Diffusion and viscosity of liquid tin: Green-Kubo relationship-based calculations from molecular dynamics simulations

Abstract

Molecular dynamics (MD) simulations of liquid tin between its melting point and 1600 °C have been performed in order to interpret and discuss the ionic structure. The interactions between ions are described by a new accurate pair potential built within the pseudopotential formalism and the linear response theory. The calculated structure factor that reflects the main information on the local atomic order in liquids is compared to diffraction measurements. Having some confidence in the ability of this pair potential to give a good representation of the atomic structure, we then focused our attention on the investigation of the atomic transport properties through the MD computations of the velocity autocorrelation function and stress autocorrelation function. Using the Green-Kubo formula (for the first time to our knowledge for liquid tin) we determine the macroscopic transport properties from the corresponding microscopic time autocorrelation functions. The selfdiffusion coefficient and the shear viscosity as functions of temperature are found to be in good agreement with the experimental data.

Evaluation of Methods for Viscosity Simulations of Lubricants at Different Temperatures and Pressures: A Case Study on PAO-2

“…Furthermore, it has been shown [15] that the Green-Kubo formula applies to quantum systems in a steady state, where the shear viscosity is expressed in terms of the symmetrized correlation function of its shear stress operator. Previous studies also include a variety of calculations for viscosity with EMD-GK combined with NEMD in most cases [16][17][18][19]. The systems in the literature include simple linear alkanes, cyclic [20] or long-chain hydrocarbons, and more complex structures such as squalane and 1-decene trimer (PAO-4) [21][22][23].…”

Structural and dynamic properties of liquid tin from a new modified embedded-atom method force field

“…Several studies utilize pair potentials (as opposed to the many-body EAM formalism) to study liquid tin. [24][25][26][27] These were not used in this work because it is known that treating metallic systems with a single pair potential cannot cover a wide range of conditions. This is illustrated in work by Canales et al 28 in which the authors developed effective pair potentials for liquid lithium but mentioned that the potentials are dependent on the thermodynamic conditions being simulated.…”

Comparison of equilibrium techniques for the viscosity calculation from DPD simulations

“…In DPD, the pressure tensor is the sum of four different contributions: the pressure due to the dissipative force, , the conservative force, , the random force, and the kinetic part of the αβ αβ αβ energy, . In literature 42,43 , the total pressure resulting from these four contributions is mainly αβ used with the GK relation. However, recently it has been shown that, for high density systems ( , if all the contributions are included within the integral of equation 2.9, the resulting > 4) viscosity in the linear regime deviates from the value obtained by using non-equilibrium approaches 18 .…”