Collective modes in liquid binary alloys. An ab initio molecular dynamics study of the LiMg and LiBa alloys

We report a study on several structural and dynamical properties of the liquid Li-Mg and Li-Ba alloys. The study has been carried out by means of the orbital free ab initio molecular dynamics method, combined with local ionic pseudopotentials constructed within the same framework. The results show good agreement with the available experimental data, accounting fairly well for the different ordering tendencies exhibited by these alloys. We analyse the dependence of the longitudinal and transverse collective modes on the concentration and the mass ratio of the alloy, with the latter ranging from mMg/mLi ∼ 3 to mBa/mLi ∼ 20