Viscosity of liquid Na-K alloys from molecular dynamics simulations

The shear viscosity of liquid Na-K alloys is computed from molecular dynamics simulations using the Green-Kubo formalism. Interatomic interactions are described using effective pair potentials obtained from Fiolhais pseudo-potential and self-consistent screening. The composition dependence of the viscosity is first investigated at 373 K, then its temperature dependence at three different compositions, namely Na₁₀-K₉₀, Na₅₀-K₅₀, and Na₉₀-K₁₀. Simulation results are first compared with available experimental data. The evolution of the viscosity of the alloys versus temperature is similar to that of a pure one component fluid. This is discussed in connection with the chemical order of the mixtures.