A theoretical study of isomerism in doped aluminum MAl12 and MAl12X12 clusters with 40 and 50 valence electrons.

Systematic density functional B3LYP calculations with the 6-31G* and 6-311+G* basis sets have been employed in order to investigate the structure, vibrational frequencies, relative energies, vertical ionization potentials, and magnetic shielding constants of endohedral and exohedral isomers in two related families of doped aluminum MAl12 and alane MAl12H12 clusters with 40 and 50 valence electrons, respectively. Isomerization barriers have been also determined. Trends in these properties with changing heteroatom M in various series have been followed. The similarities and differences between the aluminides and alanes as well as between the alanes MAl12H12 and related boranes MB12H12 and gallanes MGa12H12 have been scrutinized.