Pseudo hard-sphere viscosities from equilibrium Molecular Dynamics

• Published in: Journal of physics. Condensed matter Vol. 35; no. 42; pp. 425401 - 425410
• Main Authors: Nicasio-Collazo, Luz Adriana, Ramírez-Medina, Carlos Alberto, Torres-Carbajal, Alexis
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 23.10.2023
• Subjects: bulk viscosity; longitudinal viscosity; molecular dynamics; pseudo hard-spheres; shear viscosity; transport coefficients; Shear viscosity; Transport coefficients; Bulk viscosity; Molecular Dynamics; Longitudinal viscosity; Pseudo hard-spheres
• ISSN: 0953-8984; 1361-648X; 1361-648X
• DOI: 10.1088/1361-648X/ace7a5

Transport coefficients like shear, bulk and longitudinal viscosities are sensitive to the intermolecular interaction potential and finite size effects when are numerically determined. For the hard-sphere (HS) fluid, such transport properties are determined almost exclusively with computer simulations. However, their systematic determination and analysis throughout shear stress correlation functions and the Green-Kubo formalism can not be done due to discontinuous nature of the interaction potential. Here, we use the pseudo hard-sphere (PHS) potential to determine pressure correlation functions as a function of volume fraction in order to compute mentioned viscosities. Simulation results are compared to available event-driven molecular dynamics of the HS fluid and also used to propose empirical corrections for the Chapman–Enskog zero density limit of shear viscosity. Moreover, we show that PHS potential is a reliable representation of the HS fluid and can be used to compute transport coefficients. The molecular simulation results of the present work are valuable for further exploration of HS-type fluids or extend the approach to compute transport properties of hard-colloid suspensions.