Structure and stability of Be-6, Be-6(+), and Be-6(-) clusters

摘要

The structure and stability of Be-6, Be-6(+) and Be-6(-) clusters have been investigated at the B3LYP, B3PW91, and second-order Moller-Plesset (MP2) levels of theory, along with the 6-311G(*) basis set for neutral and cationic clusters and the 6-311+G(*) basis set for anion clusters. CCSD(T)/6-311 +G(*) has also been used to calculate some neutral structure to find the most stable structure. Twelve Be-6, six Be-6(+), and eight Be-6(-) isomers are identified. The distortion octahedron structure, pentagonal pyramids structure, and trapezoidal bipyramid structure are found to be the most stable structure on the neutral, cationic, and anionic surface, respectively. They are in agreement with the results reported previously. Natural bond orbital (NBO) analysis, molecular orbital (MO) pictures, and the nucleus independent chemical shift (NICS) values suggest aromatic of the neutral and cationic clusters and antiaromatic of the anionic cluster. The multi-center or bonds and delocalized pi bonds play important role in the bonding of the beryllium clusters. (C) 2006 Wiley Periodicals, Inc.