TY - JOUR

T1 - Revisiting the Stokes-Einstein relation without a hydrodynamic diameter

AU - Costigliola, Lorenzo

AU - Heyes, David

AU - Schrøder, Thomas

AU - Dyre, Jeppe

PY - 2019/1/10

Y1 - 2019/1/10

N2 - We present diffusion coefficient and shear viscosity data for the Lennard-Jones fluid along nine isochores above the critical density, each involving a temperature variation of roughly two orders of magnitude. The data are analyzed with respect to the Stokes-Einstein (SE) relation, which breaks down gradually at high temperatures. This is rationalized in terms of the faet that the reduced diffusion coefficient 5 and the reduced viscosity ij are both constant along the system's lines of constant excess entropy (the isomorphs). As a consequence, Dij is a function of T /T Ref(p) in which Tis the temperature, pis the density, and T Ref(p) is the temperature as a function of the density along a reference isomorph. This allows one to successfully predict the viscosity from the diffusion coefficient in the studied region of the thermodynamic phase diagram.

AB - We present diffusion coefficient and shear viscosity data for the Lennard-Jones fluid along nine isochores above the critical density, each involving a temperature variation of roughly two orders of magnitude. The data are analyzed with respect to the Stokes-Einstein (SE) relation, which breaks down gradually at high temperatures. This is rationalized in terms of the faet that the reduced diffusion coefficient 5 and the reduced viscosity ij are both constant along the system's lines of constant excess entropy (the isomorphs). As a consequence, Dij is a function of T /T Ref(p) in which Tis the temperature, pis the density, and T Ref(p) is the temperature as a function of the density along a reference isomorph. This allows one to successfully predict the viscosity from the diffusion coefficient in the studied region of the thermodynamic phase diagram.

UR - http://glass.ruc.dk/pdf/articles/2019_JChemPhys_150_021101.pdf

U2 - 10.1063/1.5080662

DO - 10.1063/1.5080662

M3 - Journal article

SN - 0021-9606

VL - 150

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

IS - 2

M1 - 021101

ER -