B80 and B101–103 clusters: Remarkable stability of the core-shell structures established by validated density functionals

Abstract

Prompted by the very recent claim that the volleyball-shaped B(80) fullerene [X. Wang, Phys. Rev. B 82, 153409 (2010)] is lower in energy than the B(80) buckyball [N. G. Szwacki, A. Sadrzadeh, and B. I. Yakobson, Phys. Rev. Lett. 98, 166804 (2007)] and core-shell structure [J. Zhao, L. Wang, F. Li, and Z. Chen, J. Phys. Chem. A 114, 9969 (2010)], and inspired by the most recent finding of another core-shell isomer as the lowest energy B(80) isomer [S. De, A. Willand, M. Amsler, P. Pochet, L. Genovese, and S. Goedecher, Phys. Rev. Lett. 106, 225502 (2011)], we carefully evaluated the performance of the density functional methods in the energetics of boron clusters and confirmed that the core-shell construction (stuffed fullerene) is thermodynamically the most favorable structural pattern for B(80). Our global minimum search showed that both B(101) and B(103) also prefer a core-shell structure and that B(103) can reach the complete core-shell configuration. We called for great attention to the theoretical community when using density functionals to investigate boron-related nanomaterials.

A new hole density as a stability measure for boron fullerenes

“…NICS values can be used as a measure of aromaticity, where negative value means aromaticity, and positive value shows antiaromaticity. Computed NICS values, shown in Table 1, reveals that all the most stable fullerene isomers B cage seems to have the largest negative NICS value -66.4 ppm with higher than any reported value for boron cages, including the core-shell structure B 101 , B 80 and B 38 cages reported in [13,31]. As an another stability measure, we compute HOMO-LUMO energy gap (E g ) [43][44][45] and they are given in Table 1.…”

“…Relative stability analysis of 2D and 3D boron isomers reveal that PBE0 and TPSS functionals are more favorable over hybrid B3LYP [33,34]. Specifically, Li et al found that PBE, PBE0, TPSS and TPSSh basis sets are more reliable to describe the relative stabilities of B 80 isomers [31]. Hence, all the DFT computations were performed using the Gaussian 09 [35] quantum chemistry package and Perdew-Burke-Ernzerhof (PBE) [36] and Tao-Perdew-Staroverov-Scuseria (TPSS) [37] functionals were used throughout the study along with the 6-31G(d; p) basis set.…”

“…Its structure contains 20 additional capped atoms on the hexagons of B 60 which is a structural analog of C 60 . Different structural patterns of B 80 might give lower energy cages like volleyball shaped B 80 [17] and other B 80 isomers [31]. Recently, Pochet et al has found an energy comparability between ordered and disordered arrangements in B 80 [32] which is, in principle, an analog of the polymorphism encountered in the boron sheets.…”

“…In this sense, we have introduced a new stability measure for boron cages which are constructed from the same core fullerene; we evaluate the energies of the fullerenes and relate it to the hole density. These results might give insight into the evolution of boron stuructures; specifically in understanding the relative stabilities of B 12 containing stuffed boron cages [31,[46][47][48][49] and boron fullerenes.…”

Comprehensive genetic algorithm forab initioglobal optimisation of clusters

“…[10] In the SA procedure, the system is first heated up to a high temperature (exceeding the melting point) and then gradually cooled down to room temperature via molecular dynamics (MD) or Monte Carlo simulations, which can be combined with either empirical potentials or first-principles methods. Even though SA procedure combined with first-principles calculations is a robust method and has been successfully employed to a series of clusters, such as Cd n Te n (n = 1-14), [11] Li n (n = 20,30,40,50), [12] P + 2m+1 (m = 1-12), [13] B 28 , [14] B 80 , [15] and B [101][102][103] , [16] it cannot guarantee the global minimum of the PES unless the annealing time is sufficiently long.…”