The memory kernel of velocity autocorrelation function on a NiZr-liquid: theory and simulation

TL;DR

This paper develops a theoretical model for the memory kernel of the velocity autocorrelation function in a Ni-Zr liquid, using mode-coupling theory and MD simulations, revealing qualitative but not perfect quantitative agreement.

Contribution

The study reformulates the mode-coupling model to apply to a binary Ni-Zr system and compares theoretical predictions with MD simulation data.

Findings

Qualitative agreement between theory and simulation

Quantitative deviations, especially for Zr subsystem

Model successfully captures key features of VACF memory kernel

Abstract

Based on Sj\"{o}gren und Sjolander's Mode-Coupling(MC)-Model, we have reformulated and calculated the memory kernel (MK) of the velocity autocorrelation function (VACF)on a Ni$_{0.2}$Zr$_{0.8}$-liquid. Reformulating means here that we have constructed the memory kernel of VACF for our binary system, instead of one for one atomic system of the Sj\"{o}gren und Sjolander's model. The data required for the theoretical calculations have been obtained from molecular dynamics (MD) simulations. The theoretical results then are compared with those directly obtained from computer simulation. We found, although it exists a qualitative agreement between theoretical predictions and simulation results, that quantitatively there is an deviations between both results, especially for Zr-subsystem.