How well does the Tang-Toennies potential represent the thermodynamic properties of argon?

Nitzke, Isabel; Pohl, Stephanie; Thol, Monika; Vrabec, Jadran

doi:10.1080/00268976.2022.2078240

Cited by 3 publications

(1 citation statement)

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“…It is well established that the accuracy that can be obtained with two body potentials is limited. There are quite a few studies applying three-body terms, ab initio MD, and in some cases even quantum particles and such models reproduce experimental data more accurately than two-body potentials. − It is not the intention of this work, however, to propose models that are better than what the state of the art is but rather to derive principles and protocols that can be generalized to molecular compounds. Therefore, we evaluate 9 different pair potentials with 2–5 parameters by fitting the parameters to the potential computed using quantum chemistry for homodimers of noble gases (He–Xe).…”

Section: Introductionmentioning

confidence: 99%

Impact of Combination Rules, Level of Theory, and Potential Function on the Modeling of Gas- and Condensed-Phase Properties of Noble Gases

Kříž,

van Maaren,

van der Spoel

2024

J. Chem. Theory Comput.

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The systems of noble gases are particularly instructive for molecular modeling due to the elemental nature of their interactions. They do not normally form bonds nor possess a (permanent) dipole moment, and the only forces determining their bonding/clustering stems from van der Waals forces� dispersion and Pauli repulsion, which can be modeled by empirical potential functions. Combination rules, that is, formulas to derive parameters for pair potentials of heterodimers from parameters of corresponding homodimers, have been studied at length for the Lennard-Jones 12-6 potentials but not in great detail for other, more accurate, potentials. In this work, we examine the usefulness of nine empirical potentials in their ability to reproduce quantum mechanical (QM) benchmark dissociation curves of noble gas dimers (He, Ne, Ar, Kr, and Xe homo-and heterodimers), and we systematically study the efficacy of different permutations of combination relations for each parameter of the potentials. Our QM benchmark comprises dissociation curves computed by several different coupled cluster implementations as well as symmetry-adapted perturbation theory. The two-parameter Lennard-Jones potentials were decisively outperformed by more elaborate potentials that sport a 25−30 times lower root-mean-square error (RMSE) when fitted to QM dissociation curves. Very good fits to the QM dissociation curves can be achieved with relatively inexpensive four-or even three-parameter potentials, for instance, the damped 14-7 potential (Halgren,

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Section: Introductionmentioning

confidence: 99%

Impact of Combination Rules, Level of Theory, and Potential Function on the Modeling of Gas- and Condensed-Phase Properties of Noble Gases

Kříž,

van Maaren,

van der Spoel

2024

J. Chem. Theory Comput.

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High-Performance Computing as a Key to New Insights into Thermodynamics

Homes,

Antolović,

Fingerhut

et al. 2024

High Performance Computing in Science and Engineering '22

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Influence of repulsion on entropy scaling and density scaling of monatomic fluids

Saric,

Bell,

Guevara-Carrion

et al. 2024

The Journal of Chemical Physics

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Entropy scaling is applied to the shear viscosity, self-diffusion coefficient, and thermal conductivity of simple monatomic fluids. An extensive molecular dynamics simulation series is performed to obtain these transport properties and the residual entropy of three potential model classes with variable repulsive exponents: n, 6 Mie (n = 9, 12, 15, and 18), Buckingham’s exponential-six (α = 12, 14, 18, and 30), and Tang–Toennies (αT = 4.051, 4.275, and 4.600). A wide range of liquid and supercritical gas- and liquid-like states is covered with a total of 1120 state points. Comparisons to equations of state, literature data, and transport property correlations are made. Although the absolute transport property values within a given potential model class may strongly depend on the repulsive exponent, it is found that the repulsive steepness plays a negligible role when entropy scaling is applied. Hence, the plus-scaled transport properties of n, 6 Mie, exponential-six, and Tang–Toennies fluids lie basically on one master curve, which closely corresponds with entropy scaling correlations for the Lennard-Jones fluid. This trend is confirmed by literature data of n, 6 Mie, and exponential-six fluids. Furthermore, entropy scaling holds for state points where the Pearson correlation coefficient R is well below 0.9. The condition R > 0.9 for strongly correlating liquids is thus not necessary for the successful application of entropy scaling, pointing out that isomorph theory may be a part of a more general framework that is behind the success of entropy scaling. Density scaling reveals a strong influence of the repulsive exponent on this particular approach.

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How well does the Tang-Toennies potential represent the thermodynamic properties of argon?

Cited by 3 publications

References 73 publications

Impact of Combination Rules, Level of Theory, and Potential Function on the Modeling of Gas- and Condensed-Phase Properties of Noble Gases

Impact of Combination Rules, Level of Theory, and Potential Function on the Modeling of Gas- and Condensed-Phase Properties of Noble Gases

High-Performance Computing as a Key to New Insights into Thermodynamics

Influence of repulsion on entropy scaling and density scaling of monatomic fluids

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