Structure and atomic transport of liquid titanium from a pair potential model

Abstract

We report structural and atomic transport properties of liquid Ti, which are poorly understood at high temperatures. The studies were performed using molecular dynamics (MD) simulation based on a potential model that accounts for the role of $d$ electrons. The interactions between ions are described by a pair potential built within the pseudopotential formalism obtained by an inverse scattering approach that consists of a repulsive core and long-range Friedel oscillations. The parameters determining the $s$- and $d$- electron contributions to the potential are deduced from the knowledge of liquid structure and diffusion coefficient at the melting temperature. The clear connection between local order and atomic transport in liquids emerges from the molecular dynamics simulation. The calculated pair correlation function and structure factor show very good agreement with recently available ab-initio molecular dynamics (AIMD) and experimental results, respectively. By comparing the temperature dependence of diffusion coefficient and viscosity, the effective pair potential based on the pseudopotential method provides a significantly important portion of the high temperature properties of liquid Ti and strongly validates the accuracy of the method. The activation energy of the liquid metals is obtained by fitting the Arrhenius formula. The approach presented herein gives a broader and deeper insight into the transition metal liquid state.