Two-molecule theory of polyethylene liquids.
| Autor: | Li H; Department of Chemical Engineering, Colorado School of Mines, Golden, Colorado 80401, USA., Donley JP; Material Science Institute, University of Oregon, Eugene, Oregon 97403, USA., Wu DT; Department of Chemical Engineering, Colorado School of Mines, Golden, Colorado 80401, USA.; Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, USA., Curro JG; Department of Materials and Metallurgical Engineering, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA., Tormey CA; Department of Chemistry, The College of Idaho, Caldwell, Idaho 83605, USA. |
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| Jazyk: | angličtina |
| Zdroj: | The Journal of chemical physics [J Chem Phys] 2024 Nov 21; Vol. 161 (19). |
| DOI: | 10.1063/5.0242204 |
| Abstrakt: | Two-molecule theory refers to a class of microscopic, self-consistent field theories for the radial distribution function in classical molecular liquids. The version examined here can be considered as one of the very few formally derived closures to the reference interaction site model (RISM) equation. The theory is applied to polyethylene liquids, computing their equilibrium structural and thermodynamic properties at melt densities. The equation for the radial distribution function, which is represented as an average over the accessible states of two molecules in an external field that mimics the effects of the other molecules in the liquid, is computed by Monte Carlo simulation along with the intramolecular structure function. An improved direct sampling algorithm is utilized to speed the equilibration. Polyethylene chains of 24 and 66 united atom CH2 units are studied. The results are compared to full, many-chain molecular dynamics (MD) simulations and self-consistent polymer-RISM (PRISM) theory with the atomic Percus-Yevick (PY) closure under the same conditions. It is shown that the two-molecule theory produces results that are close to those of MD and is thus able to overcome defects of PRISM-PY theory and predict more accurate liquid structure at both short and long ranges. Predictions for the equation of state are also discussed. (© 2024 Author(s). Published under an exclusive license by AIP Publishing.) |
| Databáze: | MEDLINE |
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