Molecular dynamics simulations of rigid and flexible water models: Temperature dependence of viscosity

• Published in: Chemical physics 2011-09, Vol.388 (1), p.9-18
• Main Authors: Medina, J.S., Prosmiti, R., Villarreal, P., Delgado-Barrio, G., Winter, G., González, B., Alemán, J.V., Collado, C.
• Format: Article
• Language: English
• Subjects: Liquid water models; Molecular dynamics simulations; Viscosity calculations
• ISSN: 0301-0104
• DOI: 10.1016/j.chemphys.2011.07.001

Green–Kubo (thin lines) and analytical Kohlrausch type (thick lines) integrals of the (a, c) shear and (b, d) bulk stress tensor autocorrelation function for SPC/E (top panels) and SPC/Fw (bottom panels) water models, respectively, at the indicated temperatures. [Display omitted] ► Transport properties of liquid water are important in bio-simulations. ► Shear and bulk viscosities calculation from NVE molecular dynamics simulations. ► Comparison with experimental data provides information on intermolecular forces. Molecular dynamics (MD) simulations are carried out on a system of rigid or flexible water molecules at a series of temperatures between 273 and 368 K. Collective transport coefficients, such as shear and bulk viscosities are calculated, and their behavior is systematically investigated as a function of flexibility and temperature. It is found that by including the intramolecular terms in the potential the calculated viscosity values are in overall much better agreement, compared to earlier and recent available experimental data, than those obtained with the rigid SPC/E model. The effect of the intramolecular degrees of freedom on transport properties of liquid water is analyzed and the incorporation of polarizability is discussed for further improvements. To our knowledge the present study constitutes the first compendium of results on viscosities for pure liquid water, including flexible models, that has been assembled.