Structure and stability of B6, B6+, and B6- clusters

Abstract

We investigated various isomer of B6, B6+, and B6- clusters with ab initio [Hartree-Fock (HF, MP2)] and density functional theory (DFT) methods. Ten B6 isomers, 6 B6+ isomers, and 6 B6- isomers are determined to be local minima on their potential energy hypersurfaces by the HF, B3LYP, B3PW91, and MP2 methods. Fourteen of these structures are first reported. The most stable neutral B6 cluster is the capped pentagonal pyramid (C5v), in agreement with the results reported previously. Hexagon B6+ (C2h) isomer and fan-shaped B6- (C2v) isomer are found to be the most stable on the cationic and anionic energy hypersurfaces, respectively. Natural bond orbital analysis suggests that there are three-centered bonds in the most stable B6 neutral and ionic clusters. The multicentered bonds are responsible for the special stability of the lowest-energy isomer.