Energetics and structures of aluminum-lithium clusters

Energetics and structures of small aluminum-lithium clusters were investigated using structure-minimization and dynamic simulated annealing on the electronic Born-Oppenheimer surface, calculated via the local-spin-density-functional method in conjunction with nonlocal pseudopotentials. It is suggested that evolutionary patterns of electronic structure, energetics, and binding in ${\mathrm{AlLi}}_{\mathit{n}}$ clusters may be analyzed within a framework where atomic-based characteristics, associated mainly with closing of the Al 3p shell, dominate for n≤5, while a perturbed delocalized electronic cluster-shell pattern, containing an ${\mathrm{AlLi}}_5$ ‘‘core,’’ develops for larger clusters (i.e., for n≥6). The ground-state electronic and geometrical structures of ${\mathrm{AlLi}}_{\mathit{n}}$ clusters, as well as those of ${\mathrm{Al}}_2$ ${\mathrm{Li}}_{10}$ which may be viewed as two slightly distorted ${\mathrm{AlLi}}_5$ units bonded to each other, are discussed.