Microscopic dynamics in liquid binary alloys: Orbital-free ab-initio molecular dynamics studies

Abstract

We report an ab-initio molecular dynamics study on the collective excitations in several s-p bonded liquid binary alloys. Results are reported for the Li-Na, Li-Mg, K-Cs and Li-Ba liquid alloys at different concentrations, which display mass ratios ranging from ≈ 3 for Li-Na to ≈ 20 for Li-Ba, and varying ordering tendencies, ranging from strong homocoordinating in Li-Na to mildly heterocoordinating for one concentration of Li-Ba. The study has been carried out using the orbital free ab-initio molecular dynamics method, combined with local ionic pseudopotentials constructed within the same framework. We analyze the dependence of the collective modes on the concentration and the mass ratio of the alloy, finding a common behaviour for all systems notwithstanding the different ordering tendencies. © D.J.González, L.E.González.