Structural Evolution and Electronic Properties of Medium-Sized Gallium Clusters from Ab Initio Genetic Algorithm Search

摘要

Using genetic algorithm incorporated with density functional theory, we have explored the size evolution of structural and electronic properties of neutral gallium clusters of 20-40 atoms in terms of their ground state structures, binding energies, second differences of energy, HOMO-LUMO gaps, distributions of bond length and bond angle, and electron density of states. In the size range studied, the Ga_n clusters exhibit several growth patterns, and the core-shell structures become dominant from Ga_(31). With high point group symmetries, Ga_(23) and Ga_(36) show particularly high stability and Ga_(36) owns a large HOMO-LUMO gap. The atomic structures and electronic states of Ga_n clusters significantly differ from the α solid but resemble β solid and liquid to certain extent.