Atomic size effect on the structures and stability of X7M (X = Al and In; M = Si-, Ge-, N and P) clusters

摘要

Based on the density functional theory, geometric and electronic properties of X7M (X = Al and In; M = Si-, Ge-, N and P) clusters are studied. The lowest-energy structures for Al7Si-, Al7Ge- and Al7P are largely different from that of Al7C-. The size effect of impurity atom on the structures and stability has been analyzed. In7C- and In7N are found to have the same geometry as Al7C-, in which the host atoms form a cage with C-3v symmetry with impurity atoms locating at the central site. A significantly large HOMO-LUMO gap, low-electron affinity, and high ionization potential are the characters of a magic cluster found for In7N, which may have potential application in cluster-assembled materials. (C) 2008 Elsevier Ltd. All rights reserved.