| Autor: |
Shi K; Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States., Shen Y; Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States., Santiso EE; Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States., Gubbins KE; Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States. |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of chemical theory and computation [J Chem Theory Comput] 2020 Sep 08; Vol. 16 (9), pp. 5548-5561. Date of Electronic Publication: 2020 Aug 13. |
| DOI: |
10.1021/acs.jctc.0c00607 |
| Abstrakt: |
The microscopic pressure tensor plays an important role in understanding the mechanical stability, transport, and high-pressure phenomena of confined phases. The lack of an exact formulation to account for the long-range Coulombic contribution to the local pressure tensor in cylindrical geometries prevents the characterization of molecular fluids confined in cylindrical pores. To address this problem, we first derive the local cylindrical pressure tensor for Lennard-Jones fluids based on the Harasima (H) definition, which is expected to be compatible with the Ewald summation method. The test of the H-definition pressure equations in a homogeneous system shows that the radial and azimuthal pressure have unphysical radial dependence near the origin, while the axial pressure gives physically meaningful values. We propose an alternative contour definition that is more appropriate for cylindrical geometry and show that it leads to physically realistic results for all three pressure tensor components. With this definition, the radial and azimuthal pressures are of Irving-Kirkwood (IK) type, and the axial pressure is of Harasima type. Because of the practical interest in the axial pressure, we develop a Harasima/Ewald (H/E) method for calculating the long-range Coulombic contribution to the local axial pressure for rigid molecules. As an application, the axial pressure profile of water inside and outside a (20, 20) single-wall carbon nanotube is determined. The H/E method is compared to the IK method, which assumes a spherically truncated Coulombic potential. Detailed analysis of the pressure profile by both methods shows that the water confined in the nanotube is in a stretched state overall in the axial direction. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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