  This work investigates the link between residual entropy and viscosity based
on wide-ranging, highly accurate experimental and simulation data. This link
was originally postulated by Rosenfeld in 1977, and it is shown that this
scaling results in an approximately monovariate relationship between residual
entropy and reduced viscosity for a wide range of molecular fluids (argon,
methane, CO2, SF6, refrigerant R-134a (1,1,1,2-tetrafluoroethane), refrigerant
R-125 (pentafluoroethane), methanol, and water), and a range of model
potentials (hard sphere, inverse power, Lennard-Jones, and
Weeks-Chandler-Andersen). While the proposed "universal" correlation of
Rosenfeld is shown to be far from universal, when used with the appropriate
density scaling for molecular fluids, the viscosity of non-associating
molecular fluids can be mapped onto the model potentials. This mapping results
in a length scale that is proportional to the cube root of experimentally
measureable liquid volume values.
