TY - JOUR

T1 - On the validity of the Stokes–Einstein relation for various water force fields

AU - Tsimpanogiannis, Ioannis N.

AU - Jamali, Seyed Hossein

AU - Economou, Ioannis G.

AU - Vlugt, Thijs J.H.

AU - Moultos, Othonas A.

PY - 2020

Y1 - 2020

N2 - The translational self-diffusion coefficient and the shear viscosity of water are related by the fractional Stokes–Einstein relation. We report extensive novel molecular dynamics simulations for the self-diffusion coefficient and the shear viscosity of water. The SPC/E and TIP4P/2005 water models are used in the temperature range 220–560 K and at 1 or 1,000 bar. We compute the fractional exponents t, and s that correspond to the two forms of the fractional Stokes–Einstein relation (Formula presented.) and (Formula presented.) respectively. We analyse other available experimental and numerical simulation data. In the current analysis two temperature ranges are considered (above or below 274 K) and in both cases deviations from the Stokes–Einstein relation are observed with different values for the fractional exponents obtained for each temperature range. For temperatures above 274 K, both water models perform comparably, while for temperatures below 274 K TIP4P/2005 outperforms SPC/E. This is a direct result of the ability of TIP4P/2005 to predict water densities more accurately and thus predict more accurately the water self-diffusion coefficient and the shear viscosity.

AB - The translational self-diffusion coefficient and the shear viscosity of water are related by the fractional Stokes–Einstein relation. We report extensive novel molecular dynamics simulations for the self-diffusion coefficient and the shear viscosity of water. The SPC/E and TIP4P/2005 water models are used in the temperature range 220–560 K and at 1 or 1,000 bar. We compute the fractional exponents t, and s that correspond to the two forms of the fractional Stokes–Einstein relation (Formula presented.) and (Formula presented.) respectively. We analyse other available experimental and numerical simulation data. In the current analysis two temperature ranges are considered (above or below 274 K) and in both cases deviations from the Stokes–Einstein relation are observed with different values for the fractional exponents obtained for each temperature range. For temperatures above 274 K, both water models perform comparably, while for temperatures below 274 K TIP4P/2005 outperforms SPC/E. This is a direct result of the ability of TIP4P/2005 to predict water densities more accurately and thus predict more accurately the water self-diffusion coefficient and the shear viscosity.

KW - molecular dynamics

KW - self-diffusivity

KW - shear viscosity

KW - Stokes–Einstein relation

KW - Water

UR - http://www.scopus.com/inward/record.url?scp=85076893208&partnerID=8YFLogxK

U2 - 10.1080/00268976.2019.1702729

DO - 10.1080/00268976.2019.1702729

M3 - Article

AN - SCOPUS:85076893208

VL - 118

JO - Molecular Physics: an international journal at the interface between chemistry and physics

JF - Molecular Physics: an international journal at the interface between chemistry and physics

SN - 0026-8976

IS - 9-10

M1 - e1702729

ER -