFs, multiple MD simulation runs in the order of several mu s were performed to evaluate the dynamic viscosity from the plateau of the time integral of the pressure autocorrelation function and the self-diffusion coefficient from the linear Einstein regime. For the latter property, it is shown that the Yeh-Hummer correction accounting for effects of the finite box size for dense liquid systems in the hydrodynamic regime can be transferred consistently to gaseous systems at various densities. A comparison of the simulated dynamical properties obtained from our ab initio-derived FFs with those obtained from established literature FFs showed that our suggested approach is superior to the other rigid all-atom approaches and in particular to flexible and united-atom models over density ranges corresponding to pressures between 0.1 and 10 MPa. For temperatures of 295, 325, and 355 K, our simulation results for the product of self-diffusion coefficient and density as well as for the dynamic viscosity with average expanded statistical uncertainties (k = 2) of 0.6% as well as 8.0%, respectively, represent the density dependency of both properties and agree with the few simulation and experimental data available in the literature. (C) 2018 Elsevier B.V. All rights reserved.


FAU-Autoren / FAU-Herausgeber

Fröba, Andreas Paul Prof. Dr.-Ing.
Lehrstuhl für Advanced Optical Technologies - Thermophysical Properties
Higgoda, Ubaya
Lehrstuhl für Advanced Optical Technologies - Thermophysical Properties
Koller, Thomas Manfred Dr.-Ing.
Lehrstuhl für Advanced Optical Technologies - Thermophysical Properties


Zusätzliche Organisationseinheit(en)
Erlangen Graduate School in Advanced Optical Technologies


Autor(en) der externen Einrichtung(en)
Universität Rostock


Zitierweisen

APA:
Higgoda, U., Hellmann, R., Koller, T.M., & Fröba, A.P. (2019). Self-diffusion coefficient and viscosity of methane and carbon dioxide via molecular dynamics simulations based on new ab initio-derived force fields. Fluid Phase Equilibria, 481, 15-27. https://dx.doi.org/10.1016/j.fluid.2018.10.011

MLA:
Higgoda, Ubaya, et al. "Self-diffusion coefficient and viscosity of methane and carbon dioxide via molecular dynamics simulations based on new ab initio-derived force fields." Fluid Phase Equilibria 481 (2019): 15-27.

BibTeX: 

Zuletzt aktualisiert 2019-13-03 um 07:38