Various structural possibilities for Al(n)B(m) (n=1-7, m=1-2) neutral isomers were investigated using B3LYP6-311G(d) and CCSD(T)6-311G(d) methods. Our calculations predicted the existence of a number of previously unknown isomers. The B atom favors to locate over/inside of all clusters in this series. All structures of the Al(n)B (n=2-7) may be derived from capping/putting a B atom over/inside the Al(n) cluster. All Al(n)B(2) (n=1-5) may be understood as two substitutions of Al atoms by B atoms in the Al(n+2) molecule. The strong B-B bond is a dominant factor in the building-up principle of mixed Al(n)B(2) neutral clusters. The second difference in energy showed that the Al(n)B(m) clusters with even n+m are more stable than those with odd n+m. Our results and analyses revealed that the mixed Al-B clusters exhibit aromatic behaviors.

Geometric structures, electronic states and energies of GanP and GanP2 (n= 1—7) clusters have been studied using the density functional theory. Structural optimization and frequency analysis were carried out at the B3LYP/6-31G* level.All ground states of GanP and GanP2 (n=1—7) clusters have been obtained.Our calculations reveal that there exists a transition from planar to spacial structures at n=5 with increasing cluster size. The strong P-P bond is favored over P-Ga in GanP2 (n=1—7) clusters. Among different GanP and GanP2 (n=1—7) clusters, Ga3P,Ga4P, GaP2, Ga2P2 and Ga4P2 are more stable. Their stability tends to reduce with the increase of the number of total atoms.