Computational investigation of GanAl (n = 1–15) clusters by the density-functional theory

Low-lying equilibrium geometric structures of aluminum-doped gallium cluster GanAl (n = 1–15) clusters obtained by an all-electron linear combination of atomic orbital approach, within spin-polarized density functional theory, are reported. The binding energy, dissociation energy, and stability of these clusters are studied with the three-parameter hybrid generalized gradient approximation (GGA) due to Becke-Lee–Yang–Parr (B3LYP). Ionization potentials, electron affinities, hardness, and static polarizabilities are calculated for the ground-state structures within the same method. The growth pattern for GanAl (n = 1–15) clusters is Al-substituted Gan + 1 clusters and it keeps the similar frameworks of the most stable Gan + 1 clusters except for Ga8Al and Ga13 Al clusters. The Al atom substituted the surface atom of the Gan + 1 clusters for n < 12. Starting from n = 12, the Al atom completely falls into the center of the Ga-frame. The Al atom substituted the center atom of the Gan + 1 clusters to form the Al-encapsulated Gan geometries for n > 12. The odd−even oscillations from GanAl (n = 5) in the dissociation energy, the second-order energy differences, the HOMO–LUMO gaps, the ionization potential, the electron affinity, and the hardness are more pronounced. The stability analysis based on the energies clearly shows the clusters from n = 5 with an even number of valence electrons are more stable than clusters with odd number of valence electrons.