A newly general geometrical model measuring the relative stability of B nN n fullerenes with octagon(s)

Abstract

Density functional theory is used to investigate the structures and stabilities of B n N n ( n = 8–14) fullerenes constructed by squares, hexagons and octagons with the alternation of B and N atoms (B n N n –F 4F 6F 8). The calculations demonstrate that the most energetically favorable structures generally have no or fewer fused squares. And for the isomers with fused squares, their relative energy generally increased with the number of fused squares. Consequently, they faithfully satisfy the isolated-square rule and the square adjacency penalty rule. Moreover, the most stable isomers have larger HOMO–LUMO gaps and more approximate sphericities than other structures. Structural analysis has demonstrated that the pyramidalization of B and N atoms involving fused squares determine the stability of considered isomers. The binding energy is fitted to the numbers of edges shared by different types of faces, and a model is proposed for predicting the relative stability of the B n N n –F 4F 6F 8 fullerenes molecules.