Ab Initio Molecular Dynamics Studies of PbmSbn (m + n ≤ 9) Alloy Clusters

Structure, stability, and dynamics of PbmSbn (m + n ≤ 9) clusters were investigated using ab initio molecular dynamics. Size dependence of binding energies, the second-order energy difference of clusters, dissociation energy, HOMO-LUMO gaps, Mayer bond order, and the diffusion coefficient of PbmSbn clusters were discussed. Results suggest that Pb3Sb2, Pb4Sb2, and Pb5Sb4 (n = 2 or 4) clusters have higher stability than other clusters, which is consistent with previous findings. In case of Pb-Sb alloy, the dynamics results show that Pb4Sb2 (Pb-22.71 wt pct Sb) can exist in gas phase at 1073 K (800 °C), which reasonably explains the azeotropic phenomenon, and the calculated values are in agreement with the experimental results (Pb-22 wt pct Sb).