Correlations between the Shear Viscosity and Thermal Conductivity Coefficients of Dense Simple Liquids

Abstract

A practical correction formula relating the self-diffusion coefficient of dense liquids from molecular dynamics simulations with periodic boundary conditions to the self-diffusion coefficient in the thermodynamic limit is discussed. This formula applies to pure dense fluids and has a very simple form D = D0(1 − γN −1/3 ), where D0 is the self-diffusion coefficient in the thermodynamic limit and N is the number of particles in the simulation. The numerical factor γ depends on the geometry of the simulation cell. Remarkably, γ ≃ 1.0 for the most popular cubic geometry. The success of this formula is supported by results from MD simulations, including very recent simulations with a "magic" simulation geometry.

Onset of transverse (shear) waves in strongly-coupled Yukawa fluids

“…( 13) the value of λ R at the freezing point is λ R 11. This is very close to λ R ∼ 10 of various models as well as real atomic and molecular liquids: Lennard-Jones, Ne, Ar, Kr, Xe, N 2 , O 2 , CO 2 , and CH 4 [66,67,70]. This potentially useful universality is violated for the HS fluid, which has λ R 14 at the freezing point [71,72].…”

Elastic properties of dense hard-sphere fluids

“…For model systems considered later in this paper an approximate relation λ R ∼ 10 works quite well on the freezing line (except hard sphere fluids where λ R ≃ 14 at the freezing point [70,71]). This quasi-universality also holds for many real atomic and molecular liquids, such as Ne, Ar, Kr, Xe, N 2 , O 2 , CO 2 , and CH 4 [26,37,72].…”

“…Note that within the isomorph theory concept the excess entropy plays no special role, because any other isomorph-invariant quantity can be used in place of excess entropy [21]. This explains for instance pronounced correlations between the viscosity and thermal conductivity coefficients of dense fluids discussed recently [26].…”

Minima of shear viscosity and thermal conductivity coefficients of classical fluids

“…This possibility has been recently examined in Ref. [12]. Rosenfeld's excess entropy scaling is a useful heuristic approach for many simple (and sometimes not so simple) systems, but counterexamples where it does not apply also exist [13][14][15].…”