A hard-core Exp-6 intermolecular potential function for determining virial coefficients of pure nonpolar and slightly-polar molecules

Peyrovedin, Hamed; Shariati, Alireza

doi:10.1016/j.fluid.2017.12.003

Cited by 6 publications

(8 citation statements)

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“…Our previous investigations indicated that because of the choice of the exponential form for the repulsion term of the potential function, and furthermore, by considering a hard core for the molecules, the hard-core Exp-6 model has superiority over other potential functions such as the Lennard-Jones, Kihara, and Exp-6 models. 6,7 However, the hard-core Exp-6 model is suitable for nonpolar and slightly polar molecules. 6 For polar substances, in addition to the repulsive and attraction terms, in this work, an additional term is added to the hard-core Exp-6 model in order to consider the permanent dipole−dipole moments of the polar molecules.…”

Section: Modelmentioning

confidence: 99%

“…6,7 However, the hard-core Exp-6 model is suitable for nonpolar and slightly polar molecules. 6 For polar substances, in addition to the repulsive and attraction terms, in this work, an additional term is added to the hard-core Exp-6 model in order to consider the permanent dipole−dipole moments of the polar molecules. In other words, in eq 1, the orientation of the polar molecules, affected by the presence of the electric charges, is neglected.…”

Section: Modelmentioning

confidence: 99%

“…Equation shows the hard-core Exp-6 model proposed by Peyrovedin and Shariati where R is the distance at which the potential function is at its minimum and has the value of −ε. In this equation, “ a ” is the hard-core diameter and “ s ” shows the steepness of the repulsive wall of the potential function.…”

Section: Modelmentioning

confidence: 99%

“…In this work, the goal was to add a dipole−dipole interaction term to the hard-core Exp-6 model 6 in order to obtain a potential function which can calculate the virial coefficients of polar gases. To investigate the accuracy of the model, in addition to the literature data, the results are compared to those of the Stockmayer, original Exp-6, and modified Kihara potential function.…”

Section: Introductionmentioning

confidence: 99%

“…In 1954, the Exponential-6 (Exp-6) model was introduced, in which the repulsion term is an exponential function of r , which is theoretically more realistic than the repulsion term of the Lennard-Jones and Kihara models . Peyrovedin and Shariati modified the Exp-6 model by considering a hard core for the molecules and showed that considering a hard core for the molecules improves the accuracy of the Exp-6 model. The application of the hard-core Exp-6 model for calculating the second osmotic virial coefficients of polymer solutions was recently examined and compared to the Kihara and Exp-6 potential functions .…”

Section: Introductionmentioning

confidence: 99%

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Polar Hard-Core Exponential-6 Intermolecular Potential Function for Determining the Thermodynamic Properties of Polar Gases

Peyrovedin

Shariati

2020

Ind. Eng. Chem. Res.

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In this study, the hard-core Exponential-6 (hard-core Exp-6) model has been modified for polar molecules by adding an electrostatic force term to the function. The parameters of this new potential function are optimized using the literature data on the second virial coefficients of 37 polar substances. The average error of the polar hard-core Exp-6 model for these 37 polar gases, over 993 literature data, was 3.33%. Furthermore, the Stockmayer potential, the original Exp-6, and a modified Kihara potential with dipole–dipole interactions have been compared for the same data, and the errors were 6.91, 4.34, and 4.46%, respectively. In order to evaluate the ability of the proposed model in predicting the properties of polar compounds, which were not used in the optimization of the model parameters, the third virial coefficients of 18 different polar gases, the compressibility factor of ammonia, and the enthalpies and entropies of ammonia were calculated with the polar hard-core Exp-6 model. Based on the various results, it is concluded that this new potential function has great capability in the prediction of the thermodynamic properties of polar gases.

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Section: Modelmentioning

confidence: 99%