A first-principles calculation of structures and stability of Al13I cluster

作者：Li, GF; Peng, P^*; Yang, F; Han, SC

来源：Chinese Journal of Structural Chemistry, 2006, 25(2): 232-239.

• Al13I cluster
• structural stability
• electronic structure
• pseudo-potential plane-wave method

Using first-principles pseudo-potential plane wave method, the energetics, geometrical and electronic structures of three Al13I cluster isomers were calculated. The calculation results of the binding energy indicate Al13I cluster is more stable than Al-13 cluster although its electrons are not a magic number as in Al-13 cluster, and among Al13I cluster isomers the '' Bridge '' structure is the most stable, the second is the '' Ontop '' structure, and the worst is the '' Hollow '' structure. By analyzing the geometrical structures of Al13I cluster isomers, it is found that after I atom and Al-13 cluster combine the geometrical structures of Al-13 moieties are changed besides Al13IHollow cluster, in which the Al-13 moiety is still a regular icosahedron. For Al13IOntop cluster, the Al-13 moiety has a shrinking trend to I, whereas in Al13IBridge, cluster it is distorted. Mulliken population analysis shows for the interaction of electrons between Al-1 atoms in Al13I cluster not only there exists an ionic bonding but there is a covalent bonding. Part of electrons in the Al-13 cluster transfer to I as Al-13 cluster and I atom combine. The order of the strength of covalent bonding between Al-13 moiety and I in Al13I cluster isomers is Al13IBridge > Al13IHollow > Al13IOntop. Further analysis of electric structures of Al-13 and Al13I clusters indicates a higher stability of Al13I cluster than Al-13 cluster can be attributed to the s-p hybridization of 3s and 3p electrons of Al in Al-13 moiety induced by I doped, which leads to fewer electrons N(E-F) at EF in Al13I and a larger energy gap Delta EH-L between HOMO and LUMO levels in Al13I cluster. The distinguish of structural stability of Al13I Cluster isomers mainly originates from their different magnitudes in decrease of N(E-F) and increase of Delta EH-L relative to Al-13 cluster. The fewest N(E-F) and the largest Delta EH-L are responsible for the high stability of Al13IBridge cluster.

• 出版日期2006
• 单位湖南大学